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maroxe
Joined: 01 Sep 2009
Posts: 18
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 Posted: Sat Sep 05, 2009 3:13 am Post subject: Gu inistialisation |
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I see sometimes in pspgu initialisation this lines:
| Code: | void* fbp0 = getStaticVramBuffer(BUF_WIDTH,SCR_HEIGHT,GU_PSM_8888);
void* fbp1 = getStaticVramBuffer(BUF_WIDTH,SCR_HEIGHT,GU_PSM_8888);
void* zbp = getStaticVramBuffer(BUF_WIDTH,SCR_HEIGHT,GU_PSM_4444); |
what's their function? |
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jojojoris
Joined: 30 Mar 2008
Posts: 261
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| Posted: Sat Sep 05, 2009 6:24 pm Post subject: |
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They do exactly that they are named.
They allocate memory in the vram so the GU can use it as a buffer.
_________________
| Code: | int main(){
SetupCallbacks();
makeNiceGame();
sceKernelExitGame();
} |
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maroxe
Joined: 01 Sep 2009
Posts: 18
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| Posted: Sun Sep 06, 2009 1:13 am Post subject: |
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| if those functions are not called, gu will use the RAM? |
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jojojoris
Joined: 30 Mar 2008
Posts: 261
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| Posted: Sun Sep 06, 2009 3:12 am Post subject: |
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When you watch the sources of those functions:
samples/gu/common/vram.c
you will see what they does.
| Code: | static unsigned int staticOffset = 0;
static unsigned int getMemorySize(unsigned int width, unsigned int height, unsigned int psm)
{
switch (psm)
{
case GU_PSM_T4:
return (width * height) >> 1;
case GU_PSM_T8:
return width * height;
case GU_PSM_5650:
case GU_PSM_5551:
case GU_PSM_4444:
case GU_PSM_T16:
return 2 * width * height;
case GU_PSM_8888:
case GU_PSM_T32:
return 4 * width * height;
default:
return 0;
}
}
void* getStaticVramBuffer(unsigned int width, unsigned int height, unsigned int psm)
{
unsigned int memSize = getMemorySize(width,height,psm);
void* result = (void*)staticOffset;
staticOffset += memSize;
return result;
} |
As you can see it just keeps track of the used memory in the vram.
If you don't use those functions you will also use vram because the pointers are relative to the vram base.
_________________
| Code: | int main(){
SetupCallbacks();
makeNiceGame();
sceKernelExitGame();
} |
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