v3:
- compare varying slot locations rather than names (Ilia Mirkin)
v2:
- ES version check (Tapani Pälli)
The conditions for which certain built-in special variables
can be declared invariant were not being checked.
GLSL ES 1.00 specification, Section "Invariance and linkage" says:
For the built-in special variables, gl_FragCoord can
only be declared invariant if and only if gl_Position is
declared invariant. Similarly gl_PointCoord can only be
declared invariant if and only if gl_PointSize is declared
invariant. It is an error to declare gl_FrontFacing as invariant.
This fixes the following piglit tests in spec/glsl-es-1.00/linker:
glsl-fcoord-invariant
glsl-fface-invariant
glsl-pcoord-invariant
Signed-off-by: Lars Hamre <cheme...@gmail.com>
---
CC: Ilia Mirkin <imir...@alum.mit.edu>
NOTE: Someone with access will need to commit this after the
review process
src/compiler/glsl/link_varyings.cpp | 43 +++++++++++++++++++++++++++++++++++--
1 file changed, 41 insertions(+), 2 deletions(-)
diff --git a/src/compiler/glsl/link_varyings.cpp
b/src/compiler/glsl/link_varyings.cpp
index 34e82c7..155a4d9 100644
--- a/src/compiler/glsl/link_varyings.cpp
+++ b/src/compiler/glsl/link_varyings.cpp
@@ -352,13 +352,23 @@ cross_validate_outputs_to_inputs(struct gl_shader_program
*prog,
glsl_symbol_table parameters;
ir_variable *explicit_locations[MAX_VARYING][4] = { {NULL, NULL} };
+ bool is_gl_position_invariant = false;
+ bool is_gl_point_size_invariant = false;
+
/* Find all shader outputs in the "producer" stage.
*/
foreach_in_list(ir_instruction, node, producer->ir) {
ir_variable *const var = node->as_variable();
if ((var == NULL) || (var->data.mode != ir_var_shader_out))
- continue;
+ continue;
+
+ if (prog->IsES && prog->Version < 300) {
+ if (var->data.location == VARYING_SLOT_POS)
+ is_gl_position_invariant = var->data.invariant;
+ if (var->data.location == VARYING_SLOT_PSIZ)
+ is_gl_point_size_invariant = var->data.invariant;
+ }
if (!var->data.explicit_location
|| var->data.location < VARYING_SLOT_VAR0)
@@ -442,7 +452,36 @@ cross_validate_outputs_to_inputs(struct gl_shader_program
*prog,
ir_variable *const input = node->as_variable();
if ((input == NULL) || (input->data.mode != ir_var_shader_in))
- continue;
+ continue;
+
+ /*
+ * GLSL ES 1.00 specification, Section "Invariance and linkage" says:
+ *
+ * "For the built-in special variables, gl_FragCoord can
+ * only be declared invariant if and only if gl_Position is
+ * declared invariant. Similarly gl_PointCoord can only be
+ * declared invariant if and only if gl_PointSize is declared
+ * invariant. It is an error to declare gl_FrontFacing as invariant."
+ */
+ if (prog->IsES && prog->Version < 300 && input->data.invariant) {
+ if (input->data.location == VARYING_SLOT_FACE) {
+ linker_error(prog,
+ "gl_FrontFacing cannot be declared invariant");
+ return;
+ } else if (!is_gl_position_invariant &&
+ !strcmp(input->name, "gl_FragCoord")) {
+ linker_error(prog,
+ "gl_FragCoord cannot be declared invariant "
+ "unless gl_Position is also invariant");
+ return;
+ } else if (!is_gl_point_size_invariant &&
+ input->data.location == VARYING_SLOT_PNTC) {
+ linker_error(prog,
+ "gl_PointCoord cannot be declared invariant "
+ "unless gl_PointSize is also invariant");
+ return;
+ }
+ }
if (strcmp(input->name, "gl_Color") == 0 && input->data.used) {
const ir_variable *const front_color =
--
2.5.5
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