vo_opengl: make size of a cropped source image available to user shaders

2 files changed, 11 insertions, 3 deletions

diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index 61a5f61a37..2a56097f77 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -4141,9 +4141,11 @@ The following video options are currently all specific to ``--vo=opengl`` and
         Specifies the size of the resulting texture for this pass. ``szexpr``
         refers to an expression in RPN (reverse polish notation), using the
         operators + - * / > < !, floating point literals, and references to
-        sizes of existing texture and OUTPUT (such as MAIN.width or
-        CHROMA.height). By default, these are set to HOOKED.w and HOOKED.h,
-        respectively.
+        sizes of existing texture (such as MAIN.width or CHROMA.height),
+        OUTPUT, or NATIVE_CROPPED (size of an input texture cropped after
+        pan-and-scan, video-align-x/y, video-pan-x/y, etc. and possibly
+        prescaled). By default, these are set to HOOKED.w and HOOKED.h,
+        espectively.
 
     WHEN <szexpr>
         Specifies a condition that needs to be true (non-zero) for the shader
diff --git a/video/out/opengl/video.c b/video/out/opengl/video.c
index 49b99e90b5..b9764063c0 100644
--- a/video/out/opengl/video.c
+++ b/video/out/opengl/video.c
@@ -1509,6 +1509,12 @@ static bool szexp_lookup(void *priv, struct bstr var, float size[2])
     struct szexp_ctx *ctx = priv;
     struct gl_video *p = ctx->p;
 
+    if (bstr_equals0(var, "NATIVE_CROPPED")) {
+        size[0] = (p->src_rect.x1 - p->src_rect.x0) * p->texture_offset.m[0][0];
+        size[1] = (p->src_rect.y1 - p->src_rect.y0) * p->texture_offset.m[1][1];
+        return true;
+    }
+
     // The size of OUTPUT is determined. It could be useful for certain
     // user shaders to skip passes.
     if (bstr_equals0(var, "OUTPUT")) {