Mesa (master): vc4: Consume the implicit varyings for points and lines.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: ba875b3a0d8119fda030dfdc28cd831d9ca51e08
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ba875b3a0d8119fda030dfdc28cd831d9ca51e08

Author: Eric Anholt <eric at anholt.net>
Date:   Tue Aug 12 15:50:53 2014 -0700

vc4: Consume the implicit varyings for points and lines.

We were triggering simulator assertion failures for not consuming these,
and presumably we want to actually make use of them some day (for things
like point/line antialiasing)

Note that this has the qreg index as 0, which is the same index as the
first GL varyings read.  This doesn't matter currently, since that number
isn't used for anything except dumping.

---

 src/gallium/drivers/vc4/vc4_context.h |    2 +-
 src/gallium/drivers/vc4/vc4_draw.c    |    2 +-
 src/gallium/drivers/vc4/vc4_program.c |   41 +++++++++++++++++++++++++--------
 3 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/src/gallium/drivers/vc4/vc4_context.h b/src/gallium/drivers/vc4/vc4_context.h
index bdd174c..641609b 100644
--- a/src/gallium/drivers/vc4/vc4_context.h
+++ b/src/gallium/drivers/vc4/vc4_context.h
@@ -227,6 +227,6 @@ void vc4_flush(struct pipe_context *pctx);
 void vc4_flush_for_bo(struct pipe_context *pctx, struct vc4_bo *bo);
 void vc4_emit_state(struct pipe_context *pctx);
 void vc4_generate_code(struct qcompile *c);
-void vc4_update_compiled_shaders(struct vc4_context *vc4);
+void vc4_update_compiled_shaders(struct vc4_context *vc4, uint8_t prim_mode);
 
 #endif /* VC4_CONTEXT_H */
diff --git a/src/gallium/drivers/vc4/vc4_draw.c b/src/gallium/drivers/vc4/vc4_draw.c
index ec218d3..3f19862 100644
--- a/src/gallium/drivers/vc4/vc4_draw.c
+++ b/src/gallium/drivers/vc4/vc4_draw.c
@@ -99,7 +99,7 @@ vc4_draw_vbo(struct pipe_context *pctx, const struct pipe_draw_info *info)
         }
 
         vc4_start_draw(vc4);
-        vc4_update_compiled_shaders(vc4);
+        vc4_update_compiled_shaders(vc4, info->mode);
 
         vc4_emit_state(pctx);
 
diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
index c87ea52..e99abc6 100644
--- a/src/gallium/drivers/vc4/vc4_program.c
+++ b/src/gallium/drivers/vc4/vc4_program.c
@@ -47,6 +47,8 @@ struct tgsi_to_qir {
         struct qreg *outputs;
         struct qreg *uniforms;
         struct qreg *consts;
+        struct qreg line_x, point_x, point_y;
+
         uint32_t num_consts;
 
         struct pipe_shader_state *shader_state;
@@ -68,6 +70,8 @@ struct vc4_fs_key {
         struct vc4_key base;
         enum pipe_format color_format;
         bool depth_enabled;
+        bool is_points;
+        bool is_lines;
 };
 
 struct vc4_vs_key {
@@ -600,20 +604,28 @@ emit_fragcoord_input(struct tgsi_to_qir *trans, int attr)
         trans->inputs[attr * 4 + 3] = qir_FRAG_RCP_W(c);
 }
 
+static struct qreg
+emit_fragment_varying(struct tgsi_to_qir *trans, int index)
+{
+        struct qcompile *c = trans->c;
+
+        struct qreg vary = {
+                QFILE_VARY,
+                index
+        };
+
+        /* XXX: multiply by W */
+        return qir_VARY_ADD_C(c, qir_MOV(c, vary));
+}
+
 static void
 emit_fragment_input(struct tgsi_to_qir *trans, int attr)
 {
         struct qcompile *c = trans->c;
 
         for (int i = 0; i < 4; i++) {
-                struct qreg vary = {
-                        QFILE_VARY,
-                        attr * 4 + i
-                };
-
-                /* XXX: multiply by W */
                 trans->inputs[attr * 4 + i] =
-                        qir_VARY_ADD_C(c, qir_MOV(c, vary));
+                        emit_fragment_varying(trans, attr * 4 + i);
                 c->num_inputs++;
         }
 }
@@ -906,6 +918,12 @@ vc4_shader_tgsi_to_qir(struct vc4_compiled_shader *shader, enum qstage stage,
         switch (stage) {
         case QSTAGE_FRAG:
                 trans->fs_key = (struct vc4_fs_key *)key;
+                if (trans->fs_key->is_points) {
+                        trans->point_x = emit_fragment_varying(trans, 0);
+                        trans->point_y = emit_fragment_varying(trans, 0);
+                } else if (trans->fs_key->is_lines) {
+                        trans->line_x = emit_fragment_varying(trans, 0);
+                }
                 break;
         case QSTAGE_VERT:
                 trans->vs_key = (struct vc4_vs_key *)key;
@@ -1047,13 +1065,16 @@ vc4_vs_compile(struct vc4_context *vc4, struct vc4_compiled_shader *shader,
 }
 
 static void
-vc4_update_compiled_fs(struct vc4_context *vc4)
+vc4_update_compiled_fs(struct vc4_context *vc4, uint8_t prim_mode)
 {
         struct vc4_fs_key local_key;
         struct vc4_fs_key *key = &local_key;
 
         memset(key, 0, sizeof(*key));
         key->base.shader_state = vc4->prog.bind_fs;
+        key->is_points = (prim_mode == PIPE_PRIM_POINTS);
+        key->is_lines = (prim_mode >= PIPE_PRIM_LINES &&
+                         prim_mode <= PIPE_PRIM_LINE_STRIP);
 
         if (vc4->framebuffer.cbufs[0])
                 key->color_format = vc4->framebuffer.cbufs[0]->format;
@@ -1101,9 +1122,9 @@ vc4_update_compiled_vs(struct vc4_context *vc4)
 }
 
 void
-vc4_update_compiled_shaders(struct vc4_context *vc4)
+vc4_update_compiled_shaders(struct vc4_context *vc4, uint8_t prim_mode)
 {
-        vc4_update_compiled_fs(vc4);
+        vc4_update_compiled_fs(vc4, prim_mode);
         vc4_update_compiled_vs(vc4);
 }