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GU_TEXTURE_8BIT not working?

 
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av



Joined: 01 Jan 2006
Posts: 7
PostPosted: Tue Jan 03, 2006 10:02 am    Post subject: GU_TEXTURE_8BIT not working? Reply with quote
Hi,

I can't get 8-bit texture coordinates to work at all. When I call:

Code:
sceGuDrawArray (pspPrimType, (GU_TEXTURE_8BIT | GU_COLOR_8888 | GU_VERTEX_16BIT | GU_TRANSFORM_3D), ...)


the results look like the vertex stride in hardware is wrong (vertices everywhere at runtime). I was using 16-bit texture coords (this works perfectly) which resulted in my vertex structure being:

Code:
int16 u, v;
uint32 color;
int16 x, y, z, pad;


I'm trying to get my vertex structure to be 32-bits smaller:

Code:
int8 u, v; //Requires GU_TEXTURE_8BIT
uint32 color;
int16 x, y, z; //No more padding!


But the hardware doesn't seem to like this. I'm hoping it's a problem with the SDK and not a hardware limitation. Does anyone have any idea why this format wouldn't work?

Thanks!
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chp



Joined: 23 Jun 2004
Posts: 313
PostPosted: Tue Jan 03, 2006 10:10 am    Post subject: Reply with quote
I can't verify everything right now, but if you declare two 8-bit values followed by a 32-bit value, you'll could probably end up with 16 bits of padding between 'v' and 'color'. What happens if you drop color from a 32-bit value to 16-bit?
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av



Joined: 01 Jan 2006
Posts: 7
PostPosted: Tue Jan 03, 2006 10:15 am    Post subject: Reply with quote
chp wrote:
What happens if you drop color from a 32-bit value to 16-bit?

Same thing. I tried changing the color to 4444 (and added a 16-bit pad to the end of the position) but had the same result. I also tried setting all values to 0 for every vertex except for the xyz position...same results, vertices everywhere.

That's why I think it's an internal stride calculation issue. When I set everything to 0 except for the xyz position and the vertices still end up everywhere, that screams bad stride to me.

Thanks.
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