softpipe: add special cases for all Z compare modes for 16-bit Z buffer

We had fast paths for PIPE_FUNC_LESS and LEQUAL before.  To satisfy
OpenGL invariance rules, all depth compare modes should produce the
same fragment Z values.

Fixes progs/demos/singlebuffer.c

2 files changed, 195 insertions, 173 deletions

diff --git a/src/gallium/drivers/softpipe/sp_quad_depth_test.c b/src/gallium/drivers/softpipe/sp_quad_depth_test.c
index 4815a0d49f1..5854cee1be0 100644
--- a/src/gallium/drivers/softpipe/sp_quad_depth_test.c
+++ b/src/gallium/drivers/softpipe/sp_quad_depth_test.c
@@ -730,169 +730,36 @@ depth_test_quads_fallback(struct quad_stage *qs,
 
 
 /**
- * Special-case Z testing for 16-bit Zbuffer, PIPE_FUNC_LESS and
- * Z buffer writes enabled.
- *
- * NOTE: there's no guarantee that the quads are sequentially side by
- * side.  The fragment shader may have culled some quads, etc.  Sliver
- * triangles may generate non-sequential quads.
+ * Special-case Z testing for 16-bit Zbuffer and Z buffer writes enabled.
  */
-static void
-depth_interp_z16_less_write(struct quad_stage *qs, 
-                            struct quad_header *quads[],
-                            unsigned nr)
-{
-   unsigned i, pass = 0;
-   const unsigned ix = quads[0]->input.x0;
-   const unsigned iy = quads[0]->input.y0;
-   const float fx = (float) ix;
-   const float fy = (float) iy;
-   const float dzdx = quads[0]->posCoef->dadx[2];
-   const float dzdy = quads[0]->posCoef->dady[2];
-   const float z0 = quads[0]->posCoef->a0[2] + dzdx * fx + dzdy * fy;
-   struct softpipe_cached_tile *tile;
-   ushort (*depth16)[TILE_SIZE];
-   ushort init_idepth[4], idepth[4], depth_step;
-   const float scale = 65535.0;
-
-   /* compute scaled depth of the four pixels in first quad */
-   init_idepth[0] = (ushort)((z0) * scale);
-   init_idepth[1] = (ushort)((z0 + dzdx) * scale);
-   init_idepth[2] = (ushort)((z0 + dzdy) * scale);
-   init_idepth[3] = (ushort)((z0 + dzdx + dzdy) * scale);
-
-   depth_step = (ushort)(dzdx * scale);
-
-   tile = sp_get_cached_tile(qs->softpipe->zsbuf_cache, ix, iy);
-
-   for (i = 0; i < nr; i++) {
-      const unsigned outmask = quads[i]->inout.mask;
-      const int dx = quads[i]->input.x0 - ix;
-      unsigned mask = 0;
-
-      /* compute depth for this quad */
-      idepth[0] = init_idepth[0] + dx * depth_step;
-      idepth[1] = init_idepth[1] + dx * depth_step;
-      idepth[2] = init_idepth[2] + dx * depth_step;
-      idepth[3] = init_idepth[3] + dx * depth_step;
-
-      depth16 = (ushort (*)[TILE_SIZE])
-         &tile->data.depth16[iy % TILE_SIZE][(ix + dx)% TILE_SIZE];
-
-      if ((outmask & 1) && idepth[0] < depth16[0][0]) {
-         depth16[0][0] = idepth[0];
-         mask |= (1 << 0);
-      }
-
-      if ((outmask & 2) && idepth[1] < depth16[0][1]) {
-         depth16[0][1] = idepth[1];
-         mask |= (1 << 1);
-      }
-
-      if ((outmask & 4) && idepth[2] < depth16[1][0]) {
-         depth16[1][0] = idepth[2];
-         mask |= (1 << 2);
-      }
-
-      if ((outmask & 8) && idepth[3] < depth16[1][1]) {
-         depth16[1][1] = idepth[3];
-         mask |= (1 << 3);
-      }
-
-      quads[i]->inout.mask = mask;
-      if (quads[i]->inout.mask)
-         quads[pass++] = quads[i];
-   }
-
-   if (pass)
-      qs->next->run(qs->next, quads, pass);
-
-}
-
-
-/**
- * Special-case Z testing for 16-bit Zbuffer, PIPE_FUNC_LEQUAL and
- * Z buffer writes enabled.
- *
- * NOTE: there's no guarantee that the quads are sequentially side by
- * side.  The fragment shader may have culled some quads, etc.  Sliver
- * triangles may generate non-sequential quads.
- */
-static void
-depth_interp_z16_lequal_write(struct quad_stage *qs, 
-                            struct quad_header *quads[],
-                            unsigned nr)
-{
-   unsigned i, pass = 0;
-   const unsigned ix = quads[0]->input.x0;
-   const unsigned iy = quads[0]->input.y0;
-   const float fx = (float) ix;
-   const float fy = (float) iy;
-   const float dzdx = quads[0]->posCoef->dadx[2];
-   const float dzdy = quads[0]->posCoef->dady[2];
-   const float z0 = quads[0]->posCoef->a0[2] + dzdx * fx + dzdy * fy;
-   struct softpipe_cached_tile *tile;
-   ushort (*depth16)[TILE_SIZE];
-   ushort init_idepth[4], idepth[4], depth_step;
-   const float scale = 65535.0;
-
-   /* compute scaled depth of the four pixels in first quad */
-   init_idepth[0] = (ushort)((z0) * scale);
-   init_idepth[1] = (ushort)((z0 + dzdx) * scale);
-   init_idepth[2] = (ushort)((z0 + dzdy) * scale);
-   init_idepth[3] = (ushort)((z0 + dzdx + dzdy) * scale);
-
-   depth_step = (ushort)(dzdx * scale);
-
-   tile = sp_get_cached_tile(qs->softpipe->zsbuf_cache, ix, iy);
-
-   for (i = 0; i < nr; i++) {
-      const unsigned outmask = quads[i]->inout.mask;
-      const int dx = quads[i]->input.x0 - ix;
-      unsigned mask = 0;
-      
-      /* compute depth for this quad */
-      idepth[0] = init_idepth[0] + dx * depth_step;
-      idepth[1] = init_idepth[1] + dx * depth_step;
-      idepth[2] = init_idepth[2] + dx * depth_step;
-      idepth[3] = init_idepth[3] + dx * depth_step;
-
-      depth16 = (ushort (*)[TILE_SIZE])
-         &tile->data.depth16[iy % TILE_SIZE][(ix + dx)% TILE_SIZE];
 
-      if ((outmask & 1) && idepth[0] <= depth16[0][0]) {
-         depth16[0][0] = idepth[0];
-         mask |= (1 << 0);
-      }
-
-      if ((outmask & 2) && idepth[1] <= depth16[0][1]) {
-         depth16[0][1] = idepth[1];
-         mask |= (1 << 1);
-      }
+#define NAME depth_interp_z16_less_write
+#define OPERATOR <
+#include "sp_quad_depth_test_tmp.h"
 
-      if ((outmask & 4) && idepth[2] <= depth16[1][0]) {
-         depth16[1][0] = idepth[2];
-         mask |= (1 << 2);
-      }
+#define NAME depth_interp_z16_equal_write
+#define OPERATOR ==
+#include "sp_quad_depth_test_tmp.h"
 
-      if ((outmask & 8) && idepth[3] <= depth16[1][1]) {
-         depth16[1][1] = idepth[3];
-         mask |= (1 << 3);
-      }
+#define NAME depth_interp_z16_lequal_write
+#define OPERATOR <=
+#include "sp_quad_depth_test_tmp.h"
 
-      depth16 = (ushort (*)[TILE_SIZE]) &depth16[0][2];
+#define NAME depth_interp_z16_greater_write
+#define OPERATOR >
+#include "sp_quad_depth_test_tmp.h"
 
-      quads[i]->inout.mask = mask;
-      if (quads[i]->inout.mask)
-         quads[pass++] = quads[i];
-   }
-
-   if (pass)
-      qs->next->run(qs->next, quads, pass);
-
-}
+#define NAME depth_interp_z16_notequal_write
+#define OPERATOR !=
+#include "sp_quad_depth_test_tmp.h"
 
+#define NAME depth_interp_z16_gequal_write
+#define OPERATOR >=
+#include "sp_quad_depth_test_tmp.h"
 
+#define NAME depth_interp_z16_always_write
+#define ALWAYS 1
+#include "sp_quad_depth_test_tmp.h"
 
 
 
@@ -926,6 +793,10 @@ choose_depth_test(struct quad_stage *qs,
 
    boolean occlusion = qs->softpipe->active_query_count;
 
+   /* default */
+   qs->run = depth_test_quads_fallback;
+
+   /* look for special cases */
    if (!alpha &&
        !depth &&
        !stencil) {
@@ -938,36 +809,40 @@ choose_depth_test(struct quad_stage *qs,
             !occlusion &&
             !stencil) 
    {
-      switch (depthfunc) {
-      case PIPE_FUNC_LESS:
-         switch (qs->softpipe->framebuffer.zsbuf->format) {
-         case PIPE_FORMAT_Z16_UNORM:
+      if (qs->softpipe->framebuffer.zsbuf->format == PIPE_FORMAT_Z16_UNORM) {
+         switch (depthfunc) {
+         case PIPE_FUNC_NEVER:
+            qs->run = depth_test_quads_fallback;
+            break;
+         case PIPE_FUNC_LESS:
             qs->run = depth_interp_z16_less_write;
             break;
-         default:
-            qs->run = depth_test_quads_fallback;
+         case PIPE_FUNC_EQUAL:
+            qs->run = depth_interp_z16_equal_write;
             break;
-         }
-         break;
-      case PIPE_FUNC_LEQUAL:
-         switch (qs->softpipe->framebuffer.zsbuf->format) {
-         case PIPE_FORMAT_Z16_UNORM:
+         case PIPE_FUNC_LEQUAL:
             qs->run = depth_interp_z16_lequal_write;
             break;
+         case PIPE_FUNC_GREATER:
+            qs->run = depth_interp_z16_greater_write;
+            break;
+         case PIPE_FUNC_NOTEQUAL:
+            qs->run = depth_interp_z16_notequal_write;
+            break;
+         case PIPE_FUNC_GEQUAL:
+            qs->run = depth_interp_z16_gequal_write;
+            break;
+         case PIPE_FUNC_ALWAYS:
+            qs->run = depth_interp_z16_always_write;
+            break;
          default:
             qs->run = depth_test_quads_fallback;
             break;
          }
-         break;
-      default:
-         qs->run = depth_test_quads_fallback;
       }
    }
-   else {
-      qs->run = depth_test_quads_fallback;
-   }
-
 
+   /* next quad/fragment stage */
    qs->run( qs, quads, nr );
 }
 
diff --git a/src/gallium/drivers/softpipe/sp_quad_depth_test_tmp.h b/src/gallium/drivers/softpipe/sp_quad_depth_test_tmp.h
new file mode 100644
index 00000000000..25af415c256
--- /dev/null
+++ b/src/gallium/drivers/softpipe/sp_quad_depth_test_tmp.h
@@ -0,0 +1,147 @@
+/**************************************************************************
+ * 
+ * Copyright 2010 VMware, Inc.  All Rights Reserved.
+ * 
+ * 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, sub license, 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 NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS 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.
+ * 
+ **************************************************************************/
+
+
+/*
+ * Template for generating Z test functions
+ * Only PIPE_FORMAT_Z16_UNORM supported at this time.
+ */
+
+
+#ifndef NAME
+#error "NAME is not defined!"
+#endif
+
+#if !defined(OPERATOR) && !defined(ALWAYS)
+#error "neither OPERATOR nor ALWAYS is defined!"
+#endif
+
+
+/*
+ * NOTE: there's no guarantee that the quads are sequentially side by
+ * side.  The fragment shader may have culled some quads, etc.  Sliver
+ * triangles may generate non-sequential quads.
+ */
+static void
+NAME(struct quad_stage *qs, 
+     struct quad_header *quads[],
+     unsigned nr)
+{
+   unsigned i, pass = 0;
+   const unsigned ix = quads[0]->input.x0;
+   const unsigned iy = quads[0]->input.y0;
+   const float fx = (float) ix;
+   const float fy = (float) iy;
+   const float dzdx = quads[0]->posCoef->dadx[2];
+   const float dzdy = quads[0]->posCoef->dady[2];
+   const float z0 = quads[0]->posCoef->a0[2] + dzdx * fx + dzdy * fy;
+   struct softpipe_cached_tile *tile;
+   ushort (*depth16)[TILE_SIZE];
+   ushort init_idepth[4], idepth[4], depth_step;
+   const float scale = 65535.0;
+
+   /* compute scaled depth of the four pixels in first quad */
+   init_idepth[0] = (ushort)((z0) * scale);
+   init_idepth[1] = (ushort)((z0 + dzdx) * scale);
+   init_idepth[2] = (ushort)((z0 + dzdy) * scale);
+   init_idepth[3] = (ushort)((z0 + dzdx + dzdy) * scale);
+
+   depth_step = (ushort)(dzdx * scale);
+
+   tile = sp_get_cached_tile(qs->softpipe->zsbuf_cache, ix, iy);
+
+   for (i = 0; i < nr; i++) {
+      const unsigned outmask = quads[i]->inout.mask;
+      const int dx = quads[i]->input.x0 - ix;
+      unsigned mask = 0;
+      
+      /* compute depth for this quad */
+      idepth[0] = init_idepth[0] + dx * depth_step;
+      idepth[1] = init_idepth[1] + dx * depth_step;
+      idepth[2] = init_idepth[2] + dx * depth_step;
+      idepth[3] = init_idepth[3] + dx * depth_step;
+
+      depth16 = (ushort (*)[TILE_SIZE])
+         &tile->data.depth16[iy % TILE_SIZE][(ix + dx)% TILE_SIZE];
+
+#ifdef ALWAYS
+      if (outmask & 1) {
+         depth16[0][0] = idepth[0];
+         mask |= (1 << 0);
+      }
+
+      if (outmask & 2) {
+         depth16[0][1] = idepth[1];
+         mask |= (1 << 1);
+      }
+
+      if (outmask & 4) {
+         depth16[1][0] = idepth[2];
+         mask |= (1 << 2);
+      }
+
+      if (outmask & 8) {
+         depth16[1][1] = idepth[3];
+         mask |= (1 << 3);
+      }
+#else
+      /* Note: OPERATOR appears here: */
+      if ((outmask & 1) && (idepth[0] OPERATOR depth16[0][0])) {
+         depth16[0][0] = idepth[0];
+         mask |= (1 << 0);
+      }
+
+      if ((outmask & 2) && (idepth[1] OPERATOR depth16[0][1])) {
+         depth16[0][1] = idepth[1];
+         mask |= (1 << 1);
+      }
+
+      if ((outmask & 4) && (idepth[2] OPERATOR depth16[1][0])) {
+         depth16[1][0] = idepth[2];
+         mask |= (1 << 2);
+      }
+
+      if ((outmask & 8) && (idepth[3] OPERATOR depth16[1][1])) {
+         depth16[1][1] = idepth[3];
+         mask |= (1 << 3);
+      }
+#endif
+
+      depth16 = (ushort (*)[TILE_SIZE]) &depth16[0][2];
+
+      quads[i]->inout.mask = mask;
+      if (quads[i]->inout.mask)
+         quads[pass++] = quads[i];
+   }
+
+   if (pass)
+      qs->next->run(qs->next, quads, pass);
+}
+
+
+#undef NAME
+#undef OPERATOR
+#undef ALWAYS