circle rendering, might change to make more efficient

include/arc/graphics/circle.h

@@ -0,0 +1,21 @@
+#ifndef ARC_GRAPHICS_CIRCLE_H_
+#define ARC_GRAPHICS_CIRCLE_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "arc/graphics/color.h"
+#include "arc/graphics/renderer.h"
+#include "arc/math/circle.h"
+#include <stdint.h>
+
+void ARC_Circle_Render(ARC_Circle *circle, ARC_Renderer *renderer, ARC_Color *color);
+
+// void ARC_Rect_RenderFill(ARC_Rect *rect, ARC_Renderer *renderer, ARC_Color *color);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // !ARC_GRAPHICS_RECT_H_

include/arc/math/circle.h

@@ -0,0 +1,20 @@
+#ifndef ARC_MATH_CIRCLE_H_
+#define ARC_MATH_CIRCLE_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct ARC_Circle {
+    int32_t x;
+    int32_t y;
+    int32_t r;
+} ARC_Circle;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // ARC_MATH_CIRCLE_H_

src/graphics/sdl/circle.c

@@ -0,0 +1,43 @@
+#ifdef ARC_SDL
+#include "arc/graphics/circle.h"
+#include "arc/graphics/sdl/renderer.h"
+#include <stdlib.h>
+
+//Modified from https://stackoverflow.com/questions/38334081/how-to-draw-circles-arcs-and-vector-graphics-in-sdl
+void ARC_Circle_Render(ARC_Circle *circle, ARC_Renderer *renderer, ARC_Color *color){
+    SDL_SetRenderDrawColor((SDL_Renderer *)renderer, color->r, color->g, color->b, color->a);
+
+    int32_t diameter = (circle->r * 2);
+
+    int32_t x = (circle->r - 1);
+    int32_t y = 0;
+    int32_t tx = 1;
+    int32_t ty = 1;
+    int32_t error = (tx - diameter);
+
+    while(x >= y){
+        //  Each of the following renders an octant of the circle
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x + x, circle->y - y);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x + x, circle->y + y);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x - x, circle->y - y);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x - x, circle->y + y);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x + y, circle->y - x);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x + y, circle->y + x);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x - y, circle->y - x);
+        SDL_RenderDrawPoint((SDL_Renderer *)renderer, circle->x - y, circle->y + x);
+
+        if(error <= 0){
+            ++y;
+            error += ty;
+            ty += 2;
+        }
+
+        if(error > 0){
+            --x;
+            tx += 2;
+            error += (tx - diameter);
+        }
+    }
+}
+
+#endif // ARC_SDL