raycaster/scratchpad/quickcg.cpp

/*
QuickCG SDL2 20190709

Copyright (c) 2004-2007, Lode Vandevenne

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

	* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
	* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
QuickCG is an SDL codebase that wraps some of the SDL functionality.
It's used by Lode's Computer Graphics Tutorial to work with simple C++ calls
to demonstrate graphical programs. This SDL2.0 port was made by Chrissy573.

QuickCG can handle some things that standard C++ doesn't but that are commonly useful, such as:
-drawing graphics
-a bitmap font
-simplified saving and loading of files
-reading keyboard and mouse input
-playing sound
-color models
-loading images
*/

#include <SDL.h>
#include "quickcg.h"
#include <cstdlib>
#include <cmath>
#include <vector>
#include <map>
#include <iostream>
#include <fstream>
#include <cassert>

namespace QuickCG
{


	////////////////////////////////////////////////////////////////////////////////
	//VARIABLES/////////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	int w; //width of the screen
	int h; //height of the screen

	std::map<int, bool> keypressed; //for the "keyPressed" function to detect a keypress only once
	SDL_Window* scr; //the single SDL window used
	SDL_Surface* srf;
	SDL_Renderer* render;
	SDL_Texture* tex;
	SDL_PixelFormat *fmt;
	const Uint8* inkeys = NULL;
	SDL_Event event = { 0 };


	////////////////////////////////////////////////////////////////////////////////
	//KEYBOARD FUNCTIONS////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	bool keyDown(int key) //this checks if the key is held down, returns true all the time until the key is up
	{
        assert(inkeys != NULL && "inkeys is not initialized!");
		// return (inkeys[key] != 0);
        return false;
	}

	bool keyPressed(int key) //this checks if the key is *just* pressed, returns true only once until the key is up again
	{
		if (keypressed.find(key) == keypressed.end()) keypressed[key] = false;
		if (inkeys[key])
		{
			if (keypressed[key] == false)
			{
				keypressed[key] = true;
				return true;
			}
		}
		else keypressed[key] = false;

		return false;
	}


	////////////////////////////////////////////////////////////////////////////////
	//BASIC SCREEN FUNCTIONS////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	//The screen function: sets up the window for 32-bit color graphics.
	//Creates a graphical screen of width*height pixels in 32-bit color.
	//Set fullscreen to 0 for a window, or to 1 for fullscreen output
	//text is the caption or title of the window
	//also inits SDL
	void screen(int width, int height, bool fullscreen, const std::string& text)
	{
		w = width;
		h = height;

		if (SDL_Init(SDL_INIT_EVERYTHING) < 0)
		{
			printf("Unable to init SDL: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}

		std::atexit(SDL_Quit);
		if (fullscreen)
		{
			scr = SDL_CreateWindow(text.c_str(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, SDL_WINDOW_FULLSCREEN | SDL_WINDOW_OPENGL);
			lock();
		}
		else
		{
			scr = SDL_CreateWindow(text.c_str(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, SDL_WINDOW_OPENGL);
		}
		if (scr == NULL)
		{
			printf("Unable to set video: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}

		render = SDL_CreateRenderer(scr, -1, 0);
		if (render == NULL)
		{
			printf("Unable to set renderer: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}

		srf = SDL_CreateRGBSurface(0, w, h, 32,
			0xFF000000,
			0x00FF0000,
			0x0000FF00,
			0x000000FF);
		if (srf == NULL)
		{
			printf("Unable to set surface: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}

		tex = SDL_CreateTexture(render, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, w, h);
		if (tex == NULL)
		{
			printf("Unable to set texture: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}
		SDL_SetTextureBlendMode(tex, SDL_BLENDMODE_BLEND);

		fmt = srf->format;
		if (fmt == NULL)
		{
			printf("Unable to set pixel format: %s\n", SDL_GetError());
			SDL_Quit();
			std::exit(1);
		}

		inkeys = SDL_GetKeyboardState(NULL);
	}

	//Locks the screen
	void lock()
	{
		if (SDL_MUSTLOCK(srf))
			if (SDL_LockSurface(srf) < 0)
				return;
	}

	//Unlocks the screen
	void unlock()
	{
		if (SDL_MUSTLOCK(srf))
			SDL_UnlockSurface(srf);
	}

	//Updates the screen.  Has to be called to view new pixels, but use only after
	//drawing the whole screen because it's slow.
	void redraw()
	{
		SDL_UpdateTexture(tex, NULL, srf->pixels, srf->pitch);
		SDL_RenderClear(render);
		SDL_RenderCopy(render, tex, NULL, NULL);
		SDL_RenderPresent(render);
	}

	//Clears the screen to black
	void cls(const ColorRGBA& color)
	{
		SDL_SetRenderDrawColor(render, color.r, color.g, color.b, color.a);
		SDL_RenderClear(render);
		SDL_RenderPresent(render);
	}

	//Puts an RGBA color pixel at position x,y
	void pset(int x, int y, const ColorRGBA& color)
	{
		if (x < 0 || y < 0 || x >= w || y >= h) return;
		Uint32 colorSDL = SDL_MapRGBA(fmt, color.r, color.g, color.b, color.a);
		Uint32* bufp;
		bufp = (Uint32*)srf->pixels + y * srf->pitch / 4 + x;
		*bufp = colorSDL;
	}

	//Gets RGB color of pixel at position x,y
	ColorRGBA pget(int x, int y)
	{
		if (x < 0 || y < 0 || x >= w || y >= h) return RGB_Black;
		Uint32* bufp;
		bufp = (Uint32*)srf->pixels + y * srf->pitch / 4 + x;
		Uint32 colorSDL = *bufp;
		ColorRGBA8bit colorRGBA;
		SDL_GetRGBA(colorSDL, fmt, &colorRGBA.r, &colorRGBA.g, &colorRGBA.b, &colorRGBA.a);
		return ColorRGBA(colorRGBA);
	}

	//Draws a buffer of pixels to the screen
	void drawBuffer(Uint32* buffer)
	{
		Uint32* bufp;
		bufp = (Uint32*)srf->pixels;

		for (int y = 0; y < h; y++)
		{
			for (int x = 0; x < w; x++)
			{
				*bufp = buffer[y * w + x];
				bufp++;
			}
			bufp += srf->pitch / 4;
			bufp -= w;
		}
	}

	void getScreenBuffer(std::vector<Uint32>& buffer)
	{
		Uint32* bufp;
		bufp = (Uint32*)srf->pixels;

		buffer.resize(w * h);

		for (int y = 0; y < h; y++)
		{
			for (int x = 0; x < w; x++)
			{
				buffer[y * w + x] = *bufp;
				bufp++;
			}
			bufp += srf->pitch / 4;
			bufp -= w;
		}
	}

	bool onScreen(int x, int y)
	{
		return (x >= 0 && y >= 0 && x < w && y < h);
	}


	////////////////////////////////////////////////////////////////////////////////
	//NON GRAPHICAL FUNCTIONS///////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	//Waits until you press a key. First the key has to be loose, this means, if you put two sleep functions in a row, the second will only work after you first released the key.
	void sleep()
	{
		int done = 0;
		SDL_PollEvent(&event);
		while (done == 0)
		{
			while (SDL_PollEvent(&event))
			{
				if (event.type == SDL_QUIT) end();
				if (event.type == SDL_KEYDOWN) done = 1;
			}
			SDL_Delay(5); //so it consumes less processing power
		}
	}

	void sleep(double seconds)
	{
		SDL_Delay((Uint32)seconds * 1000);
	}

	void waitFrame(double oldTime, double frameDuration) //in seconds
	{
		double time = getTime();
		while (time - oldTime < frameDuration)
		{
			time = getTime();
			SDL_PollEvent(&event);
			if (event.type == SDL_QUIT) end();
			inkeys = SDL_GetKeyboardState(NULL);
			if (inkeys[SDLK_ESCAPE]) end();
			SDL_Delay(5); //so it consumes less processing power
		}
	}

	//Returns 1 if you close the window or press the escape key. Also handles everything that's needed per frame.
	//Never put key input code right before done() or SDL may see the key as SDL_QUIT
	bool done(bool quit_if_esc, bool delay) //delay makes CPU have some free time, use once per frame to avoid 100% usage of a CPU core
	{
		if (delay) SDL_Delay(5); //so it consumes less processing power
		bool done = false;
		if (!SDL_PollEvent(&event)) return 0;
		readKeys();
		if (quit_if_esc && inkeys[SDLK_ESCAPE]) done = true;
		if (event.type == SDL_QUIT) done = true;
		return done;
	}

	//Ends the program
	void end()
	{
		SDL_Quit();
		std::exit(1);
	}

	//Gives value of pressed key to inkeys.
	//the variable inkeys can then be used anywhere to check for input
	//Normally you have to use readkeys every time you want to use inkeys, but the done() function also uses inkeys so it's not needed to use readkeys if you use done().
	void readKeys()
	{
		SDL_PollEvent(&event);
		inkeys = SDL_GetKeyboardState(NULL);
	}

	void getMouseState(int& mouseX, int& mouseY)
	{
		SDL_GetMouseState(&mouseX, &mouseY);
	}

	void getMouseState(int& mouseX, int& mouseY, bool& LMB, bool& RMB)
	{
		Uint8 mouseState = SDL_GetMouseState(&mouseX, &mouseY);

		if (mouseState & 1) LMB = true;
		else LMB = false;
		if (mouseState & 4) RMB = true;
		else RMB = false;
	}

	//Returns the time in milliseconds since the program started
	unsigned long getTicks()
	{
		return SDL_GetTicks();
	}


	////////////////////////////////////////////////////////////////////////////////
	//2D SHAPES/////////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	//Fast horizontal line from (x1,y) to (x2,y), with rgb color
	bool horLine(int y, int x1, int x2, const ColorRGBA& color)
	{
		if (x2 < x1) { x1 += x2; x2 = x1 - x2; x1 -= x2; } //swap x1 and x2, x1 must be the leftmost endpoint
		if (x2 < 0 || x1 >= w || y < 0 || y >= h) return 0; //no single point of the line is on screen
		if (x1 < 0) x1 = 0; //clip
		if (x2 >= w) x2 = w - 1; //clip

		Uint32 colorSDL = SDL_MapRGBA(fmt, color.r, color.g, color.b, color.a);
		Uint32* bufp;
		bufp = (Uint32*)srf->pixels + y * srf->pitch / 4 + x1;
		for (int x = x1; x <= x2; x++)
		{
			*bufp = colorSDL;
			bufp++;
		}
		return 1;
	}


	//Fast vertical line from (x,y1) to (x,y2), with rgb color
	bool verLine(int x, int y1, int y2, const ColorRGBA& color)
	{
		if (y2 < y1) { y1 += y2; y2 = y1 - y2; y1 -= y2; } //swap y1 and y2
		if (y2 < 0 || y1 >= h || x < 0 || x >= w) return 0; //no single point of the line is on screen
		if (y1 < 0) y1 = 0; //clip
		if (y2 >= w) y2 = h - 1; //clip

		Uint32 colorSDL = SDL_MapRGBA(fmt, color.r, color.g, color.b, color.a);
		Uint32* bufp;

		bufp = (Uint32*)srf->pixels + y1 * srf->pitch / 4 + x;
		for (int y = y1; y <= y2; y++)
		{
			*bufp = colorSDL;
			bufp += srf->pitch / 4;
		}
		return 1;
	}


	//Bresenham line from (x1,y1) to (x2,y2) with rgb color
	bool drawLine(int x1, int y1, int x2, int y2, const ColorRGBA& color)
	{
		if (x1 < 0 || x1 > w - 1 || x2 < 0 || x2 > w - 1 || y1 < 0 || y1 > h - 1 || y2 < 0 || y2 > h - 1) return 0;

		int deltax = std::abs(x2 - x1); //The difference between the x's
		int deltay = std::abs(y2 - y1); //The difference between the y's
		int x = x1; //Start x off at the first pixel
		int y = y1; //Start y off at the first pixel
		int xinc1, xinc2, yinc1, yinc2, den, num, numadd, numpixels, curpixel;

		if (x2 >= x1) //The x-values are increasing
		{
			xinc1 = 1;
			xinc2 = 1;
		}
		else //The x-values are decreasing
		{
			xinc1 = -1;
			xinc2 = -1;
		}
		if (y2 >= y1) //The y-values are increasing
		{
			yinc1 = 1;
			yinc2 = 1;
		}
		else //The y-values are decreasing
		{
			yinc1 = -1;
			yinc2 = -1;
		}
		if (deltax >= deltay) //There is at least one x-value for every y-value
		{
			xinc1 = 0; //Don't change the x when numerator >= denominator
			yinc2 = 0; //Don't change the y for every iteration
			den = deltax;
			num = deltax / 2;
			numadd = deltay;
			numpixels = deltax; //There are more x-values than y-values
		}
		else //There is at least one y-value for every x-value
		{
			xinc2 = 0; //Don't change the x for every iteration
			yinc1 = 0; //Don't change the y when numerator >= denominator
			den = deltay;
			num = deltay / 2;
			numadd = deltax;
			numpixels = deltay; //There are more y-values than x-values
		}
		for (curpixel = 0; curpixel <= numpixels; curpixel++)
		{
			pset(x % w, y % h, color);  //Draw the current pixel
			num += numadd;  //Increase the numerator by the top of the fraction
			if (num >= den) //Check if numerator >= denominator
			{
				num -= den; //Calculate the new numerator value
				x += xinc1; //Change the x as appropriate
				y += yinc1; //Change the y as appropriate
			}
			x += xinc2; //Change the x as appropriate
			y += yinc2; //Change the y as appropriate
		}

		return 1;
	}


	//Bresenham circle with center at (xc,yc) with radius and red green blue color
	bool drawCircle(int xc, int yc, int radius, const ColorRGBA& color)
	{
		if (xc - radius < 0 || xc + radius >= w || yc - radius < 0 || yc + radius >= h) return 0;
		int x = 0;
		int y = radius;
		int p = 3 - (radius << 1);
		int a, b, c, d, e, f, g, h;
		while (x <= y)
		{
			a = xc + x; //8 pixels can be calculated at once thanks to the symmetry
			b = yc + y;
			c = xc - x;
			d = yc - y;
			e = xc + y;
			f = yc + x;
			g = xc - y;
			h = yc - x;
			pset(a, b, color);
			pset(c, d, color);
			pset(e, f, color);
			pset(g, f, color);
			if (x > 0) //avoid drawing pixels at same position as the other ones
			{
				pset(a, d, color);
				pset(c, b, color);
				pset(e, h, color);
				pset(g, h, color);
			}
			if (p < 0) p += (x++ << 2) + 6;
			else p += ((x++ - y--) << 2) + 10;
		}

		return 1;
	}


	//Filled bresenham circle with center at (xc,yc) with radius and red green blue color
	bool drawDisk(int xc, int yc, int radius, const ColorRGBA& color)
	{
		if (xc + radius < 0 || xc - radius >= w || yc + radius < 0 || yc - radius >= h) return 0; //every single pixel outside screen, so don't waste time on it
		int x = 0;
		int y = radius;
		int p = 3 - (radius << 1);
		int a, b, c, d, e, f, g, h;
		int pb = yc + radius + 1, pd = yc + radius + 1; //previous values: to avoid drawing horizontal lines multiple times  (ensure initial value is outside the range)
		while (x <= y)
		{
			// write data
			a = xc + x;
			b = yc + y;
			c = xc - x;
			d = yc - y;
			e = xc + y;
			f = yc + x;
			g = xc - y;
			h = yc - x;
			if (b != pb) horLine(b, a, c, color);
			if (d != pd) horLine(d, a, c, color);
			if (f != b)  horLine(f, e, g, color);
			if (h != d && h != f) horLine(h, e, g, color);
			pb = b;
			pd = d;
			if (p < 0) p += (x++ << 2) + 6;
			else p += ((x++ - y--) << 2) + 10;
		}

		return 1;
	}

	//Rectangle with corners (x1,y1) and (x2,y2) and rgb color
	bool drawRect(int x1, int y1, int x2, int y2, const ColorRGBA& color)
	{
		if (x1 < 0 || x1 > w - 1 || x2 < 0 || x2 > w - 1 || y1 < 0 || y1 > h - 1 || y2 < 0 || y2 > h - 1) return 0;
		SDL_Rect rec;
		rec.x = x1;
		rec.y = y1;
		rec.w = x2 - x1 + 1;
		rec.h = y2 - y1 + 1;
		Uint32 colorSDL = SDL_MapRGBA(fmt, color.r, color.g, color.b, color.a);
		SDL_FillRect(srf, &rec, colorSDL);  //SDL's ability to draw a hardware rectangle is used for now
		return 1;
	}

	//Functions for clipping a 2D line to the screen, which is the rectangle (0,0)-(w,h)
	//This is the Cohen-Sutherland Clipping Algorithm
	//Each of 9 regions gets an outcode, based on if it's at the top, bottom, left or right of the screen
	// 1001 1000 1010  9 8 10
	// 0001 0000 0010  1 0 2
	// 0101 0100 0110  5 4 6
	//int findregion returns which of the 9 regions a point is in, void clipline does the actual clipping
	int findRegion(int x, int y)
	{
		int code = 0;
		if (y >= h)
			code |= 1; //top
		else if (y < 0)
			code |= 2; //bottom
		if (x >= w)
			code |= 4; //right
		else if (x < 0)
			code |= 8; //left
		return(code);
	}
	bool clipLine(int x1, int y1, int x2, int y2, int & x3, int & y3, int & x4, int & y4)
	{
		int code1, code2, codeout;
		bool accept = 0, done = 0;
		code1 = findRegion(x1, y1); //the region outcodes for the endpoints
		code2 = findRegion(x2, y2);
		do  //In theory, this can never end up in an infinite loop, it'll always come in one of the trivial cases eventually
		{
			if (!(code1 | code2)) accept = done = 1;  //accept because both endpoints are in screen or on the border, trivial accept
			else if (code1 & code2) done = 1; //the line isn't visible on screen, trivial reject
			else  //if no trivial reject or accept, continue the loop
			{
				int x, y;
				codeout = code1 ? code1 : code2;
				if (codeout & 1) //top
				{
					x = x1 + (x2 - x1) * (h - y1) / (y2 - y1);
					y = h - 1;
				}
				else if (codeout & 2) //bottom
				{
					x = x1 + (x2 - x1) * -y1 / (y2 - y1);
					y = 0;
				}
				else if (codeout & 4) //right
				{
					y = y1 + (y2 - y1) * (w - x1) / (x2 - x1);
					x = w - 1;
				}
				else //left
				{
					y = y1 + (y2 - y1) * -x1 / (x2 - x1);
					x = 0;
				}
				if (codeout == code1) //first endpoint was clipped
				{
					x1 = x; y1 = y;
					code1 = findRegion(x1, y1);
				}
				else //second endpoint was clipped
				{
					x2 = x; y2 = y;
					code2 = findRegion(x2, y2);
				}
			}
		} while (done == 0);

		if (accept)
		{
			x3 = x1;
			x4 = x2;
			y3 = y1;
			y4 = y2;
			return 1;
		}
		else
		{
			x3 = x4 = y3 = y4 = 0;
			return 0;
		}
	}


	////////////////////////////////////////////////////////////////////////////////
	//COLOR STRUCTS/////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////
	ColorRGBA::ColorRGBA(Uint8 r, Uint8 g, Uint8 b, Uint8 a)
	{
		this->r = r;
		this->g = g;
		this->b = b;
		this->a = a;
	}
	ColorRGBA::ColorRGBA(const ColorRGBA8bit& color)
	{
		this->r = color.r;
		this->g = color.g;
		this->b = color.b;
		this->a = color.a;
	}
	ColorRGBA::ColorRGBA()
	{
		this->r = 0;
		this->g = 0;
		this->b = 0;
		this->a = 0;
	}
	ColorRGBA8bit::ColorRGBA8bit(Uint8 r, Uint8 g, Uint8 b, Uint8 a)
	{
		this->r = r;
		this->g = g;
		this->b = b;
		this->a = a;
	}
	ColorRGBA8bit::ColorRGBA8bit(const ColorRGBA& color)
	{
		this->r = color.r;
		this->g = color.g;
		this->b = color.b;
		this->a = color.a;
	}
	ColorRGBA8bit::ColorRGBA8bit()
	{
		this->r = 0;
		this->g = 0;
		this->b = 0;
		this->a = 0;
	}

	//Add two colors
	ColorRGBA operator+(const ColorRGBA& color, const ColorRGBA& color2)
	{
		ColorRGBA c;
		c.r = color.r + color2.r;
		c.g = color.g + color2.g;
		c.b = color.b + color2.b;
		c.a = color.a + color2.a;
		return c;
	}

	//Subtract two colors
	ColorRGBA operator-(const ColorRGBA& color, const ColorRGBA& color2)
	{
		ColorRGBA c;
		c.r = color.r - color2.r;
		c.g = color.g - color2.g;
		c.b = color.b - color2.b;
		c.a = color.a - color2.a;
		return c;
	}

	//Multiplies a color with an integer
	ColorRGBA operator*(const ColorRGBA& color, int a)
	{
		ColorRGBA c;
		c.r = color.r * a;
		c.g = color.g * a;
		c.b = color.b * a;
		c.a = color.a * a;
		return c;
	}

	//Multiplies a color with an integer
	ColorRGBA operator*(int a, const ColorRGBA& color)
	{
		ColorRGBA c;
		c.r = color.r * a;
		c.g = color.g * a;
		c.b = color.b * a;
		c.a = color.a * a;
		return c;
	}

	//Divides a color through an integer
	ColorRGBA operator/(const ColorRGBA& color, int a)
	{
		if (a == 0) return color;
		ColorRGBA c;
		c.r = color.r / a;
		c.g = color.g / a;
		c.b = color.b / a;
		c.a = color.a / a;
		return c;
	}

	ColorRGBA overlay(const ColorRGBA& color, const ColorRGBA& color2)
	{
		ColorRGBA c;
		c.r = (color.r * color.a / 255) + (color2.r * color2.a * (255 - color.a) / (255 * 255));
		c.g = (color.g * color.a / 255) + (color2.g * color2.a * (255 - color.a) / (255 * 255));
		c.b = (color.b * color.a / 255) + (color2.b * color2.a * (255 - color.a) / (255 * 255));
		c.a = color.a + (color2.a * (255 - color.a) / 255);
		return c;
	}

	//Are both colors equal?
	bool operator==(const ColorRGBA& color, const ColorRGBA& color2)
	{
		return(color.r == color2.r && color.g == color2.g && color.b == color2.b && color.a == color2.a);
	}

	//Are both colors not equal?
	bool operator!=(const ColorRGBA& color, const ColorRGBA& color2)
	{
		return(!(color.r == color2.r && color.g == color2.g && color.b == color2.b && color.a == color2.a));
	}

	ColorHSL::ColorHSL(Uint8 h, Uint8 s, Uint8 l, Uint8 a)
	{
		this->h = h;
		this->s = s;
		this->l = l;
		this->a = a;
	}
	ColorHSL::ColorHSL()
	{
		this->h = 0;
		this->s = 0;
		this->l = 0;
		this->a = 0;
	}
	ColorHSV::ColorHSV(Uint8 h, Uint8 s, Uint8 v, Uint8 a)
	{
		this->h = h;
		this->s = s;
		this->v = v;
		this->a = a;
	}
	ColorHSV::ColorHSV()
	{
		this->h = 0;
		this->s = 0;
		this->v = 0;
		this->a = 0;
	}


	////////////////////////////////////////////////////////////////////////////////
	//COLOR CONVERSIONS/////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	/*
	Convert colors from one type to another
	r=red  g=green  b=blue  h=hue  s=saturation  l=lightness  v=value
	Color components from the color structs are Uint8's between 0 and 255
	color components used in the calculations are normalized between 0.0-1.0
	*/

	//Converts an RGB color to HSL color
	ColorHSL RGBtoHSL(const ColorRGBA& ColorRGBA)
	{
		double r, g, b, a, h = 0, s = 0, l; //this function works with floats between 0 and 1
		r = ColorRGBA.r / 256.0;
		g = ColorRGBA.g / 256.0;
		b = ColorRGBA.b / 256.0;
		a = ColorRGBA.a / 256.0;

		const double maxColor = std::max(r, std::max(g, b));
		const double minColor = std::min(r, std::min(g, b));

		if (minColor == maxColor) //R = G = B, so it's a shade of grey
		{
			h = 0; //it doesn't matter what value it has
			s = 0;
			l = r; //doesn't matter if you pick r, g, or b
		}
		else
		{
			l = (minColor + maxColor) / 2;

			if (l < 0.5) s = (maxColor - minColor) / (maxColor + minColor);
			if (l >= 0.5) s = (maxColor - minColor) / (2.0 - maxColor - minColor);

			if (r == maxColor) h = (g - b) / (maxColor - minColor);
			if (g == maxColor) h = 2.0 + (b - r) / (maxColor - minColor);
			if (b == maxColor) h = 4.0 + (r - g) / (maxColor - minColor);

			h /= 6; //to bring it to a number between 0 and 1
			if (h < 0) h += 1;
		}

		ColorHSL colorHSL;
		colorHSL.h = int(h * 255.0);
		colorHSL.s = int(s * 255.0);
		colorHSL.l = int(l * 255.0);
		colorHSL.a = int(a * 255.0);
		return colorHSL;
	}

	//Converts an HSL color to RGB color
	ColorRGBA HSLtoRGB(const ColorHSL& colorHSL)
	{
		double r, g, b, a, h, s, l; //this function works with floats between 0 and 1
		double temp1, temp2, tempr, tempg, tempb;
		h = colorHSL.h / 256.0;
		s = colorHSL.s / 256.0;
		l = colorHSL.l / 256.0;
		a = colorHSL.a / 256.0;

		//If saturation is 0, the color is a shade of grey
		if (s == 0) r = g = b = l;
		//If saturation > 0, more complex calculations are needed
		else
		{
			//set the temporary values
			if (l < 0.5) temp2 = l * (1 + s);
			else temp2 = (l + s) - (l * s);
			temp1 = 2 * l - temp2;
			tempr = h + 1.0 / 3.0;
			if (tempr > 1.0) tempr--;
			tempg = h;
			tempb = h - 1.0 / 3.0;
			if (tempb < 0.0) tempb++;

			//red
			if (tempr < 1.0 / 6.0) r = temp1 + (temp2 - temp1) * 6.0 * tempr;
			else if (tempr < 0.5) r = temp2;
			else if (tempr < 2.0 / 3.0) r = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempr) * 6.0;
			else r = temp1;

			//green
			if (tempg < 1.0 / 6.0) g = temp1 + (temp2 - temp1) * 6.0 * tempg;
			else if (tempg < 0.5) g = temp2;
			else if (tempg < 2.0 / 3.0) g = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempg) * 6.0;
			else g = temp1;

			//blue
			if (tempb < 1.0 / 6.0) b = temp1 + (temp2 - temp1) * 6.0 * tempb;
			else if (tempb < 0.5) b = temp2;
			else if (tempb < 2.0 / 3.0) b = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - tempb) * 6.0;
			else b = temp1;
		}

		ColorRGBA ColorRGBA;
		ColorRGBA.r = int(r * 255.0);
		ColorRGBA.g = int(g * 255.0);
		ColorRGBA.b = int(b * 255.0);
		ColorRGBA.a = int(a * 255.0);
		return ColorRGBA;
	}

	//Converts an RGB color to HSV color
	ColorHSV RGBtoHSV(const ColorRGBA& ColorRGBA)
	{
		double r, g, b, a, h = 0.0, s = 0.0, v; //this function works with floats between 0 and 1
		r = ColorRGBA.r / 256.0;
		g = ColorRGBA.g / 256.0;
		b = ColorRGBA.b / 256.0;
		a = ColorRGBA.a / 256.0;

		const double maxColor = std::max(r, std::max(g, b));
		const double minColor = std::min(r, std::min(g, b));

		v = maxColor;

		if (maxColor != 0.0) //avoid division by zero when the color is black
		{
			s = (maxColor - minColor) / maxColor;
		}

		if (s == 0.0)
		{
			h = 0.0; //it doesn't matter what value it has
		}
		else
		{
			if (r == maxColor) h = (g - b) / (maxColor - minColor);
			if (g == maxColor) h = 2.0 + (b - r) / (maxColor - minColor);
			if (b == maxColor) h = 4.0 + (r - g) / (maxColor - minColor);

			h /= 6.0; //to bring it to a number between 0 and 1
			if (h < 0.0) h++;
		}

		ColorHSV colorHSV;
		colorHSV.h = int(h * 255.0);
		colorHSV.s = int(s * 255.0);
		colorHSV.v = int(v * 255.0);
		colorHSV.a = int(a * 255.0);
		return colorHSV;
	}

	//Converts an HSV color to RGB color
	ColorRGBA HSVtoRGB(const ColorHSV& colorHSV)
	{
		double r, g, b, a, h, s, v; //this function works with floats between 0 and 1
		h = colorHSV.h / 256.0;
		s = colorHSV.s / 256.0;
		v = colorHSV.v / 256.0;
		a = colorHSV.a / 256.0;

		//if saturation is 0, the color is a shade of grey
		if (s == 0.0) r = g = b = v;
		//if saturation > 0, more complex calculations are needed
		else
		{
			double f, p, q, t;
			int i;
			h *= 6.0; //to bring hue to a number between 0 and 6, better for the calculations
			i = int(floor(h)); //e.g. 2.7 becomes 2 and 3.01 becomes 3 or 4.9999 becomes 4
			f = h - i;//the fractional part of h

			p = v * (1.0 - s);
			q = v * (1.0 - (s * f));
			t = v * (1.0 - (s * (1.0 - f)));

			switch (i)
			{
			case 0: r = v; g = t; b = p; break;
			case 1: r = q; g = v; b = p; break;
			case 2: r = p; g = v; b = t; break;
			case 3: r = p; g = q; b = v; break;
			case 4: r = t; g = p; b = v; break;
			case 5: r = v; g = p; b = q; break;
			default: r = g = b = 0; break;
			}
		}
		ColorRGBA ColorRGBA;
		ColorRGBA.r = int(r * 255.0);
		ColorRGBA.g = int(g * 255.0);
		ColorRGBA.b = int(b * 255.0);
		ColorRGBA.a = int(a * 255.0);
		return ColorRGBA;
	}

	Uint32 RGBtoINT(const ColorRGBA& ColorRGBA)
	{
		return (ColorRGBA.a | (ColorRGBA.b << 8) | (ColorRGBA.g << 16) | (ColorRGBA.r << 24));
	}

	ColorRGBA INTtoRGB(Uint32 colorINT)
	{
		ColorRGBA ColorRGBA;
		ColorRGBA.r = (colorINT & 0xFF000000) >> 24;
		ColorRGBA.g = (colorINT & 0x00FF0000) >> 16;
		ColorRGBA.b = (colorINT & 0x0000FF00) >> 8;
		ColorRGBA.a = (colorINT & 0x000000FF);
		return ColorRGBA;
	}

	////////////////////////////////////////////////////////////////////////////////
	//FILE FUNCTIONS////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	void loadFile(std::vector<unsigned char>& buffer, const std::string& filename) //designed for loading files from hard disk in an std::vector
	{
		std::ifstream file(filename.c_str(), std::ios::in | std::ios::binary | std::ios::ate);

		//get filesize
		std::streamsize size = 0;
		if (file.seekg(0, std::ios::end).good()) size = file.tellg();
		if (file.seekg(0, std::ios::beg).good()) size -= file.tellg();

		//read contents of the file into the vector
		buffer.resize(size_t(size));
		if (size > 0) file.read((char*)(&buffer[0]), size);
	}

	//write given buffer to the file, overwriting the file, it doesn't append to it.
	void saveFile(const std::vector<unsigned char>& buffer, const std::string& filename)
	{
		std::ofstream file(filename.c_str(), std::ios::out | std::ios::binary);
		file.write(buffer.size() ? (char*)&buffer[0] : 0, std::streamsize(buffer.size()));
	}

	////////////////////////////////////////////////////////////////////////////////
	//IMAGE FUNCTIONS///////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	int loadImage(std::vector<ColorRGBA>& out, unsigned long& w, unsigned long& h, const std::string& filename)
	{
		std::vector<unsigned char> file, image;
		loadFile(file, filename);
		if (decodePNG(image, w, h, file)) return 1;

		out.resize(image.size() / 4);

		for (size_t i = 0; i < out.size(); i++)
		{
			out[i].r = image[i * 4 + 0];
			out[i].g = image[i * 4 + 1];
			out[i].b = image[i * 4 + 2];
			out[i].a = image[i * 4 + 3];
		}

		return 0;
	}

	int loadImage(std::vector<Uint32>& out, unsigned long& w, unsigned long& h, const std::string& filename)
	{
		std::vector<unsigned char> file, image;
		loadFile(file, filename);
		if (decodePNG(image, w, h, file)) return 1;

		out.resize(image.size() / 4);

		for (size_t i = 0; i < out.size(); i++)
		{
			out[i] = (Uint32)0x100000000 * image[i * 4 + 3] + 0x10000 * image[i * 4 + 0] + 0x100 * image[i * 4 + 1] + image[i * 4 + 2];
		}

		return 0;
	}

	////////////////////////////////////////////////////////////////////////////////
	//TEXT FUNCTIONS////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	//Draws character n at position x,y with color RGB and, if enabled, background color
	//This function is used by the text printing functions below, and uses the font data
	//defined below to draw the letter pixel by pixel
	void drawLetter(unsigned char n, int x, int y, const ColorRGBA& color, bool bg, const ColorRGBA& color2)
	{
		int u, v;

		for (v = 0; v < 8; v++)
			for (u = 0; u < 8; u++)
			{
				if (font[n][u][v]) pset(x + u, y + v, color);
				else if (bg) pset(x + u, y + v, color2);
			}
	}

	//Draws a string of text
	int printString(const std::string& text, int x, int y, const ColorRGBA& color, bool bg, const ColorRGBA& color2, int forceLength)
	{
		int amount = 0;
		for (size_t i = 0; i < text.size(); i++)
		{
			amount++;
			drawLetter(text[i], x, y, color, bg, color2);
			x += 8;
			if (x > w - 8) { x %= 8; y += 8; }
			if (y > h - 8) { y %= 8; }
		}
		while (amount < forceLength)
		{
			amount++;
			drawLetter(' ', x, y, color, bg, color2);
			x += 8;
			if (x > w - 8) { x %= 8; y += 8; }
			if (y > h - 8) { y %= 8; }
		}
		return h * x + y;
	}

	////////////////////////////////////////////////////////////////////////////////
	//TEXT INPUT FUNCTIONS//////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	const int ASCII_ENTER = 13;
	const int ASCII_BACKSPACE = 8;
	const int ASCII_SPACE = 32; //smallest printable ascii char

	Uint8 getInputCharacter()
	{
		int ascii = 0;
		static int previouschar = 0;

		if ((event.key.keysym.sym & 0xFF80) == 0)
		{
			if (event.type == SDL_KEYDOWN)
			{
				ascii = event.key.keysym.sym & 0x7F;
			}
		}

		if (ascii < ASCII_SPACE && ascii != ASCII_ENTER && ascii != ASCII_BACKSPACE) ascii = 0; //<32 ones, except enter and backspace

		if (ascii != previouschar) previouschar = ascii;
		else ascii = 0;

		return ascii;
	}
	//returns a string, length is the maximum length of the given string array
	void getInputString(std::string& text, const std::string& message, bool clear, int x, int y, const ColorRGBA& color, bool bg, const ColorRGBA& color2)
	{
		std::vector<Uint32> screenBuffer;
		getScreenBuffer(screenBuffer);

		bool enter = 0;
		bool change = 1;
		text.clear();

		while (enter == 0)
		{
			if (done()) end();
			Uint8 temp = getInputCharacter();
			if (temp >= ASCII_SPACE)
			{
				text.push_back(temp);
				change = 1;
			}
			if (temp == ASCII_BACKSPACE && text.size() > 0) { text.resize(text.size() - 1); change = 1; }

			if (change)
			{
				drawBuffer(&screenBuffer[0]);
				int pos = print(message, x, y, color, bg, color2);
				int x2 = pos / h, y2 = pos % h;
				print(text, x2, y2, color, bg, color2);
				redraw();
			}
			if (temp == ASCII_ENTER) { enter = 1; }
		}

		//remove the input stuff from the screen again so there is room for possible next input
		if (clear)
		{
			drawBuffer(&screenBuffer[0]);
			redraw();
		}
	}

	void encodeBase64(const std::vector<unsigned char>& in, std::string& out)
	{
		const std::string characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		unsigned long bit24 = 0;
		unsigned long sextet[4] = { 0, 0, 0, 0 };
		unsigned long octet[3] = { 0, 0, 0 };

		out.clear();
		out.reserve((4 * in.size()) / 3);

		for (size_t pos = 0; pos < in.size(); pos += 3)
		{
			octet[0] = in[pos + 0];
			octet[1] = (pos + 1 < in.size()) ? in[pos + 1] : 0;
			octet[2] = (pos + 2 < in.size()) ? in[pos + 2] : 0;

			bit24 = 256 * 256 * octet[0];
			bit24 += 256 * octet[1];
			bit24 += octet[2];

			sextet[0] = (bit24 / (64 * 64 * 64)) % 64;
			sextet[1] = (bit24 / (64 * 64)) % 64;
			sextet[2] = (bit24 / (64)) % 64;
			sextet[3] = (bit24 / (1)) % 64;

			for (size_t i = 0; i < 4; i++)
			{
				if (pos + i - 1 < in.size()) out.push_back(characters[sextet[i]]);
				else out.push_back('=');
			}

			if (pos % 57 == 0 && pos != 0) out.push_back(10); //newline char every 76 chars (57 = 3/4th of 76)
		}
	}

	void decodeBase64(std::vector<unsigned char>& out, const std::string& in)
	{
		unsigned long bit24 = 0;
		unsigned long sextet[4] = { 0, 0, 0, 0 };
		unsigned char octet[3] = { 0, 0, 0 };

		out.clear();
		out.reserve((3 * in.size()) / 4);

		for (size_t pos = 0; pos < in.size() - 3; pos += 4)
		{
			for (size_t i = 0; i < 4; i++)
			{
				unsigned long c = in[pos + i];
				if (c >= 65 && c <= 90) sextet[i] = c - 65;
				else if (c >= 97 && c <= 122) sextet[i] = c - 71;
				else if (c >= 48 && c <= 57) sextet[i] = c + 4;
				else if (c == '+') sextet[i] = 62;
				else if (c == '/') sextet[i] = 63;
				else if (c == '=') sextet[i] = 0; //value doesn't matter
				else //unknown char, can be whitespace, newline, ...
				{
					pos++;
					if (pos > in.size() - 3) return;
					i--;
				}
			}

			bit24 = 64 * 64 * 64 * sextet[0];
			bit24 += 64 * 64 * sextet[1];
			bit24 += 64 * sextet[2];
			bit24 += sextet[3];

			octet[0] = (bit24 / (256 * 256)) % 256;
			octet[1] = (bit24 / (256)) % 256;
			octet[2] = (bit24 / (1)) % 256;

			for (size_t i = 0; i < 3; i++)
			{
				if (in[pos + 1 + i] != '=') out.push_back(octet[i]);
			}
		}
	}

	////////////////////////////////////////////////////////////////////////////////
	// PNG                                                                        //
	////////////////////////////////////////////////////////////////////////////////

	int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width, unsigned long& image_height, const unsigned char* in_png, size_t in_size, bool convert_to_rgba32)
	{
		// picoPNG version 20101224
		// Copyright (c) 2005-2010 Lode Vandevenne
		//
		// This software is provided 'as-is', without any express or implied
		// warranty. In no event will the authors be held liable for any damages
		// arising from the use of this software.
		//
		// Permission is granted to anyone to use this software for any purpose,
		// including commercial applications, and to alter it and redistribute it
		// freely, subject to the following restrictions:
		//
		//     1. The origin of this software must not be misrepresented; you must not
		//     claim that you wrote the original software. If you use this software
		//     in a product, an acknowledgment in the product documentation would be
		//     appreciated but is not required.
		//     2. Altered source versions must be plainly marked as such, and must not be
		//     misrepresented as being the original software.
		//     3. This notice may not be removed or altered from any source distribution.

		static const unsigned long LENBASE[29] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258 };
		static const unsigned long LENEXTRA[29] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
		static const unsigned long DISTBASE[30] = { 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577 };
		static const unsigned long DISTEXTRA[30] = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13 };
		static const unsigned long CLCL[19] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; //code length code lengths
		struct Zlib //nested functions for zlib decompression
		{
			static unsigned long readBitFromStream(size_t& bitp, const unsigned char* bits) { unsigned long result = (bits[bitp >> 3] >> (bitp & 0x7)) & 1; bitp++; return result; }
			static unsigned long readBitsFromStream(size_t& bitp, const unsigned char* bits, size_t nbits)
			{
				unsigned long result = 0;
				for (size_t i = 0; i < nbits; i++) result += (readBitFromStream(bitp, bits)) << i;
				return result;
			}
			struct HuffmanTree
			{
				int makeFromLengths(const std::vector<unsigned long>& bitlen, unsigned long maxbitlen)
				{ //make tree given the lengths
					unsigned long numcodes = (unsigned long)(bitlen.size()), treepos = 0, nodefilled = 0;
					std::vector<unsigned long> tree1d(numcodes), blcount(maxbitlen + 1, 0), nextcode(maxbitlen + 1, 0);
					for (unsigned long bits = 0; bits < numcodes; bits++) blcount[bitlen[bits]]++; //count number of instances of each code length
					for (unsigned long bits = 1; bits <= maxbitlen; bits++) nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1;
					for (unsigned long n = 0; n < numcodes; n++) if (bitlen[n] != 0) tree1d[n] = nextcode[bitlen[n]]++; //generate all the codes
					tree2d.clear(); tree2d.resize(numcodes * 2, 32767); //32767 here means the tree2d isn't filled there yet
					for (unsigned long n = 0; n < numcodes; n++) //the codes
						for (unsigned long i = 0; i < bitlen[n]; i++) //the bits for this code
						{
							unsigned long bit = (tree1d[n] >> (bitlen[n] - i - 1)) & 1;
							if (treepos > numcodes - 2) return 55;
							if (tree2d[2 * treepos + bit] == 32767) //not yet filled in
							{
								if (i + 1 == bitlen[n]) { tree2d[2 * treepos + bit] = n; treepos = 0; } //last bit
								else { tree2d[2 * treepos + bit] = ++nodefilled + numcodes; treepos = nodefilled; } //addresses are encoded as values > numcodes
							}
							else treepos = tree2d[2 * treepos + bit] - numcodes; //subtract numcodes from address to get address value
						}
					return 0;
				}
				int decode(bool& decoded, unsigned long& result, size_t& treepos, unsigned long bit) const
				{ //Decodes a symbol from the tree
					unsigned long numcodes = (unsigned long)tree2d.size() / 2;
					if (treepos >= numcodes) return 11; //error: you appeared outside the codetree
					result = tree2d[2 * treepos + bit];
					decoded = (result < numcodes);
					treepos = decoded ? 0 : result - numcodes;
					return 0;
				}
				std::vector<unsigned long> tree2d; //2D representation of a huffman tree: The one dimension is "0" or "1", the other contains all nodes and leaves of the tree.
			};
			struct Inflator
			{
				int error;
				void inflate(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, size_t inpos = 0)
				{
					size_t bp = 0, pos = 0; //bit pointer and byte pointer
					error = 0;
					unsigned long BFINAL = 0;
					while (!BFINAL && !error)
					{
						if (bp >> 3 >= in.size()) { error = 52; return; } //error, bit pointer will jump past memory
						BFINAL = readBitFromStream(bp, &in[inpos]);
						unsigned long BTYPE = readBitFromStream(bp, &in[inpos]); BTYPE += 2 * readBitFromStream(bp, &in[inpos]);
						if (BTYPE == 3) { error = 20; return; } //error: invalid BTYPE
						else if (BTYPE == 0) inflateNoCompression(out, &in[inpos], bp, pos, in.size());
						else inflateHuffmanBlock(out, &in[inpos], bp, pos, in.size(), BTYPE);
					}
					if (!error) out.resize(pos); //Only now we know the true size of out, resize it to that
				}
				void generateFixedTrees(HuffmanTree& tree, HuffmanTree& treeD) //get the tree of a deflated block with fixed tree
				{
					std::vector<unsigned long> bitlen(288, 8), bitlenD(32, 5);;
					for (size_t i = 144; i <= 255; i++) bitlen[i] = 9;
					for (size_t i = 256; i <= 279; i++) bitlen[i] = 7;
					tree.makeFromLengths(bitlen, 15);
					treeD.makeFromLengths(bitlenD, 15);
				}
				HuffmanTree codetree, codetreeD, codelengthcodetree; //the code tree for Huffman codes, dist codes, and code length codes
				unsigned long huffmanDecodeSymbol(const unsigned char* in, size_t& bp, const HuffmanTree& codetree, size_t inlength)
				{ //decode a single symbol from given list of bits with given code tree. return value is the symbol
					bool decoded; unsigned long ct;
					for (size_t treepos = 0;;)
					{
						if ((bp & 0x07) == 0 && (bp >> 3) > inlength) { error = 10; return 0; } //error: end reached without endcode
						error = codetree.decode(decoded, ct, treepos, readBitFromStream(bp, in)); if (error) return 0; //stop, an error happened
						if (decoded) return ct;
					}
				}
				void getTreeInflateDynamic(HuffmanTree& tree, HuffmanTree& treeD, const unsigned char* in, size_t& bp, size_t inlength)
				{ //get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree
					std::vector<unsigned long> bitlen(288, 0), bitlenD(32, 0);
					if (bp >> 3 >= inlength - 2) { error = 49; return; } //the bit pointer is or will go past the memory
					size_t HLIT = readBitsFromStream(bp, in, 5) + 257; //number of literal/length codes + 257
					size_t HDIST = readBitsFromStream(bp, in, 5) + 1; //number of dist codes + 1
					size_t HCLEN = readBitsFromStream(bp, in, 4) + 4; //number of code length codes + 4
					std::vector<unsigned long> codelengthcode(19); //lengths of tree to decode the lengths of the dynamic tree
					for (size_t i = 0; i < 19; i++) codelengthcode[CLCL[i]] = (i < HCLEN) ? readBitsFromStream(bp, in, 3) : 0;
					error = codelengthcodetree.makeFromLengths(codelengthcode, 7); if (error) return;
					size_t i = 0, replength;
					while (i < HLIT + HDIST)
					{
						unsigned long code = huffmanDecodeSymbol(in, bp, codelengthcodetree, inlength); if (error) return;
						if (code <= 15)  { if (i < HLIT) bitlen[i++] = code; else bitlenD[i++ - HLIT] = code; } //a length code
						else if (code == 16) //repeat previous
						{
							if (bp >> 3 >= inlength) { error = 50; return; } //error, bit pointer jumps past memory
							replength = 3 + readBitsFromStream(bp, in, 2);
							unsigned long value; //set value to the previous code
							if ((i - 1) < HLIT) value = bitlen[i - 1];
							else value = bitlenD[i - HLIT - 1];
							for (size_t n = 0; n < replength; n++) //repeat this value in the next lengths
							{
								if (i >= HLIT + HDIST) { error = 13; return; } //error: i is larger than the amount of codes
								if (i < HLIT) bitlen[i++] = value; else bitlenD[i++ - HLIT] = value;
							}
						}
						else if (code == 17) //repeat "0" 3-10 times
						{
							if (bp >> 3 >= inlength) { error = 50; return; } //error, bit pointer jumps past memory
							replength = 3 + readBitsFromStream(bp, in, 3);
							for (size_t n = 0; n < replength; n++) //repeat this value in the next lengths
							{
								if (i >= HLIT + HDIST) { error = 14; return; } //error: i is larger than the amount of codes
								if (i < HLIT) bitlen[i++] = 0; else bitlenD[i++ - HLIT] = 0;
							}
						}
						else if (code == 18) //repeat "0" 11-138 times
						{
							if (bp >> 3 >= inlength) { error = 50; return; } //error, bit pointer jumps past memory
							replength = 11 + readBitsFromStream(bp, in, 7);
							for (size_t n = 0; n < replength; n++) //repeat this value in the next lengths
							{
								if (i >= HLIT + HDIST) { error = 15; return; } //error: i is larger than the amount of codes
								if (i < HLIT) bitlen[i++] = 0; else bitlenD[i++ - HLIT] = 0;
							}
						}
						else { error = 16; return; } //error: somehow an unexisting code appeared. This can never happen.
					}
					if (bitlen[256] == 0) { error = 64; return; } //the length of the end code 256 must be larger than 0
					error = tree.makeFromLengths(bitlen, 15); if (error) return; //now we've finally got HLIT and HDIST, so generate the code trees, and the function is done
					error = treeD.makeFromLengths(bitlenD, 15); if (error) return;
				}
				void inflateHuffmanBlock(std::vector<unsigned char>& out, const unsigned char* in, size_t& bp, size_t& pos, size_t inlength, unsigned long btype)
				{
					if (btype == 1) { generateFixedTrees(codetree, codetreeD); }
					else if (btype == 2) { getTreeInflateDynamic(codetree, codetreeD, in, bp, inlength); if (error) return; }
					for (;;)
					{
						unsigned long code = huffmanDecodeSymbol(in, bp, codetree, inlength); if (error) return;
						if (code == 256) return; //end code
						else if (code <= 255) //literal symbol
						{
							if (pos >= out.size()) out.resize((pos + 1) * 2); //reserve more room
							out[pos++] = (unsigned char)(code);
						}
						else if (code >= 257 && code <= 285) //length code
						{
							size_t length = LENBASE[code - 257], numextrabits = LENEXTRA[code - 257];
							if ((bp >> 3) >= inlength) { error = 51; return; } //error, bit pointer will jump past memory
							length += readBitsFromStream(bp, in, numextrabits);
							unsigned long codeD = huffmanDecodeSymbol(in, bp, codetreeD, inlength); if (error) return;
							if (codeD > 29) { error = 18; return; } //error: invalid dist code (30-31 are never used)
							unsigned long dist = DISTBASE[codeD], numextrabitsD = DISTEXTRA[codeD];
							if ((bp >> 3) >= inlength) { error = 51; return; } //error, bit pointer will jump past memory
							dist += readBitsFromStream(bp, in, numextrabitsD);
							size_t start = pos, back = start - dist; //backwards
							if (pos + length >= out.size()) out.resize((pos + length) * 2); //reserve more room
							for (size_t i = 0; i < length; i++) { out[pos++] = out[back++]; if (back >= start) back = start - dist; }
						}
					}
				}
				void inflateNoCompression(std::vector<unsigned char>& out, const unsigned char* in, size_t& bp, size_t& pos, size_t inlength)
				{
					while ((bp & 0x7) != 0) bp++; //go to first boundary of byte
					size_t p = bp / 8;
					if (p >= inlength - 4) { error = 52; return; } //error, bit pointer will jump past memory
					unsigned long LEN = in[p] + 256 * in[p + 1], NLEN = in[p + 2] + 256 * in[p + 3]; p += 4;
					if (LEN + NLEN != 65535) { error = 21; return; } //error: NLEN is not one's complement of LEN
					if (pos + LEN >= out.size()) out.resize(pos + LEN);
					if (p + LEN > inlength) { error = 23; return; } //error: reading outside of in buffer
					for (unsigned long n = 0; n < LEN; n++) out[pos++] = in[p++]; //read LEN bytes of literal data
					bp = p * 8;
				}
			};
			int decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in) //returns error value
			{
				Inflator inflator;
				if (in.size() < 2) { return 53; } //error, size of zlib data too small
				if ((in[0] * 256 + in[1]) % 31 != 0) { return 24; } //error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way
				unsigned long CM = in[0] & 15, CINFO = (in[0] >> 4) & 15, FDICT = (in[1] >> 5) & 1;
				if (CM != 8 || CINFO > 7) { return 25; } //error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec
				if (FDICT != 0) { return 26; } //error: the specification of PNG says about the zlib stream: "The additional flags shall not specify a preset dictionary."
				inflator.inflate(out, in, 2);
				return inflator.error; //note: adler32 checksum was skipped and ignored
			}
		};
		struct PNG //nested functions for PNG decoding
		{
			struct Info
			{
				unsigned long width, height, colorType, bitDepth, compressionMethod, filterMethod, interlaceMethod, key_r, key_g, key_b, key_a;
				bool key_defined; //is a transparent color key given?
				std::vector<unsigned char> palette;
			} info;
			int error;
			void decode(std::vector<unsigned char>& out, const unsigned char* in, size_t size, bool convert_to_rgba32)
			{
				error = 0;
				if (size == 0 || in == 0) { error = 48; return; } //the given data is empty
				readPngHeader(&in[0], size); if (error) return;
				size_t pos = 33; //first byte of the first chunk after the header
				std::vector<unsigned char> idat; //the data from idat chunks
				bool IEND = false, known_type = true;
				info.key_defined = false;
				while (!IEND) //loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. IDAT data is put at the start of the in buffer
				{
					if (pos + 8 >= size) { error = 30; return; } //error: size of the in buffer too small to contain next chunk
					size_t chunkLength = read32bitInt(&in[pos]); pos += 4;
					if (chunkLength > 2147483647) { error = 63; return; }
					if (pos + chunkLength >= size) { error = 35; return; } //error: size of the in buffer too small to contain next chunk
					if (in[pos + 0] == 'I' && in[pos + 1] == 'D' && in[pos + 2] == 'A' && in[pos + 3] == 'T') //IDAT chunk, containing compressed image data
					{
						idat.insert(idat.end(), &in[pos + 4], &in[pos + 4 + chunkLength]);
						pos += (4 + chunkLength);
					}
					else if (in[pos + 0] == 'I' && in[pos + 1] == 'E' && in[pos + 2] == 'N' && in[pos + 3] == 'D')  { pos += 4; IEND = true; }
					else if (in[pos + 0] == 'P' && in[pos + 1] == 'L' && in[pos + 2] == 'T' && in[pos + 3] == 'E') //palette chunk (PLTE)
					{
						pos += 4; //go after the 4 letters
						info.palette.resize(4 * (chunkLength / 3));
						if (info.palette.size() > (4 * 256)) { error = 38; return; } //error: palette too big
						for (size_t i = 0; i < info.palette.size(); i += 4)
						{
							for (size_t j = 0; j < 4; j++) info.palette[i + j] = in[pos++]; //RGBA
						}
					}
					else if (in[pos + 0] == 't' && in[pos + 1] == 'R' && in[pos + 2] == 'N' && in[pos + 3] == 'S') //palette transparency chunk (tRNS)
					{
						pos += 4; //go after the 4 letters
						if (info.colorType == 3)
						{
							if (4 * chunkLength > info.palette.size()) { error = 39; return; } //error: more alpha values given than there are palette entries
							for (size_t i = 0; i < chunkLength; i++) info.palette[4 * i + 3] = in[pos++];
						}
						else if (info.colorType == 0)
						{
							if (chunkLength != 2) { error = 40; return; } //error: this chunk must be 2 bytes for greyscale image
							info.key_defined = 1; info.key_r = info.key_g = info.key_b = 256 * in[pos] + in[pos + 1]; pos += 2;
						}
						else if (info.colorType == 2)
						{
							if (chunkLength != 6) { error = 41; return; } //error: this chunk must be 6 bytes for RGB image
							info.key_defined = 1;
							info.key_r = 256 * in[pos] + in[pos + 1]; pos += 2;
							info.key_g = 256 * in[pos] + in[pos + 1]; pos += 2;
							info.key_b = 256 * in[pos] + in[pos + 1]; pos += 2;
						}
						else { error = 42; return; } //error: tRNS chunk not allowed for other color models
					}
					else //it's not an implemented chunk type, so ignore it: skip over the data
					{
						if (!(in[pos + 0] & 32)) { error = 69; return; } //error: unknown critical chunk (5th bit of first byte of chunk type is 0)
						pos += (chunkLength + 4); //skip 4 letters and uninterpreted data of unimplemented chunk
						known_type = false;
					}
					pos += 4; //step over CRC (which is ignored)
				}
				unsigned long bpp = getBpp(info);
				std::vector<unsigned char> scanlines(((info.width * (info.height * bpp + 7)) / 8) + info.height); //now the out buffer will be filled
				Zlib zlib; //decompress with the Zlib decompressor
				error = zlib.decompress(scanlines, idat); if (error) return; //stop if the zlib decompressor returned an error
				size_t bytewidth = (bpp + 7) / 8, outlength = (info.height * info.width * bpp + 7) / 8;
				out.resize(outlength); //time to fill the out buffer
				unsigned char* out_ = outlength ? &out[0] : 0; //use a regular pointer to the std::vector for faster code if compiled without optimization
				if (info.interlaceMethod == 0) //no interlace, just filter
				{
					size_t linestart = 0, linelength = (info.width * bpp + 7) / 8; //length in bytes of a scanline, excluding the filtertype byte
					if (bpp >= 8) //byte per byte
						for (unsigned long y = 0; y < info.height; y++)
						{
							unsigned long filterType = scanlines[linestart];
							const unsigned char* prevline = (y == 0) ? 0 : &out_[(y - 1) * info.width * bytewidth];
							unFilterScanline(&out_[linestart - y], &scanlines[linestart + 1], prevline, bytewidth, filterType, linelength); if (error) return;
							linestart += (1 + linelength); //go to start of next scanline
						}
					else //less than 8 bits per pixel, so fill it up bit per bit
					{
						std::vector<unsigned char> templine((info.width * bpp + 7) >> 3); //only used if bpp < 8
						for (size_t y = 0, obp = 0; y < info.height; y++)
						{
							unsigned long filterType = scanlines[linestart];
							const unsigned char* prevline = (y == 0) ? 0 : &out_[(y - 1) * info.width * bytewidth];
							unFilterScanline(&templine[0], &scanlines[linestart + 1], prevline, bytewidth, filterType, linelength); if (error) return;
							for (size_t bp = 0; bp < info.width * bpp;) setBitOfReversedStream(obp, out_, readBitFromReversedStream(bp, &templine[0]));
							linestart += (1 + linelength); //go to start of next scanline
						}
					}
				}
				else //interlaceMethod is 1 (Adam7)
				{
					size_t passw[7] = { (info.width + 7) / 8, (info.width + 3) / 8, (info.width + 3) / 4, (info.width + 1) / 4, (info.width + 1) / 2, (info.width + 0) / 2, (info.width + 0) / 1 };
					size_t passh[7] = { (info.height + 7) / 8, (info.height + 7) / 8, (info.height + 3) / 8, (info.height + 3) / 4, (info.height + 1) / 4, (info.height + 1) / 2, (info.height + 0) / 2 };
					size_t passstart[7] = { 0 };
					size_t pattern[28] = { 0, 4, 0, 2, 0, 1, 0, 0, 0, 4, 0, 2, 0, 1, 8, 8, 4, 4, 2, 2, 1, 8, 8, 8, 4, 4, 2, 2 }; //values for the adam7 passes
					for (int i = 0; i < 6; i++) passstart[i + 1] = passstart[i] + passh[i] * ((passw[i] ? 1 : 0) + (passw[i] * bpp + 7) / 8);
					std::vector<unsigned char> scanlineo((info.width * bpp + 7) / 8), scanlinen((info.width * bpp + 7) / 8); //"old" and "new" scanline
					for (int i = 0; i < 7; i++)
						adam7Pass(&out_[0], &scanlinen[0], &scanlineo[0], &scanlines[passstart[i]], info.width, pattern[i], pattern[i + 7], pattern[i + 14], pattern[i + 21], passw[i], passh[i], bpp);
				}
				if (convert_to_rgba32 && (info.colorType != 6 || info.bitDepth != 8)) //conversion needed
				{
					std::vector<unsigned char> data = out;
					error = convert(out, &data[0], info, info.width, info.height);
				}
			}
			void readPngHeader(const unsigned char* in, size_t inlength) //read the information from the header and store it in the Info
			{
				if (inlength < 29) { error = 27; return; } //error: the data length is smaller than the length of the header
				if (in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { error = 28; return; } //no PNG signature
				if (in[12] != 'I' || in[13] != 'H' || in[14] != 'D' || in[15] != 'R') { error = 29; return; } //error: it doesn't start with a IHDR chunk!
				info.width = read32bitInt(&in[16]); info.height = read32bitInt(&in[20]);
				info.bitDepth = in[24]; info.colorType = in[25];
				info.compressionMethod = in[26]; if (in[26] != 0) { error = 32; return; } //error: only compression method 0 is allowed in the specification
				info.filterMethod = in[27]; if (in[27] != 0) { error = 33; return; } //error: only filter method 0 is allowed in the specification
				info.interlaceMethod = in[28]; if (in[28] > 1) { error = 34; return; } //error: only interlace methods 0 and 1 exist in the specification
				error = checkColorValidity(info.colorType, info.bitDepth);
			}
			void unFilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon, size_t bytewidth, unsigned long filterType, size_t length)
			{
				switch (filterType)
				{
				case 0: for (size_t i = 0; i < length; i++) recon[i] = scanline[i]; break;
				case 1:
					for (size_t i = 0; i < bytewidth; i++) recon[i] = scanline[i];
					for (size_t i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth];
					break;
				case 2:
					if (precon) for (size_t i = 0; i < length; i++) recon[i] = scanline[i] + precon[i];
					else       for (size_t i = 0; i < length; i++) recon[i] = scanline[i];
					break;
				case 3:
					if (precon)
					{
						for (size_t i = 0; i < bytewidth; i++) recon[i] = scanline[i] + precon[i] / 2;
						for (size_t i = bytewidth; i < length; i++) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) / 2);
					}
					else
					{
						for (size_t i = 0; i < bytewidth; i++) recon[i] = scanline[i];
						for (size_t i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth] / 2;
					}
					break;
				case 4:
					if (precon)
					{
						for (size_t i = 0; i < bytewidth; i++) recon[i] = scanline[i] + paethPredictor(0, precon[i], 0);
						for (size_t i = bytewidth; i < length; i++) recon[i] = scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth]);
					}
					else
					{
						for (size_t i = 0; i < bytewidth; i++) recon[i] = scanline[i];
						for (size_t i = bytewidth; i < length; i++) recon[i] = scanline[i] + paethPredictor(recon[i - bytewidth], 0, 0);
					}
					break;
				default: error = 36; return; //error: unexisting filter type given
				}
			}
			void adam7Pass(unsigned char* out, unsigned char* linen, unsigned char* lineo, const unsigned char* in, unsigned long w, size_t passleft, size_t passtop, size_t spacex, size_t spacey, size_t passw, size_t passh, unsigned long bpp)
			{ //filter and reposition the pixels into the output when the image is Adam7 interlaced. This function can only do it after the full image is already decoded. The out buffer must have the correct allocated memory size already.
				if (passw == 0) return;
				size_t bytewidth = (bpp + 7) / 8, linelength = 1 + ((bpp * passw + 7) / 8);
				for (unsigned long y = 0; y < passh; y++)
				{
					unsigned char filterType = in[y * linelength], *prevline = (y == 0) ? 0 : lineo;
					unFilterScanline(linen, &in[y * linelength + 1], prevline, bytewidth, filterType, (w * bpp + 7) / 8); if (error) return;
					if (bpp >= 8) for (size_t i = 0; i < passw; i++) for (size_t b = 0; b < bytewidth; b++) //b = current byte of this pixel
						out[bytewidth * w * (passtop + spacey * y) + bytewidth * (passleft + spacex * i) + b] = linen[bytewidth * i + b];
					else for (size_t i = 0; i < passw; i++)
					{
						size_t obp = bpp * w * (passtop + spacey * y) + bpp * (passleft + spacex * i), bp = i * bpp;
						for (size_t b = 0; b < bpp; b++) setBitOfReversedStream(obp, out, readBitFromReversedStream(bp, &linen[0]));
					}
					unsigned char* temp = linen; linen = lineo; lineo = temp; //swap the two buffer pointers "line old" and "line new"
				}
			}
			static unsigned long readBitFromReversedStream(size_t& bitp, const unsigned char* bits) { unsigned long result = (bits[bitp >> 3] >> (7 - (bitp & 0x7))) & 1; bitp++; return result; }
			static unsigned long readBitsFromReversedStream(size_t& bitp, const unsigned char* bits, unsigned long nbits)
			{
				unsigned long result = 0;
				for (size_t i = nbits - 1; i < nbits; i--) result += ((readBitFromReversedStream(bitp, bits)) << i);
				return result;
			}
			void setBitOfReversedStream(size_t& bitp, unsigned char* bits, unsigned long bit) { bits[bitp >> 3] |= (bit << (7 - (bitp & 0x7))); bitp++; }
			unsigned long read32bitInt(const unsigned char* buffer) { return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]; }
			int checkColorValidity(unsigned long colorType, unsigned long bd) //return type is a LodePNG error code
			{
				if ((colorType == 2 || colorType == 4 || colorType == 6)) { if (!(bd == 8 || bd == 16)) return 37; else return 0; }
				else if (colorType == 0) { if (!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; else return 0; }
				else if (colorType == 3) { if (!(bd == 1 || bd == 2 || bd == 4 || bd == 8)) return 37; else return 0; }
				else return 31; //unexisting color type
			}
			unsigned long getBpp(const Info& info)
			{
				if (info.colorType == 2) return (3 * info.bitDepth);
				else if (info.colorType >= 4) return (info.colorType - 2) * info.bitDepth;
				else return info.bitDepth;
			}
			int convert(std::vector<unsigned char>& out, const unsigned char* in, Info& infoIn, unsigned long w, unsigned long h)
			{ //converts from any color type to 32-bit. return value = LodePNG error code
				size_t numpixels = w * h, bp = 0;
				out.resize(numpixels * 4);
				unsigned char* out_ = out.empty() ? 0 : &out[0]; //faster if compiled without optimization
				if (infoIn.bitDepth == 8 && infoIn.colorType == 0) //greyscale
					for (size_t i = 0; i < numpixels; i++)
					{
						out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = in[i];
						out_[4 * i + 3] = (infoIn.key_defined && in[i] == infoIn.key_r) ? 0 : 255;
					}
				else if (infoIn.bitDepth == 8 && infoIn.colorType == 2) //RGB color
					for (size_t i = 0; i < numpixels; i++)
					{
						for (size_t c = 0; c < 3; c++) out_[4 * i + c] = in[3 * i + c];
						out_[4 * i + 3] = (infoIn.key_defined == 1 && in[3 * i + 0] == infoIn.key_r && in[3 * i + 1] == infoIn.key_g && in[3 * i + 2] == infoIn.key_b) ? 0 : 255;
					}
				else if (infoIn.bitDepth == 8 && infoIn.colorType == 3) //indexed color (palette)
					for (size_t i = 0; i < numpixels; i++)
					{
						if (4U * in[i] >= infoIn.palette.size()) return 46;
						for (size_t c = 0; c < 4; c++) out_[4 * i + c] = infoIn.palette[4 * in[i] + c]; //get rgb colors from the palette
					}
				else if (infoIn.bitDepth == 8 && infoIn.colorType == 4) //greyscale with alpha
					for (size_t i = 0; i < numpixels; i++)
					{
						out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = in[2 * i + 0];
						out_[4 * i + 3] = in[2 * i + 1];
					}
				else if (infoIn.bitDepth == 8 && infoIn.colorType == 6) for (size_t i = 0; i < numpixels; i++) for (size_t c = 0; c < 4; c++) out_[4 * i + c] = in[4 * i + c]; //RGB with alpha
				else if (infoIn.bitDepth == 16 && infoIn.colorType == 0) //greyscale
					for (size_t i = 0; i < numpixels; i++)
					{
						out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = in[2 * i];
						out_[4 * i + 3] = (infoIn.key_defined && 256U * in[i] + in[i + 1] == infoIn.key_r) ? 0 : 255;
					}
				else if (infoIn.bitDepth == 16 && infoIn.colorType == 2) //RGB color
					for (size_t i = 0; i < numpixels; i++)
					{
						for (size_t c = 0; c < 3; c++) out_[4 * i + c] = in[6 * i + 2 * c];
						out_[4 * i + 3] = (infoIn.key_defined && 256U * in[6 * i + 0] + in[6 * i + 1] == infoIn.key_r && 256U * in[6 * i + 2] + in[6 * i + 3] == infoIn.key_g && 256U * in[6 * i + 4] + in[6 * i + 5] == infoIn.key_b) ? 0 : 255;
					}
				else if (infoIn.bitDepth == 16 && infoIn.colorType == 4) //greyscale with alpha
					for (size_t i = 0; i < numpixels; i++)
					{
						out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = in[4 * i]; //most significant byte
						out_[4 * i + 3] = in[4 * i + 2];
					}
				else if (infoIn.bitDepth == 16 && infoIn.colorType == 6) for (size_t i = 0; i < numpixels; i++) for (size_t c = 0; c < 4; c++) out_[4 * i + c] = in[8 * i + 2 * c]; //RGB with alpha
				else if (infoIn.bitDepth < 8 && infoIn.colorType == 0) //greyscale
					for (size_t i = 0; i < numpixels; i++)
					{
						unsigned long value = (readBitsFromReversedStream(bp, in, infoIn.bitDepth) * 255) / ((1 << infoIn.bitDepth) - 1); //scale value from 0 to 255
						out_[4 * i + 0] = out_[4 * i + 1] = out_[4 * i + 2] = (unsigned char)(value);
						out_[4 * i + 3] = (infoIn.key_defined && value && ((1U << infoIn.bitDepth) - 1U) == infoIn.key_r && ((1U << infoIn.bitDepth) - 1U)) ? 0 : 255;
					}
				else if (infoIn.bitDepth < 8 && infoIn.colorType == 3) //palette
					for (size_t i = 0; i < numpixels; i++)
					{
						unsigned long value = readBitsFromReversedStream(bp, in, infoIn.bitDepth);
						if (4 * value >= infoIn.palette.size()) return 47;
						for (size_t c = 0; c < 4; c++) out_[4 * i + c] = infoIn.palette[4 * value + c]; //get rgb colors from the palette
					}
				return 0;
			}
			unsigned char paethPredictor(short a, short b, short c) //Paeth predicter, used by PNG filter type 4
			{
				short p = a + b - c, pa = p > a ? (p - a) : (a - p), pb = p > b ? (p - b) : (b - p), pc = p > c ? (p - c) : (c - p);
				return (unsigned char)((pa <= pb && pa <= pc) ? a : pb <= pc ? b : c);
			}
		};
		PNG decoder; decoder.decode(out_image, in_png, in_size, convert_to_rgba32);
		image_width = decoder.info.width; image_height = decoder.info.height;
		return decoder.error;
	}

	int decodePNG(std::vector<unsigned char>& out_image_32bit, unsigned long& image_width, unsigned long& image_height, const std::vector<unsigned char>& in_png)
	{
		return decodePNG(out_image_32bit, image_width, image_height, in_png.size() ? &in_png[0] : 0, in_png.size());
	}


	////////////////////////////////////////////////////////////////////////////////
	//DATA//////////////////////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////


	bool font[256][8][8];
	struct GenerateFont
	{
		GenerateFont()
		{
			/*
			The full extended ASCII character set, in the form 256 bitmap symbols of 8x8
			pixels in one 128x128 PNG.
			The background color is black, not transparent.
			*/

			std::vector<unsigned char> png, image;
			loadFile(png, "charset.png");

			unsigned long w, h;
			decodePNG(image, w, h, &png[0], png.size());
			for (size_t c = 0; c < 256; c++)
				for (size_t y = 0; y < 8; y++)
					for (size_t x = 0; x < 8; x++)
					{
						font[c][x][y] = image[4 * 128 * (8 * (c / 16) + y) + 4 * (8 * (c % 16) + x)] != 0;
					}
		}
	};
	GenerateFont generateFont;

	////////////////////////////////////////////////////////////////////////////////
	//Multithreading helper functions///////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	//SDL's C functions don't have destructors and such so therefore this here is needed

	//currently only needed for audio, therefor it's not in a different cpp file.

	//this creates SDL mutexes and makes sure that they're destroyed at the end. MutexFactory does the deletion!
	struct MutexFactory
	{
		SDL_mutex* createMutex()
		{
			mutexes.push_back(SDL_CreateMutex());
			return mutexes.back();
		}

		~MutexFactory()
		{
			for (size_t i = 0; i < mutexes.size(); i++)
				SDL_DestroyMutex(mutexes[i]);
		}

	private:

		std::vector<SDL_mutex*> mutexes;
	};

	MutexFactory mutexFactory;

	//this does SDL_mutexP in the ctor and SDL_mutexV in the dtor so no matter where you leave a function, SDL_mutexV is called
	struct Mutex
	{
		SDL_mutex** m;

		Mutex(SDL_mutex*& mutex)
		{
			m = &mutex;
			SDL_mutexP(*m);
		}

		~Mutex()
		{
			SDL_mutexV(*m);
		}
	};

	////////////////////////////////////////////////////////////////////////////////
	//Soundcard functions///////////////////////////////////////////////////////////
	////////////////////////////////////////////////////////////////////////////////

	size_t audio_min_samples = 4096; //safety buffer to avoid clicks
	size_t audio_max_samples = 8192; //avoid too long queue

	double audio_volume = 1.0;
	int audio_mode = 2; //0=off, 1=full (volume ignored), 2=volume-controlled

	void audioSetBufferSamplesRange(size_t min_samples, size_t max_samples)
	{
		audio_min_samples = min_samples;
		audio_max_samples = max_samples;
	}

	void audioSetMode(int mode) //0: silent, 1: full (no volume calculations ==> faster), 2: volume-controlled (= default value)
	{
		audio_mode = mode;
	}

	void audioSetVolume(double volume) //multiplier used if mode is 2 (volume-controlled). Default value is 1.0.
	{
		audio_volume = volume;
	}

	/*
	Avoid the callback function and pushSamples function to be called at the same time,
	or the std::vector can be invalid as two threads at the same time change it.
	This SDL_mutex helps eliminate that problem.
	*/
	SDL_mutex* audio_lock = mutexFactory.createMutex();

	std::vector<double> audio_data(audio_min_samples, 0);

	SDL_AudioSpec audiospec_wanted, audiospec_obtained;

	size_t audioSamplesShortage() //returns value > 0 if the soundcard is consuming more samples than you're producing
	{
		if (audio_data.size() < audio_min_samples) return audio_min_samples - audio_data.size();
		else return 0;
	}

	size_t audioSamplesOverflow() //returns value > 0 if you're producing more samples than the soundard is consuming - so take it easy a bit
	{
		if (audio_data.size() > audio_max_samples) return audio_data.size() - audio_max_samples;
		else return 0;
	}

	void audioCallback(void* /*userdata*/, Uint8* stream, int len)
	{
		Mutex mutex(audio_lock);

		size_t dataLengthLeft = audio_data.size();

		//only play if we have data left
		if (dataLengthLeft <= 0) return;

		int nsamples = len / 2; //always 16-bit, so always 2 bytes per sample, hence the amount of samples being len / 2
		size_t fill_len = (nsamples < dataLengthLeft ? nsamples : dataLengthLeft);

		for (int i = 0; i < nsamples; i++)
		{
			if (i < fill_len)
			{
				int s = int(audio_data[i] * 32768);
				if (s < -32768) s = -32768;
				if (s > 32767) s = 32767;

				stream[i * 2 + 0] = Uint8(s % 256);
				stream[i * 2 + 1] = Uint8(s / 256);
			}
			else stream[i * 2 + 0] = stream[i * 2 + 1] = 0;
		}

		audio_data.erase(audio_data.begin(), audio_data.begin() + fill_len);
	}

	int audioOpen(int samplerate, int framesize) //always 16-bit mono sound for now
	{
		//set the audio format
		audiospec_wanted.freq = samplerate;
		audiospec_wanted.format = AUDIO_S16;
		audiospec_wanted.channels = 1;  //1 = mono, 2 = stereo
		audiospec_wanted.samples = framesize;
		audiospec_wanted.callback = audioCallback;
		audiospec_wanted.userdata = NULL;

		/*
		when using alsa and 44100 samples/second, then the framesize (samples)
		will be 940 instead of 1024. Resampled to 48000Hz, this gives back 1024.
		*/

		//open the audio device, forcing the wanted format
		if (SDL_OpenAudio(&audiospec_wanted, &audiospec_obtained) < 0)
		{
			return 1;
		}

		SDL_PauseAudio(0);

		return 0;
	}

	void audioClose()
	{
		SDL_CloseAudio();
	}

	int audioReOpen() //closes and opens again with same parameters
	{
		SDL_PauseAudio(1);
		SDL_CloseAudio();
		if (SDL_OpenAudio(&audiospec_wanted, &audiospec_obtained) < 0)
		{
			return 1;
		}
		SDL_PauseAudio(0);

		return 0;
	}


	//only works correct for 16 bit audio currently
	void audioPushSamples(const std::vector<double>& samples, size_t pos, size_t end)
	{
		if (audio_mode == 0) return;

		Mutex mutex(audio_lock);

		if (audio_mode == 1)
		{
			audio_data.insert(audio_data.end(), samples.begin() + pos, samples.begin() + end);
		}
		else if (audio_mode == 2)
		{
			size_t j = audio_data.size();
			audio_data.resize(j + samples.size());
			for (size_t i = 0; i < samples.size(); i++)
			{
				audio_data[j + i] = samples[i] * audio_volume;
			}
		}
	}

	void audioPlay(const std::vector<double>& samples)
	{
		if (audio_mode == 0) return;

		Mutex mutex(audio_lock);

		//the *current* time is at the first sample of audio_data, the rest has been played through soundcard already

		if (samples.size() > audio_data.size()) audio_data.resize(samples.size(), 0.0);

		if (audio_mode == 1) for (size_t i = 0; i < samples.size(); i++) audio_data[i] += samples[i];
		else if (audio_mode == 2) for (size_t i = 0; i < samples.size(); i++) audio_data[i] += samples[i] * audio_volume;
	}

}