[Mesa-dev] [PATCH] softpipe: add depth clamping support.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This passes the piglit depth clamp tests.

this is required for GL 3.2.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/drivers/softpipe/sp_quad_depth_test.c | 37 ++++++++++++++++++-----
 src/gallium/drivers/softpipe/sp_screen.c          |  2 +-
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/src/gallium/drivers/softpipe/sp_quad_depth_test.c b/src/gallium/drivers/softpipe/sp_quad_depth_test.c
index f4d7993..2a63fa0 100644
--- a/src/gallium/drivers/softpipe/sp_quad_depth_test.c
+++ b/src/gallium/drivers/softpipe/sp_quad_depth_test.c
@@ -148,10 +148,11 @@ interpolate_quad_depth( struct quad_header *quad )
  * Compute the depth_data::qzzzz[] values from the float fragment Z values.
  */
 static void
-convert_quad_depth( struct depth_data *data, 
+convert_quad_depth( struct quad_stage *qs, struct depth_data *data, 
                     const struct quad_header *quad )
 {
    unsigned j;
+   float dvals[TGSI_QUAD_SIZE];
 
    /* Convert quad's float depth values to int depth values (qzzzz).
     * If the Z buffer stores integer values, we _have_ to do the depth
@@ -159,13 +160,31 @@ convert_quad_depth( struct depth_data *data,
     * conversion of Z values (which isn't an identity function) will cause
     * Z-fighting errors.
     */
+   if (!qs->softpipe->rasterizer->depth_clip) {
+      float near_val, far_val;
+      float minval, maxval;
+
+      near_val = qs->softpipe->viewport.translate[2] - qs->softpipe->viewport.scale[2];
+      far_val = near_val + (qs->softpipe->viewport.scale[2] * 2.0);
+
+      minval = MIN2(near_val, far_val);
+      maxval = MAX2(near_val, far_val);
+      for (j = 0; j < TGSI_QUAD_SIZE; j++) {
+         dvals[j] = CLAMP(quad->output.depth[j], minval, maxval);
+      }
+   } else {
+      for (j = 0; j < TGSI_QUAD_SIZE; j++) {
+         dvals[j] = quad->output.depth[j];
+      }
+   }
+
    switch (data->format) {
    case PIPE_FORMAT_Z16_UNORM:
       {
          float scale = 65535.0;
 
          for (j = 0; j < TGSI_QUAD_SIZE; j++) {
-            data->qzzzz[j] = (unsigned) (quad->output.depth[j] * scale);
+            data->qzzzz[j] = (unsigned) (dvals[j] * scale);
          }
       }
       break;
@@ -174,7 +193,7 @@ convert_quad_depth( struct depth_data *data,
          double scale = (double) (uint) ~0UL;
 
          for (j = 0; j < TGSI_QUAD_SIZE; j++) {
-            data->qzzzz[j] = (unsigned) (quad->output.depth[j] * scale);
+            data->qzzzz[j] = (unsigned) (dvals[j] * scale);
          }
       }
       break;
@@ -184,7 +203,7 @@ convert_quad_depth( struct depth_data *data,
          float scale = (float) ((1 << 24) - 1);
 
          for (j = 0; j < TGSI_QUAD_SIZE; j++) {
-            data->qzzzz[j] = (unsigned) (quad->output.depth[j] * scale);
+            data->qzzzz[j] = (unsigned) (dvals[j] * scale);
          }
       }
       break;
@@ -194,7 +213,7 @@ convert_quad_depth( struct depth_data *data,
          float scale = (float) ((1 << 24) - 1);
 
          for (j = 0; j < TGSI_QUAD_SIZE; j++) {
-            data->qzzzz[j] = (unsigned) (quad->output.depth[j] * scale);
+            data->qzzzz[j] = (unsigned) (dvals[j] * scale);
          }
       }
       break;
@@ -204,7 +223,7 @@ convert_quad_depth( struct depth_data *data,
          union fi fui;
 
          for (j = 0; j < TGSI_QUAD_SIZE; j++) {
-            fui.f = quad->output.depth[j];
+            fui.f = dvals[j];
             data->qzzzz[j] = fui.ui;
          }
       }
@@ -796,7 +815,7 @@ depth_test_quads_fallback(struct quad_stage *qs,
             if (interp_depth)
                interpolate_quad_depth(quads[i]);
 
-            convert_quad_depth(&data, quads[i]);
+            convert_quad_depth(qs, &data, quads[i]);
          }
 
          if (qs->softpipe->depth_stencil->stencil[0].enabled) {
@@ -895,6 +914,8 @@ choose_depth_test(struct quad_stage *qs,
 
    boolean occlusion = qs->softpipe->active_query_count;
 
+   boolean clipped = qs->softpipe->rasterizer->depth_clip;
+
    if(!qs->softpipe->framebuffer.zsbuf)
       depth = depthwrite = stencil = FALSE;
 
@@ -905,6 +926,7 @@ choose_depth_test(struct quad_stage *qs,
    if (!alpha &&
        !depth &&
        !occlusion &&
+       !clipped && 
        !stencil) {
       qs->run = depth_noop;
    }
@@ -913,6 +935,7 @@ choose_depth_test(struct quad_stage *qs,
             depth && 
             depthwrite && 
             !occlusion &&
+            !clipped &&
             !stencil) 
    {
       if (qs->softpipe->framebuffer.zsbuf->format == PIPE_FORMAT_Z16_UNORM) {
diff --git a/src/gallium/drivers/softpipe/sp_screen.c b/src/gallium/drivers/softpipe/sp_screen.c
index 34dbb91..7851777 100644
--- a/src/gallium/drivers/softpipe/sp_screen.c
+++ b/src/gallium/drivers/softpipe/sp_screen.c
@@ -111,7 +111,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER:
       return 1;
    case PIPE_CAP_DEPTH_CLIP_DISABLE:
-      return 0;
+      return 1;
    case PIPE_CAP_MAX_STREAM_OUTPUT_BUFFERS:
       return PIPE_MAX_SO_BUFFERS;
    case PIPE_CAP_MAX_STREAM_OUTPUT_SEPARATE_COMPONENTS:
-- 
1.9.3