vo_gpu: export the GLSL format qualifier for ra_format

Backported from @haasn's change to libplacebo, except in the current RA,
there's nothing to indicate an ra_format can be bound as a storage
image, so there's no way to force all of these formats to have a
glsl_format. Instead, the layout qualifier will be removed if
glsl_format is NULL.

This is needed for the upcoming ra_d3d11 backend. In Direct3D 11, while
loading float values from unorm images often works as expected, it's
technically undefined behaviour, and in Windows 10, it will cause the
debug layer to spam the log with error messages. Also, apparently in
GLSL, the format name must match the image's format exactly (but in
Direct3D, it just has to have the same component type.)

1 files changed, 6 insertions, 0 deletions

diff --git a/video/out/gpu/ra.h b/video/out/gpu/ra.h
index 5c5c851e64..b10ab76124 100644
--- a/video/out/gpu/ra.h
+++ b/video/out/gpu/ra.h
@@ -87,6 +87,10 @@ struct ra_format {
     // shader representation is given by the special_imgfmt_desc pointer.
     int special_imgfmt;
     const struct ra_imgfmt_desc *special_imgfmt_desc;
+
+    // This gives the GLSL image format corresponding to the format, if any.
+    // (e.g. rgba16ui)
+    const char *glsl_format;
 };
 
 struct ra_tex_params {
@@ -494,6 +498,8 @@ struct ra_imgfmt_desc {
     uint8_t components[4][4];
 };
 
+const char *ra_fmt_glsl_format(const struct ra_format *fmt);
+
 bool ra_get_imgfmt_desc(struct ra *ra, int imgfmt, struct ra_imgfmt_desc *out);
 
 void ra_dump_tex_formats(struct ra *ra, int msgl);