Create bresenham_circle.c

Books/MathGraphicsGames/bresenham_circle.c

@@ -0,0 +1,83 @@
+//
+// Bresenham circle algorithm. (centerx, centery, radius.)
+//
+// From the book - mathmatics for computer graphics and game programming.
+//
+
+
+#include "raylib.h"
+
+void circleBres(int xc, int yc, int r);
+void putpixelBres(int xc, int yc, int x, int y);
+
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib example.");
+ 
+    SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        
+        
+        //----------------------------------------------------------------------------------
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+            circleBres(100,100,100);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+
+
+}
+
+void circleBres(int xc, int yc, int r) 
+{ 
+    int x=0;
+    int y=r;
+    int p=1-r;
+    while(x<=y){
+        putpixelBres(xc,yc,x,y);
+        if(p<=0){
+            x=x+1;
+            y=y;
+            p=p+(x*2)+3;
+        }else if(p>0)
+        {
+            x=x+1;
+            y=y-1;
+            p=p+(x*2)-(y*2)+5;
+        }
+    }
+}    
+void putpixelBres(int xc, int yc, int x, int y) 
+{     
+    DrawPixel(xc+x, yc+y, RED); 
+    DrawPixel(xc-x, yc+y, RED); 
+    DrawPixel(xc+x, yc-y, RED); 
+    DrawPixel(xc-x, yc-y, RED); 
+    DrawPixel(xc+y, yc+x, RED); 
+    DrawPixel(xc-y, yc+x, RED); 
+    DrawPixel(xc+y, yc-x, RED); 
+    DrawPixel(xc-y, yc-x, RED); 
+}