/* grab-ximage.c --- grab the screen to an XImage for use with OpenGL.
- * xscreensaver, Copyright (c) 2001, 2003, 2004 Jamie Zawinski <jwz@jwz.org>
+ * xscreensaver, Copyright (c) 2001-2005 Jamie Zawinski <jwz@jwz.org>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
#ifndef __GRAB_XIMAGE_H__
#define __GRAB_XIMAGE_H__
-/* Returns an XImage structure containing an image of the desktop.
- (As a side-effect, that image *may* be painted onto the given Window.)
- This XImage will be 32 bits per pixel, 8 each per R, G, and B, with the
- extra byte set to 0xFF.
+/* Grabs an image of the desktop (or another random image file) and
+ loads tht image into GL's texture memory.
+
+ As a side-effect, that image *may* be painted onto the given Window.
+
+ If mipmap_p is true, then make mipmaps instead of just a single texture.
+
+ If desired_width/height are non-zero, then (if possible) the image
+ will be scaled to fit in that rectangle. If they are 0, then the size
+ of the window is used. These parameters are so that you can hint to
+ the image loader that smaller images are acceptable (if you will never
+ be displaying the texture at 100% magnification, you can get away with
+ smaller textures.)
+
+ Returns the sizes of various things:
+
+ texture_width/height: The size of the texture itself, in pixels.
+ This will often be larger than the grabbed
+ image, since OpenGL sometimes requires texture
+ dimensions to be a power of 2.
+
+ image_width/height: The size of the image: this will usually be the
+ same as the desired_width/height you passed in
+ (but may be the size of the Window instead.)
+
+ geometry: The position in the texture of the image bits.
+ When image files are loaded, they are scaled up
+ to the size of the window, but if the image does
+ not have the same aspect ratio as the window,
+ there will be black bars on the top/bottom or
+ left/right. This geometry specification tells
+ you where the "real" image bits are.
+
+ So, don't use texture coordinates from 0.0 to 1.0. Instead use:
+
+ [0.0 - iw/tw] If you want to display a quad that is the same
+ [0.0 - ih/th] size as the window; or
+
+ [gx/tw - (gx+gw)/tw] If you want to display a quad that is the same
+ [gy/th - (gy+gh)/th] size as the loaded image file.
+
+ Writes to stderr and returns False on error.
*/
-XImage * screen_to_ximage (Screen *screen, Window window,
- char **filename_return);
+Bool screen_to_texture (Screen *screen, Window window,
+ int desired_width, int desired_height,
+ Bool mipmap_p,
+ char **filename_return,
+ XRectangle *geometry_return,
+ int *image_width_return,
+ int *image_height_return,
+ int *texture_width_return,
+ int *texture_height_return);
+
+
+/* Like the above, but the image is loaded in a background process,
+ and a callback is run when the loading is complete.
+ When the callback is called, the image data will have been loaded
+ into texture number `texid' (via glBindTexture.)
-/* Like the above, but loads the image in the background and runs the
- given callback once it has been loaded.
+ If an error occurred, width/height will be 0.
*/
-void fork_screen_to_ximage (Screen *screen, Window window,
- void (*callback) (Screen *, Window, XImage *,
- const char *filename,
- void *closure,
- double cvt_time),
- void *closure);
+void screen_to_texture_async (Screen *screen, Window window,
+ int desired_width, int desired_height,
+ Bool mipmap_p,
+ GLuint texid,
+ void (*callback) (const char *filename,
+ XRectangle *geometry,
+ int image_width,
+ int image_height,
+ int texture_width,
+ int texture_height,
+ void *closure),
+ void *closure);
#endif /* __GRAB_XIMAGE_H__ */
projects / xscreensaver / blobdiff