Mesa (master): i965: Gen4/5: use IEEE floating point mode for GLSL shaders.

[Chris Forbes]

Module: Mesa
Branch: master
Commit: b616d0166158872a135153e27c391424fe655117
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=b616d0166158872a135153e27c391424fe655117

Author: Chris Forbes <chrisf at ijw.co.nz>
Date:   Mon Jun 10 08:01:41 2013 +1200

i965: Gen4/5: use IEEE floating point mode for GLSL shaders.

Fixes isinf(), isnan() from GLSL 1.30

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/mesa/drivers/dri/i965/brw_vs_state.c |    9 ++++++++-
 src/mesa/drivers/dri/i965/brw_wm_state.c |   10 +++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vs_state.c b/src/mesa/drivers/dri/i965/brw_vs_state.c
index 54ff754..4dda522 100644
--- a/src/mesa/drivers/dri/i965/brw_vs_state.c
+++ b/src/mesa/drivers/dri/i965/brw_vs_state.c
@@ -55,7 +55,14 @@ brw_upload_vs_unit(struct brw_context *brw)
 			brw->vs.prog_offset +
 			(vs->thread0.grf_reg_count << 1)) >> 6;
 
-   vs->thread1.floating_point_mode = BRW_FLOATING_POINT_NON_IEEE_754;
+   /* Use ALT floating point mode for ARB vertex programs, because they
+    * require 0^0 == 1.
+    */
+   if (brw->ctx.Shader.CurrentVertexProgram == NULL)
+      vs->thread1.floating_point_mode = BRW_FLOATING_POINT_NON_IEEE_754;
+   else
+      vs->thread1.floating_point_mode = BRW_FLOATING_POINT_IEEE_754;
+
    /* Choosing multiple program flow means that we may get 2-vertex threads,
     * which will have the channel mask for dwords 4-7 enabled in the thread,
     * and those dwords will be written to the second URB handle when we
diff --git a/src/mesa/drivers/dri/i965/brw_wm_state.c b/src/mesa/drivers/dri/i965/brw_wm_state.c
index f221846..631f351 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_state.c
@@ -110,7 +110,15 @@ brw_upload_wm_unit(struct brw_context *brw)
 			(wm->wm9.grf_reg_count_2 << 1)) >> 6;
 
    wm->thread1.depth_coef_urb_read_offset = 1;
-   wm->thread1.floating_point_mode = BRW_FLOATING_POINT_NON_IEEE_754;
+   /* Use ALT floating point mode for ARB fragment programs, because they
+    * require 0^0 == 1.  Even though _CurrentFragmentProgram is used for
+    * rendering, CurrentFragmentProgram is used for this check to
+    * differentiate between the GLSL and non-GLSL cases.
+    */
+   if (ctx->Shader.CurrentFragmentProgram == NULL)
+      wm->thread1.floating_point_mode = BRW_FLOATING_POINT_NON_IEEE_754;
+   else
+      wm->thread1.floating_point_mode = BRW_FLOATING_POINT_IEEE_754;
 
    wm->thread1.binding_table_entry_count = 0;