From 8b9fbecd74e339db01fb46fb24040ea414b2144e Mon Sep 17 00:00:00 2001
From: Francesco Abbate <francesco.bbt@gmail.com>
Date: Tue, 27 Apr 2021 09:52:02 +0200
Subject: [PATCH] Ensure we update only modified rects

---
 src/renderer.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/renderer.c b/src/renderer.c
index e4e9dcbf..3bd237c0 100644
--- a/src/renderer.c
+++ b/src/renderer.c
@@ -176,9 +176,12 @@ void ren_update_rects(RenRect *rects, int count) {
     initial_frame = false;
   }
 
-  // FIXME: we ignore the rects here.
   SDL_UpdateTexture(renderer.texture, NULL, renderer.surface->pixels, renderer.surface->w * 4);
-  SDL_RenderCopy(renderer.renderer, renderer.texture, NULL, NULL);
+  for (int i = 0; i < count; i++) {
+    const RenRect *r = &rects[i];
+    SDL_Rect sr = {.x = r->x, .y = r->y, .w = r->width, .h = r->height};
+    SDL_RenderCopy(renderer.renderer, renderer.texture, &sr, &sr);
+  }
   SDL_RenderPresent(renderer.renderer);
 }