摘要：在vtkGPUVolumeRayCastMapper_HeaderFS.glsl中 vec4 noiseValue=texture2D(noiseTexture,pos.xy*100.0); // with repeat/tiling mode on the noise texture. pos+=(noiseValue.x)*rayDir;用途：// 2D noise texture to jitter the starting point of the ray in order to// remove patterns when the opacity transfer functi... 阅读全文