gtk/gdk/gdkgl.c
Benjamin Otte 64f10eff20 gdk: Remove unused gdk_gl_texture_quads() function
That function carried a lot of baggage.
2021-10-06 03:44:36 +02:00

178 lines
6.4 KiB
C

/* GDK - The GIMP Drawing Kit
* Copyright (C) 2014 Red Hat, Inc.
*
* 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/>.
*/
#include "config.h"
#include "gdkcairo.h"
#include "gdkglcontextprivate.h"
#include "gdksurfaceprivate.h"
#include <epoxy/gl.h>
#include <math.h>
#include <string.h>
/* x,y,width,height describes a rectangle in the gl render buffer
coordinate space, and its top left corner is drawn at the current
position according to the cairo translation. */
/**
* gdk_cairo_draw_from_gl:
* @cr: a cairo context
* @surface: The surface we're rendering for (not necessarily into)
* @source: The GL ID of the source buffer
* @source_type: The type of the @source
* @buffer_scale: The scale-factor that the @source buffer is allocated for
* @x: The source x position in @source to start copying from in GL coordinates
* @y: The source y position in @source to start copying from in GL coordinates
* @width: The width of the region to draw
* @height: The height of the region to draw
*
* The main way to not draw GL content in GTK.
*
* It takes a render buffer ID (@source_type == GL_RENDERBUFFER) or a texture
* id (@source_type == GL_TEXTURE) and draws it onto @cr with an OVER operation,
* respecting the current clip. The top left corner of the rectangle specified
* by @x, @y, @width and @height will be drawn at the current (0,0) position of
* the `cairo_t`.
*
* This will work for *all* `cairo_t`, as long as @surface is realized, but the
* fallback implementation that reads back the pixels from the buffer may be
* used in the general case. In the case of direct drawing to a surface with
* no special effects applied to @cr it will however use a more efficient
* approach.
*
* For GL_RENDERBUFFER the code will always fall back to software for buffers
* with alpha components, so make sure you use GL_TEXTURE if using alpha.
*
* Calling this may change the current GL context.
*
* Deprecated: 4.6: The function is overly complex and produces broken output
* in various combinations of arguments. If you want to draw with GL textures
* in GTK, use [ctor@Gdk.GLTexture.new]; if you want to use that texture in
* Cairo, use [method@Gdk.Texture.download] to download the data into a Cairo
* image surface.
*/
void
gdk_cairo_draw_from_gl (cairo_t *cr,
GdkSurface *surface,
int source,
int source_type,
int buffer_scale,
int x,
int y,
int width,
int height)
{
GdkGLContext *paint_context;
cairo_surface_t *image;
guint framebuffer;
int alpha_size = 0;
int major, minor, version;
gboolean es_use_bgra = FALSE;
paint_context = gdk_surface_get_paint_gl_context (surface, NULL);
if (paint_context == NULL)
{
g_warning ("gdk_cairo_draw_gl_render_buffer failed - no paint context");
return;
}
es_use_bgra = gdk_gl_context_use_es_bgra (paint_context);
gdk_gl_context_make_current (paint_context);
glGenFramebuffers (1, &framebuffer);
if (source_type == GL_RENDERBUFFER)
{
glBindRenderbuffer (GL_RENDERBUFFER, source);
glGetRenderbufferParameteriv (GL_RENDERBUFFER, GL_RENDERBUFFER_ALPHA_SIZE, &alpha_size);
}
else if (source_type == GL_TEXTURE)
{
glBindTexture (GL_TEXTURE_2D, source);
if (gdk_gl_context_get_use_es (paint_context))
alpha_size = 1;
else
glGetTexLevelParameteriv (GL_TEXTURE_2D, 0, GL_TEXTURE_ALPHA_SIZE, &alpha_size);
}
else
{
g_warning ("Unsupported gl source type %d\n", source_type);
return;
}
gdk_gl_context_get_version (paint_context, &major, &minor);
version = major * 100 + minor;
/* TODO: Use glTexSubImage2D() and do a row-by-row copy to replace
* the GL_UNPACK_ROW_LENGTH support
*/
if (gdk_gl_context_get_use_es (paint_context) &&
!(version >= 300 || gdk_gl_context_has_unpack_subimage (paint_context)))
return;
/* TODO: avoid reading back non-required data due to dest clip */
image = cairo_surface_create_similar_image (cairo_get_target (cr),
(alpha_size == 0) ? CAIRO_FORMAT_RGB24 : CAIRO_FORMAT_ARGB32,
width, height);
cairo_surface_set_device_scale (image, buffer_scale, buffer_scale);
glBindFramebuffer (GL_FRAMEBUFFER, framebuffer);
if (source_type == GL_RENDERBUFFER)
{
/* Create a framebuffer with the source renderbuffer and
make it the current target for reads */
glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_RENDERBUFFER, source);
}
else
{
glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, source, 0);
}
glPixelStorei (GL_PACK_ALIGNMENT, 4);
glPixelStorei (GL_PACK_ROW_LENGTH, cairo_image_surface_get_stride (image) / 4);
/* The implicit format conversion is going to make this path slower */
if (!gdk_gl_context_get_use_es (paint_context))
glReadPixels (x, y, width, height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV,
cairo_image_surface_get_data (image));
else
glReadPixels (x, y, width, height, es_use_bgra ? GL_BGRA : GL_RGBA, GL_UNSIGNED_BYTE,
cairo_image_surface_get_data (image));
glPixelStorei (GL_PACK_ROW_LENGTH, 0);
glBindFramebuffer (GL_FRAMEBUFFER, 0);
glDeleteFramebuffers (1, &framebuffer);
cairo_surface_mark_dirty (image);
cairo_set_source_surface (cr, image, 0, 0);
cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
cairo_paint (cr);
cairo_surface_destroy (image);
}