1 files changed, 47 insertions, 0 deletions
diff --git a/Week1-Pacman/src/demo.c b/Week1-Pacman/src/demo.c
new file mode 100644
index 0000000..5ab6c39
--- /dev/null
+++ b/Week1-Pacman/src/demo.c
@@ -0,0 +1,47 @@
+#include <SDL2/SDL.h>
+#include "demo.h"
+
+void update_demo(struct demo* demo) {
+  int width, height;
+  int pixel_width, pixel_height;
+
+  SDL_GetWindowSize(demo->win, &width, &height);
+  SDL_GetRendererOutputSize(demo->ren, &pixel_width, &pixel_height);
+
+  demo->display_scale_x = pixel_width / width;
+  demo->display_scale_y = pixel_height / height;
+}
+
+void demo_rendercopy(struct demo* demo,
+                     SDL_Texture* texture,
+                     SDL_Rect* s_rect,
+                     SDL_Rect* d_rect) {
+  const float scale_x = demo->display_scale_x;
+  const float scale_y = demo->display_scale_y;
+
+  SDL_Rect new_srect;
+  SDL_Rect new_drect;
+
+  if(s_rect) {
+    new_srect = (SDL_Rect){
+      .x = s_rect->x * scale_x,
+      .y = s_rect->y * scale_y,
+      .w = s_rect->w * scale_x,
+      .h = s_rect->h * scale_y
+    };
+  }
+
+  if(d_rect) {
+    new_drect = (SDL_Rect){
+      .x = d_rect->x * scale_x,
+      .y = d_rect->y * scale_y,
+      .w = d_rect->w * scale_x,
+      .h = d_rect->h * scale_y
+    };
+  }
+
+  //Handle edge case where s_rect or d_rect are NULL
+  SDL_RenderCopy(demo->ren, texture,
+                 s_rect ? &new_srect : NULL,
+                 d_rect ?&new_drect : NULL);
+}