glamor: Replace some goofy enum-likes with a real enum.

This unpacks the bitfield into an int size, but my experience has been
that packing bitfields doesn't matter for performance.

v2: Convert more comparisons against numbers or implicit bool
    comparisons to comparisons against the enum names, and fix up some
    comments.

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Markus Wick <markus@selfnet.de>

glamor/glamor_copyarea.c

@@ -137,7 +137,7 @@ glamor_copy_n_to_n_textured(DrawablePtr src,
     src_pixmap_priv = glamor_get_pixmap_private(src_pixmap);
     dst_pixmap_priv = glamor_get_pixmap_private(dst_pixmap);
 
-    if (!src_pixmap_priv->base.gl_fbo) {
+    if (src_pixmap_priv->base.gl_fbo == GLAMOR_FBO_UNATTACHED) {
 #ifndef GLAMOR_PIXMAP_DYNAMIC_UPLOAD
         glamor_delayed_fallback(dst->pScreen, "src has no fbo.\n");
         return FALSE;

glamor/glamor_core.c

@@ -42,7 +42,8 @@ glamor_get_drawable_location(const DrawablePtr drawable)
     glamor_pixmap_private *pixmap_priv = glamor_get_pixmap_private(pixmap);
     glamor_screen_private *glamor_priv =
         glamor_get_screen_private(drawable->pScreen);
-    if (pixmap_priv == NULL || pixmap_priv->base.gl_fbo == 0)
+    if (pixmap_priv == NULL ||
+        pixmap_priv->base.gl_fbo == GLAMOR_FBO_UNATTACHED)
         return 'm';
     if (pixmap_priv->base.fbo->fb == glamor_priv->screen_fbo)
         return 's';

glamor/glamor_fbo.c

@@ -505,7 +505,7 @@ glamor_pixmap_attach_fbo(PixmapPtr pixmap, glamor_pixmap_fbo *fbo)
     case GLAMOR_TEXTURE_LARGE:
     case GLAMOR_TEXTURE_ONLY:
     case GLAMOR_TEXTURE_DRM:
-        pixmap_priv->base.gl_fbo = 1;
+        pixmap_priv->base.gl_fbo = GLAMOR_FBO_NORMAL;
         if (fbo->tex != 0)
             pixmap_priv->base.gl_tex = 1;
         else {

glamor/glamor_pixmap.c

@@ -886,7 +886,7 @@ glamor_pixmap_upload_prepare(PixmapPtr pixmap, GLenum format, int no_alpha,
     pixmap_priv = glamor_get_pixmap_private(pixmap);
     glamor_priv = glamor_get_screen_private(pixmap->drawable.pScreen);
 
-    if (pixmap_priv->base.gl_fbo)
+    if (pixmap_priv->base.gl_fbo != GLAMOR_FBO_UNATTACHED)
         return 0;
 
     if (pixmap_priv->base.fbo

glamor/glamor_priv.h

@@ -291,8 +291,21 @@ typedef enum glamor_access {
     GLAMOR_ACCESS_WO,
 } glamor_access_t;
 
-#define GLAMOR_FBO_NORMAL     1
+enum glamor_fbo_state {
-#define GLAMOR_FBO_DOWNLOADED 2
+    /** There is no storage attached to the pixmap. */
+    GLAMOR_FBO_UNATTACHED,
+    /**
+     * The pixmap has FBO storage attached, but devPrivate.ptr doesn't
+     * point at anything.
+     */
+    GLAMOR_FBO_NORMAL,
+    /**
+     * The FBO is present and can be accessed as a linear memory
+     * mapping through devPrivate.ptr.
+     */
+    GLAMOR_FBO_DOWNLOADED,
+};
+
 /* glamor_pixmap_fbo:
  * @list:    to be used to link to the cache pool list.
  * @expire:  when push to cache pool list, set a expire count.
@@ -324,12 +337,6 @@ typedef struct glamor_pixmap_fbo {
 
 /*
  * glamor_pixmap_private - glamor pixmap's private structure.
- * @gl_fbo:
- * 	0 		  	- The pixmap doesn't has a fbo attached to it.
- * 	GLAMOR_FBO_NORMAL 	- The pixmap has a fbo and can be accessed normally.
- * 	GLAMOR_FBO_DOWNLOADED 	- The pixmap has a fbo and already downloaded to
- * 				  CPU, so it can only be treated as a in-memory pixmap
- * 				  if this bit is set.
  * @gl_tex:  The pixmap is in a gl texture originally.
  * @is_picture: The drawable is attached to a picture.
  * @pict_format: the corresponding picture's format.
@@ -403,7 +410,7 @@ typedef struct glamor_pixmap_clipped_regions {
 
 typedef struct glamor_pixmap_private_base {
     glamor_pixmap_type_t type;
-    unsigned char gl_fbo:2;
+    enum glamor_fbo_state gl_fbo;
     unsigned char is_picture:1;
     unsigned char gl_tex:1;
     glamor_pixmap_fbo *fbo;
@@ -777,7 +784,7 @@ glamor_put_vbo_space(ScreenPtr screen);
  * One copy of current pixmap's texture will be put into
  * the pixmap->devPrivate.ptr. Will use pbo to map to 
  * the pointer if possible.
- * The pixmap must be a gl texture pixmap. gl_fbo and
+ * The pixmap must be a gl texture pixmap. gl_fbo must be GLAMOR_FBO_NORMAL and
  * gl_tex must be 1. Used by glamor_prepare_access.
  *
  */
@@ -792,9 +799,8 @@ void *glamor_download_sub_pixmap_to_cpu(PixmapPtr pixmap, int x, int y, int w,
  * glamor_download_pixmap_to_cpu to its original 
  * gl texture. Used by glamor_finish_access. 
  *
- * The pixmap must be
+ * The pixmap must originally be a texture -- gl_fbo must be
- * in texture originally. In other word, the gl_fbo
+ * GLAMOR_FBO_NORMAL.
- * must be 1.
  **/
 void glamor_restore_pixmap_to_texture(PixmapPtr pixmap);
 

glamor/glamor_render.c

@@ -961,7 +961,7 @@ glamor_composite_choose_shader(CARD8 op,
              * Does it need special handle? */
             glamor_fallback("source == dest\n");
         }
-        if (source_pixmap_priv->base.gl_fbo == 0) {
+        if (source_pixmap_priv->base.gl_fbo == GLAMOR_FBO_UNATTACHED) {
             /* XXX in Xephyr, we may have gl_fbo equal to 1 but gl_tex
              * equal to zero when the pixmap is screen pixmap. Then we may
              * refer the tex zero directly latter in the composition.
@@ -982,7 +982,7 @@ glamor_composite_choose_shader(CARD8 op,
             glamor_fallback("mask == dest\n");
             goto fail;
         }
-        if (mask_pixmap_priv->base.gl_fbo == 0) {
+        if (mask_pixmap_priv->base.gl_fbo == GLAMOR_FBO_UNATTACHED) {
 #ifdef GLAMOR_PIXMAP_DYNAMIC_UPLOAD
             mask_status = GLAMOR_UPLOAD_PENDING;
 #else