texture: Remove reading the texture data back in ::unrealize()

Reading back the texture data in unrealize does not seem like a
desirable feature any more, clutter has evolved a lot since it was
implemented.

What's wrong with it now:

  * It takes *a lot* of time to read the data back with glReadPixel(),
  * When several textures share the same CoglTexture, the same data can
    be read back multiple times,
  * If the underlying material uses multiple texture units, only the
    first one was copied back,
  * In ClutterCairoTexture, we end up having two separate copies of the
    data,
  * GL actually manages texture memory accross system/video memory
    for us!

For all the reasons above, let's get rid of the glReadPixel() in
Texture::unrealize()

Fixes: OHB#1842
This commit is contained in:
Damien Lespiau 2009-11-02 17:08:55 +00:00
parent 778e08e4e2
commit 18d96005ec

View File

@ -34,12 +34,6 @@
* clutter_texture_set_from_file() functions are used to copy image
* data into texture memory and subsequently realize the texture.
*
* If texture reads are supported by underlying GL implementation,
* unrealizing frees image data from texture memory moving to main
* system memory. Re-realizing then performs the opposite operation.
* This process allows basic management of commonly limited available
* texture memory.
*
* Note: a ClutterTexture will scale its contents to fit the bounding
* box requested using clutter_actor_set_size(). To display an area of
* a texture without scaling, you should set the clip area using
@ -86,16 +80,9 @@ struct _ClutterTexturePrivate
ClutterActor *fbo_source;
CoglHandle fbo_handle;
/* Non video memory copy of image data */
guint local_data_width, local_data_height;
guint local_data_rowstride;
guint local_data_has_alpha;
guchar *local_data;
guint sync_actor_size : 1;
guint repeat_x : 1;
guint repeat_y : 1;
guint in_dispose : 1;
guint keep_aspect_ratio : 1;
guint load_size_async : 1;
guint load_data_async : 1;
@ -172,12 +159,6 @@ static GStaticMutex upload_list_mutex = G_STATIC_MUTEX_INIT;
static void
texture_fbo_free_resources (ClutterTexture *texture);
static void
clutter_texture_save_to_local_data (ClutterTexture *texture);
static void
clutter_texture_load_from_local_data (ClutterTexture *texture);
GQuark
clutter_texture_error_quark (void)
{
@ -241,14 +222,6 @@ clutter_texture_unrealize (ClutterActor *actor)
if (priv->material == COGL_INVALID_HANDLE)
return;
/* there's no need to read the pixels back when unrealizing inside
* a dispose run, and the dispose() call will release the GL
* texture data as well, so we can safely bail out now
*/
if ((CLUTTER_PRIVATE_FLAGS (actor) & CLUTTER_ACTOR_IN_DESTRUCTION) ||
priv->in_dispose)
return;
CLUTTER_MARK();
if (priv->fbo_source != NULL)
@ -260,24 +233,6 @@ clutter_texture_unrealize (ClutterActor *actor)
return;
}
if (clutter_feature_available (CLUTTER_FEATURE_TEXTURE_READ_PIXELS))
{
/* Move image data from video to main memory.
* GL/ES cant do this - it probably makes sense
* to move this kind of thing into a ClutterProxyTexture
* where this behaviour can be better controlled.
*
* Or make it controllable via a property.
*/
if (priv->local_data == NULL)
{
clutter_texture_save_to_local_data (texture);
CLUTTER_NOTE (TEXTURE, "moved pixels into system mem");
}
texture_free_gl_resources (texture);
}
CLUTTER_NOTE (TEXTURE, "Texture unrealized");
}
@ -327,25 +282,14 @@ clutter_texture_realize (ClutterActor *actor)
return;
}
if (priv->local_data != NULL)
{
/* Move any local image data we have from unrealization
* back into video memory.
/* If the texture is not a FBO, then realization is a no-op but
* we still want to be in REALIZED state to maintain invariants.
* We may have already created the texture if someone set some
* data earlier, or we may create it later if someone sets some
* data later. The fact that we may have created it earlier is
* really a bug, since it means ClutterTexture can have GL
* resources without being realized.
*/
clutter_texture_load_from_local_data (texture);
}
else
{
/* If we have no data, then realization is a no-op but
* we still want to be in REALIZED state to maintain
* invariants. We may have already created the texture
* if someone set some data earlier, or we may create it
* later if someone sets some data later. The fact that
* we may have created it earlier is really a bug, since
* it means ClutterTexture can have GL resources without
* being realized.
*/
}
CLUTTER_NOTE (TEXTURE, "Texture realized");
}
@ -705,23 +649,9 @@ clutter_texture_dispose (GObject *object)
priv = texture->priv;
/* mark that we are in dispose, so when the parent class'
* dispose implementation will call unrealize on us we'll
* not try to copy back the resources from video memory
* to system memory
*/
if (!priv->in_dispose)
priv->in_dispose = TRUE;
texture_free_gl_resources (texture);
texture_fbo_free_resources (texture);
if (priv->local_data != NULL)
{
g_free (priv->local_data);
priv->local_data = NULL;
}
clutter_texture_async_load_cancel (texture);
G_OBJECT_CLASS (clutter_texture_parent_class)->dispose (object);
@ -1177,78 +1107,9 @@ clutter_texture_init (ClutterTexture *self)
priv->sync_actor_size = TRUE;
priv->material = cogl_material_new ();
priv->fbo_handle = COGL_INVALID_HANDLE;
priv->local_data = NULL;
priv->keep_aspect_ratio = FALSE;
}
static void
clutter_texture_save_to_local_data (ClutterTexture *texture)
{
ClutterTexturePrivate *priv;
int bpp;
CoglPixelFormat pixel_format;
CoglHandle cogl_texture;
priv = texture->priv;
if (priv->local_data)
{
g_free (priv->local_data);
priv->local_data = NULL;
}
if (priv->material == COGL_INVALID_HANDLE)
return;
cogl_texture = clutter_texture_get_cogl_texture (texture);
priv->local_data_width = cogl_texture_get_width (cogl_texture);
priv->local_data_height = cogl_texture_get_height (cogl_texture);
pixel_format = cogl_texture_get_format (cogl_texture);
priv->local_data_has_alpha = pixel_format & COGL_A_BIT;
bpp = priv->local_data_has_alpha ? 4 : 3;
/* Align to 4 bytes */
priv->local_data_rowstride = (priv->local_data_width * bpp + 3) & ~3;
priv->local_data = g_malloc (priv->local_data_rowstride
* priv->local_data_height);
if (cogl_texture_get_data (cogl_texture,
priv->local_data_has_alpha
? COGL_PIXEL_FORMAT_RGBA_8888_PRE
: COGL_PIXEL_FORMAT_RGB_888,
priv->local_data_rowstride,
priv->local_data) == 0)
{
g_free (priv->local_data);
priv->local_data = NULL;
}
}
static void
clutter_texture_load_from_local_data (ClutterTexture *texture)
{
ClutterTexturePrivate *priv;
priv = texture->priv;
if (priv->local_data == NULL)
return;
clutter_texture_set_from_rgb_data (texture,
priv->local_data,
priv->local_data_has_alpha,
priv->local_data_width,
priv->local_data_height,
priv->local_data_rowstride,
priv->local_data_has_alpha ? 4: 3,
CLUTTER_TEXTURE_RGB_FLAG_PREMULT, NULL);
g_free (priv->local_data);
priv->local_data = NULL;
}
/**
* clutter_texture_get_cogl_material:
* @texture: A #ClutterTexture
@ -1393,15 +1254,7 @@ clutter_texture_set_cogl_texture (ClutterTexture *texture,
/* Remove old texture */
texture_free_gl_resources (texture);
/* Free any saved data so realization doesn't resend it to GL */
if (priv->local_data)
{
g_free (priv->local_data);
priv->local_data = NULL;
}
/* Use the new texture */
cogl_material_set_layer (priv->material, 0, cogl_tex);
/* The material now holds a reference to the texture so we can