Accessing Texels..

Graphics and GPU Programming Programming

Started by EonStrife December 03, 2007 03:40 AM

2 comments, last by V-man 16 years, 4 months ago

122

Author

December 03, 2007 03:40 AM

Hi, Suppose I use FBO to render the resulting color to a texture (because of some reasons, I am unable to use RenderBuffer), how do I access each texel of the resulting texture ? Thanks.

V-man

813

December 03, 2007 06:22 AM

Use the FBO as a render to texture. Access the texture in your shader with

vec4 texel = texture2D(tex, gl_TexCoord[0].xy);

or if you want to read back the FBO use glReadPixels
or to read back from the texture glGetTexImage

Sig: http://glhlib.sourceforge.net
an open source GLU replacement library. Much more modern than GLU.
float matrix[16], inverse_matrix[16];
glhLoadIdentityf2(matrix);
glhTranslatef2(matrix, 0.0, 0.0, 5.0);
glhRotateAboutXf2(matrix, angleInRadians);
glhScalef2(matrix, 1.0, 1.0, -1.0);
glhQuickInvertMatrixf2(matrix, inverse_matrix);
glUniformMatrix4fv(uniformLocation1, 1, FALSE, matrix);
glUniformMatrix4fv(uniformLocation2, 1, FALSE, inverse_matrix);

EonStrife

122

Author

December 03, 2007 06:42 PM

Thanks.
BTW, last question, can I access and modify the interpolated depth value in the fragment shader of Cg ?