What is it about shaders that even potentially makes if statements performance problems? It has to do with how shaders get executed and where GPUs get their massive computing performance from. Separate shader invocations are usually executed in parallel, executing the same instructions at the same time. They’re simply executing them on different sets of … Read more
For very simple pseudorandom-looking stuff, I use this oneliner that I found on the internet somewhere: float rand(vec2 co){ return fract(sin(dot(co, vec2(12.9898, 78.233))) * 43758.5453); } You can also generate a noise texture using whatever PRNG you like, then upload this in the normal fashion and sample the values in your shader; I can dig … Read more
but I still don’t know whether or not the gl_FragCoord.z is linear. Whether gl_FragCoord.z is linear or not depends on, the projection matrix. While for Orthographic Projection gl_FragCoord.z is linear, for Perspective Projection it is not linear. In general, the depth (gl_FragCoord.z and gl_FragDepth) is calculated as follows (see GLSL gl_FragCoord.z Calculation and Setting gl_FragDepth): … Read more
+1 for interesting problem. Was curious so I tried to code this. I need the use of arrays so I chose #version 420 core. My app is rendering single quad covering screen with coordinates <-1,+1>. I am using whole ASCII 8×8 pixel 32×8 characters font texture I created some years ago: The vertex is simple: … Read more
ray and ellipsoid intersection accuracy improvement
normal/bump maps Provide fine details without increasing complexity of geometry that means more details at very low performance cost. Normal/bump maps are optional of coarse. normal shading (fragment shader) Normal is vector perpendicular to fragment/face/primitive there are 2 use for it: dull surface illumination lets have: color – per fragment/face/primitive color (modulated with texture) normal … Read more