RGBA pixel data into D3DLOCKED_RECT - c++

Question

I'm trying to update a 128x128 D3DLOCKED_RECT with sub images using the following code, but it seems to squish them down along the top, the X offset is ignored and the y offset is 60 percent off.
I've also tried to make the texture the correct size and copy it into a 128x128 texture at the correct location using RECT, however this is very slow and didn't seem to work correctly when I attempted it. There must be way to do it using the raw pixel data?
Any help would be much appreciated :)
EDIT: I got it semi working using the below code, the locations are now correct and the sizes. But it's only using the blue channel and everything is grey scale (blue scale?)
srcdata = (byte *) pixels;
dstdata = (unsigned int *)lockrect.pBits;
for (y = yoffset; y < (yoffset + height); y++)
{
for (x = xoffset; x < (xoffset + width); x++)
{
dstdata[ ( y * lockrect.Pitch / dstbytes + x ) + 0] = (unsigned int)srcdata[0];
dstdata[ ( y * lockrect.Pitch / dstbytes + x ) + 1] = (unsigned int)srcdata[1];
dstdata[ ( y * lockrect.Pitch / dstbytes + x ) + 2] = (unsigned int)srcdata[0];
dstdata[ ( y * lockrect.Pitch / dstbytes + x ) + 3] = (unsigned int)srcdata[3];
srcdata += srcbytes;
}
}'
END Edit
Test call after creating the 128x128 texture:
int x, y;
byte temp[132*132*4];
// Test texture (pink and black checker)
for( y = 0; y < 16; y++ )
{
for( x = 0; x < 16; x++ )
{
if(( y < 8 ) ^ ( x < 8 ))
((uint *)&temp)[y*16+x] = 0xFFFF00FF;
else ((uint *)&temp)[y*16+x] = 0xFF000000;
}
}
UpdateSubImage (0, 0, 16, 16, temp )
The update Fuction:
void UpdateSubImage (int xoffset, int yoffset, int width, int height, const
GLvoid *pixels)
{
int x, y;
int srcbytes = 4; //Hard coded for now, as all tests are RGBA
int dstbytes = 4; // ^
byte *srcdata;
byte *dstdata;
D3DLOCKED_RECT lockrect;
pTexture->LockRect( 0, &lockrect, NULL, 0);
srcdata = (byte *) pixels;
dstdata = (byte *) lockrect.pBits;
dstdata += (yoffset * width + xoffset) * dstbytes;
for (y = yoffset; y < (yoffset + height); y++)
{
for (x = xoffset; x < (xoffset + width); x++)
{
if (srcbytes == 1)
{
if (dstbytes == 1)
dstdata[0] = srcdata[0];
else if (dstbytes == 4)
{
dstdata[0] = srcdata[0];
dstdata[1] = srcdata[0];
dstdata[2] = srcdata[0];
dstdata[3] = srcdata[0];
}
}
else if (srcbytes == 3)
{
if (dstbytes == 1)
dstdata[0] = ((int) srcdata[0] + (int) srcdata[1] + (int) srcdata[2]) / 3;
else if (dstbytes == 4)
{
dstdata[0] = srcdata[2];
dstdata[1] = srcdata[1];
dstdata[2] = srcdata[0];
dstdata[3] = 255;
}
}
else if (srcbytes == 4)
{
if (dstbytes == 1)
dstdata[0] = ((int) srcdata[0] + (int) srcdata[1] + (int) srcdata[2]) / 3;
else if (dstbytes == 4)
{
dstdata[0] = srcdata[2];
dstdata[1] = srcdata[1];
dstdata[2] = srcdata[0];
dstdata[3] = srcdata[3];
}
}
// advance
srcdata += srcbytes;
dstdata += dstbytes;
}
}
pTexture->UnlockRect(0);
}
What the output looks like:
What the output should look like:

Answer 1

You're assuming that the data accessable through lockrect.pBits is linear in memory. This is in general not the case. Instead you have a constant offset between your rows which is defined by the lockrect.Pitch value.
To get the address of a pixel in the destination use:
byte * destAddr = (lockrect.pBits + y * lockrect.Pitch + 4 * x);
// for 32 bit images. For other formats adjust the hard-coded 4.

Answer 2

Thanks for the help :), in the end the following code worked:
Can it be made faster?
for (y = yoffset; y < (yoffset + height); y++)
{
for (x = xoffset; x < (xoffset + width); x++)
{
ARGB pixel;
pixel.r = srcdata[0];
pixel.g = srcdata[1];
pixel.b = srcdata[2];
pixel.a = srcdata[3];
memcpy( &dstdata[lockrect.Pitch * y + dstbytes * x], &pixel, dstbytes );
srcdata += srcbytes;
}
}