[cogl/wip/virtual-framebuffer: 21/37] stash: deal with fb winding state like other fb state

[Robert Bragg <rbragg src gnome org>]

commit c7f57231117d25020fc8a5061e3d515590cfe884
Author: Robert Bragg <robert linux intel com>
Date:   Mon Nov 21 20:48:23 2011 +0000

    stash: deal with fb winding state like other fb state

 cogl/cogl-framebuffer-private.h |   32 ++++++++++---------
 cogl/cogl-framebuffer.c         |   63 ++++++++++++++++++++++++++------------
 2 files changed, 60 insertions(+), 35 deletions(-)
---
diff --git a/cogl/cogl-framebuffer-private.h b/cogl/cogl-framebuffer-private.h
index 2d1329d..b0ba352 100644
--- a/cogl/cogl-framebuffer-private.h
+++ b/cogl/cogl-framebuffer-private.h
@@ -65,25 +65,27 @@ typedef enum
  */
 typedef enum _CoglFramebufferStateIndex
 {
-  COGL_FRAMEBUFFER_STATE_INDEX_BIND       = 0,
-  COGL_FRAMEBUFFER_STATE_INDEX_VIEWPORT   = 1,
-  COGL_FRAMEBUFFER_STATE_INDEX_CLIP       = 2,
-  COGL_FRAMEBUFFER_STATE_INDEX_DITHER     = 3,
-  COGL_FRAMEBUFFER_STATE_INDEX_MODELVIEW  = 4,
-  COGL_FRAMEBUFFER_STATE_INDEX_PROJECTION = 5,
-  COGL_FRAMEBUFFER_STATE_INDEX_COLOR_MASK = 6,
-  COGL_FRAMEBUFFER_STATE_INDEX_MAX        = 7
+  COGL_FRAMEBUFFER_STATE_INDEX_BIND               = 0,
+  COGL_FRAMEBUFFER_STATE_INDEX_VIEWPORT           = 1,
+  COGL_FRAMEBUFFER_STATE_INDEX_CLIP               = 2,
+  COGL_FRAMEBUFFER_STATE_INDEX_DITHER             = 3,
+  COGL_FRAMEBUFFER_STATE_INDEX_MODELVIEW          = 4,
+  COGL_FRAMEBUFFER_STATE_INDEX_PROJECTION         = 5,
+  COGL_FRAMEBUFFER_STATE_INDEX_COLOR_MASK         = 6,
+  COGL_FRAMEBUFFER_STATE_INDEX_FRONT_FACE_WINDING = 7,
+  COGL_FRAMEBUFFER_STATE_INDEX_MAX                = 8
 } CoglFramebufferStateIndex;
 
 typedef enum _CoglFramebufferState
 {
-  COGL_FRAMEBUFFER_STATE_BIND       = 1<<0,
-  COGL_FRAMEBUFFER_STATE_VIEWPORT   = 1<<1,
-  COGL_FRAMEBUFFER_STATE_CLIP       = 1<<2,
-  COGL_FRAMEBUFFER_STATE_DITHER     = 1<<3,
-  COGL_FRAMEBUFFER_STATE_MODELVIEW  = 1<<4,
-  COGL_FRAMEBUFFER_STATE_PROJECTION = 1<<5,
-  COGL_FRAMEBUFFER_STATE_COLOR_MASK = 1<<6
+  COGL_FRAMEBUFFER_STATE_BIND               = 1<<0,
+  COGL_FRAMEBUFFER_STATE_VIEWPORT           = 1<<1,
+  COGL_FRAMEBUFFER_STATE_CLIP               = 1<<2,
+  COGL_FRAMEBUFFER_STATE_DITHER             = 1<<3,
+  COGL_FRAMEBUFFER_STATE_MODELVIEW          = 1<<4,
+  COGL_FRAMEBUFFER_STATE_PROJECTION         = 1<<5,
+  COGL_FRAMEBUFFER_STATE_COLOR_MASK         = 1<<6,
+  COGL_FRAMEBUFFER_STATE_FRONT_FACE_WINDING = 1<<7
 } CoglFramebufferState;
 
 #define COGL_FRAMEBUFFER_STATE_ALL ((1<<COGL_FRAMEBUFFER_STATE_INDEX_MAX) - 1)
diff --git a/cogl/cogl-framebuffer.c b/cogl/cogl-framebuffer.c
index 7803f4f..76845af 100644
--- a/cogl/cogl-framebuffer.c
+++ b/cogl/cogl-framebuffer.c
@@ -1098,25 +1098,6 @@ notify_buffers_changed (CoglFramebuffer *old_draw_buffer,
                         CoglFramebuffer *old_read_buffer,
                         CoglFramebuffer *new_read_buffer)
 {
-  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
-
-  if (old_draw_buffer && new_draw_buffer)
-    {
-      /* If we're switching from onscreen to offscreen and the last
-         flush pipeline is using backface culling then we also need to
-         reflush the cull face state because the winding order of the
-         front face is flipped for offscreen buffers */
-      if (old_draw_buffer->type != new_draw_buffer->type &&
-          ctx->current_pipeline &&
-          cogl_pipeline_get_cull_face_mode (ctx->current_pipeline) !=
-          COGL_PIPELINE_CULL_FACE_MODE_NONE)
-        {
-          ctx->current_pipeline_changes_since_flush |=
-            COGL_PIPELINE_STATE_CULL_FACE;
-          ctx->current_pipeline_age--;
-        }
-    }
-
   /* XXX: To support the deprecated cogl_set_draw_buffer API we keep
    * track of the last onscreen framebuffer that was set so that it
    * can be restored if the COGL_WINDOW_BUFFER enum is used. A
@@ -1126,7 +1107,7 @@ notify_buffers_changed (CoglFramebuffer *old_draw_buffer,
    * _cogl_onscreen_free as a kind of a cheap weak reference */
   if (new_draw_buffer &&
       new_draw_buffer->type == COGL_FRAMEBUFFER_TYPE_ONSCREEN)
-    ctx->window_buffer = new_draw_buffer;
+    new_draw_buffer->context->window_buffer = new_draw_buffer;
 }
 
 /* Set the current framebuffer without checking if it's already the
@@ -1420,6 +1401,16 @@ _cogl_framebuffer_compare_color_mask_state (CoglFramebuffer *a,
 }
 
 static unsigned long
+_cogl_framebuffer_compare_front_face_winding_state (CoglFramebuffer *a,
+                                                    CoglFramebuffer *b)
+{
+  if (a->type != b->type)
+    return COGL_FRAMEBUFFER_STATE_FRONT_FACE_WINDING;
+  else
+    return 0;
+}
+
+static unsigned long
 _cogl_framebuffer_compare (CoglFramebuffer *a,
                            CoglFramebuffer *b,
                            CoglFramebufferState state)
@@ -1550,6 +1541,38 @@ _cogl_framebuffer_flush_color_mask_state (CoglFramebuffer *framebuffer)
   context->current_pipeline_age--;
 }
 
+static void
+_cogl_framebuffer_flush_front_face_winding_state (CoglFramebuffer *framebuffer)
+{
+  CoglContext *context = framebuffer->context;
+  CoglPipelineCullFaceMode mode;
+
+  /* NB: The face winding state is actually owned by the current
+   * CoglPipeline.
+   *
+   * If we don't have a current pipeline then we can just assume that
+   * when we later do flush a pipeline we will check the current
+   * framebuffer to know how to setup the winding */
+  if (!context->current_pipeline)
+    return;
+
+  mode = _cogl_pipeline_get_cull_face_mode (ctx->current_pipeline);
+
+  /* If the current CoglPipeline has a culling mode that doesn't care
+   * about the winding we can avoid forcing an update of the state and
+   * bail out. */
+  if (mode == COGL_PIPELINE_CULL_FACE_MODE_NONE ||
+      mode == COGL_PIPELINE_CULL_FACE_MODE_BOTH)
+    return;
+
+  /* Since the winding state is really owned by the current pipeline
+   * the way we "flush" an updated winding is to dirty the pipeline
+   * state... */
+  context->current_pipeline_changes_since_flush |=
+    COGL_PIPELINE_STATE_CULL_FACE;
+  context->current_pipeline_age--;
+}
+
 void
 _cogl_framebuffer_flush_state (CoglFramebuffer *draw_buffer,
                                CoglFramebuffer *read_buffer,