cogl-pixel-buffer: add a pixel buffer object class

This subclass of CoglBuffer aims at wrapping PBOs or other system
surfaces like DRM buffer objects. Two constructors are available:

cogl_pixel_buffer_new() with a size when you only care about the size of
the buffer (such a buffer can be used to store several texture data such
as the three planes of a I420 frame).

cogl_pixel_buffer_new_full() is more a 1:1 mapping between the data and
an underlying surface, with the possibility of having access to a low
level memory buffer that may have a stride.

cogl/cogl-pixel-buffer.h

@@ -0,0 +1,165 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2008,2009 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Authors:
+ *   Robert Bragg <robert@linux.intel.com>
+ */
+
+#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
+#error "Only <cogl/cogl.h> can be included directly."
+#endif
+
+#ifndef __COGL_PIXEL_BUFFER_H__
+#define __COGL_PIXEL_BUFFER_H__
+
+#include <glib.h>
+#include <cogl/cogl-types.h>
+
+G_BEGIN_DECLS
+
+/**
+ * cogl_pixel_buffer_new:
+ * @size: size of the buffer in bytes
+ *
+ * Creates a new buffer to store pixel data. You can create a new texture from
+ * this buffer using cogl_texture_new_from_buffer().
+ *
+ * Return value: a #CoglHandle representing the newly created buffer or
+ *               %COGL_INVALID_HANDLE on failure
+ *
+ * Since: 1.2
+ * Stability: Unstable
+ */
+CoglHandle
+cogl_pixel_buffer_new (guint size);
+
+/**
+ * cogl_pixel_buffer_new_for_size:
+ * @width: width of the pixel buffer in pixels
+ * @height: height of the pixel buffer in pixels
+ * @format: the format of the pixels the buffer will store
+ * @stride: if not %NULL the function will return the stride of the buffer
+ *          in bytes
+ *
+ * Creates a new buffer to store pixel data.
+ *
+ * <note>COGL will try its best to provide a hardware buffer you can map,
+ * write into and effectively do a zero copy upload when creating a texture
+ * from it with cogl_texture_new_from_buffer(). For various reasons, such
+ * buffers are likely to have a stride larger than width * bytes_per_pixel. The
+ * user must take the stride into account when writing into it.</note>
+ *
+ * Return value: a #CoglHandle representing the newly created buffer or
+ *               %COGL_INVALID_HANDLE on failure
+ *
+ * Since: 1.2
+ * Stability: Unstable
+ */
+CoglHandle
+cogl_pixel_buffer_new_for_size (guint            width,
+                                guint            height,
+                                CoglPixelFormat  format,
+                                guint           *stride);
+
+/**
+ * cogl_is_pixel_buffer:
+ * @handle: a #CoglHandle to test
+ *
+ * Checks whether @handle is a pixel buffer.
+ *
+ * Return value: %TRUE if the @handle is a pixel buffer, and %FALSE
+ *   otherwise
+ *
+ * Since: 1.2
+ * Stability: Unstable
+ */
+gboolean
+cogl_is_pixel_buffer (CoglHandle handle);
+
+/*
+ * cogl_pixel_buffer_set_region:
+ * @buffer: the #CoglHandle of a pixel buffer
+ * @data: pixel data to upload to @buffer
+ * @src_width: width in pixels of the region to update
+ * @src_height: height in pixels of the region to update
+ * @src_rowstride: row stride in bytes of the source buffer
+ * @dst_x: upper left destination horizontal coordinate
+ * @dst_y: upper left destination vertical coordinate
+ *
+ * Uploads new data into a pixel buffer. The source data pointed by @data can
+ * have a different stride than @buffer in which case the function will do the
+ * right thing for you. For performance reasons, it is recommended for the
+ * source data to have the same stride than @buffer.
+ *
+ * Return value: %TRUE if the upload succeeded, %FALSE otherwise
+ *
+ * Since: 1.2
+ * Stability: Unstable
+ */
+#if 0
+gboolean
+cogl_pixel_buffer_set_region (CoglHandle  buffer,
+                              guchar     *data,
+                              guint       src_width,
+                              guint       src_height,
+                              guint       src_rowstride,
+                              guint       dst_x,
+                              guint       dst_y);
+#endif
+
+/* the functions above are experimental, the actual symbols are suffixed by
+ * _EXP so we can ensure ABI compatibility and leave the cogl_buffer namespace
+ * free for future use. A bunch of defines translates the symbols documented
+ * above into the real symbols */
+
+CoglHandle
+cogl_pixel_buffer_new_EXP (guint size);
+
+CoglHandle
+cogl_pixel_buffer_new_for_size_EXP (guint            width,
+                                    guint            height,
+                                    CoglPixelFormat  format,
+                                    guint           *stride);
+gboolean
+cogl_is_pixel_buffer_EXP (CoglHandle handle);
+
+#if 0
+gboolean
+cogl_pixel_buffer_set_region_EXP (CoglHandle  buffer,
+                                  guchar     *data,
+                                  guint       src_width,
+                                  guint       src_height,
+                                  guint       src_rowstride,
+                                  guint       dst_x,
+                                  guint       dst_y);
+#endif
+
+#define cogl_pixel_buffer_new cogl_pixel_buffer_new_EXP
+#define cogl_pixel_buffer_new_for_size cogl_pixel_buffer_new_for_size_EXP
+#define cogl_is_pixel_buffer cogl_is_pixel_buffer_EXP
+#if 0
+#define cogl_pixel_buffer_set_region cogl_pixel_buffer_set_region_EXP
+#endif
+
+G_END_DECLS
+
+#endif /* __COGL_PIXEL_BUFFER_H__ */