From 61ef3501c115bbaaced8f9c78685243ed4f31881 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Fri, 3 Mar 2017 19:08:27 -0800
Subject: [PATCH] DS Video: Minor extended background fixes

---
 include/mgba/internal/ds/video.h |  2 ++
 src/ds/renderers/software.c      | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/mgba/internal/ds/video.h b/include/mgba/internal/ds/video.h
index e7c7afdae..14aa68dd6 100644
--- a/include/mgba/internal/ds/video.h
+++ b/include/mgba/internal/ds/video.h
@@ -64,6 +64,8 @@ DECL_BITFIELD(DSRegisterPOWCNT1, uint16_t);
 // TODO
 DECL_BIT(DSRegisterPOWCNT1, Swap, 15);
 
+DECL_BIT(GBARegisterBGCNT, ExtendedMode0, 2);
+DECL_BIT(GBARegisterBGCNT, ExtendedMode1, 7);
 DECL_BIT(GBARegisterBGCNT, ExtPaletteSlot, 13);
 
 DECL_BITFIELD(DSRegisterMASTER_BRIGHT, uint16_t);
diff --git a/src/ds/renderers/software.c b/src/ds/renderers/software.c
index 17ea5a082..78e08722c 100644
--- a/src/ds/renderers/software.c
+++ b/src/ds/renderers/software.c
@@ -414,7 +414,11 @@ static void DSVideoSoftwareRendererDrawGBAScanline(struct GBAVideoRenderer* rend
 					GBAVideoSoftwareRendererDrawBackgroundMode2(softwareRenderer, &softwareRenderer->bg[2], y);
 					break;
 				case 5:
-					DSVideoSoftwareRendererDrawBackgroundExt0(softwareRenderer, &softwareRenderer->bg[2], y);
+					if (!GBARegisterBGCNTIsExtendedMode1(softwareRenderer->bg[2].control)) {
+						DSVideoSoftwareRendererDrawBackgroundExt0(softwareRenderer, &softwareRenderer->bg[2], y);
+					} else {
+						// TODO
+					}
 					break;
 				}
 			}
@@ -430,7 +434,11 @@ static void DSVideoSoftwareRendererDrawGBAScanline(struct GBAVideoRenderer* rend
 				case 3:
 				case 4:
 				case 5:
-					DSVideoSoftwareRendererDrawBackgroundExt0(softwareRenderer, &softwareRenderer->bg[3], y);
+					if (!GBARegisterBGCNTIsExtendedMode1(softwareRenderer->bg[3].control)) {
+						DSVideoSoftwareRendererDrawBackgroundExt0(softwareRenderer, &softwareRenderer->bg[3], y);
+					} else {
+						// TODO
+					}
 					break;
 				}
 			}
@@ -659,7 +667,10 @@ void DSVideoSoftwareRendererDrawBackgroundExt0(struct GBAVideoSoftwareRenderer*
 
 	color_t* mainPalette = background->extPalette;
 	if (variant) {
-		palette = background->variantPalette;
+		mainPalette = background->variantPalette;
+	}
+	if (!mainPalette) {
+		return;
 	}
 	int paletteData;