[Mesa-dev] [PATCH 2/6] mesa: Clamp GetUniformuiv values to be >= 0

[Iago Toral Quiroga]

From: Kenneth Graunke <kenneth at whitecape.org>

Section 2.2.2 (Data Conversions For State Query Commands) of the
OpenGL 4.5 October 24th 2016 specification says:

"If a command returning unsigned integer data is called, such as
 GetSamplerParameterIuiv, negative values are clamped to zero."

v2: uint to int conversion should clamp to INT_MAX (Nicolai)

v3 (Iago)
  - Add conversions conversions from 64-bit integer paths
  - Rebase on master

Fixes:
KHR-GL45.gpu_shader_fp64.state_query

Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com> (v2)
---
 src/mesa/main/uniform_query.cpp | 64 ++++++++++++++++++++++++++++++++---------
 1 file changed, 51 insertions(+), 13 deletions(-)

diff --git a/src/mesa/main/uniform_query.cpp b/src/mesa/main/uniform_query.cpp
index bd5b4c4..315973a 100644
--- a/src/mesa/main/uniform_query.cpp
+++ b/src/mesa/main/uniform_query.cpp
@@ -352,18 +352,9 @@ _mesa_get_uniform(struct gl_context *ctx, GLuint program, GLint location,
        * just memcpy the data.  If the types are not compatible, perform a
        * slower convert-and-copy process.
        */
-      if (returnType == uni->type->base_type
-          || ((returnType == GLSL_TYPE_INT
-               || returnType == GLSL_TYPE_UINT)
-              &&
-              (uni->type->base_type == GLSL_TYPE_INT
-               || uni->type->base_type == GLSL_TYPE_UINT
-               || uni->type->is_sampler()
-               || uni->type->is_image()))
-               || ((returnType == GLSL_TYPE_UINT64 ||
-                    returnType == GLSL_TYPE_INT64) &&
-                  (uni->type->base_type == GLSL_TYPE_UINT64 ||
-                   uni->type->base_type == GLSL_TYPE_INT64))) {
+      if (returnType == uni->type->base_type ||
+          ((returnType == GLSL_TYPE_INT || returnType == GLSL_TYPE_UINT) &&
+           (uni->type->is_sampler() || uni->type->is_image()))) {
          memcpy(paramsOut, src, bytes);
       } else {
          union gl_constant_value *const dst =
@@ -461,7 +452,6 @@ _mesa_get_uniform(struct gl_context *ctx, GLuint program, GLint location,
                break;
 
             case GLSL_TYPE_INT:
-            case GLSL_TYPE_UINT:
                switch (uni->type->base_type) {
                case GLSL_TYPE_FLOAT:
                   /* While the GL 3.2 core spec doesn't explicitly
@@ -486,6 +476,9 @@ _mesa_get_uniform(struct gl_context *ctx, GLuint program, GLint location,
                case GLSL_TYPE_BOOL:
                   dst[didx].i = src[sidx].i ? 1 : 0;
                   break;
+               case GLSL_TYPE_UINT:
+                  dst[didx].i = MIN2(src[sidx].i, INT_MAX);
+                  break;
                case GLSL_TYPE_DOUBLE: {
                   double tmp;
                   memcpy(&tmp, &src[sidx].f, sizeof(tmp));
@@ -510,6 +503,51 @@ _mesa_get_uniform(struct gl_context *ctx, GLuint program, GLint location,
                }
                break;
 
+            case GLSL_TYPE_UINT:
+               switch (uni->type->base_type) {
+               case GLSL_TYPE_FLOAT:
+                  /* The spec isn't terribly clear how to handle negative
+                   * values with an unsigned return type.
+                   *
+                   * GL 4.5 section 2.2.2 ("Data Conversions for State
+                   * Query Commands") says:
+                   *
+                   * "If a value is so large in magnitude that it cannot be
+                   *  represented by the returned data type, then the nearest
+                   *  value representable using the requested type is
+                   *  returned."
+                   */
+                  dst[didx].i = src[sidx].f < 0.0f ? 0 : IROUND(src[sidx].f);
+                  break;
+               case GLSL_TYPE_BOOL:
+                  dst[didx].i = src[sidx].i ? 1 : 0;
+                  break;
+               case GLSL_TYPE_INT:
+                  dst[didx].i = MAX2(src[sidx].i, 0);
+                  break;
+               case GLSL_TYPE_DOUBLE: {
+                  double tmp;
+                  memcpy(&tmp, &src[sidx].f, sizeof(tmp));
+                  dst[didx].i = tmp < 0.0 ? 0 : IROUNDD(tmp);
+                  break;
+               }
+               case GLSL_TYPE_UINT64: {
+                  uint64_t tmp;
+                  memcpy(&tmp, &src[sidx].u, sizeof(tmp));
+                  dst[didx].i = MIN2(tmp, INT_MAX);
+                  break;
+               }
+               case GLSL_TYPE_INT64: {
+                  int64_t tmp;
+                  memcpy(&tmp, &src[sidx].i, sizeof(tmp));
+                  dst[didx].i = MAX2(tmp, 0);
+                  break;
+               }
+               default:
+                  unreachable("invalid uniform type");
+               }
+               break;
+
             case GLSL_TYPE_INT64:
             case GLSL_TYPE_UINT64:
                switch (uni->type->base_type) {
-- 
2.9.3