mesa: new _mesa_set_vp_override() function for driver-override of vertex program

Patch provide by Keith.
Used in state tracker by DrawPixels to indicate that the state tracker (driver)
is using its own vertex program.  This prevents the texenvprogram code from
replacing conventional shader inputs with state vars.
Fixes glDraw/CopyPixels regressions.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/mesa/main/texenvprogram.c b/src/mesa/main/texenvprogram.c
index 638d6be5ad6..f3bac86dfe0 100644
--- a/src/mesa/main/texenvprogram.c
+++ b/src/mesa/main/texenvprogram.c
@@ -205,8 +205,18 @@ static GLbitfield get_fp_input_mask( GLcontext *ctx )
 {
    GLbitfield fp_inputs = 0x0;
 
-   if (!ctx->VertexProgram._Enabled ||
-       !ctx->VertexProgram._Current) {
+   if (ctx->VertexProgram._Overriden) {
+      /* Somebody's messing with the vertex program and we don't have
+       * a clue what's happening.  Assume that it could be producing
+       * all possible outputs.
+       */
+      fp_inputs = ~0;
+   }
+   else if (ctx->RenderMode == GL_FEEDBACK) {
+      fp_inputs = (FRAG_BIT_COL0 | FRAG_BIT_TEX0);
+   }
+   else if (!ctx->VertexProgram._Enabled ||
+            !ctx->VertexProgram._Current) {
 
       /* Fixed function logic */
       GLbitfield varying_inputs = ctx->varying_vp_inputs;