Add motion blur mod

mods/motion_blur.diff

@@ -0,0 +1,51 @@
+Simple dithered motion blur effect, applied to whole rendering.
+
+diff --git a/game.h b/game.h
+index 1ad5131..d886e0b 100644
+--- a/game.h
++++ b/game.h
+@@ -347,6 +347,8 @@ struct
+   char popupStr[LCR_POPUP_STR_SIZE];
+   uint8_t popupCountdown;
+ 
++  int_fast8_t frameCycle;
++
+   struct
+   {
+     uint8_t selectedTab;
+@@ -399,6 +401,9 @@ uint8_t LCR_gameMusicOn(void)
+ 
+ void LCR_gameDrawPixel(unsigned long index, uint16_t color)
+ {
++  if ((index % LCR_SETTING_MOTION_BLUR_FRAMES) != LCR_game.frameCycle)
++    return;
++
+ #if LCR_SETTING_RESOLUTION_SUBDIVIDE <= 1
+   LCR_drawPixel(index,color);
+ #else
+@@ -1899,6 +1904,8 @@ uint8_t LCR_gameStep(uint32_t time)
+     {
+       LCR_LOG2("rendering next frame");
+ 
++      LCR_game.frameCycle = LCR_renderer.frame % LCR_SETTING_MOTION_BLUR_FRAMES;
++
+       while (time >= LCR_game.nextRenderFrameTime)
+         LCR_game.nextRenderFrameTime += 1000 / LCR_SETTING_FPS;
+ 
+diff --git a/settings.h b/settings.h
+index 332df45..4c28e70 100644
+--- a/settings.h
++++ b/settings.h
+@@ -222,6 +222,12 @@
+   #define LCR_SETTING_TIME_MULTIPLIER 100
+ #endif
+ 
++#ifndef LCR_SETTING_MOTION_BLUR_FRAMES
++  #define LCR_SETTING_MOTION_BLUR_FRAMES 2
++  /** Length of the motion blur rendering cycle. The longer, the more pronounced
++  the effect. Should be kept a power of two else performance suffers greatly. */
++#endif
++
+ #ifndef LCR_SETTING_GHOST_STEP
+   /** Step (in physics engine ticks) by which the samples for ghost car will be
+   spaced (positions inbetween will be interpolated). Lower step along with more