mesa: fix issues around multisample enable

multisample enable is enabled by default, however gl mandates multisample
rendering rules only apply if there's also a multisampled buffer.

3 files changed, 19 insertions, 1 deletions

diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index b08095465d8..5ab969e0ebb 100644
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -829,7 +829,7 @@ _mesa_init_scissor(GLcontext *ctx)
 void
 _mesa_init_multisample(GLcontext *ctx)
 {
-   ctx->Multisample.Enabled = GL_FALSE;
+   ctx->Multisample.Enabled = GL_TRUE;
    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
    ctx->Multisample.SampleCoverage = GL_FALSE;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 04da767ec91..9339146e25c 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -958,6 +958,7 @@ struct gl_list_extensions
 struct gl_multisample_attrib
 {
    GLboolean Enabled;
+   GLboolean _Enabled;   /**< true if Enabled and multisample buffer */
    GLboolean SampleAlphaToCoverage;
    GLboolean SampleAlphaToOne;
    GLboolean SampleCoverage;
diff --git a/src/mesa/main/state.c b/src/mesa/main/state.c
index 1c73c5c462b..7192bed4a3d 100644
--- a/src/mesa/main/state.c
+++ b/src/mesa/main/state.c
@@ -1061,6 +1061,20 @@ update_viewport_matrix(GLcontext *ctx)
 
 
 /**
+ * Update derived multisample state.
+ */
+static void
+update_multisample(GLcontext *ctx)
+{
+   ctx->Multisample._Enabled = GL_FALSE;
+   if (ctx->DrawBuffer) {
+      if (ctx->DrawBuffer->Visual.sampleBuffers)
+         ctx->Multisample._Enabled = GL_TRUE;
+   }
+}
+
+
+/**
  * Update derived color/blend/logicop state.
  */
 static void
@@ -1223,6 +1237,9 @@ _mesa_update_state_locked( GLcontext *ctx )
    if (new_state & (_NEW_BUFFERS | _NEW_VIEWPORT))
       update_viewport_matrix(ctx);
 
+   if (new_state & _NEW_MULTISAMPLE)
+      update_multisample( ctx );
+
    if (new_state & _NEW_COLOR)
       update_color( ctx );