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authorBrian Paul <brian.paul@tungstengraphics.com>2008-12-10 18:02:27 -0700
committerBrian Paul <brian.paul@tungstengraphics.com>2008-12-10 18:06:44 -0700
commitd0bc5293d6e1e9c34fa822b7c2928932ed22462c (patch)
tree097faccccfa6a17402b1cbb86c4db719bfea9fdf /src/gallium/auxiliary/draw
parent8137da952b6f30329adf7d49d2d9e58625534dd4 (diff)
gallium: added draw_set_mrd() function to fix polygon offset
The Minimum Resolvable Depth factor depends on the driver and can't just be computed from the number of Z buffer bits. Glean's polygon offset test now passes with softpipe. Still need to determine the MRD factor for other gallium drivers, if they use the draw module's polygon offset stage...
Diffstat (limited to 'src/gallium/auxiliary/draw')
-rw-r--r--src/gallium/auxiliary/draw/draw_context.c12
-rw-r--r--src/gallium/auxiliary/draw/draw_context.h1
-rw-r--r--src/gallium/auxiliary/draw/draw_pipe_offset.c3
-rw-r--r--src/gallium/auxiliary/draw/draw_private.h2
4 files changed, 16 insertions, 2 deletions
diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index 74deb44bd2..fab8fc95fc 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -103,6 +103,18 @@ void draw_flush( struct draw_context *draw )
}
+/**
+ * Specify the Minimum Resolvable Depth factor for polygon offset.
+ * This factor potentially depends on the number of Z buffer bits,
+ * the rasterization algorithm and the arithmetic performed on Z
+ * values between vertex shading and rasterization. It will vary
+ * from one driver to another.
+ */
+void draw_set_mrd(struct draw_context *draw, double mrd)
+{
+ draw->mrd = mrd;
+}
+
/**
* Register new primitive rasterization/rendering state.
diff --git a/src/gallium/auxiliary/draw/draw_context.h b/src/gallium/auxiliary/draw/draw_context.h
index 1d40c6c3be..a29bb01d81 100644
--- a/src/gallium/auxiliary/draw/draw_context.h
+++ b/src/gallium/auxiliary/draw/draw_context.h
@@ -72,6 +72,7 @@ void draw_enable_line_stipple(struct draw_context *draw, boolean enable);
void draw_enable_point_sprites(struct draw_context *draw, boolean enable);
+void draw_set_mrd(struct draw_context *draw, double mrd);
boolean
draw_install_aaline_stage(struct draw_context *draw, struct pipe_context *pipe);
diff --git a/src/gallium/auxiliary/draw/draw_pipe_offset.c b/src/gallium/auxiliary/draw/draw_pipe_offset.c
index 1fea5e6dcb..8ddc4ee617 100644
--- a/src/gallium/auxiliary/draw/draw_pipe_offset.c
+++ b/src/gallium/auxiliary/draw/draw_pipe_offset.c
@@ -122,9 +122,8 @@ static void offset_first_tri( struct draw_stage *stage,
struct prim_header *header )
{
struct offset_stage *offset = offset_stage(stage);
- float mrd = 1.0f / 65535.0f; /* XXX this depends on depthbuffer bits! */
- offset->units = stage->draw->rasterizer->offset_units * mrd;
+ offset->units = stage->draw->rasterizer->offset_units * stage->draw->mrd;
offset->scale = stage->draw->rasterizer->offset_scale;
stage->tri = offset_tri;
diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 37c4c87f87..a16b45d340 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -172,6 +172,8 @@ struct draw_context
boolean force_passthrough; /**< never clip or shade */
+ double mrd; /**< minimum resolvable depth value, for polygon offset */
+
/* pipe state that we need: */
const struct pipe_rasterizer_state *rasterizer;
struct pipe_viewport_state viewport;