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Re: Float textures in shaders

I duplicated your problem on my G4 powerbook, Radeon 9600. When I change to GL_RGB_FLOAT16_APPLE,
your program works properly. When I change to GL_RGB, it works as well.
Therefore, there might be a bug with GL_RGB_FLOAT32_APPLE.

What proof do you have that you are actually using a float texture. The fact that the results (with a single texture) are
the same whether in 32, 16, or 8 bit tells me that the format could be anything. You probably have to experiment
with glReadPixels() to determine what is actually in your textures.

 Gordon


email@hidden wrote:

Here's how I'm using it:

glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB_FLOAT32_APPLE, width, height, 0, GL_RGB, GL_FLOAT, float_texels );

And here's a small GLUT program that successfully uses a float texture in a shader (though shows the artifacts when used at the same time as a non-float texture):

http://www.acm.uiuc.edu/~kcrane/fptex_artifacts.tar.gz


Keenan

---- Original message ----


Date: Tue, 23 Nov 2004 14:36:17 -0500
From: Gordon Erlebacher <email@hidden> Subject: Re: Float textures in shaders To: email@hidden
Cc: email@hidden

I have had my share of problems with GL_RGB_FLOAT32_APPLE. Could you

please


send the full line with glTexImage2D? I have never been convinced that the floating textures
work properly. Thanks.

Gordon


email@hidden wrote:



I'm getting artifacts like this:

http://www.acm.uiuc.edu/~kcrane/floattex_artifacts.jpg

when I try to multiply a floating-point texture (using

GL_RGB_FLOAT32_APPLE)

with an 8 bit/component RGB texture in a fragment shader. The strange

thing

is I only get these artifacts when the output color is dependent on both

textures

-- passing through one texture or the other gives the correct results. I'm

using 

a mobility 9700, 10.3.6, and Cg version 1.2.1001 w/ arbfp1

Keenan
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