Implement simple line drawing

renderer.h

@@ -1,6 +1,8 @@
 #ifndef RENDERER_H
 #define RENDERER_H
 
+#include "maths.h"
+
 #include <stdint.h>
 
 typedef struct {
@@ -15,5 +17,6 @@ void renderer_handle();
 void renderer_clear();
 void renderer_swap();
 
-void renderer_draw();
+void renderer_draw(const vec2_t *vs, unsigned count);
+
 #endif