From 8f58343e2b3ff091f51254983c54e581581b118e Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Thu, 23 Mar 2017 21:23:47 -0700
Subject: [PATCH] DS GX: Move rendering until first scanline is requested

---
 include/mgba/internal/ds/gx/software.h |  1 +
 src/ds/gx/software.c                   | 18 +++++++++++-------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/mgba/internal/ds/gx/software.h b/include/mgba/internal/ds/gx/software.h
index b11e41f46..7abbf64c0 100644
--- a/include/mgba/internal/ds/gx/software.h
+++ b/include/mgba/internal/ds/gx/software.h
@@ -93,6 +93,7 @@ struct DSGXSoftwareRenderer {
 	uint8_t* stencilBuffer;
 	color_t* scanlineCache;
 	int sort;
+	bool flushPending;
 
 	struct DSGXVertex* verts;
 };
diff --git a/src/ds/gx/software.c b/src/ds/gx/software.c
index f258f4693..2e8aa5636 100644
--- a/src/ds/gx/software.c
+++ b/src/ds/gx/software.c
@@ -697,18 +697,27 @@ static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSG
 		softwareRenderer->depthBuffer[i + 2] = INT32_MAX;
 		softwareRenderer->depthBuffer[i + 3] = INT32_MAX;
 	}
+	softwareRenderer->flushPending = true;
+}
+
+static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y) {
+	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
+	if (!softwareRenderer->flushPending || y) {
+		return;
+	}
 
 	size_t p;
 	for (p = 0; p < DSGXSoftwarePolygonListSize(&softwareRenderer->activePolys); ++p) {
 		struct DSGXSoftwarePolygon* poly = DSGXSoftwarePolygonListGetPointer(&softwareRenderer->activePolys, p);
 		DSGXSoftwareEdgeListClear(&softwareRenderer->activeEdges);
-		_preparePoly(renderer, verts, poly);
+		_preparePoly(renderer, softwareRenderer->verts, poly);
 		int y;
 		for (y = poly->minY; y <= poly->maxY; ++y) {
 			struct DSGXSoftwareSpan span = {
 				.poly = poly,
 				.polyId = DSGXPolygonAttrsGetId(poly->polyParams),
 			};
+			size_t i;
 			for (i = 0; i < DSGXSoftwareEdgeListSize(&softwareRenderer->activeEdges); ++i) {
 				struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListGetPointer(&softwareRenderer->activeEdges, i);
 				if (edge->y1 < (y << 12)) {
@@ -729,12 +738,7 @@ static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSG
 			}
 		}
 	}
-}
-
-static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y) {
-	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
-	UNUSED(softwareRenderer);
-	UNUSED(y);
+	softwareRenderer->flushPending = false;
 }
 
 static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, const color_t** output) {