From: Ian Romanick <ian.d.romanick@intel.com>
Date: Thu, 20 Jan 2011 20:05:38 +0000 (-0800)
Subject: mesa: Set correct values for range/precision of shader integer types
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=04dca296e0a5e5ffbb8acb699e013a23ebd7b645;p=mesa.git

mesa: Set correct values for range/precision of shader integer types
---

diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index fe370fa369b..e017939a45c 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -534,8 +534,17 @@ init_program_limits(GLenum type, struct gl_program_constants *prog)
    prog->MediumFloat.RangeMax = 127;
    prog->MediumFloat.Precision = 23;
    prog->LowFloat = prog->HighFloat = prog->MediumFloat;
-   /* assume ints are stored as floats for now */
-   prog->LowInt = prog->MediumInt = prog->HighInt = prog->MediumFloat;
+
+   /* Assume ints are stored as floats for now, since this is the least-common
+    * denominator.  The OpenGL ES spec implies (page 132) that the precision
+    * of integer types should be 0.  Practically speaking, IEEE
+    * single-precision floating point values can only store integers in the
+    * range [-0x01000000, 0x01000000] without loss of precision.
+    */
+   prog->MediumInt.RangeMin = 24;
+   prog->MediumInt.RangeMax = 24;
+   prog->MediumInt.Precision = 0;
+   prog->LowInt = prog->HighInt = prog->MediumInt;
 }