A very jank circle algorithm that overdraws many of the lines but mostly works.

tests/matrix.cpp

@@ -224,3 +224,25 @@ TEST_CASE("prototype line algorithm", "[matrix:line]") {
     REQUIRE(f_found);
   }
 }
+
+TEST_CASE("prototype circle algorithm", "[matrix:circle]") {
+  size_t width = Random::uniform<size_t>(10, 13);
+  size_t height = Random::uniform<size_t>(10, 15);
+  Map map(width,height);
+  // create a target for the paths
+  Point start{.x=map.width() / 2, .y=map.height()/2};
+
+  for(int radius = 2; radius < 5; radius++) {
+    // use an empty map
+    Matrix result = map.walls();
+
+    for(matrix::circle it{start, radius}; it.next();) {
+      println("y={}, x0={}, x1={}", it.y, it.x0, it.x1);
+      for(int i = it.x0; i < it.x1; i++) {
+        result[it.y][i] += 1;
+      }
+    }
+
+    matrix::dump("RESULT AFTER CIRCLE", result, start.x, start.y);
+  }
+}