OpenGL 3.0 and writing to an integer framebuffer

[soconne]

The error code is 1280, but the string returned by glewGetErrorString returns "Unknown Error".

[LangFox]

Try using DrawBuffers enum value instead of 0?

[soconne]

Well I take back the error. That 1280 was being caused by my call to glDisable(GL_CLAMP_FRAGMENT_COLOR), b/c I thought that's how it was suppose to be called.

I commented it out and now no errors are reported. Yet my texture remains black.

But I did try what you said with using DrawBuffers, but a 1281 error is reported immediately after. I've tried the following:

glBindFragDataLocation(program, GL_DRAW_BUFFER, "myIntOutput");
glBindFragDataLocation(program, GL_DRAW_BUFFER0, "myIntOutput");

Well I changed my texture format from GL_ALPHAUI32_EXT to GL_RGBAUI32_EXT and my texture is filled with the correct integer RGBA values. But I really need this to work for a single channel texture.

Any suggestions? And thanks to everybody for all your help so far.

[soconne]

Well I discovered using GL_LUMINANCE32UI_EXT instead of GL_ALPHA32UI_EXT worked. Thanks again for everybody's help!

[LangFox]

Maybe R32UI is better than LUMINANCE32UI for forward compatibility.

[martinsm]

Isn't gl_ModelViewProjectionMatrix supposed to be deprecated in glsl 1.3? Or only the matrix stacks ?

It is deprecated only in forward compatbile context. In full 3.0 context you can use whatever you want - even fixed functionality rendering.

0 ir valid argument for colorNumber for glBindFragDataLocation function. It means it will write to 0 attachment of FBO. If it would expect enum there then function signature would include GLenum type, not uint.

[BionicBytes]

Hang on... for integer textures you need to change your texture parameters according to the spec EXT_TEXTURE_INTEGER

void TexParameterIivEXT( enum target, enum pname, int *params );
void TexParameterIuivEXT( enum target, enum pname, uint *params );

You are setting up the textures with plain old normalised glTexParameteri.

Secondly, what makes you think EXT_FBO actually supports integer textures. I have checked ARB_FBO and that definately does..but reading the EXT_Integer_Texture I'm not so sure that it applies to EXT_FBO.

[martinsm]

TexParameterIivEXT and TexParameterIuivEXT are needed only for GL_TEXTURE_BORDER_COLOR pname to specify color with integer values.

[ludanqqqq]

I encountered the same problem in my program, the difference is that I used cg shader:

glTexImage1D(GL_TEXTURE_1D, 0, GL_ALPHA8UI_EXT,8, 0, GL_ALPHA_INTEGER_EXT, GL_UNSIGNED_BYTE, sBitflag);

param = cgGetNamedParameter(program, par);
cgGLSetTextureParameter(param, tex);
cgGLEnableTextureParameter(param);

how to solve this problem?