Cooperating glTextureStorage3D, glTextureSubImage3D and usampler2DArray

OpenGL OpenGL: Basic Coding
1

Hi! I am trying to load a 2D texture array to GPU, but I get GL_INVALID_OPERATION on the call in the following code:

So, the fragment shader has the sampler definition:

layout (binding = 0) uniform usampler2DArray tex_object_x;

The is the OpenGL code:


const GLsizei levels = 1, width = sampler.width, height = sampler.height, depth = sampler.depth;

glTextureStorage3D(texture_array_buffers[0], levels, GL_RGBA8UI, width, height, depth);

// Fails with GL_INVALID_OPERATION (but not with GL_RGBA instead of GL_RGBA8UI in the operation above)
for (int sliceindex = 0; sliceindex < depth; sliceindex++)
  glTextureSubImage3D(
    /* GLenum target         */ texture_array_buffers[0],
    /* GLint level           */ 0,
    /* GLint xoffset         */ 0,
    /* GLint yoffset         */ 0,
    /* GLint zoffset         */ sliceindex,
    /* GLsizei width         */ width,
    /* GLsizei height        */ height,
    /* GLsizei depth         */ 1,
    /* GLenum format         */ GL_RGBA,
    /* GLenum type           */ GL_UNSIGNED_BYTE,
    /* const GLvoid * pixels */ &(sampler.slice_z(sliceindex)[0]));

If I use GL_RGBA instead of GL_RGBA8UI, there is no error, but the data is transferred in a wrong way. This is, I suppose, because I have usampler2DArray, which is unsigned, and GL_RGBA8 in the call to glTextureStorage3D is signed. That’s why I am trying to use GL_RGBA8UI.

Please, help.

2

If I use GL_RGBA instead of GL_RGBA8UI, there is no error

That’s not possible. All of the Storage functions explicitly require sized internal formats. You will get GL_INVALID_ENUM otherwise.

Also:

/* GLenum target         */ texture_array_buffers[0],

That’s a GLuint, not a GLenum.

BTW, you’re probably mis-identifying the source of the GL_INVALID_OPERATION error. It’s likely due to:

/* GLenum format         */ GL_RGBA,

No, that’s wrong. When uploading to integer textures, you must use _INTEGER pixel transfer formats. So you would need GL_RGBA_INTEGER.

3

My bad, I meant to write GL_RGBA8 there.

[QUOTE=Alfonse Reinheart;1288945]
When uploading to integer textures, you must use _INTEGER pixel transfer formats. So you would need GL_RGBA_INTEGER.[/QUOTE]

Solved the problem : ) Makes me wonder why _INTEGER is not listed or mentioned here. But the pixel transfer page you provided is very helpful. Thanks a lot, Alfonse!