The i965 back-end needs to compile dFdy() differently for FBOs and
window system framebuffers, because Y coordinates are flipped between
the two (see commit 82d2596: i965: Compute dFdy() correctly for FBOs).
This patch avoids unnecessarily recompiling shaders that don't use
dFdy(), by only setting render_to_fbo in the wm program key if the
shader actually uses dFdy().
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 8 +-------
src/mesa/drivers/dri/i965/brw_fs_emit.cpp | 4 ++++
src/mesa/drivers/dri/i965/brw_wm.c | 8 +-------
src/mesa/drivers/dri/i965/brw_wm_emit.c | 4 ++++
4 files changed, 10 insertions(+), 14 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
index b3b25cc..e78ea57 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2121,19 +2121,13 @@ brw_fs_precompile(struct gl_context *ctx, struct
gl_shader_program *prog)
struct brw_context *brw = brw_context(ctx);
struct brw_wm_prog_key key;
- /* As a temporary measure we assume that all programs use dFdy() (and hence
- * need to be compiled differently depending on whether we're rendering to
- * an FBO). FIXME: set this bool correctly based on the contents of the
- * program.
- */
- bool program_uses_dfdy = true;
-
if (!prog->_LinkedShaders[MESA_SHADER_FRAGMENT])
return true;
struct gl_fragment_program *fp = (struct gl_fragment_program *)
prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program;
struct brw_fragment_program *bfp = brw_fragment_program(fp);
+ bool program_uses_dfdy = fp->UsesDFdy;
memset(&key, 0, sizeof(key));
diff --git a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
index bfa62c3..dc5f3e1 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
@@ -931,6 +931,10 @@ fs_visitor::generate_code()
generate_ddx(inst, dst, src[0]);
break;
case FS_OPCODE_DDY:
+ /* Make sure fp->UsesDFdy flag got set (otherwise there's no
+ * guarantee that c->key.render_to_fbo is set).
+ */
+ assert(fp->UsesDFdy);
generate_ddy(inst, dst, src[0], c->key.render_to_fbo);
break;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c
b/src/mesa/drivers/dri/i965/brw_wm.c
index 587cc35..37bc114 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -441,13 +441,7 @@ static void brw_wm_populate_key( struct brw_context *brw,
const struct gl_program *prog = (struct gl_program *) brw->fragment_program;
GLuint lookup = 0;
GLuint line_aa;
-
- /* As a temporary measure we assume that all programs use dFdy() (and hence
- * need to be compiled differently depending on whether we're rendering to
- * an FBO). FIXME: set this bool correctly based on the contents of the
- * program.
- */
- bool program_uses_dfdy = true;
+ bool program_uses_dfdy = fp->program.UsesDFdy;
memset(key, 0, sizeof(*key));
diff --git a/src/mesa/drivers/dri/i965/brw_wm_emit.c
b/src/mesa/drivers/dri/i965/brw_wm_emit.c
index 1258efe..61f66e7 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_emit.c
@@ -1757,6 +1757,10 @@ void brw_wm_emit( struct brw_wm_compile *c )
break;
case OPCODE_DDY:
+ /* Make sure fp->program.UsesDFdy flag got set (otherwise there's no
+ * guarantee that c->key.render_to_fbo is set).
+ */
+ assert(c->fp->program.UsesDFdy);
emit_ddxy(p, dst, dst_flags, false, args[0], c->key.render_to_fbo);
break;
--
1.7.7.6
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