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authorBrian Paul <brianp@vmware.com>2010-06-01 09:02:07 -0600
committerBrian Paul <brianp@vmware.com>2010-06-01 09:02:10 -0600
commit1bbf803e3bc8eeabcc2c24b89bc30a30b2445c59 (patch)
tree8c23e8e224404078ead401b179ea088aef843088 /src/mesa/shader
parent7356d1c140f2989df9e8645cf4b85962f27d0fca (diff)
mesa: use split_location_offset() in GetUniform() functions
Commit 5d0e136eff54a34258b5adaeda4cb267831e8234 exposed a long-standing bug in the glGetUniform*() code paths. We weren't properly decoding the location parameter. Fixes fd.o bug/regression 28344 Note: this patch should go into the 7.8 branch after the above-mentioned commit.
Diffstat (limited to 'src/mesa/shader')
-rw-r--r--src/mesa/shader/uniforms.c101
1 files changed, 54 insertions, 47 deletions
diff --git a/src/mesa/shader/uniforms.c b/src/mesa/shader/uniforms.c
index 69758ea73f..b1fb90d020 100644
--- a/src/mesa/shader/uniforms.c
+++ b/src/mesa/shader/uniforms.c
@@ -319,6 +319,54 @@ lookup_uniform_parameter(GLcontext *ctx, GLuint program, GLint location,
/**
+ * GLGL uniform arrays and structs require special handling.
+ *
+ * The GL_ARB_shader_objects spec says that if you use
+ * glGetUniformLocation to get the location of an array, you CANNOT
+ * access other elements of the array by adding an offset to the
+ * returned location. For example, you must call
+ * glGetUniformLocation("foo[16]") if you want to set the 16th element
+ * of the array with glUniform().
+ *
+ * HOWEVER, some other OpenGL drivers allow accessing array elements
+ * by adding an offset to the returned array location. And some apps
+ * seem to depend on that behaviour.
+ *
+ * Mesa's gl_uniform_list doesn't directly support this since each
+ * entry in the list describes one uniform variable, not one uniform
+ * element. We could insert dummy entries in the list for each array
+ * element after [0] but that causes complications elsewhere.
+ *
+ * We solve this problem by encoding two values in the location that's
+ * returned by glGetUniformLocation():
+ * a) index into gl_uniform_list::Uniforms[] for the uniform
+ * b) an array/field offset (0 for simple types)
+ *
+ * These two values are encoded in the high and low halves of a GLint.
+ * By putting the uniform number in the high part and the offset in the
+ * low part, we can support the unofficial ability to index into arrays
+ * by adding offsets to the location value.
+ */
+static void
+merge_location_offset(GLint *location, GLint offset)
+{
+ *location = (*location << 16) | offset;
+}
+
+
+/**
+ * Separate the uniform location and parameter offset. See above.
+ */
+static void
+split_location_offset(GLint *location, GLint *offset)
+{
+ *offset = *location & 0xffff;
+ *location = *location >> 16;
+}
+
+
+
+/**
* Called via ctx->Driver.GetUniformfv().
*/
static void
@@ -327,6 +375,9 @@ _mesa_get_uniformfv(GLcontext *ctx, GLuint program, GLint location,
{
struct gl_program *prog;
GLint paramPos;
+ GLint offset;
+
+ split_location_offset(&location, &offset);
lookup_uniform_parameter(ctx, program, location, &prog, &paramPos);
@@ -357,6 +408,9 @@ _mesa_get_uniformiv(GLcontext *ctx, GLuint program, GLint location,
{
struct gl_program *prog;
GLint paramPos;
+ GLint offset;
+
+ split_location_offset(&location, &offset);
lookup_uniform_parameter(ctx, program, location, &prog, &paramPos);
@@ -378,53 +432,6 @@ _mesa_get_uniformiv(GLcontext *ctx, GLuint program, GLint location,
/**
- * GLGL uniform arrays and structs require special handling.
- *
- * The GL_ARB_shader_objects spec says that if you use
- * glGetUniformLocation to get the location of an array, you CANNOT
- * access other elements of the array by adding an offset to the
- * returned location. For example, you must call
- * glGetUniformLocation("foo[16]") if you want to set the 16th element
- * of the array with glUniform().
- *
- * HOWEVER, some other OpenGL drivers allow accessing array elements
- * by adding an offset to the returned array location. And some apps
- * seem to depend on that behaviour.
- *
- * Mesa's gl_uniform_list doesn't directly support this since each
- * entry in the list describes one uniform variable, not one uniform
- * element. We could insert dummy entries in the list for each array
- * element after [0] but that causes complications elsewhere.
- *
- * We solve this problem by encoding two values in the location that's
- * returned by glGetUniformLocation():
- * a) index into gl_uniform_list::Uniforms[] for the uniform
- * b) an array/field offset (0 for simple types)
- *
- * These two values are encoded in the high and low halves of a GLint.
- * By putting the uniform number in the high part and the offset in the
- * low part, we can support the unofficial ability to index into arrays
- * by adding offsets to the location value.
- */
-static void
-merge_location_offset(GLint *location, GLint offset)
-{
- *location = (*location << 16) | offset;
-}
-
-
-/**
- * Seperate the uniform location and parameter offset. See above.
- */
-static void
-split_location_offset(GLint *location, GLint *offset)
-{
- *offset = *location & 0xffff;
- *location = *location >> 16;
-}
-
-
-/**
* Called via ctx->Driver.GetUniformLocation().
*
* The return value will encode two values, the uniform location and an