From 857cd2f91040573ff52a20aea9319c425c8b65ee Mon Sep 17 00:00:00 2001
From: "Zed A. Shaw" <zed.shaw@gmail.com>
Date: Wed, 25 Dec 2024 01:15:33 -0500
Subject: [PATCH] Circle iterator now compensates for the matrix size and won't
 overflow.

---
 lights.cpp       | 10 +++-------
 matrix.cpp       | 15 +++++++++------
 matrix.hpp       |  4 +++-
 tests/matrix.cpp | 13 ++++++++-----
 worldbuilder.cpp |  6 ++----
 5 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/lights.cpp b/lights.cpp
index 6b86c62..d3c70b3 100644
--- a/lights.cpp
+++ b/lights.cpp
@@ -7,14 +7,10 @@ using std::vector;
 namespace lighting {
 
   void LightRender::render_circle_light(LightSource source, Point at, PointList &has_light) {
-    for(matrix::circle it{at, source.distance + 1}; it.next();) {
+    for(matrix::circle it{$lightmap, at, source.distance + 1}; it.next();) {
       for(int x = it.left; x < it.right; x++) {
-        if(matrix::inbounds($paths.$paths, x, it.y) &&
-            $paths.$paths[it.y][x] != WALL_PATH_LIMIT)
-        {
-          $lightmap[it.y][x] = light_level(source.strength, x, it.y);
-          has_light.push_back({(size_t)x, (size_t)it.y});
-        }
+        $lightmap[it.y][x] = light_level(source.strength, x, it.y);
+        has_light.push_back({(size_t)x, (size_t)it.y});
       }
     }
   }
diff --git a/matrix.cpp b/matrix.cpp
index 0a4e6d6..edc4681 100644
--- a/matrix.cpp
+++ b/matrix.cpp
@@ -180,21 +180,24 @@ namespace matrix {
   }
 
 
-  circle::circle(Point center, int radius) :
+  circle::circle(Matrix &mat, Point center, int radius) :
     center(center), radius(radius)
   {
-    top = max(center.y - radius, size_t(0));
-    bottom = center.y + radius;
+    width = matrix::width(mat);
+    height = matrix::height(mat);
+    top = max(int(center.y - radius), 0);
+    bottom = min(int(center.y + radius), height);
+
     y = top;
   }
 
   bool circle::next() {
     y++;
-    if(y <= bottom) {
+    if(y < bottom) {
       dy = y - center.y;
       dx = floor(sqrt(radius * radius - dy * dy));
-      left = center.x - dx;
-      right = center.x + dx;
+      left = max(0, int(center.x - dx));
+      right = min(width, int(center.x + dx));
       return true;
     } else {
       return false;
diff --git a/matrix.hpp b/matrix.hpp
index b1715bf..710a1ef 100644
--- a/matrix.hpp
+++ b/matrix.hpp
@@ -127,8 +127,10 @@ namespace matrix {
     int right = 0;
     int top = 0;
     int bottom = 0;
+    int width = 0;
+    int height = 0;
 
-    circle(Point center, int radius);
+    circle(Matrix &mat, Point center, int radius);
     void update();
     bool next();
   };
diff --git a/tests/matrix.cpp b/tests/matrix.cpp
index 1e2421b..5ff10ff 100644
--- a/tests/matrix.cpp
+++ b/tests/matrix.cpp
@@ -226,7 +226,7 @@ TEST_CASE("prototype line algorithm", "[matrix:line]") {
 }
 
 TEST_CASE("prototype circle algorithm", "[matrix:circle]") {
-  for(int count = 0; count < 20; count++) {
+  for(int count = 0; count < 2000; count++) {
     size_t width = Random::uniform<size_t>(10, 13);
     size_t height = Random::uniform<size_t>(10, 15);
     int pos_mod = Random::uniform<int>(-3,3);
@@ -238,12 +238,15 @@ TEST_CASE("prototype circle algorithm", "[matrix:circle]") {
       // use an empty map
       Matrix result = map.walls();
 
-      for(matrix::circle it{start, radius}; it.next();) {
+      for(matrix::circle it{result, start, radius}; it.next();) {
         for(int x = it.left; x < it.right; x++) {
           // println("top={}, bottom={}, center.y={}, dy={}, left={}, right={}, x={}, y={}", it.top, it.bottom, it.center.y, it.dy, it.left, it.right, x, it.y);
-          if(matrix::inbounds(result, x, it.y)) {
-            result[it.y][x] += 1;
-          }
+          // println("RESULT {},{}", matrix::width(result), matrix::height(result));
+          REQUIRE(it.y >= 0);
+          REQUIRE(x >= 0);
+          REQUIRE(it.y < int(matrix::height(result)));
+          REQUIRE(x < int(matrix::width(result)));
+          result[it.y][x] += 1;
         }
       }
 
diff --git a/worldbuilder.cpp b/worldbuilder.cpp
index 6c0d666..25bef4b 100644
--- a/worldbuilder.cpp
+++ b/worldbuilder.cpp
@@ -142,11 +142,9 @@ void WorldBuilder::generate() {
   $map.load_tiles();
 
   Point center = $map.place_entity(1);
-  for(matrix::circle it{center, 3}; it.next();) {
+  for(matrix::circle it{$map.$walls, center, 3}; it.next();) {
     for(int x = it.left; x < it.right; x++) {
-      if($map.inmap(x, it.y) && !$map.iswall(x, it.y)) {
-        $map.$tiles.set_tile(x, it.y, "WATER_TILE");
-      }
+      $map.$tiles.set_tile(x, it.y, "WATER_TILE");
     }
   }
 }