Integer Texture don't work well


I tried to upload integer red texture, but it does not work well.
Anybody can check below code and let me know the reason?
The screen wanted to be red color, but it is black screen now.


You should use NEAREST for the sampling mode as there’s no mipmaps and a single pixel in the texture:

Though I don’t know why it doesn’t work as you are using texelFetch in the shader which should not depend on the sampler filtering…