[Mesa-dev] [PATCH 1/4] mesa/main: consider multisampling enabled when number of samples == 1

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

There are some differences between how non-multisampled framebuffers (i.e.
samples == 0) and multisampled framebuffers with a single sample should be
treated.  For example, alpha to coverage and writing to gl_SampleMask has an
effect with single-sample multisample framebuffers, but not on
non-multisample framebuffers.

This fixes GL45-CTS.sample_variables.mask.*.samples_1.* at least for
Gallium drivers (and possibly others, though at least radeonsi needs an
additional fix).
---
 src/mesa/main/framebuffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index 9c7f0c9..20d03fe 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -996,21 +996,21 @@ _mesa_geometric_nonvalidated_samples(const struct gl_framebuffer *buffer)
 
 bool
 _mesa_is_multisample_enabled(const struct gl_context *ctx)
 {
    /* The sample count may not be validated by the driver, but when it is set,
     * we know that is in a valid range and no driver should ever validate a
     * multisampled framebuffer to non-multisampled and vice-versa.
     */
    return ctx->Multisample.Enabled &&
           ctx->DrawBuffer &&
-          _mesa_geometric_nonvalidated_samples(ctx->DrawBuffer) > 1;
+          _mesa_geometric_nonvalidated_samples(ctx->DrawBuffer) >= 1;
 }
 
 /**
  * Is alpha testing enabled and applicable to the currently bound
  * framebuffer?
  */
 bool
 _mesa_is_alpha_test_enabled(const struct gl_context *ctx)
 {
    bool buffer0_is_integer = ctx->DrawBuffer->_IntegerBuffers & 0x1;
-- 
2.7.4