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GORETHRASHER
Joined: 10 Sep 2008
Posts: 12
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 Posted: Thu Sep 18, 2008 3:31 am Post subject: Trouble understanding sceGuTexImage() |
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| Code: | void sceGuTexImage ( int mipmap,
int width,
int height,
int tbw,
const void * tbp
)
Set current texturemap.
Textures may reside in main RAM, but it has a huge speed-penalty. Swizzle textures to get maximum speed.
Note:
Data must be aligned to 1 quad word (16 bytes)
Parameters:
mipmap - Mipmap level
width - Width of texture (must be a power of 2)
height - Height of texture (must be a power of 2)
tbw - Texture Buffer Width (block-aligned)
tbp - Texture buffer pointer (16 byte aligned) |
What does it mean by 16 byte aligned, and block aligned?
How should the pixel data look like in my array? Currently I am reading a bitmap to an unsigned char array
| Code: | int j = 0;
for (i=0; i < (int)width * (int)height; i++)
{
fread(&rgb, sizeof(rgb), 1, l_file);
l_texture[j+0] = rgb.rgbtRed; // Red component
l_texture[j+1] = rgb.rgbtGreen; // Green component
l_texture[j+2] = rgb.rgbtBlue; // Blue component
j += 3; // Go to the next position
} |
Which sceGuTexMode and sceGuTexImage calls do I need to get it rendering properly? |
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Pirata Nervo
Joined: 09 Oct 2007
Posts: 409
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Raphael
Joined: 17 Jan 2006
Posts: 646
Location: Germany
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| Posted: Thu Sep 18, 2008 6:22 am Post subject: |
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Also take a look at the supported texture pixel formats. There is no RGB888 24bit format.
_________________
<Don't push the river, it flows.>
http://wordpress.fx-world.org - my devblog
http://wiki.fx-world.org - VFPU documentation wiki
Alexander Berl |
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GORETHRASHER
Joined: 10 Sep 2008
Posts: 12
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| Posted: Thu Sep 18, 2008 11:44 am Post subject: |
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I decided upon Using GU_PSM_4444 - Hicolor, 16-bit for the internal pixel format
So here is what I have got so far, does it make sense?
| Code: |
int size = width * height * 2; //Using GU_PSM_4444
l_texture = (BYTE *) malloc(size); //Assign memory
memset(l_texture, 0, size); //Clear the memory
//... check memory ...
char a,b;
for (i=0; i < width * height; i++)
{
fread(&rgb, sizeof(rgb), 1, l_file);
//We have to convert a 24bit 888 image to a 16bit 4444(RGBA) image
a = (rgb.rgbtRed/255.0f) * 0xF; //divide the value by 255 then multiply by 15
a = a << 4; //Shift left by 4 bits to make room for next value
b = (rgb.rgbtGreen/255.0f) * 0xF; //do this again to get 4 bit number for green
a = a | b; //OR the two numbers together
l_texture[j+0] = a; // Red and Green component
a = (rgb.rgbtBlue/255.0f) * 0xF; //Same goes for this pair of values
a = a << 4; //each value will take up 4 bits or half a byte
a = a | 0xF; //Set alpha to 0xF
l_texture[j+1] = a; // Green and Alpha component
j += 2; // Go to the next position
} |
Later on I try to use it
| Code: | sceGuTexMode(GU_PSM_4444,0,0,0);
sceGuTexImage(0,image_size,image_size,buffer_width,texture); |
image_size is 128 and same for buffer_width, texture points to the texture above.
It seems to render one frame then crash, I see no texture either, any ideas? |
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Raphael
Joined: 17 Jan 2006
Posts: 646
Location: Germany
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| Posted: Thu Sep 18, 2008 10:52 pm Post subject: |
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The crash must be caused by some other error in your program, but the texture not showing has to do with the CPU cache:
http://www.goop.org/psp/cache-howto.html
You need to writeback the cache after the conversion to make sure the data is in RAM, so the GPU reads the proper values.
_________________
<Don't push the river, it flows.>
http://wordpress.fx-world.org - my devblog
http://wiki.fx-world.org - VFPU documentation wiki
Alexander Berl |
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