correction to the new affine bg handling: parameters must be reset to the last user-specified value before scanline 0.

desmume/src/GPU.cpp

@@ -1704,8 +1704,8 @@ FORCEINLINE void rot_scale_op(GPU * gpu, u8 * dst, u16 H, s32 X, s32 Y, s16 PA,
 	u32 i;
 	s32 auxX, auxY;
 	
-	x.val = X + (s32)H;
+	x.val = X;
-	y.val = Y + (s32)H;
+	y.val = Y;
 
 	for(i = 0; i < LG; ++i)
 	{
@@ -3232,6 +3232,21 @@ void GPU_ligne(NDS_Screen * screen, u16 l)
 {
 	GPU * gpu = screen->gpu;
 
+	//here is some setup which is only done on line 0
+	if(l == 0) {
+		for(int num=2;num<=3;num++)
+		{
+			BGxPARMS * parms;
+			if (num==2)
+				parms = &(gpu->dispx_st)->dispx_BG2PARMS;
+			else
+				parms = &(gpu->dispx_st)->dispx_BG3PARMS;		
+
+			parms->BGxX = gpu->affineInfo[num-2].x;
+			parms->BGxY = gpu->affineInfo[num-2].y;
+		}
+	}
+
 	//cache some parameters which are assumed to be stable throughout the rendering of the entire line
 	gpu->currLine = (u8)l;
 	u16 mosaic_control = T1ReadWord((u8 *)&gpu->dispx_st->dispx_MISC.MOSAIC, 0);
@@ -3310,7 +3325,11 @@ bool gpu_loadstate(std::istream* is)
 	return !is->fail();
 }
 
-
+void GPU::setAffineStart(int layer, int xy, u32 val)
+{
+	if(xy==0) affineInfo[layer-2].x = val;
+	else affineInfo[layer-2].y = val;
+}
 
 //here is an old bg mosaic with some old code commented out. I am going to leave it here for a while to look at it
 //sometimes in case I find a problem with the mosaic.

desmume/src/GPU.h

@@ -722,7 +722,12 @@ struct GPU
 	SpriteRenderFunct spriteRender;
 
 	void __setFinalColorBck(u8 *dst, u16 color, u8 x, bool opaque);
+	void setAffineStart(int layer, int xy, u32 val);
 
+	struct AffineInfo {
+		AffineInfo() : x(0), y(0) {}
+		u32 x, y;
+	} affineInfo[2];
 
 	void renderline_checkWindows(u16 x, bool &draw, bool &effect) const;
 

desmume/src/MMU.cpp

@@ -2432,6 +2432,31 @@ static void FASTCALL _MMU_ARM9_write32(u32 adr, u32 val)
 
 		switch(adr)
 		{
+			case REG_DISPA_BG2XL:
+				MainScreen.gpu->setAffineStart(2,0,val);
+				break;
+			case REG_DISPA_BG2YL:
+				MainScreen.gpu->setAffineStart(2,1,val);
+				break;
+			case REG_DISPB_BG2XL:
+				SubScreen.gpu->setAffineStart(2,0,val);
+				break;
+			case REG_DISPB_BG2YL:
+				SubScreen.gpu->setAffineStart(2,1,val);
+				break;
+			case REG_DISPA_BG3XL:
+				MainScreen.gpu->setAffineStart(3,0,val);
+				break;
+			case REG_DISPA_BG3YL:
+				MainScreen.gpu->setAffineStart(3,1,val);
+				break;
+			case REG_DISPB_BG3XL:
+				SubScreen.gpu->setAffineStart(3,0,val);
+				break;
+			case REG_DISPB_BG3YL:
+				SubScreen.gpu->setAffineStart(3,1,val);
+				break;
+
 			case 0x04000600:
 				GFX_FIFOcnt(val);
 				return;