vo_opengl: replace uniform variable image_size with input_size

input_size can be the size of a cropped image

Signed-off-by: wm4 <wm4@nowhere>

DOCS/interface-changes.rst

@@ -26,6 +26,8 @@ Interface changes
       --vo-image-format options
     - the "jpeg" choice in the option above now leads to a ".jpg" file extension
     - --af=drc is gone (you can use e.g. lavfi/acompressor instead)
+    - remove image_size predefined uniform from OpenGL user shaders. Use
+      input_size instead
  --- mpv 0.24.0 ---
     - deprecate --hwdec-api and replace it with --opengl-hwdec-interop.
       The new option accepts both --hwdec values, as well as named backends.

DOCS/man/options.rst

@@ -4199,8 +4199,8 @@ The following video options are currently all specific to ``--vo=opengl`` and
     int frame
         A simple count of frames rendered, increases by one per frame and never
         resets (regardless of seeks).
-    vec2 image_size
-        The size in pixels of the input image.
+    vec2 input_size
+        The size in pixels of the input image (possibly cropped and prescaled).
     vec2 target_size
         The size in pixels of the visible part of the scaled (and possibly
         cropped) image.

video/out/opengl/video.c

@@ -1224,8 +1224,11 @@ static void load_shader(struct gl_video *p, struct bstr body)
     gl_sc_hadd_bstr(p->sc, body);
     gl_sc_uniform_f(p->sc, "random", (double)av_lfg_get(&p->lfg) / UINT32_MAX);
     gl_sc_uniform_f(p->sc, "frame", p->frames_uploaded);
-    gl_sc_uniform_vec2(p->sc, "image_size", (GLfloat[]){p->image_params.w,
-                                                        p->image_params.h});
+    gl_sc_uniform_vec2(p->sc, "input_size",
+                       (GLfloat[]){(p->src_rect.x1 - p->src_rect.x0) *
+                                   p->texture_offset.m[0][0],
+                                   (p->src_rect.y1 - p->src_rect.y0) *
+                                   p->texture_offset.m[1][1]});
     gl_sc_uniform_vec2(p->sc, "target_size",
                        (GLfloat[]){p->dst_rect.x1 - p->dst_rect.x0,
                                    p->dst_rect.y1 - p->dst_rect.y0});