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path: root/src/mesa/shader/programopt.c
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Diffstat (limited to 'src/mesa/shader/programopt.c')
-rw-r--r--src/mesa/shader/programopt.c45
1 files changed, 23 insertions, 22 deletions
diff --git a/src/mesa/shader/programopt.c b/src/mesa/shader/programopt.c
index 015d01a1d8..199202edf7 100644
--- a/src/mesa/shader/programopt.c
+++ b/src/mesa/shader/programopt.c
@@ -41,15 +41,16 @@
/**
- * This is used for helping with position-invariant vertex programs.
- * It appends extra instructions to the given program to do the
- * vertex position transformation (multiply by the MVP matrix).
+ * This function inserts instructions for coordinate modelview * projection
+ * into a vertex program.
+ * May be used to implement the position_invariant option.
*/
void
-_mesa_append_modelview_code(GLcontext *ctx, struct gl_vertex_program *vprog)
+_mesa_insert_mvp_code(GLcontext *ctx, struct gl_vertex_program *vprog)
{
- struct prog_instruction newInst[5];
+ struct prog_instruction *newInst;
const GLuint origLen = vprog->Base.NumInstructions;
+ const GLuint newLen = origLen + 4;
GLuint i;
/*
@@ -69,13 +70,20 @@ _mesa_append_modelview_code(GLcontext *ctx, struct gl_vertex_program *vprog)
mvpState[i]);
}
+ /* Alloc storage for new instructions */
+ newInst = _mesa_alloc_instructions(newLen);
+ if (!newInst) {
+ _mesa_error(ctx, GL_OUT_OF_MEMORY,
+ "glProgramString(inserting position_invariant code)");
+ return;
+ }
+
/*
* Generated instructions:
* newInst[0] = DP4 result.position.x, mvp.row[0], vertex.position;
* newInst[1] = DP4 result.position.y, mvp.row[1], vertex.position;
* newInst[2] = DP4 result.position.z, mvp.row[2], vertex.position;
* newInst[3] = DP4 result.position.w, mvp.row[3], vertex.position;
- * newInst[4] = END;
*/
for (i = 0; i < 4; i++) {
_mesa_init_instruction(newInst + i);
@@ -90,24 +98,17 @@ _mesa_append_modelview_code(GLcontext *ctx, struct gl_vertex_program *vprog)
newInst[i].SrcReg[1].Index = VERT_ATTRIB_POS;
newInst[i].SrcReg[1].Swizzle = SWIZZLE_NOOP;
}
- newInst[4].Opcode = OPCODE_END;
- /*
- * Append new instructions onto program.
- */
- vprog->Base.Instructions
- = _mesa_realloc_instructions(vprog->Base.Instructions,
- origLen, origLen + 4);
- if (!vprog->Base.Instructions) {
- _mesa_error(ctx, GL_OUT_OF_MEMORY,
- "glProgramString(generating position transformation code)");
- return;
- }
- /* subtract one to overwrite original program's END instruction */
- _mesa_memcpy(vprog->Base.Instructions + origLen - 1,
- newInst, sizeof(newInst));
+ /* Append original instructions after new instructions */
+ _mesa_memcpy(newInst + 4, vprog->Base.Instructions,
+ origLen * sizeof(struct prog_instruction));
+
+ /* free old instructions */
+ _mesa_free(vprog->Base.Instructions);
- vprog->Base.NumInstructions = origLen + 4;
+ /* install new instructions */
+ vprog->Base.Instructions = newInst;
+ vprog->Base.NumInstructions = newLen;
vprog->Base.InputsRead |= VERT_BIT_POS;
vprog->Base.OutputsWritten |= (1 << VERT_RESULT_HPOS);
}