st/mesa: add support for POSITION and FACE system values

Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com
Reviewed-by: Brian Paul <brianp@vmware.com>

4 files changed, 44 insertions, 16 deletions

diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 91ad169d786..2a3e52362e4 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -327,6 +327,11 @@ void st_init_limits(struct pipe_screen *screen,
          c->Program[MESA_SHADER_FRAGMENT].MaxUniformBlocks;
       assert(c->MaxCombinedUniformBlocks <= MAX_COMBINED_UNIFORM_BUFFERS);
    }
+
+   c->GLSLFragCoordIsSysVal =
+      screen->get_param(screen, PIPE_CAP_TGSI_FS_POSITION_IS_SYSVAL);
+   c->GLSLFrontFacingIsSysVal =
+      screen->get_param(screen, PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL);
 }
 
 
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 9308eb4841e..27a0a4f51e1 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -4906,10 +4906,11 @@ compile_tgsi_instruction(struct st_translate *t,
  * a FBO is bound (STATE_FB_WPOS_Y_TRANSFORM).
  */
 static void
-emit_wpos_adjustment( struct st_translate *t,
-                      int wpos_transform_const,
-                      boolean invert,
-                      GLfloat adjX, GLfloat adjY[2])
+emit_wpos_adjustment(struct gl_context *ctx,
+                     struct st_translate *t,
+                     int wpos_transform_const,
+                     boolean invert,
+                     GLfloat adjX, GLfloat adjY[2])
 {
    struct ureg_program *ureg = t->ureg;
 
@@ -4921,7 +4922,11 @@ emit_wpos_adjustment( struct st_translate *t,
     */
    struct ureg_src wpostrans = ureg_DECL_constant(ureg, wpos_transform_const);
    struct ureg_dst wpos_temp = ureg_DECL_temporary( ureg );
-   struct ureg_src wpos_input = t->inputs[t->inputMapping[VARYING_SLOT_POS]];
+   struct ureg_src *wpos =
+      ctx->Const.GLSLFragCoordIsSysVal ?
+         &t->systemValues[SYSTEM_VALUE_FRAG_COORD] :
+         &t->inputs[t->inputMapping[VARYING_SLOT_POS]];
+   struct ureg_src wpos_input = *wpos;
 
    /* First, apply the coordinate shift: */
    if (adjX || adjY[0] || adjY[1]) {
@@ -4972,7 +4977,7 @@ emit_wpos_adjustment( struct st_translate *t,
 
    /* Use wpos_temp as position input from here on:
     */
-   t->inputs[t->inputMapping[VARYING_SLOT_POS]] = ureg_src(wpos_temp);
+   *wpos = ureg_src(wpos_temp);
 }
 
 
@@ -5081,7 +5086,7 @@ emit_wpos(struct st_context *st,
 
    /* we invert after adjustment so that we avoid the MOV to temporary,
     * and reuse the adjustment ADD instead */
-   emit_wpos_adjustment(t, wpos_transform_const, invert, adjX, adjY);
+   emit_wpos_adjustment(st->ctx, t, wpos_transform_const, invert, adjX, adjY);
 }
 
 /**
@@ -5399,6 +5404,11 @@ st_translate_program(
                }
             }
 
+            if (procType == TGSI_PROCESSOR_FRAGMENT &&
+                semName == TGSI_SEMANTIC_POSITION)
+               emit_wpos(st_context(ctx), t, proginfo, ureg,
+                         program->wpos_transform_const);
+
             sysInputs &= ~(1 << i);
          }
       }
@@ -5685,7 +5695,8 @@ get_mesa_program(struct gl_context *ctx,
 
    /* This must be done before the uniform storage is associated. */
    if (shader->Type == GL_FRAGMENT_SHADER &&
-       prog->InputsRead & VARYING_BIT_POS){
+       (prog->InputsRead & VARYING_BIT_POS ||
+        prog->SystemValuesRead & (1 << SYSTEM_VALUE_FRAG_COORD))) {
       static const gl_state_index wposTransformState[STATE_LENGTH] = {
          STATE_INTERNAL, STATE_FB_WPOS_Y_TRANSFORM
       };
diff --git a/src/mesa/state_tracker/st_mesa_to_tgsi.c b/src/mesa/state_tracker/st_mesa_to_tgsi.c
index 20dc3d15df7..be47823a048 100644
--- a/src/mesa/state_tracker/st_mesa_to_tgsi.c
+++ b/src/mesa/state_tracker/st_mesa_to_tgsi.c
@@ -717,10 +717,11 @@ compile_instruction(
  * a FBO is bound (STATE_FB_WPOS_Y_TRANSFORM).
  */
 static void
-emit_wpos_adjustment( struct st_translate *t,
-                      const struct gl_program *program,
-                      boolean invert,
-                      GLfloat adjX, GLfloat adjY[2])
+emit_wpos_adjustment(struct gl_context *ctx,
+                     struct st_translate *t,
+                     const struct gl_program *program,
+                     boolean invert,
+                     GLfloat adjX, GLfloat adjY[2])
 {
    struct ureg_program *ureg = t->ureg;
 
@@ -740,7 +741,11 @@ emit_wpos_adjustment( struct st_translate *t,
 
    struct ureg_src wpostrans = ureg_DECL_constant( ureg, wposTransConst );
    struct ureg_dst wpos_temp = ureg_DECL_temporary( ureg );
-   struct ureg_src wpos_input = t->inputs[t->inputMapping[VARYING_SLOT_POS]];
+   struct ureg_src *wpos =
+      ctx->Const.GLSLFragCoordIsSysVal ?
+         &t->systemValues[SYSTEM_VALUE_FRAG_COORD] :
+         &t->inputs[t->inputMapping[VARYING_SLOT_POS]];
+   struct ureg_src wpos_input = *wpos;
 
    /* First, apply the coordinate shift: */
    if (adjX || adjY[0] || adjY[1]) {
@@ -791,7 +796,7 @@ emit_wpos_adjustment( struct st_translate *t,
 
    /* Use wpos_temp as position input from here on:
     */
-   t->inputs[t->inputMapping[VARYING_SLOT_POS]] = ureg_src(wpos_temp);
+   *wpos = ureg_src(wpos_temp);
 }
 
 
@@ -899,7 +904,7 @@ emit_wpos(struct st_context *st,
 
    /* we invert after adjustment so that we avoid the MOV to temporary,
     * and reuse the adjustment ADD instead */
-   emit_wpos_adjustment(t, program, invert, adjX, adjY);
+   emit_wpos_adjustment(st->ctx, t, program, invert, adjX, adjY);
 }
 
 
@@ -1077,6 +1082,10 @@ st_translate_mesa_program(
                }
             }
 
+            if (procType == TGSI_PROCESSOR_FRAGMENT &&
+                semName == TGSI_SEMANTIC_POSITION)
+               emit_wpos(st_context(ctx), t, program, ureg);
+
             sysInputs &= ~(1 << i);
          }
       }
diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index 39c54c256e0..b3954547418 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -581,8 +581,11 @@ st_translate_fragment_program(struct st_context *st,
 
    memset(inputSlotToAttr, ~0, sizeof(inputSlotToAttr));
 
-   if (!stfp->glsl_to_tgsi)
+   if (!stfp->glsl_to_tgsi) {
       _mesa_remove_output_reads(&stfp->Base.Base, PROGRAM_OUTPUT);
+      if (st->ctx->Const.GLSLFragCoordIsSysVal)
+         _mesa_program_fragment_position_to_sysval(&stfp->Base.Base);
+   }
 
    /*
     * Convert Mesa program inputs to TGSI input register semantics.