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Implement BgAffineSet

This commit is contained in:
Jeffrey Pfau 2013-05-04 01:20:42 -07:00
parent fb2ddd6c32
commit ac0c7ba792
1 changed files with 48 additions and 0 deletions
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48
src/gba/gba-bios.c
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@ -78,6 +78,51 @@ static void _FastCpuSet(struct GBA* gba) {
}
}
static void _BgAffineSet(struct GBA* gba) {
int i = gba->cpu.gprs[2];
float ox, oy;
float cx, cy;
float sx, sy;
float theta;
int offset = gba->cpu.gprs[0];
int destination = gba->cpu.gprs[1];
int diff = gba->cpu.gprs[3];
(void)(diff); // Are we supposed to use this?
float a, b, c, d;
float rx, ry;
while (i--) {
// [ sx 0 0 ] [ cos(theta) -sin(theta) 0 ] [ 1 0 cx - ox ] [ A B rx ]
// [ 0 sy 0 ] * [ sin(theta) cos(theta) 0 ] * [ 0 1 cy - oy ] = [ C D ry ]
// [ 0 0 1 ] [ 0 0 1 ] [ 0 0 1 ] [ 0 0 1 ]
ox = GBALoad32(&gba->memory.d, offset) / 256.f;
oy = GBALoad32(&gba->memory.d, offset + 4) / 256.f;
cx = GBALoad16(&gba->memory.d, offset + 8);
cy = GBALoad16(&gba->memory.d, offset + 10);
sx = GBALoad16(&gba->memory.d, offset + 12) / 256.f;
sy = GBALoad16(&gba->memory.d, offset + 14) / 256.f;
theta = (GBALoadU16(&gba->memory.d, offset + 16) >> 8) / 128.f * M_PI;
offset += 20;
// Rotation
a = d = cosf(theta);
b = c = sinf(theta);
// Scale
a *= sx;
b *= -sx;
c *= sy;
d *= sy;
// Translate
rx = ox - (a * cx + b * cy);
ry = oy - (c * cx + d * cy);
GBAStore16(&gba->memory.d, destination, a * 256);
GBAStore16(&gba->memory.d, destination + 2, b * 256);
GBAStore16(&gba->memory.d, destination + 4, c * 256);
GBAStore16(&gba->memory.d, destination + 6, d * 256);
GBAStore32(&gba->memory.d, destination + 8, rx * 256);
GBAStore32(&gba->memory.d, destination + 12, ry * 256);
destination += 16;
}
}
static void _ObjAffineSet(struct GBA* gba) {
int i = gba->cpu.gprs[2];
float sx, sy;
@ -162,6 +207,9 @@ void GBASwi16(struct ARMBoard* board, int immediate) {
case 0xC:
_FastCpuSet(gba);
break;
case 0xE:
_BgAffineSet(gba);
break;
case 0xF:
_ObjAffineSet(gba);
break;