i965 Gen4/5: Introduce 'interpolation map' alongside the VUE map

The interpolation map (in brw->interpolation_mode) is a new auxiliary
structure alongside the post-GS VUE map, which describes the
interpolation modes for each VUE slot, for use by the clip and SF
stages.

This patch introduces a new state atom to compute the interpolation map,
and adjusts the program keys for the clip and SF stages, but it is not
actually used yet.

[V1-2]: Signed-off-by: Olivier Galibert <galibert at pobox.com>

V3: Updated for vue_map changes, intel -> brw merge, etc. (Chris Forbes)
V4: Compute interpolation map as a new state atom rather than tacking it
on the front of the clip setup
V5: Rework commit message, make interpolation_mode_map a struct.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i965/Makefile.sources

@@ -62,6 +62,7 @@ i965_FILES = \
 	brw_gs.c \
 	brw_gs_emit.c \
 	brw_gs_state.c \
+	brw_interpolation_map.c \
 	brw_lower_texture_gradients.cpp \
 	brw_misc_state.c \
 	brw_program.c \

src/mesa/drivers/dri/i965/brw_clip.c

@@ -141,6 +141,10 @@ brw_upload_clip_prog(struct brw_context *brw)
 
    /* Populate the key:
     */
+
+   /* BRW_NEW_INTERPOLATION_MAP */
+   key.interpolation_mode = brw->interpolation_mode;
+
    /* BRW_NEW_REDUCED_PRIMITIVE */
    key.primitive = brw->reduced_primitive;
    /* BRW_NEW_VUE_MAP_GEOM_OUT */
@@ -256,7 +260,9 @@ const struct brw_tracked_state brw_clip_prog = {
 		_NEW_TRANSFORM |
 		_NEW_POLYGON | 
 		_NEW_BUFFERS),
-      .brw   = (BRW_NEW_REDUCED_PRIMITIVE | BRW_NEW_VUE_MAP_GEOM_OUT)
+      .brw   = (BRW_NEW_REDUCED_PRIMITIVE |
+                BRW_NEW_VUE_MAP_GEOM_OUT |
+                BRW_NEW_INTERPOLATION_MAP)
    },
    .emit = brw_upload_clip_prog
 };

src/mesa/drivers/dri/i965/brw_clip.h

@@ -43,6 +43,7 @@
  */
 struct brw_clip_prog_key {
    GLbitfield64 attrs;
+   struct interpolation_mode_map interpolation_mode;
    GLuint primitive:4;
    GLuint nr_userclip:4;
    GLuint do_flat_shading:1;

src/mesa/drivers/dri/i965/brw_context.h

@@ -154,6 +154,7 @@ enum brw_state_id {
    BRW_STATE_STATS_WM,
    BRW_STATE_UNIFORM_BUFFER,
    BRW_STATE_META_IN_PROGRESS,
+   BRW_STATE_INTERPOLATION_MAP,
 };
 
 #define BRW_NEW_URB_FENCE               (1 << BRW_STATE_URB_FENCE)
@@ -186,6 +187,7 @@ enum brw_state_id {
 #define BRW_NEW_STATS_WM		(1 << BRW_STATE_STATS_WM)
 #define BRW_NEW_UNIFORM_BUFFER          (1 << BRW_STATE_UNIFORM_BUFFER)
 #define BRW_NEW_META_IN_PROGRESS        (1 << BRW_STATE_META_IN_PROGRESS)
+#define BRW_NEW_INTERPOLATION_MAP       (1 << BRW_STATE_INTERPOLATION_MAP)
 
 struct brw_state_flags {
    /** State update flags signalled by mesa internals */
@@ -411,6 +413,14 @@ void brw_compute_vue_map(struct brw_context *brw, struct brw_vue_map *vue_map,
                          GLbitfield64 slots_valid, bool userclip_active);
 
 
+/*
+ * Mapping of VUE map slots to interpolation modes.
+ */
+struct interpolation_mode_map {
+   unsigned char mode[BRW_VARYING_SLOT_COUNT];
+};
+
+
 struct brw_sf_prog_data {
    GLuint urb_read_length;
    GLuint total_grf;
@@ -1203,6 +1213,11 @@ struct brw_context
    uint32_t render_target_format[MESA_FORMAT_COUNT];
    bool format_supported_as_render_target[MESA_FORMAT_COUNT];
 
+   /* Interpolation modes, one byte per vue slot.
+    * Used Gen4/5 by the clip|sf|wm stages. Ignored on Gen6+.
+    */
+   struct interpolation_mode_map interpolation_mode;
+
    /* PrimitiveRestart */
    struct {
       bool in_progress;

src/mesa/drivers/dri/i965/brw_interpolation_map.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "brw_state.h"
+
+
+/* Set up interpolation modes for every element in the VUE */
+static void
+brw_setup_vue_interpolation(struct brw_context *brw)
+{
+   const struct gl_fragment_program *fprog = brw->fragment_program;
+   struct brw_vue_map *vue_map = &brw->vue_map_geom_out;
+
+   memset(&brw->interpolation_mode, INTERP_QUALIFIER_NONE, sizeof(brw->interpolation_mode));
+
+   brw->state.dirty.brw |= BRW_NEW_INTERPOLATION_MAP;
+
+   if (!fprog)
+      return;
+
+   for (int i = 0; i < vue_map->num_slots; i++) {
+      int varying = vue_map->slot_to_varying[i];
+      if (varying == -1)
+         continue;
+
+      /* HPOS always wants noperspective. setting it up here allows
+       * us to not need special handling in the SF program. */
+      if (varying == VARYING_SLOT_POS) {
+         brw->interpolation_mode.mode[i] = INTERP_QUALIFIER_NOPERSPECTIVE;
+         continue;
+      }
+
+      int frag_attrib = varying;
+      if (varying == VARYING_SLOT_BFC0 || varying == VARYING_SLOT_BFC1)
+         frag_attrib = varying - VARYING_SLOT_BFC0 + VARYING_SLOT_COL0;
+
+      if (!(fprog->Base.InputsRead & BITFIELD64_BIT(frag_attrib)))
+         continue;
+
+      enum glsl_interp_qualifier mode = fprog->InterpQualifier[frag_attrib];
+
+      /* If the mode is not specified, the default varies: Color values
+       * follow GL_SHADE_MODEL; everything else is smooth.
+       */
+      if (mode == INTERP_QUALIFIER_NONE) {
+         if (frag_attrib == VARYING_SLOT_COL0 || frag_attrib == VARYING_SLOT_COL1)
+            mode = brw->ctx.Light.ShadeModel == GL_FLAT
+               ? INTERP_QUALIFIER_FLAT : INTERP_QUALIFIER_SMOOTH;
+         else
+            mode = INTERP_QUALIFIER_SMOOTH;
+      }
+
+      brw->interpolation_mode.mode[i] = mode;
+   }
+}
+
+
+const struct brw_tracked_state brw_interpolation_map = {
+   .dirty = {
+      .mesa  = _NEW_LIGHT,
+      .brw   = (BRW_NEW_FRAGMENT_PROGRAM |
+                BRW_NEW_VUE_MAP_GEOM_OUT)
+   },
+   .emit = brw_setup_vue_interpolation
+};

src/mesa/drivers/dri/i965/brw_sf.c

@@ -189,6 +189,9 @@ brw_upload_sf_prog(struct brw_context *brw)
    if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo)
       key.sprite_origin_lower_left = true;
 
+   /* BRW_NEW_INTERPOLATION_MAP */
+   key.interpolation_mode = brw->interpolation_mode;
+
    /* _NEW_LIGHT | _NEW_PROGRAM */
    key.do_flat_shading = (ctx->Light.ShadeModel == GL_FLAT);
    key.do_twoside_color = ((ctx->Light.Enabled && ctx->Light.Model.TwoSide) ||
@@ -215,7 +218,9 @@ const struct brw_tracked_state brw_sf_prog = {
    .dirty = {
       .mesa  = (_NEW_HINT | _NEW_LIGHT | _NEW_POLYGON | _NEW_POINT |
                 _NEW_TRANSFORM | _NEW_BUFFERS | _NEW_PROGRAM),
-      .brw   = (BRW_NEW_REDUCED_PRIMITIVE | BRW_NEW_VUE_MAP_GEOM_OUT)
+      .brw   = (BRW_NEW_REDUCED_PRIMITIVE |
+                BRW_NEW_VUE_MAP_GEOM_OUT |
+                BRW_NEW_INTERPOLATION_MAP)
    },
    .emit = brw_upload_sf_prog
 };

src/mesa/drivers/dri/i965/brw_sf.h

@@ -46,6 +46,7 @@
 
 struct brw_sf_prog_key {
    GLbitfield64 attrs;
+   struct interpolation_mode_map interpolation_mode;
    uint8_t point_sprite_coord_replace;
    GLuint primitive:2;
    GLuint do_twoside_color:1;

src/mesa/drivers/dri/i965/brw_state.h

@@ -76,6 +76,7 @@ extern const struct brw_tracked_state brw_wm_binding_table;
 extern const struct brw_tracked_state brw_vs_binding_table;
 extern const struct brw_tracked_state brw_wm_ubo_surfaces;
 extern const struct brw_tracked_state brw_wm_unit;
+extern const struct brw_tracked_state brw_interpolation_map;
 
 extern const struct brw_tracked_state brw_psp_urb_cbs;
 

src/mesa/drivers/dri/i965/brw_state_upload.c

@@ -41,6 +41,9 @@ static const struct brw_tracked_state *gen4_atoms[] =
 {
    &brw_vs_prog, /* must do before GS prog, state base address. */
    &brw_gs_prog, /* must do before state base address */
+
+   &brw_interpolation_map,
+
    &brw_clip_prog, /* must do before state base address */
    &brw_sf_prog, /* must do before state base address */
    &brw_wm_prog, /* must do before state base address */