From 9b5bda237a75d6d82fafe5a8406811bd6b017b9d Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Fri, 3 Mar 2017 18:37:48 -0800
Subject: [PATCH] DS GX: Add color modulation

---
 include/mgba/internal/ds/gx.h          | 10 ++++++++++
 include/mgba/internal/ds/gx/software.h |  1 +
 src/ds/gx/software.c                   | 14 +++++++++++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/include/mgba/internal/ds/gx.h b/include/mgba/internal/ds/gx.h
index 97c55b594..03957be60 100644
--- a/include/mgba/internal/ds/gx.h
+++ b/include/mgba/internal/ds/gx.h
@@ -47,6 +47,16 @@ DECL_BITS(DSGXTexParams, Format, 26, 3);
 DECL_BIT(DSGXTexParams, 0Transparent, 29);
 DECL_BITS(DSGXTexParams, CoordTfMode, 30, 2);
 
+DECL_BITFIELD(DSGXPolygonAttrs, uint32_t);
+DECL_BIT(DSGXPolygonAttrs, Light0, 0);
+DECL_BIT(DSGXPolygonAttrs, Light1, 1);
+DECL_BIT(DSGXPolygonAttrs, Light2, 2);
+DECL_BIT(DSGXPolygonAttrs, Light3, 3);
+DECL_BITS(DSGXPolygonAttrs, Mode, 4, 2);
+DECL_BIT(DSGXPolygonAttrs, FrontFace, 6);
+DECL_BIT(DSGXPolygonAttrs, BackFace, 7);
+// TODO
+
 enum DSGXCommand {
 	DS_GX_CMD_NOP = 0,
 	DS_GX_CMD_MTX_MODE = 0x10,
diff --git a/include/mgba/internal/ds/gx/software.h b/include/mgba/internal/ds/gx/software.h
index 3cbfd014e..928910ae0 100644
--- a/include/mgba/internal/ds/gx/software.h
+++ b/include/mgba/internal/ds/gx/software.h
@@ -20,6 +20,7 @@ struct DSGXSoftwarePolygon {
 	uint16_t* texBase;
 	uint16_t* palBase;
 	int texFormat;
+	int blendFormat;
 	int texW;
 	int texH;
 };
diff --git a/src/ds/gx/software.c b/src/ds/gx/software.c
index 0887f087b..634e9ca79 100644
--- a/src/ds/gx/software.c
+++ b/src/ds/gx/software.c
@@ -109,9 +109,20 @@ static color_t _lookupColor(struct DSGXSoftwareEndpoint* ep, struct DSGXSoftware
 		return FLAG_UNWRITTEN;
 	}
 	uint8_t r, g, b;
+	unsigned wr, wg, wb;
 	texel = poly->palBase[texel];
 	_expandColor(texel, &r, &g, &b);
-	return _finishColor(r, g, b);
+	switch (poly->blendFormat) {
+	case 1:
+	default:
+		// TODO: Alpha
+		return _finishColor(r, g, b);
+	case 0:
+		wr = ((r + 1) * (ep->cr + 1) - 1) >> 6;
+		wg = ((g + 1) * (ep->cg + 1) - 1) >> 6;
+		wb = ((b + 1) * (ep->cb + 1) - 1) >> 6;
+		return _finishColor(wr, wg, wb);
+	}
 }
 
 static int _edgeSort(const void* a, const void* b) {
@@ -285,6 +296,7 @@ static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSG
 		struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
 		poly->poly = &polys[i];
 		poly->texFormat = DSGXTexParamsGetFormat(poly->poly->texParams);
+		poly->blendFormat = DSGXPolygonAttrsGetMode(poly->poly->polyParams);
 		poly->texW = 8 << DSGXTexParamsGetSSize(poly->poly->texParams);
 		poly->texH = 8 << DSGXTexParamsGetTSize(poly->poly->texParams);
 		switch (poly->texFormat) {