Depth texture as color attachment

Question

I d'like to attach a depth texture as a color attachment to the framebuffer. (I'm on iOS and GL_OES_depth_texture is supported)

So I setup a texture like this:

glGenTextures(1, &TextureName);
glBindTexture(GL_TEXTURE_2D, TextureName);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, ImageSize.Width, ImageSize.Height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, 0);


glGenFramebuffers(1, &ColorFrameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, ColorFrameBuffer);

glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, TextureName, 0);

But now if I check the framebuffer status I get a GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT

What am I doing wrong here?

I also tried some combinations with GL_DEPTH_COMPONENT16 , GL_DEPTH_COMPONENT24_OES , GL_DEPTH_COMPONENT32_OES but non of these worked (GL_OES_depth24 is also supported)

Answer 1

You can't. Textures with depth internal formats can only be attached to depth attachments. Textures with color internal formats can only be attached to color attachments.

Answer 2

As previous answer mentioned, you cannot attach a texture with depth format as a color surface. Now looking at your comment, you're really after rendering to a 1-channel float format.

You could look at http://www.khronos.org/registry/gles/extensions/OES/OES_texture_float.txt which allows you to have a Texture format of float format.

You can then initialize the texture to be a Alpha map, which would only include 1 channel.

glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, ImageSize.Width, ImageSize.Height, 0, GL_ALPHA, GL_FLOAT, 0);

This may or may not work depending on what extensions supported by your device.