static bool ogl_lock_region_backbuffer(
ALLEGRO_BITMAP *bitmap, ALLEGRO_BITMAP_EXTRA_OPENGL *ogl_bitmap,
int x, int gl_y, int w, int h, int format, int flags)
{
const int pixel_size = al_get_pixel_size(format);
const int pitch = ogl_pitch(w, pixel_size);
GLenum e;
ogl_bitmap->lock_buffer = al_malloc(pitch * h);
if (ogl_bitmap->lock_buffer == NULL) {
return false;
}
if (!(flags & ALLEGRO_LOCK_WRITEONLY)) {
glReadPixels(x, gl_y, w, h,
get_glformat(format, 2),
get_glformat(format, 1),
ogl_bitmap->lock_buffer);
e = glGetError();
if (e) {
ALLEGRO_ERROR("glReadPixels for format %s failed (%s).\n",
_al_pixel_format_name(format), _al_gl_error_string(e));
al_free(ogl_bitmap->lock_buffer);
ogl_bitmap->lock_buffer = NULL;
return false;
}
}
bitmap->locked_region.data = ogl_bitmap->lock_buffer + pitch * (h - 1);
bitmap->locked_region.format = format;
bitmap->locked_region.pitch = -pitch;
bitmap->locked_region.pixel_size = pixel_size;
return true;
}
static void ogl_lock_region_nonbb_readwrite_fbo(
ALLEGRO_BITMAP *bitmap, ALLEGRO_BITMAP_EXTRA_OPENGL *ogl_bitmap,
int x, int gl_y, int w, int h, int format)
{
const int pixel_size = al_get_pixel_size(format);
const int pitch = ogl_pitch(w, pixel_size);
GLint old_fbo;
GLenum e;
glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &old_fbo);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, ogl_bitmap->fbo_info->fbo);
ogl_bitmap->lock_buffer = al_malloc(pitch * h);
glReadPixels(x, gl_y, w, h,
get_glformat(format, 2),
get_glformat(format, 1),
ogl_bitmap->lock_buffer);
e = glGetError();
if (e) {
ALLEGRO_ERROR("glReadPixels for format %s failed (%s).\n",
_al_format_name(format), _al_gl_error_string(e));
}
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, old_fbo);
bitmap->locked_region.data = ogl_bitmap->lock_buffer + pitch * (h - 1);
bitmap->locked_region.format = format;
bitmap->locked_region.pitch = -pitch;
bitmap->locked_region.pixel_size = pixel_size;
}
static void ogl_lock_region_nonbb_readwrite_nonfbo(
ALLEGRO_BITMAP *bitmap, ALLEGRO_BITMAP_EXTRA_OPENGL *ogl_bitmap,
int x, int gl_y, int w, int h, int format)
{
/* No FBO - fallback to reading the entire texture */
const int pixel_size = al_get_pixel_size(format);
const int pitch = ogl_pitch(ogl_bitmap->true_w, pixel_size);
GLenum e;
(void) w;
ogl_bitmap->lock_buffer = al_malloc(pitch * ogl_bitmap->true_h);
glBindTexture(GL_TEXTURE_2D, ogl_bitmap->texture);
glGetTexImage(GL_TEXTURE_2D, 0,
get_glformat(format, 2),
get_glformat(format, 1),
ogl_bitmap->lock_buffer);
e = glGetError();
if (e) {
ALLEGRO_ERROR("glGetTexImage for format %s failed (%s).\n",
_al_format_name(format), _al_gl_error_string(e));
}
bitmap->locked_region.data = ogl_bitmap->lock_buffer +
pitch * (gl_y + h - 1) + pixel_size * x;
bitmap->locked_region.format = format;
bitmap->locked_region.pitch = -pitch;
bitmap->locked_region.pixel_size = pixel_size;
}
static void ogl_lock_region_nonbb_writeonly(
ALLEGRO_BITMAP *bitmap, ALLEGRO_BITMAP_EXTRA_OPENGL *ogl_bitmap,
int x, int gl_y, int w, int h, int format)
{
const int pixel_size = al_get_pixel_size(format);
const int pitch = ogl_pitch(w, pixel_size);
(void) x;
(void) gl_y;
ogl_bitmap->lock_buffer = al_malloc(pitch * h);
bitmap->locked_region.data = ogl_bitmap->lock_buffer + pitch * (h - 1);
bitmap->locked_region.format = format;
bitmap->locked_region.pitch = -pitch;
bitmap->locked_region.pixel_size = pixel_size;
}