FBO + Accumulation buffer support?

Graphics and GPU Programming Programming

Started by pioneer93 March 16, 2009 10:11 AM

3 comments, last by HuntsMan 15 years, 1 month ago

122

Author

March 16, 2009 10:11 AM

Hi, I'm using FBO for multiple lights simulation in Geforce 8800 GTX. Does FBO supports accumulation buffer? It used to support only at normal framebuffer not in 32bit floating point FBO a year ago. I know a blending function can simluate the accumulation but I'd rather use accumulation buffer. Many thanks for any comments.

V-man

813

March 16, 2009 01:49 PM

If you make a GL_RGBA16 format texture, then it will do the job.
no, you can't attach a accum buffer to a FBO.

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);

pioneer93

122

Author

March 16, 2009 05:12 PM

tried GL_RGBA16 format, but it doesn't work.

V-man

813

March 16, 2009 08:48 PM

It works. Geforce 8800 supports that format. You probably would want to scale down the values that you are adding up. For example, in your shader you can do
gl_FragColor = total * 0.3;

and also setup the additive blending
glBlendFunc(GL_ONE, GL_ONE);
glEnable(GL_BLEND);

HuntsMan

370

March 16, 2009 09:43 PM

Also, doesn't work doesn't mean anything. Do you get errors? Corrupted textures? Black textures? Something? Also posting testing code is useful :)

FBO + Accumulation buffer support?

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