3 Replies Latest reply on Nov 17, 2014 12:16 PM by Robert_U

    OpenGL GLSL sin, cos, and sqrt precision on Intel HD 5000


      What is the maximum, actual precision of the sin, cos, and sqrt functions on an Intel HD 5000? I am working with a Surface Pro 3.


      I have a calculation in a shader which generates a cartesian position from a WGS84 location.


      The result is off by about 0.00001 radians. This would seem to suggest that Intel's trig precision is the bottom of the barrel for GLSL support -- 1/100000.


      This function works perfectly on an ancient NVidia Geforce 8400 GS. The exact same shader, with the same inputs, produces an output with an undesirable offset.


      I need to know the precision to know whether I just have to avoid Intel cards entirely.


      I may be able to provide more info as needed, but I need to use this as a starting point.


      Alternatively, are there any caveats or gotchyas with Intel GLSL math, as opposed to NVidias, that someone might know of?