[Mesa-dev] [PATCH 2/2] i965/fs: Assume FBO rendering in precompile if MRT.

[Chris Forbes]

If multiple color outputs are written, this shader is unlikely to be
useful with a winsys framebuffer.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index d6ebe50..b7d51df 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3585,14 +3585,15 @@ brw_fs_precompile(struct gl_context *ctx, struct gl_shader_program *prog)
       key.drawable_height = ctx->DrawBuffer->Height;
    }
 
-   if ((fp->Base.InputsRead & VARYING_BIT_POS) || program_uses_dfdy) {
-      key.render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
-   }
-
    key.nr_color_regions = _mesa_bitcount_64(fp->Base.OutputsWritten &
          ~(BITFIELD64_BIT(FRAG_RESULT_DEPTH) |
          BITFIELD64_BIT(FRAG_RESULT_SAMPLE_MASK)));
 
+   if ((fp->Base.InputsRead & VARYING_BIT_POS) || program_uses_dfdy) {
+      key.render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer) ||
+                          key.nr_color_regions > 1;
+   }
+
    /* GL_FRAGMENT_SHADER_DERIVATIVE_HINT is almost always GL_DONT_CARE.  The
     * quality of the derivatives is likely to be determined by the driconf
     * option.
-- 
1.8.5.3