According to the GLSL ES specification, section 4.5, "The built-in macro GL_FRAGMENT_PRECISION_HIGH is defined to one on systems supporting highp precision in the fragment language #define GL_FRAGMENT_PRECISION_HIGH 1 and is not defined on systems not supporting highp precision in the fragment language. When defined, this macro is available in both the vertex and fragment languages. The highp qualifier is an optional feature in the fragment language and is not enabled by #extension." glcpp currently does not define this macro for GLSL ES. As far as I know, all Mesa drivers currently support highp, so perhaps we should just define it unconditionally. However, I imagine this may not always be the case...
commit 302fe4049c1f409655eb283e20f9ab6397ac3db4 Author: Kenneth Graunke <kenneth@whitecape.org> Date: Wed Nov 17 12:53:07 2010 -0800 Regenerate glcpp parser. commit d719bf8fb4b8f511fbb00dd990fb644efc510c0e Author: Kenneth Graunke <kenneth@whitecape.org> Date: Wed Nov 17 12:50:35 2010 -0800 glsl: Unconditionally define GL_FRAGMENT_PRECISION_HIGH in ES2 shaders. This is really supposed to be defined only if the driver supports highp in the fragment shader - but all of our current ES2 implementations do. So, just define it. In the future, we'll need to add a flag to gl_context and only define the macro if the flag is set. "Fixes" freedesktop.org bug #31673.
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