texture: Add gdk_texture_download_texture()

A private vfunc that downloads a texture as a GdkMemoryTexture in
whatever format the texture deems best.

There are multiple reasons for this:

 * GLES cannot download the Cairo format. But it can download some
   format and then just delegate to the GdkMemoryTexture implementation.

 * All the other download vfuncs (including the ones still coming) can
   be implemented via download_texture() and delegation, making the
   interface easier.

 * We want to implement image loading and saving support. By using
   download_texture(), we can save in the actual format of the texture.

 * A potential GdkCompressedTexture could be implemented by just
   providing this one vfunc as a compress() step.
This commit is contained in:
Benjamin Otte 2021-09-12 04:42:24 +02:00
parent 9c8e464b04
commit 4f17f3ac24
4 changed files with 116 additions and 6 deletions

View File

@ -21,7 +21,7 @@
#include "gdkgltextureprivate.h"
#include "gdkcairo.h"
#include "gdkmemorytexture.h"
#include "gdkmemorytextureprivate.h"
#include "gdktextureprivate.h"
#include <epoxy/gl.h>
@ -70,6 +70,75 @@ gdk_gl_texture_dispose (GObject *object)
G_OBJECT_CLASS (gdk_gl_texture_parent_class)->dispose (object);
}
static GdkTexture *
gdk_gl_texture_download_texture (GdkTexture *texture)
{
GdkGLTexture *self = GDK_GL_TEXTURE (texture);
GdkTexture *result;
int active_texture;
GdkMemoryFormat format;
GLint internal_format, gl_format, gl_type;
guchar *data;
gsize stride;
GBytes *bytes;
if (self->saved)
return g_object_ref (self->saved);
gdk_gl_context_make_current (self->context);
glGetIntegerv (GL_TEXTURE_BINDING_2D, &active_texture);
glBindTexture (GL_TEXTURE_2D, self->id);
glGetTexLevelParameteriv (GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, &internal_format);
switch (internal_format)
{
case GL_RGB8:
format = GDK_MEMORY_R8G8B8;
gl_format = GL_RGB;
gl_type = GL_UNSIGNED_BYTE;
break;
case GL_RGBA8:
format = GDK_MEMORY_R8G8B8A8_PREMULTIPLIED;
gl_format = GL_RGBA;
gl_type = GL_UNSIGNED_BYTE;
break;
default:
g_warning ("Texture in unexpected format 0x%X (%d). File a bug about adding it to GTK", internal_format, internal_format);
/* fallback to the dumbest possible format
* so that even age old GLES can do it */
format = GDK_MEMORY_R8G8B8A8_PREMULTIPLIED;
gl_format = GL_RGBA;
gl_type = GL_UNSIGNED_BYTE;
break;
}
stride = gdk_memory_format_bytes_per_pixel (format) * texture->width;
data = g_malloc (stride * texture->height);
glGetTexImage (GL_TEXTURE_2D,
0,
gl_format,
gl_type,
data);
bytes = g_bytes_new_take (data, stride * texture->height);
result = gdk_memory_texture_new (texture->width,
texture->height,
format,
bytes,
stride);
g_bytes_unref (bytes);
glBindTexture (GL_TEXTURE_2D, active_texture);
return result;
}
static void
gdk_gl_texture_download (GdkTexture *texture,
guchar *data,
@ -112,6 +181,7 @@ gdk_gl_texture_class_init (GdkGLTextureClass *klass)
GdkTextureClass *texture_class = GDK_TEXTURE_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
texture_class->download_texture = gdk_gl_texture_download_texture;
texture_class->download = gdk_gl_texture_download;
gobject_class->dispose = gdk_gl_texture_dispose;
}

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@ -79,6 +79,12 @@ gdk_memory_texture_dispose (GObject *object)
G_OBJECT_CLASS (gdk_memory_texture_parent_class)->dispose (object);
}
static GdkTexture *
gdk_memory_texture_download_texture (GdkTexture *texture)
{
return g_object_ref (texture);
}
static void
gdk_memory_texture_download (GdkTexture *texture,
guchar *data,
@ -101,6 +107,7 @@ gdk_memory_texture_class_init (GdkMemoryTextureClass *klass)
GdkTextureClass *texture_class = GDK_TEXTURE_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
texture_class->download_texture = gdk_memory_texture_download_texture;
texture_class->download = gdk_memory_texture_download;
gobject_class->dispose = gdk_memory_texture_dispose;
}

View File

@ -115,12 +115,23 @@ G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GdkTexture, gdk_texture, G_TYPE_OBJECT,
#define GDK_TEXTURE_WARN_NOT_IMPLEMENTED_METHOD(obj,method) \
g_critical ("Texture of type '%s' does not implement GdkTexture::" # method, G_OBJECT_TYPE_NAME (obj))
static void
gdk_texture_real_download (GdkTexture *self,
guchar *data,
gsize stride)
static GdkTexture *
gdk_texture_real_download_texture (GdkTexture *self)
{
GDK_TEXTURE_WARN_NOT_IMPLEMENTED_METHOD (self, download);
GDK_TEXTURE_WARN_NOT_IMPLEMENTED_METHOD (self, download_texture);
return NULL;
}
static void
gdk_texture_real_download (GdkTexture *texture,
guchar *data,
gsize stride)
{
GdkTexture *memory_texture;
memory_texture = gdk_texture_download_texture (texture);
gdk_texture_download (memory_texture, data, stride);
g_object_unref (memory_texture);
}
static void
@ -186,6 +197,7 @@ gdk_texture_class_init (GdkTextureClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
klass->download_texture = gdk_texture_real_download_texture;
klass->download = gdk_texture_real_download;
gobject_class->set_property = gdk_texture_set_property;
@ -473,6 +485,22 @@ gdk_texture_download (GdkTexture *texture,
GDK_TEXTURE_GET_CLASS (texture)->download (texture, data, stride);
}
GdkTexture *
gdk_texture_download_texture (GdkTexture *texture)
{
g_return_val_if_fail (GDK_IS_TEXTURE (texture), NULL);
g_object_ref (texture);
while (!GDK_IS_MEMORY_TEXTURE (texture))
{
GdkTexture *downloaded = GDK_TEXTURE_GET_CLASS (texture)->download_texture (texture);
g_object_unref (texture);
texture = downloaded;
}
return texture;
}
gboolean
gdk_texture_set_render_data (GdkTexture *self,
gpointer key,

View File

@ -24,6 +24,9 @@ struct _GdkTexture
struct _GdkTextureClass {
GObjectClass parent_class;
/* mandatory: Download into a GdkMemoryTexture */
GdkTexture * (* download_texture) (GdkTexture *texture);
/* optional */
void (* download) (GdkTexture *texture,
guchar *data,
gsize stride);
@ -34,6 +37,8 @@ gpointer gdk_texture_new (const GdkTextureClass
int height);
GdkTexture * gdk_texture_new_for_surface (cairo_surface_t *surface);
cairo_surface_t * gdk_texture_download_surface (GdkTexture *texture);
/* NB: GdkMemoryTexture */
GdkTexture * gdk_texture_download_texture (GdkTexture *texture);
gboolean gdk_texture_set_render_data (GdkTexture *self,
gpointer key,