vo_opengl: make size of OUTPUT available to user shaders

1 files changed, 9 insertions, 0 deletions

diff --git a/video/out/opengl/video.c b/video/out/opengl/video.c
index 21eda6bc7d..c9179c7800 100644
--- a/video/out/opengl/video.c
+++ b/video/out/opengl/video.c
@@ -1688,6 +1688,15 @@ static bool eval_szexpr(struct gl_video *p, struct img_tex tex,
             struct bstr name = expr[i].val.varname;
             struct img_tex var_tex;
 
+            // The size of OUTPUT is determined. It could be useful for certain
+            // user shaders to skip passes.
+            if (bstr_equals0(name, "OUTPUT")) {
+                int vp_w = p->dst_rect.x1 - p->dst_rect.x0;
+                int vp_h = p->dst_rect.y1 - p->dst_rect.y0;
+                stack[idx++] = (expr[i].tag == SZEXP_VAR_W) ? vp_w : vp_h;
+                continue;
+            }
+
             // HOOKED is a special case
             if (bstr_equals0(name, "HOOKED")) {
                 var_tex = tex;