more fixes to bg affine parameter handling. I am becoming increasingly dissatisfied with the way this is handled, but we need to collect more test cases. this actually reverts the changes from rev 2010 and fixes it a better way (by adding support for 16bit affine parameter startpoint writes)

desmume/src/GPU.cpp

@@ -2364,7 +2364,10 @@ void GPU::_spriteRender(u8 * dst, u8 * dst_alpha, u8 * typeTab, u8 * prioTab)
 					//NOT TESTED:
 
 					if (dispCnt->OBJ_BMP_2D_dim) // 256*256
+					{
+						//verified by heroes of mana FMV intro
 						src = (u8 *)MMU_RenderMapToLCD(gpu->sprMem + (((spriteInfo->TileIndex&0x3E0) * 64  + (spriteInfo->TileIndex&0x1F) *8 + ( y << 8)) << 1));
+					}
 					else // 128 * 512
 						src = (u8 *)MMU_RenderMapToLCD(gpu->sprMem + (((spriteInfo->TileIndex&0x3F0) * 64  + (spriteInfo->TileIndex&0x0F) *8 + ( y << 8)) << 1));
 				}
@@ -3042,6 +3045,20 @@ void GPU_ligne(NDS_Screen * screen, u16 l)
 	GPU * gpu = screen->gpu;
 	GPU_tempScanline_valid = false;
 
+	//here is some setup which is only done on line 0
+	if(l == 0) {
+		//this is speculative. the idea is as follows:
+		//whenever the user updates the affine start position regs, it goes into the active regs immediately
+		//(this is handled on the set event from MMU)
+		//maybe it shouldnt take effect until the next hblank or something..
+		//this is a based on a combination of:
+		//heroes of mana intro FMV
+		//SPP level 3-8 rotoscale room
+		//NSMB raster fx backdrops
+		//bubble bobble revolution classic mode
+		gpu->refreshAffineStartRegs();
+	}
+
 	//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);
@@ -3134,6 +3151,42 @@ bool gpu_loadstate(std::istream* is)
 	return !is->fail();
 }
 
+u32 GPU::getAffineStart(int layer, int xy)
+{
+	if(xy==0) return affineInfo[layer-2].x;
+	else return affineInfo[layer-2].y;
+}
+
+void GPU::setAffineStartWord(int layer, int xy, u16 val, int word)
+{
+	u32 curr = getAffineStart(layer,xy);
+	if(word==0) curr = (curr&0xFFFF0000)|val;
+	else curr = (curr&0x0000FFFF)|(((u32)val)<<16);
+	setAffineStart(layer,xy,curr);
+}
+
+void GPU::setAffineStart(int layer, int xy, u32 val)
+{
+	if(xy==0) affineInfo[layer-2].x = val;
+	else affineInfo[layer-2].y = val;
+	refreshAffineStartRegs();
+}
+
+void GPU::refreshAffineStartRegs()
+{
+	for(int num=2;num<=3;num++)
+	{
+		BGxPARMS * parms;
+		if (num==2)
+			parms = &(dispx_st)->dispx_BG2PARMS;
+		else
+			parms = &(dispx_st)->dispx_BG3PARMS;		
+
+		parms->BGxX = affineInfo[num-2].x;
+		parms->BGxY = affineInfo[num-2].y;
+	}
+}
+
 void gpu_UpdateRender()
 {
 	int x = 0, y = 0;

desmume/src/GPU.h

@@ -761,6 +761,15 @@ struct GPU
 
 
 	void __setFinalColorBck(u16 color, u8 x, bool opaque);
+	void setAffineStart(int layer, int xy, u32 val);
+	void setAffineStartWord(int layer, int xy, u16 val, int word);
+	u32 getAffineStart(int layer, int xy);
+	void refreshAffineStartRegs();
+
+	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

@@ -1556,6 +1556,23 @@ void FASTCALL _MMU_ARM9_write16(u32 adr, u16 val)
 		// Address is an IO register
 		switch(adr)
 		{
+		case REG_DISPA_BG2XL: MainScreen.gpu->setAffineStartWord(2,0,val,0); break;
+		case REG_DISPA_BG2XH: MainScreen.gpu->setAffineStartWord(2,0,val,1); break;
+		case REG_DISPA_BG2YL: MainScreen.gpu->setAffineStartWord(2,1,val,0); break;
+		case REG_DISPA_BG2YH: MainScreen.gpu->setAffineStartWord(2,1,val,1); break;
+		case REG_DISPA_BG3XL: MainScreen.gpu->setAffineStartWord(3,0,val,0); break;
+		case REG_DISPA_BG3XH: MainScreen.gpu->setAffineStartWord(3,0,val,1); break;
+		case REG_DISPA_BG3YL: MainScreen.gpu->setAffineStartWord(3,1,val,0); break;
+		case REG_DISPA_BG3YH: MainScreen.gpu->setAffineStartWord(3,1,val,1); break;
+		case REG_DISPB_BG2XL: SubScreen.gpu->setAffineStartWord(2,0,val,0); break;
+		case REG_DISPB_BG2XH: SubScreen.gpu->setAffineStartWord(2,0,val,1); break;
+		case REG_DISPB_BG2YL: SubScreen.gpu->setAffineStartWord(2,1,val,0); break;
+		case REG_DISPB_BG2YH: SubScreen.gpu->setAffineStartWord(2,1,val,1); break;
+		case REG_DISPB_BG3XL: SubScreen.gpu->setAffineStartWord(3,0,val,0); break;
+		case REG_DISPB_BG3XH: SubScreen.gpu->setAffineStartWord(3,0,val,1); break;
+		case REG_DISPB_BG3YL: SubScreen.gpu->setAffineStartWord(3,1,val,0); break;
+		case REG_DISPB_BG3YH: SubScreen.gpu->setAffineStartWord(3,1,val,1); break;
+
 			case REG_DISPA_DISP3DCNT:
 			{
 				MainScreen.gpu->dispx_st->dispA_DISP3DCNT.val = val;
@@ -2194,6 +2211,31 @@ void FASTCALL _MMU_ARM9_write32(u32 adr, u32 val)
 
 		switch(adr)
 		{
+			case REG_DISPA_BG2XL:
+				MainScreen.gpu->setAffineStart(2,0,val);
+				return;
+			case REG_DISPA_BG2YL:
+				MainScreen.gpu->setAffineStart(2,1,val);
+				return;
+			case REG_DISPB_BG2XL:
+				SubScreen.gpu->setAffineStart(2,0,val);
+				return;
+			case REG_DISPB_BG2YL:
+				SubScreen.gpu->setAffineStart(2,1,val);
+				return;
+			case REG_DISPA_BG3XL:
+				MainScreen.gpu->setAffineStart(3,0,val);
+				return;
+			case REG_DISPA_BG3YL:
+				MainScreen.gpu->setAffineStart(3,1,val);
+				return;
+			case REG_DISPB_BG3XL:
+				SubScreen.gpu->setAffineStart(3,0,val);
+				return;
+			case REG_DISPB_BG3YL:
+				SubScreen.gpu->setAffineStart(3,1,val);
+				return;
+
 			case 0x04000600:
 				GFX_FIFOcnt(val);
 				return;