From d5291eb1b65c29b629c8d10d65d6cdf2d4449e48 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Fri, 25 Oct 2013 00:27:42 -0700
Subject: [PATCH] Remove unnecessary sprite post-processing passes

---
 src/gba/renderers/video-software.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/gba/renderers/video-software.c b/src/gba/renderers/video-software.c
index 4ccef5a73..c4bae85ae 100644
--- a/src/gba/renderers/video-software.c
+++ b/src/gba/renderers/video-software.c
@@ -531,6 +531,7 @@ static void GBAVideoSoftwareRendererWriteBLDCNT(struct GBAVideoSoftwareRenderer*
 static void _drawScanline(struct GBAVideoSoftwareRenderer* renderer, int y) {
 	int w;
 	renderer->end = 0;
+	int spriteLayers = 0;
 	if (renderer->dispcnt.objEnable) {
 		for (w = 0; w < renderer->nWindows; ++w) {
 			renderer->start = renderer->end;
@@ -543,8 +544,10 @@ static void _drawScanline(struct GBAVideoSoftwareRenderer* renderer, int y) {
 			for (i = 0; i < 128; ++i) {
 				struct GBAObj* sprite = &renderer->d.oam->obj[i];
 				if (sprite->transformed) {
+					spriteLayers |= 1 << sprite->priority;
 					_preprocessTransformedSprite(renderer, &renderer->d.oam->tobj[i], y);
 				} else if (!sprite->disable) {
+					spriteLayers |= 1 << sprite->priority;
 					_preprocessSprite(renderer, sprite, y);
 				}
 			}
@@ -553,7 +556,9 @@ static void _drawScanline(struct GBAVideoSoftwareRenderer* renderer, int y) {
 
 	int priority;
 	for (priority = 0; priority < 4; ++priority) {
-		_postprocessSprite(renderer, priority);
+		if (spriteLayers & (1 << priority)) {
+			_postprocessSprite(renderer, priority);
+		}
 		renderer->end = 0;
 		for (w = 0; w < renderer->nWindows; ++w) {
 			renderer->start = renderer->end;