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mutter/cogl/driver/gl/gles/cogl-texture-driver-gles.c
Neil Roberts ff11a2b207 Use GL_ARB_texture_swizzle to emulate GL_ALPHA textures 
The core profile of GL3 has removed support for component-alpha
textures. Previously the GL3 driver would just ignore this and try to
create them anyway. This would generate a GL error on Mesa.

To fix this the GL texture driver will now create a GL_RED texture
when GL_ALPHA textures are not supported natively. It will then set a
texture swizzle using the GL_ARB_texture_swizzle extension so that the
alpha component will be taken from the red component of the texture.
The swizzle is part of the texture object state so it only needs to be
set once when the texture is created.

The ‘gen’ virtual function of the texture driver has been changed to
also take the internal format as a parameter. The GL driver will now
set the swizzle as appropriate here.

The GL3 driver now reports an error if the texture swizzle extension
is not available because Cogl can't really work properly without out
it. The extension is part of GL 3.3 so it is quite likely that it has
wide support from drivers. Eventually we could get rid of this
requirement if we have our own GLSL front-end and we could generate
the swizzle ourselves.

When uploading or downloading texture data to or from a
component-alpha texture, we can no longer rely on GL to do the
conversion. The swizzle doesn't have any effect on the texture data
functions. In these cases Cogl will now force an intermediate buffer
to be used and it will manually do the conversion as it does for the
GLES drivers.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 32bacf81ebaa3be21a8f26af07d8f6eed6607652)
2013-01-22 17:48:04 +00:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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, see <http://www.gnu.org/licenses/>.
*
*
*
* Authors:
* Matthew Allum <mallum@openedhand.com>
* Neil Roberts <neil@linux.intel.com>
* Robert Bragg <robert@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl-private.h"
#include "cogl-util.h"
#include "cogl-bitmap.h"
#include "cogl-bitmap-private.h"
#include "cogl-texture-private.h"
#include "cogl-pipeline.h"
#include "cogl-pipeline-opengl-private.h"
#include "cogl-context-private.h"
#include "cogl-object-private.h"
#include "cogl-primitives.h"
#include <string.h>
#include <stdlib.h>
#include <math.h>
#ifndef GL_TEXTURE_3D
#define GL_TEXTURE_3D 0x806F
#endif
#ifndef GL_MAX_3D_TEXTURE_SIZE_OES
#define GL_MAX_3D_TEXTURE_SIZE_OES 0x8073
#endif
/* This extension isn't available for GLES 1.1 so these won't be
defined */
#ifndef GL_UNPACK_ROW_LENGTH
#define GL_UNPACK_ROW_LENGTH 0x0CF2
#endif
#ifndef GL_UNPACK_SKIP_ROWS
#define GL_UNPACK_SKIP_ROWS 0x0CF3
#endif
#ifndef GL_UNPACK_SKIP_PIXELS
#define GL_UNPACK_SKIP_PIXELS 0x0CF4
#endif
static GLuint
_cogl_texture_driver_gen (CoglContext *ctx,
GLenum gl_target,
CoglPixelFormat internal_format)
{
GLuint tex;
GE (ctx, glGenTextures (1, &tex));
_cogl_bind_gl_texture_transient (gl_target, tex, FALSE);
switch (gl_target)
{
case GL_TEXTURE_2D:
case GL_TEXTURE_3D:
/* GL_TEXTURE_MAG_FILTER defaults to GL_LINEAR, no need to set it */
GE( ctx, glTexParameteri (gl_target,
GL_TEXTURE_MIN_FILTER,
GL_LINEAR) );
break;
default:
g_assert_not_reached();
}
return tex;
}
static void
prep_gl_for_pixels_upload_full (CoglContext *ctx,
int pixels_rowstride,
int pixels_src_x,
int pixels_src_y,
int pixels_bpp)
{
if ((ctx->private_feature_flags & COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE))
{
GE( ctx, glPixelStorei (GL_UNPACK_ROW_LENGTH,
pixels_rowstride / pixels_bpp) );
GE( ctx, glPixelStorei (GL_UNPACK_SKIP_PIXELS, pixels_src_x) );
GE( ctx, glPixelStorei (GL_UNPACK_SKIP_ROWS, pixels_src_y) );
}
else
{
g_assert (pixels_src_x == 0);
g_assert (pixels_src_y == 0);
}
_cogl_texture_prep_gl_alignment_for_pixels_upload (pixels_rowstride);
}
static void
_cogl_texture_driver_prep_gl_for_pixels_upload (CoglContext *ctx,
int pixels_rowstride,
int pixels_bpp)
{
prep_gl_for_pixels_upload_full (ctx,
pixels_rowstride,
0, 0, /* src_x/y */
pixels_bpp);
}
static void
_cogl_texture_driver_prep_gl_for_pixels_download (CoglContext *ctx,
int pixels_rowstride,
int image_width,
int pixels_bpp)
{
_cogl_texture_prep_gl_alignment_for_pixels_download (pixels_bpp,
image_width,
pixels_rowstride);
}
static CoglBitmap *
prepare_bitmap_alignment_for_upload (CoglContext *ctx,
CoglBitmap *src_bmp)
{
CoglPixelFormat format = cogl_bitmap_get_format (src_bmp);
int bpp = _cogl_pixel_format_get_bytes_per_pixel (format);
int src_rowstride = cogl_bitmap_get_rowstride (src_bmp);
int width = cogl_bitmap_get_width (src_bmp);
int alignment = 1;
if ((ctx->private_feature_flags & COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE) ||
src_rowstride == 0)
return cogl_object_ref (src_bmp);
/* Work out the alignment of the source rowstride */
alignment = 1 << (_cogl_util_ffs (src_rowstride) - 1);
alignment = MIN (alignment, 8);
/* If the aligned data equals the rowstride then we can upload from
the bitmap directly using GL_UNPACK_ALIGNMENT */
if (((width * bpp + alignment - 1) & ~(alignment - 1)) == src_rowstride)
return cogl_object_ref (src_bmp);
/* Otherwise we need to copy the bitmap to pack the alignment
because GLES has no GL_ROW_LENGTH */
else
return _cogl_bitmap_copy (src_bmp);
}
static void
_cogl_texture_driver_upload_subregion_to_gl (CoglContext *ctx,
GLenum gl_target,
GLuint gl_handle,
CoglBool is_foreign,
int src_x,
int src_y,
int dst_x,
int dst_y,
int width,
int height,
CoglBitmap *source_bmp,
GLuint source_gl_format,
GLuint source_gl_type)
{
uint8_t *data;
CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
CoglBitmap *slice_bmp;
int rowstride;
/* If we have the GL_EXT_unpack_subimage extension then we can
upload from subregions directly. Otherwise we may need to copy
the bitmap */
if (!(ctx->private_feature_flags & COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE) &&
(src_x != 0 || src_y != 0 ||
width != cogl_bitmap_get_width (source_bmp) ||
height != cogl_bitmap_get_height (source_bmp)))
{
slice_bmp =
_cogl_bitmap_new_with_malloc_buffer (ctx,
width, height,
source_format);
_cogl_bitmap_copy_subregion (source_bmp,
slice_bmp,
src_x, src_y,
0, 0, /* dst_x/y */
width, height);
src_x = src_y = 0;
}
else
slice_bmp = prepare_bitmap_alignment_for_upload (ctx, source_bmp);
rowstride = cogl_bitmap_get_rowstride (slice_bmp);
/* Setup gl alignment to match rowstride and top-left corner */
prep_gl_for_pixels_upload_full (ctx, rowstride, src_x, src_y, bpp);
data = _cogl_bitmap_gl_bind (slice_bmp, COGL_BUFFER_ACCESS_READ, 0);
_cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);
GE( ctx, glTexSubImage2D (gl_target, 0,
dst_x, dst_y,
width, height,
source_gl_format,
source_gl_type,
data) );
_cogl_bitmap_gl_unbind (slice_bmp);
cogl_object_unref (slice_bmp);
}
static void
_cogl_texture_driver_upload_to_gl (CoglContext *ctx,
GLenum gl_target,
GLuint gl_handle,
CoglBool is_foreign,
CoglBitmap *source_bmp,
GLint internal_gl_format,
GLuint source_gl_format,
GLuint source_gl_type)
{
CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
int rowstride;
int bmp_width = cogl_bitmap_get_width (source_bmp);
int bmp_height = cogl_bitmap_get_height (source_bmp);
CoglBitmap *bmp;
uint8_t *data;
bmp = prepare_bitmap_alignment_for_upload (ctx, source_bmp);
rowstride = cogl_bitmap_get_rowstride (bmp);
/* Setup gl alignment to match rowstride and top-left corner */
_cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);
_cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);
data = _cogl_bitmap_gl_bind (bmp, COGL_BUFFER_ACCESS_READ, 0);
GE( ctx, glTexImage2D (gl_target, 0,
internal_gl_format,
bmp_width, bmp_height,
0,
source_gl_format,
source_gl_type,
data) );
_cogl_bitmap_gl_unbind (bmp);
cogl_object_unref (bmp);
}
static void
_cogl_texture_driver_upload_to_gl_3d (CoglContext *ctx,
GLenum gl_target,
GLuint gl_handle,
CoglBool is_foreign,
GLint height,
GLint depth,
CoglBitmap *source_bmp,
GLint internal_gl_format,
GLuint source_gl_format,
GLuint source_gl_type)
{
CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
int rowstride = cogl_bitmap_get_rowstride (source_bmp);
int bmp_width = cogl_bitmap_get_width (source_bmp);
int bmp_height = cogl_bitmap_get_height (source_bmp);
uint8_t *data;
_cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);
/* If the rowstride or image height can't be specified with just
GL_ALIGNMENT alone then we need to copy the bitmap because there
is no GL_ROW_LENGTH */
if (rowstride / bpp != bmp_width ||
height != bmp_height / depth)
{
CoglBitmap *bmp;
int image_height = bmp_height / depth;
CoglPixelFormat source_bmp_format = cogl_bitmap_get_format (source_bmp);
int i;
_cogl_texture_driver_prep_gl_for_pixels_upload (ctx, bmp_width * bpp, bpp);
/* Initialize the texture with empty data and then upload each
image with a sub-region update */
GE( ctx, glTexImage3D (gl_target,
0, /* level */
internal_gl_format,
bmp_width,
height,
depth,
0,
source_gl_format,
source_gl_type,
NULL) );
bmp = _cogl_bitmap_new_with_malloc_buffer (ctx,
bmp_width,
height,
source_bmp_format);
for (i = 0; i < depth; i++)
{
_cogl_bitmap_copy_subregion (source_bmp,
bmp,
0, image_height * i,
0, 0,
bmp_width,
height);
data = _cogl_bitmap_gl_bind (bmp,
COGL_BUFFER_ACCESS_READ, 0);
GE( ctx, glTexSubImage3D (gl_target,
0, /* level */
0, /* xoffset */
0, /* yoffset */
i, /* zoffset */
bmp_width, /* width */
height, /* height */
1, /* depth */
source_gl_format,
source_gl_type,
data) );
_cogl_bitmap_gl_unbind (bmp);
}
cogl_object_unref (bmp);
}
else
{
data = _cogl_bitmap_gl_bind (source_bmp, COGL_BUFFER_ACCESS_READ, 0);
_cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);
GE( ctx, glTexImage3D (gl_target,
0, /* level */
internal_gl_format,
bmp_width,
height,
depth,
0,
source_gl_format,
source_gl_type,
data) );
_cogl_bitmap_gl_unbind (source_bmp);
}
}
/* NB: GLES doesn't support glGetTexImage2D, so cogl-texture will instead
* fallback to a generic render + readpixels approach to downloading
* texture data. (See _cogl_texture_draw_and_read() ) */
static CoglBool
_cogl_texture_driver_gl_get_tex_image (CoglContext *ctx,
GLenum gl_target,
GLenum dest_gl_format,
GLenum dest_gl_type,
uint8_t *dest)
{
return FALSE;
}
static CoglBool
_cogl_texture_driver_size_supported_3d (CoglContext *ctx,
GLenum gl_target,
GLenum gl_format,
GLenum gl_type,
int width,
int height,
int depth)
{
GLint max_size;
/* GLES doesn't support a proxy texture target so let's at least
check whether the size is greater than
GL_MAX_3D_TEXTURE_SIZE_OES */
GE( ctx, glGetIntegerv (GL_MAX_3D_TEXTURE_SIZE_OES, &max_size) );
return width <= max_size && height <= max_size && depth <= max_size;
}
static CoglBool
_cogl_texture_driver_size_supported (CoglContext *ctx,
GLenum gl_target,
GLenum gl_intformat,
GLenum gl_format,
GLenum gl_type,
int width,
int height)
{
GLint max_size;
/* GLES doesn't support a proxy texture target so let's at least
check whether the size is greater than GL_MAX_TEXTURE_SIZE */
GE( ctx, glGetIntegerv (GL_MAX_TEXTURE_SIZE, &max_size) );
return width <= max_size && height <= max_size;
}
static void
_cogl_texture_driver_try_setting_gl_border_color
(CoglContext *ctx,
GLuint gl_target,
const GLfloat *transparent_color)
{
/* FAIL! */
}
static CoglBool
_cogl_texture_driver_allows_foreign_gl_target (CoglContext *ctx,
GLenum gl_target)
{
/* Allow 2-dimensional textures only */
if (gl_target != GL_TEXTURE_2D)
return FALSE;
return TRUE;
}
static void
_cogl_texture_driver_gl_generate_mipmaps (CoglContext *ctx,
GLenum gl_target)
{
if (ctx->driver == COGL_DRIVER_GLES2)
GE( ctx, glGenerateMipmap (gl_target) );
}
static CoglPixelFormat
_cogl_texture_driver_find_best_gl_get_data_format
(CoglContext *context,
CoglPixelFormat format,
GLenum *closest_gl_format,
GLenum *closest_gl_type)
{
/* Find closest format that's supported by GL
(Can't use _cogl_pixel_format_to_gl since available formats
when reading pixels on GLES are severely limited) */
*closest_gl_format = GL_RGBA;
*closest_gl_type = GL_UNSIGNED_BYTE;
return COGL_PIXEL_FORMAT_RGBA_8888;
}
const CoglTextureDriver
_cogl_texture_driver_gles =
{
_cogl_texture_driver_gen,
_cogl_texture_driver_prep_gl_for_pixels_upload,
_cogl_texture_driver_upload_subregion_to_gl,
_cogl_texture_driver_upload_to_gl,
_cogl_texture_driver_upload_to_gl_3d,
_cogl_texture_driver_prep_gl_for_pixels_download,
_cogl_texture_driver_gl_get_tex_image,
_cogl_texture_driver_size_supported,
_cogl_texture_driver_size_supported_3d,
_cogl_texture_driver_try_setting_gl_border_color,
_cogl_texture_driver_allows_foreign_gl_target,
_cogl_texture_driver_gl_generate_mipmaps,
_cogl_texture_driver_find_best_gl_get_data_format
};
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