On 02/25/2014 01:15 PM, Anuj Phogat wrote:
On Tue, Feb 25, 2014 at 7:47 AM, Ian Romanick <i...@freedesktop.org> wrote:
On 02/24/2014 05:34 PM, Anuj Phogat wrote:
Section 4.3.8.1, page 39 of GLSL 1.50 spec says:
"Within any shader, the first redeclarations of gl_FragCoord
must appear before any use of gl_FragCoord."
GLSL compiler should generate an error in following case:
vec4 p = gl_FragCoord;
layout(origin_upper_left) in vec4 gl_FragCoord;
void main()
{
}
Signed-off-by: Anuj Phogat <anuj.pho...@gmail.com>
Cc: <mesa-sta...@lists.freedesktop.org>
---
src/glsl/ast_to_hir.cpp | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 9fe3095..f5dacfd 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -2490,6 +2490,22 @@ apply_type_qualifier_to_variable(const struct
ast_type_qualifier *qual,
}
if (strcmp(var->name, "gl_FragCoord") == 0) {
+ /* Section 4.3.8.1, page 39 of GLSL 1.50 spec says:
+ *
+ * "Within any shader, the first redeclarations of gl_FragCoord
+ * must appear before any use of gl_FragCoord."
+ *
+ * Generate a compiler error if above condition is not met by the
+ * fragment shader.
+ */
+ ir_variable *earlier = state->symbols->get_variable("gl_FragCoord");
+ if (earlier != NULL &&
+ earlier->data.used &&
+ !state->fs_redeclares_gl_fragcoord) {
I don't think '!state->fs_redeclares_gl_fragcoord' should be there. What about
a shader like:
layout(origin_upper_left) in vec4 gl_FragCoord;
vec4 p = gl_FragCoord;
layout(origin_upper_left) in vec4 gl_FragCoord;
void main()
{
}
This shader compiles successfully as I expected. Only the first re-declaration
must appear before gl_FragCoord usage. Do you interpret the spec differently?
I've added new piglit tests which cover this case as well:
http://patchwork.freedesktop.org/project/piglit/list/?submitter=Anuj+Phogat&q=glsl-1.50
I overlooked "the first" in that sentence. Your code should be correct,
then. :)
+ _mesa_glsl_error(loc, state,
+ "gl_FragCoord used before its first redeclaration "
+ "in fragment shader");
+ }
/* Make sure all gl_FragCoord redeclarations specify the same layout
* qualifiers.
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