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added speedchecks to alphablending, added comments to explain its steps, replaced another set of bitmasks against defines

This commit is contained in:
mightymax 2007-01-07 21:49:28 +00:00
parent eafe6526c6
commit b86c3f4ee6
2 changed files with 26 additions and 24 deletions
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39
desmume/src/GPU.c
View File

@ -558,19 +558,26 @@ INLINE void renderline_setFinalColor(GPU *gpu,u32 passing,u8 bgnum,u8 *dst,u16 c
case 0x40: /* alpha blending */
{
#define min(a,b) (((a)<(b))?(a):(b))
if (!(color & 0x8000)) return ; /* we cant do alpha on an invisible pixel */
u16 sourceFraction = (gpu->BLDALPHA & 0x1F) ;
u16 targetFraction = (gpu->BLDALPHA & 0x1F00) >> 8 ;
u16 sourceR = ((color & 0x1F) * sourceFraction) >> 4 ;
if (!sourceFraction) return ; /* no fraction of this BG to be showed, so don't do anything */
u16 sourceR = ((color & 0x1F) * sourceFraction) >> 4 ; /* weighted component from color to draw */
u16 sourceG = (((color>>5) & 0x1F) * sourceFraction) >> 4 ;
u16 sourceB = (((color>>10) & 0x1F) * sourceFraction) >> 4 ;
u16 targetFraction = (gpu->BLDALPHA & 0x1F00) >> 8 ;
if (targetFraction) { /* when we dont take any fraction from existing pixel, we can just draw */
color = T2ReadWord(dst, passing) ;
u16 targetR = ((color & 0x1F) * targetFraction) >> 4 ;
if (color & 0x8000) { /* the existing pixel is not invisible */
u16 targetR = ((color & 0x1F) * targetFraction) >> 4 ; /* weighted component from color we draw on */
u16 targetG = (((color>>5) & 0x1F) * targetFraction) >> 4 ;
u16 targetB = (((color>>10) & 0x1F) * targetFraction) >> 4 ;
targetR = min(0x1F,targetR+sourceR) ;
targetG = min(0x1F,targetG+sourceG) ;
targetB = min(0x1F,targetB+sourceB) ;
color = (targetR & 0x1F) | ((targetG & 0x1F) << 5) | ((targetB & 0x1F) << 10) | 0x8000 ;
sourceR = min(0x1F,targetR+sourceR) ; /* limit combined components to 31 max */
sourceG = min(0x1F,targetG+sourceG) ;
sourceB = min(0x1F,targetB+sourceB) ;
}
}
color = (sourceR & 0x1F) | ((sourceG & 0x1F) << 5) | ((sourceB & 0x1F) << 10) | 0x8000 ;
#undef min
}
T2WriteWord(dst, passing, color) ;
break ;
@ -628,24 +635,16 @@ INLINE void renderline_textBG(GPU * gpu, u8 num, u8 * DST, u16 X, u16 Y, u16 LG)
if(tmp>31)
{
switch(bgprop >> 14)
{
case 2 :
map += 32 * 32 * 2;
break;
case 3 :
map += 32 * 64 * 2;
break;
}
map+= ADDRESS_STEP_512B << BGCNT_SCREENSIZE(bgprop) ;
}
tile = (u8*) gpu->BG_tile_ram[num];
if((!tile) || (!gpu->BG_map_ram[num])) return; /* no tiles or no map*/
xoff = X;
if(!(bgprop & 0x80)) /* color: 16 palette entries */
if(!BGCNT_256COL(bgprop)) /* color: 16 palette entries */
{
yoff = ((Y&7)<<2);
pal = ARM9Mem.ARM9_VMEM + gpu->core * 0x400;
pal = ARM9Mem.ARM9_VMEM + gpu->core * ADDRESS_STEP_1KB ;
for(x = 0; x < LG;)
{
u8 * mapinfo;
@ -687,10 +686,10 @@ INLINE void renderline_textBG(GPU * gpu, u8 num, u8 * DST, u16 X, u16 Y, u16 LG)
}
return;
}
if(!(gpu->prop & 0x40000000)) /* color: no extended palette */
if(!DISPCNT_USEEXTPAL(gpu->prop)) /* color: no extended palette */
{
yoff = ((Y&7)<<3);
pal = ARM9Mem.ARM9_VMEM + gpu->core * 0x400;
pal = ARM9Mem.ARM9_VMEM + gpu->core * ADDRESS_STEP_1KB ;
for(x = 0; x < LG;)
{
u8 * mapinfo;

3
desmume/src/GPU.h
View File

@ -37,6 +37,7 @@ extern "C" {
#define GPU_SUB 1
/* human readable bitmask names */
#define ADDRESS_STEP_512B 0x00200
#define ADDRESS_STEP_1KB 0x00400
#define ADDRESS_STEP_2KB 0x00800
#define ADDRESS_STEP_4KB 0x01000
@ -58,9 +59,11 @@ extern "C" {
#define DISPCNT_TILEOBJ1D_BOUNDARY(val) (((val) >> 20) & 3)
#define DISPCNT_BMPOBJ1D_BOUNDARY(val) (((val) >> 22) & 1)
#define DISPCNT_SCREENBASEBLOCK(val) (((val) >> 27) & 7)
#define DISPCNT_USEEXTPAL(val) (((val) >> 30) & 1)
#define BGCNT_PRIORITY(val) ((val) & 3)
#define BGCNT_CHARBASEBLOCK(val) (((val) >> 2) & 0x0F)
#define BGCNT_256COL(val) (((val) >> 7) & 0x1)
#define BGCNT_SCREENBASEBLOCK(val) (((val) >> 8) & 0x1F)
#define BGCNT_EXTPALSLOT(val) (((val) >> 13) & 0x1)
#define BGCNT_SCREENSIZE(val) (((val) >> 14) & 0x3)