How to properly blend colors across two triangles and remove diagonal smear
问题 I am learning WebGL and I've drawn a full screen quad with colors for each vertex. No lighting or normals or perspective matrix or depth buffer; I'm just drawing a gradient background. This is what I get: It looks good but I cannot help noticing the diagonal smear from the bottom right to the top left. I feel this is an artifact of linear interpolating the far opposite vertices. I'm drawing two triangles: the bottom left, and the top right. I think I would get similar results using OpenGL