gl/msaa: Don't emit alpha when emitting vertices

The color attribute is disabled when not in spans mode, so the emitted
alpha is simply overwritten by the next vertex. Additionally, this can
potentially cause the alpha to be written past the end of the buffer.

1 files changed, 11 insertions, 13 deletions

diff --git a/src/cairo-gl-composite.c b/src/cairo-gl-composite.c
index de45028b..d8166b83 100644
--- a/src/cairo-gl-composite.c
+++ b/src/cairo-gl-composite.c
@@ -904,13 +904,11 @@ _cairo_gl_composite_emit_alpha_vertex (cairo_gl_context_t *ctx,
 
 static void
 _cairo_gl_composite_emit_point (cairo_gl_context_t	*ctx,
-				const cairo_point_t	*point,
-				uint8_t alpha)
+				const cairo_point_t	*point)
 {
-    _cairo_gl_composite_emit_alpha_vertex (ctx,
-					   _cairo_fixed_to_double (point->x),
-					   _cairo_fixed_to_double (point->y),
-					   alpha);
+    _cairo_gl_composite_emit_vertex (ctx,
+				     _cairo_fixed_to_double (point->x),
+				     _cairo_fixed_to_double (point->y));
 }
 
 static void
@@ -1194,14 +1192,14 @@ _cairo_gl_composite_emit_quad_as_tristrip (cairo_gl_context_t	*ctx,
     _cairo_gl_composite_prepare_buffer (ctx, 4,
 					CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
 
-    _cairo_gl_composite_emit_point (ctx, &quad[0], 0);
-    _cairo_gl_composite_emit_point (ctx, &quad[1], 0);
+    _cairo_gl_composite_emit_point (ctx, &quad[0]);
+    _cairo_gl_composite_emit_point (ctx, &quad[1]);
 
     /* Cairo stores quad vertices in counter-clockwise order, but we need to
        emit them from top to bottom in the triangle strip, so we need to reverse
        the order of the last two vertices. */
-    _cairo_gl_composite_emit_point (ctx, &quad[3], 0);
-    _cairo_gl_composite_emit_point (ctx, &quad[2], 0);
+    _cairo_gl_composite_emit_point (ctx, &quad[3]);
+    _cairo_gl_composite_emit_point (ctx, &quad[2]);
 
     return _cairo_gl_composite_append_vertex_indices (ctx, 4);
 }
@@ -1214,8 +1212,8 @@ _cairo_gl_composite_emit_triangle_as_tristrip (cairo_gl_context_t	*ctx,
     _cairo_gl_composite_prepare_buffer (ctx, 3,
 					CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
 
-    _cairo_gl_composite_emit_point (ctx, &triangle[0], 0);
-    _cairo_gl_composite_emit_point (ctx, &triangle[1], 0);
-    _cairo_gl_composite_emit_point (ctx, &triangle[2], 0);
+    _cairo_gl_composite_emit_point (ctx, &triangle[0]);
+    _cairo_gl_composite_emit_point (ctx, &triangle[1]);
+    _cairo_gl_composite_emit_point (ctx, &triangle[2]);
     return _cairo_gl_composite_append_vertex_indices (ctx, 3);
 }