vec2 computeMotionVector(vec4 NDC, vec4 NDCPrevious){ vec2 ndc = NDC.xy / NDC.w; vec2 ndcPrevious = NDCPrevious.xy / NDCPrevious.w; vec2 uv = ndc * 0.5 + 0.5; vec2 uvPrevious = ndcPrevious * 0.5 + 0.5; return uvPrevious - uv; }