In the learningwebgl tutorial1 I've found an interesting line in the fragment shader.
precision mediump float;
I've found an article about it here, but I still can't understand what does it mean?
And if I remove this line, nothing changes. Everything is the same.
So what does
precision mediump float mean?
This determines how much precision the GPU uses when calculating floats.
highp is high precision, and of course more intensive than
mediump (medium precision) and
lowp (low precision).
Some systems do not support
highp at all, which will cause code not to work at all on those systems.
On systems that DO support
highp, you will see a performance hit, and should use
lowp wherever possible. A good rule of thumb that I saw was:
highp for vertex positions,
mediump for texture coordinates,
lowp for colors.
Hope that helps!
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