Mesa (gallium-mesa-7.4): glsl: fix link failure for variable-indexed varying output arrays
Alan Hourihane
alanh at kemper.freedesktop.org
Tue Feb 24 10:44:30 UTC 2009
Module: Mesa
Branch: gallium-mesa-7.4
Commit: 409d4f839ccdcbb93a8fbb1ed215c2cd96713428
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=409d4f839ccdcbb93a8fbb1ed215c2cd96713428
Author: Brian Paul <brianp at vmware.com>
Date: Wed Feb 18 14:29:46 2009 -0700
glsl: fix link failure for variable-indexed varying output arrays
If the vertex shader writes to a varying array with a variable index,
mark all the elements of that array as being written.
For example, if the vertex shader does:
for (i = 0; i < 4; i++)
gl_TexCoord[i] = expr;
Mark all texcoord outputs as being written, not just the first.
Linking will fail if a fragment shader tries to read an input that's not
written by the vertex shader. Before this fix, this linker test could fail.
(cherry picked from master, commit dac19f17f360b730a0e6d651ef2e5b03c59b9b53)
---
src/mesa/shader/slang/slang_link.c | 25 +++++++++++++++++++++++++
1 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/src/mesa/shader/slang/slang_link.c b/src/mesa/shader/slang/slang_link.c
index c6d5cc0..4c1708e 100644
--- a/src/mesa/shader/slang/slang_link.c
+++ b/src/mesa/shader/slang/slang_link.c
@@ -486,8 +486,33 @@ _slang_update_inputs_outputs(struct gl_program *prog)
maxAddrReg = MAX2(maxAddrReg, (GLuint) (inst->SrcReg[j].Index + 1));
}
}
+
if (inst->DstReg.File == PROGRAM_OUTPUT) {
prog->OutputsWritten |= 1 << inst->DstReg.Index;
+ if (inst->DstReg.RelAddr) {
+ /* If the output attribute is indexed with relative addressing
+ * we know that it must be a varying or texcoord such as
+ * gl_TexCoord[i] = v; In this case, mark all the texcoords
+ * or varying outputs as being written. It's not an error if
+ * a vertex shader writes varying vars that aren't used by the
+ * fragment shader. But it is an error for a fragment shader
+ * to use varyings that are not written by the vertex shader.
+ */
+ if (prog->Target == GL_VERTEX_PROGRAM_ARB) {
+ if (inst->DstReg.Index == VERT_RESULT_TEX0) {
+ /* mark all texcoord outputs as written */
+ const GLbitfield mask =
+ ((1 << MAX_TEXTURE_COORD_UNITS) - 1) << VERT_RESULT_TEX0;
+ prog->OutputsWritten |= mask;
+ }
+ else if (inst->DstReg.Index == VERT_RESULT_VAR0) {
+ /* mark all generic varying outputs as written */
+ const GLbitfield mask =
+ ((1 << MAX_VARYING) - 1) << VERT_RESULT_VAR0;
+ prog->OutputsWritten |= mask;
+ }
+ }
+ }
}
else if (inst->DstReg.File == PROGRAM_ADDRESS) {
maxAddrReg = MAX2(maxAddrReg, inst->DstReg.Index + 1);
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