mesa: Implement ARB_clip_control.

Implement the mesa parts of ARB_clip_control.
So far no driver enables this.

v3:
Restrict getting clip control state to the availability
of ARB_clip_control.
Move to transformation state.
Handle clip control state with the GL_TRANSFORM_BIT.
Move _FrontBit update into state.c.

Reviewed-by: Brian Paul <[email protected]>
Signed-off-by: Mathias Froehlich <[email protected]>

1 files changed, 16 insertions, 0 deletions

diff --git a/src/mesa/main/state.c b/src/mesa/main/state.c
index 3dbbfaac76c..45bce78fd4a 100644
--- a/src/mesa/main/state.c
+++ b/src/mesa/main/state.c
@@ -292,6 +292,19 @@ update_viewport_matrix(struct gl_context *ctx)
 
 
 /**
+ * Update the ctx->Polygon._FrontBit flag.
+ */
+static void
+update_frontbit(struct gl_context *ctx)
+{
+   if (ctx->Transform.ClipOrigin == GL_LOWER_LEFT)
+      ctx->Polygon._FrontBit = (ctx->Polygon.FrontFace == GL_CW);
+   else
+      ctx->Polygon._FrontBit = (ctx->Polygon.FrontFace == GL_CCW);
+}
+
+
+/**
  * Update derived multisample state.
  */
 static void
@@ -373,6 +386,9 @@ _mesa_update_state_locked( struct gl_context *ctx )
    if (new_state & (_NEW_PROGRAM|_NEW_TEXTURE|_NEW_TEXTURE_MATRIX))
       _mesa_update_texture( ctx, new_state );
 
+   if (new_state & _NEW_POLYGON)
+      update_frontbit( ctx );
+
    if (new_state & _NEW_BUFFERS)
       _mesa_update_framebuffer(ctx);