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glsl: fix link failure for variable-indexed varying output arrays

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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 dac19f17f3)
This commit is contained in:
Brian Paul 2009-02-18 14:29:46 -07:00
parent 0ab36958ea
commit 409d4f839c
1 changed files with 25 additions and 0 deletions
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25
src/mesa/shader/slang/slang_link.c
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@ -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);