From 23a8889f9b5e00879bdbe2b3d49571c7714db5ba Mon Sep 17 00:00:00 2001
From: Gordon Williams <gw@pur3.co.uk>
Date: Wed, 19 Mar 2014 10:12:16 +0000
Subject: [PATCH] improve SDL performance by only flipping when idle

---
 libs/graphics/lcd_sdl.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libs/graphics/lcd_sdl.c b/libs/graphics/lcd_sdl.c
index a746c16f3..b3c0764ab 100644
--- a/libs/graphics/lcd_sdl.c
+++ b/libs/graphics/lcd_sdl.c
@@ -21,6 +21,7 @@
 #define DEPTH 32
 
 SDL_Surface *screen = 0;
+bool needsFlip = false;
 
 unsigned int lcdGetPixel_SDL(JsGraphics *gfx, short x, short y) {
   if (!screen) return 0;
@@ -43,7 +44,7 @@ void lcdSetPixel_SDL(JsGraphics *gfx, short x, short y, unsigned int col) {
   unsigned int *pixmem32 = ((unsigned int*)screen->pixels) + y*gfx->data.width + x;
   *pixmem32 = col;
   if(SDL_MUSTLOCK(screen)) SDL_UnlockSurface(screen);
-  SDL_Flip(screen);
+  needsFlip = true;
 }
 
 void lcdInit_SDL(JsGraphics *gfx) {
@@ -60,6 +61,10 @@ void lcdInit_SDL(JsGraphics *gfx) {
 }
 
 void lcdIdle_SDL() {
+  if (needsFlip) {
+    needsFlip = false;
+    SDL_Flip(screen);
+  }
 }
 
 void lcdSetCallbacks_SDL(JsGraphics *gfx) {