Hi, I'm using an OpenGL texture as buffer to contain the painting in a painting program (this program is geared towards myself for editing textures for my own game projects). I'm doing this as a 8-bit per channel texture now, but for some image operations it's better of the drawing is represented by something with higher precision than 8-bit per channel. I'm considering two options: 1) Keep using 8-bit per channel texture for OpenGL, and use a floating point buffer to contain the image, and constantly convert it to the OpenGL texture to draw it. But, I think this would be really slow, is that true or not? 2) Use a floating point OpenGL texture (32 bit floating point per channel). I have some questions for this option though... -Are such floating point textures supported on all video cards? Or will there be compatibility problems? -Does such a texture also support alpha channel? -Are the values in range 0.0-1.0, and what happens to smaller and larger values? -What's the performance of floating point textures? (and how does it compare to option 1) above?) -If I'd use approach 1), what's the fastest way to convert a float or double buffer of RGBA values to a 8-bit per channel OpenGL texture? Is there an OpenGL call that can do it directly? Thanks! [Edited by - Lode on March 13, 2009 6:00:43 AM]

1) I'll leave that up to you. It's your app and you know what is best for your needs.

2) http://www.opengl.org/wiki/Floating_point_and_mipmapping_and_filtering

Quote:Original post by Lode
-Are such floating point textures supported on all video cards? Or will there be compatibility problems?

In general, anything OpenGL 2.0+ will support floating point textures, but even recent intel integrated cards seem to have issues.

Quote:-If I'd use approach 1), what's the fastest way to convert a float or double buffer of RGBA values to a 8-bit per channel OpenGL texture? Is there an OpenGL call that can do it directly?

glTexImage2D(GL_TEXTURE_2D, 0, G_RGBA, width, height, 0 GL_RGBA, GL_FLOAT, data), or similar.