How will it be when in glTexImage2D I choose a different internal format from the way I tried it in the shader?

Question

How will it be when in glTexImage2D I choose a different internal format from the way I tried it in the shader?

For example, I write this in code:

glTexImage2D(GL_TEXTURE_2D, i, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);

and in the shader:

glFragColor = texture2D(sampler, uv).rgba

what will happen, is there an official definition for this situation?

+3

c ++ graphics opengl glsl

Eagle lau Jul 17 17 at 10:27

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1 answer

Rabbid76 · Accepted Answer · 2017-07-17T11:05:44+0000

The aspect ratio in the Khronos group spec says:

Image formats don't have to store every component. When a shader samples such a texture, it will still be allowed for a 4-digit RGBA vector. Components not saved in image format are filled in automatically. Zeros are used if R, G, or B are missing, and missing Alpha always resolves to 1.

Note: Rewinding the texture can change missing values.

How will it be when in glTexImage2D I choose a different internal format from the way I tried it in the shader?

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