Mesa (intel-2008-q4): i965: allow gl_FragData[0] usage when there' s only one color buffer

[Haihao Xiang]

Module: Mesa
Branch: intel-2008-q4
Commit: 32e43b60027eb7a3be31abde661a221de97963b1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=32e43b60027eb7a3be31abde661a221de97963b1

Author: Brian Paul <brianp at vmware.com>
Date:   Wed Jan  7 18:45:49 2009 -0700

i965: allow gl_FragData[0] usage when there's only one color buffer

If gl_FragData[0] is written but not gl_FragCOlor, use the former.
(cherry picked from commit f68f94c2bc950405d4c91a1e5582a35ff4b15bdf)

---

 src/mesa/drivers/dri/i965/brw_wm_fp.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_wm_fp.c b/src/mesa/drivers/dri/i965/brw_wm_fp.c
index cb1e400..f458387 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_fp.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_fp.c
@@ -864,9 +864,9 @@ static void emit_fog( struct brw_wm_compile *c )
 
 static void emit_fb_write( struct brw_wm_compile *c )
 {
-   struct prog_src_register outcolor = src_reg(PROGRAM_OUTPUT, FRAG_RESULT_COLR);
    struct prog_src_register payload_r0_depth = src_reg(PROGRAM_PAYLOAD, PAYLOAD_DEPTH);
    struct prog_src_register outdepth = src_reg(PROGRAM_OUTPUT, FRAG_RESULT_DEPR);
+   struct prog_src_register outcolor;
    GLuint i;
 
    struct prog_instruction *inst, *last_inst;
@@ -890,7 +890,14 @@ static void emit_fb_write( struct brw_wm_compile *c )
 	   }
        }
        last_inst->Sampler |= 1; //eot
-   }else {
+   }
+   else {
+      /* if gl_FragData[0] is written, use it, else use gl_FragColor */
+      if (c->fp->program.Base.OutputsWritten & (1 << FRAG_RESULT_DATA0))
+         outcolor = src_reg(PROGRAM_OUTPUT, FRAG_RESULT_DATA0);
+      else 
+         outcolor = src_reg(PROGRAM_OUTPUT, FRAG_RESULT_COLR);
+
        inst = emit_op(c, WM_FB_WRITE, dst_mask(dst_undef(),0),
 	       0, 0, 0, outcolor, payload_r0_depth, outdepth);
        inst->Sampler = 1|(0<<1);