From 19a0ba130fd0d0f3b86181a8d05cf5391420360d Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Fri, 26 Jun 2015 15:05:13 -0700 Subject: [PATCH] i965/vs: Move compute_clip_distance() out of emit_urb_writes(). 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 Reviewed-by: Jason Ekstrand Reviewed-by: Chris Forbes --- 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 4292aa6b9fb..8658554e96b 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 243baf688de..d08d438a40e 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 0cbaf17f1e4..34bf32d7ab3 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp @@ -1731,6 +1731,12 @@ 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 = @@ -1738,6 +1744,10 @@ 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 @@ -1781,7 +1791,7 @@ 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 = @@ -1794,10 +1804,6 @@ 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. This includes 1 slot of undefined data, * because it's invalid to write 0 data: -- 2.30.2