Hello, I am in the process of modifying the GLHeightfield example, and
have added some patch inputs that do various things, and have modified
some of the openGL state variables, and would like to texture the
output geometry rather than simply color it.
Ive done a bit of reading on texturing vertex buffers arrays, and it
seems the 'proper' technique is to use interleaved buffers by
rendering out the texture coordinates, etc next to the vertex values,
but implementing this is a bit above my head. *cough* ok more than a
bit.
Ive added an image input named "image" (I renamed the original image
input to imageLuma (the actual texture that does the displacement) -
to clarify the two sources), and have wrapped the VBO drawing code
with texture binding code. It seems however the VBO does not have any
'useful' texture coordinates.
So, in short, how does one specify texture coordinates for the
glDrawElements without using interleaved buffers?
Thanks very much,
Anton
(some code below)
Apologies if this is received twice, I sent this once from an address
unsubscribed from the list.
Also, apologies if this belongs more in the OpenGL dev list.
Thanks again,
<snip>
/* Draw the VBO */
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
if(image && [image lockTextureRepresentationWithColorSpace:[image
imageColorSpace] forBounds:[image imageBounds]])
{
[image bindTextureRepresentationToCGLContext:cgl_ctx
textureUnit:GL_TEXTURE1 normalizeCoordinates:YES];
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glVertexPointer(4, GL_FLOAT, 0, NULL);
glDrawElements(GL_TRIANGLES, (kSize - 1) * (kSize - 1) * 6,
GL_UNSIGNED_INT, _indices);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glDisableClientState(GL_VERTEX_ARRAY);
[image unbindTextureRepresentationFromCGLContext:cgl_ctx
textureUnit:GL_TEXTURE1];
[image unlockTextureRepresentation];
} // end addition by vade
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