GPU memory usage of RGB textures

[hjimbens]

Creating textures with

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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, (GLsizei)mWidth, (GLsizei)mHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, GetPixels ());

seems to use the same amount of GPU memory as creating them with

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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)mWidth, (GLsizei)mHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, GetPixels ());

.
In both cases vcdbg shows a texture blob that uses approximately 4*mHeight*mWidth bytes.
That is a pity because it wastes 30% of GPU memory.

[lb]

GPUs typically don't support RGB formats in hardware, due to the horrible alignment issues it poses. It's quite normal. If you can, use ETC1 texture compression. You'll lose some quality, but at just 4 bits per pixel, the data size will be very small.