Questions tagged [performance]

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22 votes
1 answer
3k views

Why is this conditional in my fragment shader so slow?

I have set up some FPS-measuring code in WebGL (based on this SO answer) and have discovered some oddities with the performance of my fragment shader. The code just renders a single quad (or rather ...
Martin Ender's user avatar
  • 2,720
16 votes
1 answer
1k views

Is a constant condition more costly than switching shaders?

In general, branching in shaders is not a good idea. But now I have a shader with a condition that is constant with respect to the entire draw call. So the branch that is executed is always the same ...
nikitablack's user avatar
11 votes
3 answers
3k views

Why do Vertex Buffer Objects improve performance?

From my basic understanding, a Vertex Buffer Object works something like this (pseudo code): Normally, if one wanted to say, draw a square, one could issue line drawing commands. ...
Ethan Bierlein's user avatar
59 votes
3 answers
35k views

When is a compute shader more efficient than a pixel shader for image filtering?

Image filtering operations such as blurs, SSAO, bloom and so forth are usually done using pixel shaders and "gather" operations, where each pixel shader invocation issues a number of texture fetches ...
Nathan Reed's user avatar
  • 24.7k
0 votes
1 answer
203 views

Convert one triangle to another in matrix4x4?

The context openGL instances learning. I want to transform a reference triangle to another one. So final goal is to have one triangle and the instance being a transformation of that initial triangle. ...
Kroma's user avatar
  • 103