Legacy user clipping (using gl_Position or gl_ClipVertex) is handled by
turning those into the modern gl_ClipDistance equivalents.
This is unnecessary in Core Profile: if user clipping is enabled, but
the shader doesn't write the corresponding gl_ClipDistance entry,
results are undefined. Hence, it is also unnecessary for geometry
shaders.
This patch moves the call up to run_vs(). This is equivalent for VS,
but removes the need to pass clip distances into emit_urb_writes().
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 4 +++-
src/mesa/drivers/dri/i965/brw_fs.h | 2 +-
src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 16 +++++++++++-----
3 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 4292aa6..8658554 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3816,7 +3816,9 @@ fs_visitor::run_vs(gl_clip_plane *clip_planes)
if (failed)
return false;
- emit_urb_writes(clip_planes);
+ compute_clip_distance(clip_planes);
+
+ emit_urb_writes();
if (shader_time_index >= 0)
emit_shader_time_end();
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h
b/src/mesa/drivers/dri/i965/brw_fs.h
index 243baf6..d08d438 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -271,7 +271,7 @@ public:
fs_reg src0_alpha, unsigned components,
unsigned exec_size, bool use_2nd_half =
false);
void emit_fb_writes();
- void emit_urb_writes(gl_clip_plane *clip_planes);
+ void emit_urb_writes();
void emit_cs_terminate();
void emit_barrier();
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 7074b5c..854e49b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -1730,6 +1730,12 @@ fs_visitor::setup_uniform_clipplane_values(gl_clip_plane
*clip_planes)
}
}
+/**
+ * Lower legacy fixed-function and gl_ClipVertex clipping to clip distances.
+ *
+ * This does nothing if the shader uses gl_ClipDistance or user clipping is
+ * disabled altogether.
+ */
void fs_visitor::compute_clip_distance(gl_clip_plane *clip_planes)
{
struct brw_vue_prog_data *vue_prog_data =
@@ -1737,6 +1743,10 @@ void fs_visitor::compute_clip_distance(gl_clip_plane
*clip_planes)
const struct brw_vue_prog_key *key =
(const struct brw_vue_prog_key *) this->key;
+ /* Bail unless some sort of legacy clipping is enabled */
+ if (!key->userclip_active || prog->UsesClipDistanceOut)
+ return;
+
/* From the GLSL 1.30 spec, section 7.1 (Vertex Shader Special Variables):
*
* "If a linked set of shaders forming the vertex stage contains no
@@ -1780,7 +1790,7 @@ void fs_visitor::compute_clip_distance(gl_clip_plane
*clip_planes)
}
void
-fs_visitor::emit_urb_writes(gl_clip_plane *clip_planes)
+fs_visitor::emit_urb_writes()
{
int slot, urb_offset, length;
struct brw_vs_prog_data *vs_prog_data =
@@ -1793,10 +1803,6 @@ fs_visitor::emit_urb_writes(gl_clip_plane *clip_planes)
bool flush;
fs_reg sources[8];
- /* Lower legacy ff and ClipVertex clipping to clip distances */
- if (key->base.userclip_active && !prog->UsesClipDistanceOut)
- compute_clip_distance(clip_planes);
-
/* If we don't have any valid slots to write, just do a minimal urb write
* send to terminate the shader. */
if (vue_map->slots_valid == 0) {
--
1.7.10.4
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