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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
#include <string.h>
#include <clutter/clutter.h>
#include <cogl/cogl.h>
#include <GL/gl.h>
#include <GL/glx.h>
#include <GL/glext.h>
#include "cinnamon-screen-grabber.h"
PFNGLBINDBUFFERARBPROC pf_glBindBufferARB;
PFNGLBUFFERDATAARBPROC pf_glBufferDataARB;
PFNGLDELETEBUFFERSARBPROC pf_glDeleteBuffersARB;
PFNGLGENBUFFERSARBPROC pf_glGenBuffersARB;
PFNGLMAPBUFFERARBPROC pf_glMapBufferARB;
PFNGLUNMAPBUFFERARBPROC pf_glUnmapBufferARB;
struct _CinnamonScreenGrabberClass
{
GObjectClass parent_class;
};
struct _CinnamonScreenGrabber
{
GObject parent_instance;
int have_pixel_buffers;
int have_pack_invert;
int width, height;
GLuint pixel_buffer;
};
G_DEFINE_TYPE(CinnamonScreenGrabber, cinnamon_screen_grabber, G_TYPE_OBJECT);
static void
cinnamon_screen_grabber_finalize (GObject *gobject)
{
CinnamonScreenGrabber *grabber = CINNAMON_SCREEN_GRABBER (gobject);
if (grabber->pixel_buffer != 0)
pf_glDeleteBuffersARB (1, &grabber->pixel_buffer);
}
static void
cinnamon_screen_grabber_class_init (CinnamonScreenGrabberClass *grabber_class)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (grabber_class);
gobject_class->finalize = cinnamon_screen_grabber_finalize;
}
static void
cinnamon_screen_grabber_init (CinnamonScreenGrabber *grabber)
{
grabber->have_pixel_buffers = -1;
grabber->width = -1;
grabber->height= -1;
grabber->pixel_buffer = 0;
}
CinnamonScreenGrabber *
cinnamon_screen_grabber_new (void)
{
return g_object_new (CINNAMON_TYPE_SCREEN_GRABBER, NULL);
}
/**
* cinnamon_screen_grabber_grab:
* x: X coordinate of the rectangle to grab
* y: Y coordinate of the rectangle to grab
* width: width of the rectangle to grab
* height: heigth of the rectangle to grab
*
* Grabs pixel data from a portion of the screen.
*
* Return value: buffer holding the grabbed data. The data is stored as 32-bit
* words with native-endian xRGB pixels (i.e., the same as CAIRO_FORMAT_RGB24)
* with no padding on the rows. So, the size of the buffer is width * height * 4
* bytes. Free with g_free().
**/
guchar *
cinnamon_screen_grabber_grab (CinnamonScreenGrabber *grabber,
int x,
int y,
int width,
int height)
{
guchar *data;
gsize row_bytes;
gsize data_size;
row_bytes = width * 4;
data_size = row_bytes * height;
data = g_malloc (data_size);
if (grabber->have_pixel_buffers == -1)
{
const GLubyte* extensions = glGetString (GL_EXTENSIONS);
grabber->have_pixel_buffers = strstr ((const char *)extensions, "GL_EXT_pixel_buffer_object") != NULL;
grabber->have_pack_invert = strstr ((const char *)extensions, "GL_MESA_pack_invert") != NULL;
}
if (grabber->have_pixel_buffers)
{
GLubyte *mapped_data;
GLint old_swap_bytes, old_lsb_first, old_row_length, old_skip_pixels, old_skip_rows, old_alignment;
GLint old_pack_invert = GL_FALSE;
GLint vp_size[4];
guchar *src_row, *dest_row;
int i;
cogl_flush ();
if (pf_glBindBufferARB == NULL)
{
pf_glBindBufferARB = (PFNGLBINDBUFFERARBPROC) cogl_get_proc_address ("glBindBufferARB");
pf_glBufferDataARB = (PFNGLBUFFERDATAARBPROC) cogl_get_proc_address ("glBufferDataARB");
pf_glDeleteBuffersARB = (PFNGLDELETEBUFFERSARBPROC) cogl_get_proc_address ("glDeleteBuffersARB");
pf_glGenBuffersARB = (PFNGLGENBUFFERSARBPROC) cogl_get_proc_address ("glGenBuffersARB");
pf_glMapBufferARB = (PFNGLMAPBUFFERARBPROC) cogl_get_proc_address ("glMapBufferARB");
pf_glUnmapBufferARB = (PFNGLUNMAPBUFFERARBPROC) cogl_get_proc_address ("glUnmapBufferARB");
}
glGetIntegerv (GL_PACK_SWAP_BYTES, &old_swap_bytes);
glGetIntegerv (GL_PACK_LSB_FIRST, &old_lsb_first);
glGetIntegerv (GL_PACK_ROW_LENGTH, &old_row_length);
glGetIntegerv (GL_PACK_SKIP_PIXELS, &old_skip_pixels);
glGetIntegerv (GL_PACK_SKIP_ROWS, &old_skip_rows);
glGetIntegerv (GL_PACK_ALIGNMENT, &old_alignment);
glPixelStorei (GL_PACK_SWAP_BYTES, GL_FALSE);
glPixelStorei (GL_PACK_LSB_FIRST, GL_FALSE);
glPixelStorei (GL_PACK_ROW_LENGTH, 0);
glPixelStorei (GL_PACK_SKIP_PIXELS, 0);
glPixelStorei (GL_PACK_SKIP_ROWS, 0);
glPixelStorei (GL_PACK_ALIGNMENT, 1);
if (grabber->have_pack_invert)
{
glGetIntegerv (GL_PACK_INVERT_MESA, &old_pack_invert);
glPixelStorei (GL_PACK_INVERT_MESA, GL_FALSE);
}
if (grabber->pixel_buffer != 0 &&
(grabber->width != width ||
grabber->height != height))
{
pf_glDeleteBuffersARB (1, &grabber->pixel_buffer);
grabber->pixel_buffer = 0;
}
if (grabber->pixel_buffer == 0)
{
pf_glGenBuffersARB (1, &grabber->pixel_buffer);
pf_glBindBufferARB (GL_PIXEL_PACK_BUFFER_ARB, grabber->pixel_buffer);
pf_glBufferDataARB (GL_PIXEL_PACK_BUFFER_ARB, data_size, 0, GL_STREAM_READ_ARB);
grabber->width = width;
grabber->height = height;
}
else
{
pf_glBindBufferARB (GL_PIXEL_PACK_BUFFER_ARB, grabber->pixel_buffer);
}
/* In OpenGL, (x,y) specifies the bottom-left corner rather than the
* top-left */
glGetIntegerv (GL_VIEWPORT, vp_size);
y = vp_size[3] - (y + height);
glReadPixels (x, y, width, height, GL_BGRA, GL_UNSIGNED_BYTE, 0);
mapped_data = pf_glMapBufferARB (GL_PIXEL_PACK_BUFFER_ARB, GL_READ_ONLY_ARB);
src_row = mapped_data + (height - 1) * row_bytes;
dest_row = data;
for (i = 0; i < height; i++)
{
memcpy (dest_row, src_row, row_bytes);
src_row -= row_bytes;
dest_row += row_bytes;
}
pf_glUnmapBufferARB (GL_PIXEL_PACK_BUFFER_ARB);
pf_glBindBufferARB (GL_PIXEL_PACK_BUFFER_ARB, 0);
glPixelStorei (GL_PACK_SWAP_BYTES, old_swap_bytes);
glPixelStorei (GL_PACK_LSB_FIRST, old_lsb_first);
glPixelStorei (GL_PACK_ROW_LENGTH, old_row_length);
glPixelStorei (GL_PACK_SKIP_PIXELS, old_skip_pixels);
glPixelStorei (GL_PACK_SKIP_ROWS, old_skip_rows);
glPixelStorei (GL_PACK_ALIGNMENT, old_alignment);
if (grabber->have_pack_invert)
glPixelStorei (GL_PACK_INVERT_MESA, old_pack_invert);
}
else
{
cogl_read_pixels (x, y,
width, height,
COGL_READ_PIXELS_COLOR_BUFFER,
CLUTTER_CAIRO_FORMAT_ARGB32,
data);
}
return data;
}
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