Don't always declare frag shader INPUT[0] as fragment position.

We were doing this for the sake of softpipe and the tgsi intergrepter since
we always need the fragment position and W-coordinate information in order
to compute fragment interpolants.
But that's not appropriate for hardware drivers.
The tgsi interpreter now get x,y,w information from a separate tgsi_exec_vector
variable setup by softpipe.
The new pipe_shader_state->input_map[] defines how vert shader outputs map
to frag shader inputs.  It may go away though, since one can also examine
the semantic label on frag shader input[0] to figure things out.

2 files changed, 11 insertions, 18 deletions

diff --git a/src/mesa/pipe/tgsi/exec/tgsi_exec.c b/src/mesa/pipe/tgsi/exec/tgsi_exec.c
index 03997f90996..1f43f3643ef 100644
--- a/src/mesa/pipe/tgsi/exec/tgsi_exec.c
+++ b/src/mesa/pipe/tgsi/exec/tgsi_exec.c
@@ -1352,7 +1352,8 @@ linear_interpolation(
    unsigned attrib,
    unsigned chan )
 {
-   const float x = mach->QuadX, y = mach->QuadY;
+   const float x = mach->QuadPos.xyzw[0].f[0];
+   const float y = mach->QuadPos.xyzw[1].f[0];
    const float dadx = mach->InterpCoefs[attrib].dadx[chan];
    const float dady = mach->InterpCoefs[attrib].dady[chan];
    const float a0 = mach->InterpCoefs[attrib].a0[chan] + dadx * x + dady * y;
@@ -1368,14 +1369,17 @@ perspective_interpolation(
    unsigned attrib,
    unsigned chan )
 {
-   const float x = mach->QuadX, y = mach->QuadY;
+   const float x = mach->QuadPos.xyzw[0].f[0];
+   const float y = mach->QuadPos.xyzw[1].f[0];
    const float dadx = mach->InterpCoefs[attrib].dadx[chan];
    const float dady = mach->InterpCoefs[attrib].dady[chan];
    const float a0 = mach->InterpCoefs[attrib].a0[chan] + dadx * x + dady * y;
-   mach->Inputs[attrib].xyzw[chan].f[0] = a0 / mach->Inputs[0].xyzw[3].f[0];
-   mach->Inputs[attrib].xyzw[chan].f[1] = (a0 + dadx) / mach->Inputs[0].xyzw[3].f[1];
-   mach->Inputs[attrib].xyzw[chan].f[2] = (a0 + dady) / mach->Inputs[0].xyzw[3].f[2];
-   mach->Inputs[attrib].xyzw[chan].f[3] = (a0 + dadx + dady) / mach->Inputs[0].xyzw[3].f[3];
+   const float *w = mach->QuadPos.xyzw[3].f;
+   /* divide by W here */
+   mach->Inputs[attrib].xyzw[chan].f[0] = a0 / w[0];
+   mach->Inputs[attrib].xyzw[chan].f[1] = (a0 + dadx) / w[1];
+   mach->Inputs[attrib].xyzw[chan].f[2] = (a0 + dady) / w[2];
+   mach->Inputs[attrib].xyzw[chan].f[3] = (a0 + dadx + dady) / w[3];
 }
 
 
@@ -1400,17 +1404,6 @@ exec_declaration(
          last = decl->u.DeclarationRange.Last;
          mask = decl->Declaration.UsageMask;
 
-         /* Do not touch WPOS.xy */
-         if( first == 0 ) {
-            mask &= ~TGSI_WRITEMASK_XY;
-            if( mask == TGSI_WRITEMASK_NONE ) {
-               first++;
-               if( first > last ) {
-                  return;
-               }
-            }
-         }
-
          switch( decl->Interpolation.Interpolate ) {
          case TGSI_INTERPOLATE_CONSTANT:
             interp = constant_interpolation;
diff --git a/src/mesa/pipe/tgsi/exec/tgsi_exec.h b/src/mesa/pipe/tgsi/exec/tgsi_exec.h
index 8d166bb5f42..db92e282dfb 100644
--- a/src/mesa/pipe/tgsi/exec/tgsi_exec.h
+++ b/src/mesa/pipe/tgsi/exec/tgsi_exec.h
@@ -170,7 +170,6 @@ struct tgsi_exec_machine
    struct tgsi_exec_vector       *Inputs;
    struct tgsi_exec_vector       *Outputs;
    const struct tgsi_token       *Tokens;
-   float                         QuadX, QuadY; /**< for frag progs only */
    unsigned                      Processor;
 
    /* GEOMETRY processor only. */
@@ -178,6 +177,7 @@ struct tgsi_exec_machine
 
    /* FRAGMENT processor only. */
    const struct tgsi_interp_coef *InterpCoefs;
+   struct tgsi_exec_vector       QuadPos;
 
    /* Conditional execution masks */
    uint CondMask;  /**< For IF/ELSE/ENDIF */