[QUOTE=mbentrup;1264955]The color gradient is not produced by the shaders, it is part of the rasterization process.
The shader has some limited influence on the interpolation, it can choose between three interpolation modes: flat (no interpolation, the value of one vertex is used for the whole triangle), noperspective (the values are interpolated based on their screen position) and smooth (the values are interpolated based on their 3d-position).
If you didn’t specify an interpolation mode in your shaders, the default is smooth interpolation.[/QUOTE]
If you didn’t specify an interpolation mode in your shaders, the default is smooth interpolation
Thank you, that’s what I expected! most texts say only if you don’t specify shaders, the glsl will use their default inner shader, which can implement smooth interpolation and other operations like shift, transformation…
but here we specify a simple shader, in which there is a gl_fragcolor output. then we can fond no interpolation operation. That is our question. now yours is answer.