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Implement BLDALPHA

This commit is contained in:
Jeffrey Pfau 2013-04-24 01:16:03 -07:00
parent 40b00e7927
commit 1c0af22990
2 changed files with 48 additions and 2 deletions
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47
src/gba/renderers/video-software.c
View File

@ -22,6 +22,7 @@ static void _drawBackgroundMode0(struct GBAVideoSoftwareRenderer* renderer, stru
static void _updatePalettes(struct GBAVideoSoftwareRenderer* renderer);
static inline uint16_t _brighten(uint16_t color, int y);
static inline uint16_t _darken(uint16_t color, int y);
static uint16_t _mix(int weightA, uint16_t colorA, int weightB, uint16_t colorB);
static void _sortBackgrounds(struct GBAVideoSoftwareRenderer* renderer);
static int _backgroundComparator(const void* a, const void* b);
@ -62,6 +63,8 @@ static void GBAVideoSoftwareRendererInit(struct GBAVideoRenderer* renderer) {
softwareRenderer->blendEffect = BLEND_NONE;
memset(softwareRenderer->variantPalette, 0, sizeof(softwareRenderer->variantPalette));
softwareRenderer->blda = 0;
softwareRenderer->bldb = 0;
softwareRenderer->bldy = 0;
for (i = 0; i < 4; ++i) {
@ -159,6 +162,16 @@ static uint16_t GBAVideoSoftwareRendererWriteVideoRegister(struct GBAVideoRender
case REG_BLDCNT:
GBAVideoSoftwareRendererWriteBLDCNT(softwareRenderer, value);
break;
case REG_BLDALPHA:
softwareRenderer->blda = value & 0x1F;
if (softwareRenderer->blda > 0x10) {
softwareRenderer->blda = 0x10;
}
softwareRenderer->bldb = (value >> 8) & 0x1F;
if (softwareRenderer->bldb > 0x10) {
softwareRenderer->bldb = 0x10;
}
break;
case REG_BLDY:
softwareRenderer->bldy = value & 0x1F;
if (softwareRenderer->bldy > 0x10) {
@ -266,12 +279,26 @@ static void GBAVideoSoftwareRendererWriteBLDCNT(struct GBAVideoSoftwareRenderer*
}
static void _composite(struct GBAVideoSoftwareRenderer* renderer, int offset, int entry, struct PixelFlags flags) {
if (renderer->blendEffect == BLEND_NONE || !flags.target1) {
if (renderer->blendEffect == BLEND_NONE || (!flags.target1 && !flags.target2)) {
renderer->row[offset] = renderer->d.palette[entry];
renderer->flags[offset].finalized = 1;
} else if (renderer->blendEffect == BLEND_BRIGHTEN || renderer->blendEffect == BLEND_DARKEN) {
renderer->row[offset] = renderer->variantPalette[entry];
renderer->flags[offset].finalized = 1;
} else if (renderer->blendEffect == BLEND_ALPHA) {
if (renderer->flags[offset].written) {
if (renderer->flags[offset].target1 && flags.target2) {
renderer->row[offset] = _mix(renderer->bldb, renderer->d.palette[entry], renderer->blda, renderer->row[offset]);
renderer->flags[offset].finalized = 1;
} else {
renderer->flags[offset].finalized = 1;
}
} else {
renderer->row[offset] = renderer->d.palette[entry];
renderer->flags[offset].target1 = flags.target1;
}
}
renderer->flags[offset].finalized = 1;
renderer->flags[offset].written = 1;
}
static void _drawBackgroundMode0(struct GBAVideoSoftwareRenderer* renderer, struct GBAVideoSoftwareBackground* background, int y) {
@ -345,6 +372,22 @@ static inline uint16_t _darken(uint16_t c, int y) {
return color.packed;
}
static uint16_t _mix(int weightA, uint16_t colorA, int weightB, uint16_t colorB) {
union GBAColor ca = { .packed = colorA };
union GBAColor cb = { .packed = colorB };
int r = (ca.r * weightA + cb.r * weightB) / 16;
ca.r = r > 0x1F ? 0x1F : r;
int g = (ca.g * weightA + cb.g * weightB) / 16;
ca.g = g > 0x1F ? 0x1F : g;
int b = (ca.b * weightA + cb.b * weightB) / 16;
ca.b = b > 0x1F ? 0x1F : b;
return ca.packed;
}
static void _sortBackgrounds(struct GBAVideoSoftwareRenderer* renderer) {
qsort(renderer->sortedBg, 4, sizeof(struct GBAVideoSoftwareBackground*), _backgroundComparator);
}

3
src/gba/renderers/video-software.h
View File

@ -37,6 +37,7 @@ enum BlendEffect {
};
struct PixelFlags {
unsigned written : 1;
unsigned finalized : 1;
unsigned target1 : 1;
unsigned target2 : 1;
@ -60,6 +61,8 @@ struct GBAVideoSoftwareRenderer {
enum BlendEffect blendEffect;
uint16_t variantPalette[512];
uint16_t blda;
uint16_t bldb;
uint16_t bldy;
struct GBAVideoSoftwareBackground bg[4];