[cairo] [PATCH 1/2] gl: Don't reset the FBO draw/readbuffers every time we bind the FBO.

[Eric Anholt]

Draw/readbuffers are a property of the framebuffer, not of the
context.  So we can leave them in place across bindings.  I left the
window drawbuffer setting in place until we decide how to handle
interoperating of cairo-gl with normal GL usage.

[  0]  before      firefox-talos-gfx   67.552   67.561   0.22%    3/3
[  0]  after       firefox-talos-gfx   66.689   66.913   0.41%    3/3
---
 src/cairo-gl-device.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cairo-gl-device.c b/src/cairo-gl-device.c
index 25423e0..3d3cf0e 100644
--- a/src/cairo-gl-device.c
+++ b/src/cairo-gl-device.c
@@ -248,6 +248,8 @@ _cairo_gl_ensure_framebuffer (cairo_gl_context_t *ctx,
 				    ctx->tex_target,
 				    surface->tex,
 				    0);
+    glDrawBuffer (GL_COLOR_ATTACHMENT0);
+    glReadBuffer (GL_COLOR_ATTACHMENT0);
 
     status = dispatch->CheckFramebufferStatus (GL_FRAMEBUFFER);
     if (status != GL_FRAMEBUFFER_COMPLETE) {
@@ -284,8 +286,6 @@ _cairo_gl_context_set_destination (cairo_gl_context_t *ctx,
     if (_cairo_gl_surface_is_texture (surface)) {
         _cairo_gl_ensure_framebuffer (ctx, surface);
         ctx->dispatch.BindFramebuffer (GL_FRAMEBUFFER, surface->fb);
-        glDrawBuffer (GL_COLOR_ATTACHMENT0);
-        glReadBuffer (GL_COLOR_ATTACHMENT0);
     } else {
         ctx->make_current (ctx, surface);
         ctx->dispatch.BindFramebuffer (GL_FRAMEBUFFER, 0);
-- 
1.7.2.3