vo_opengl_old: fix OSD regression

Commit 0e8fbdbd removed the rg_texture requirement from vo_opengl;
commit 541f6731 changed to a more convenient method. Both commits broke
vo_opengl_old in some ways. vo_opengl_old always requires GL_ALPHA for
single-channel texture, because it draws the OSD without shaders and by
using certain blend modes.

So we need to explicitly distinguish between vo_opengl and vo_opengl_old
in the OSD renderer, and force fixed texture formats for vo_opengl_old.
The other logic is specific to the internals of vo_opengl. (Although it
might be possible to get the same result by playing with the old GL
fixed-function functions in vo_opengl_old. But seems like a waste of
time.)

Fixes #1370.

1 files changed, 12 insertions, 4 deletions

diff --git a/video/out/gl_osd.c b/video/out/gl_osd.c
index 2bac4ef357..5219e3fbf8 100644
--- a/video/out/gl_osd.c
+++ b/video/out/gl_osd.c
@@ -47,12 +47,18 @@ static const struct osd_fmt_entry osd_to_gles3_formats[SUBBITMAP_COUNT] = {
     [SUBBITMAP_RGBA] =   {GL_RGBA8, GL_BGRA,  GL_UNSIGNED_BYTE},
 };
 
-static const struct osd_fmt_entry osd_to_gl_legacy_formats[SUBBITMAP_COUNT] = {
+static const struct osd_fmt_entry osd_to_gl2_formats[SUBBITMAP_COUNT] = {
     [SUBBITMAP_LIBASS] = {GL_LUMINANCE, GL_LUMINANCE,   GL_UNSIGNED_BYTE},
     [SUBBITMAP_RGBA] =   {GL_RGBA,      GL_BGRA,        GL_UNSIGNED_BYTE},
 };
 
-struct mpgl_osd *mpgl_osd_init(GL *gl, struct mp_log *log, struct osd_state *osd)
+static const struct osd_fmt_entry osd_to_gl_legacy_formats[SUBBITMAP_COUNT] = {
+    [SUBBITMAP_LIBASS] = {GL_ALPHA, GL_ALPHA,   GL_UNSIGNED_BYTE},
+    [SUBBITMAP_RGBA] =   {GL_RGBA,  GL_BGRA,    GL_UNSIGNED_BYTE},
+};
+
+struct mpgl_osd *mpgl_osd_init(GL *gl, struct mp_log *log, struct osd_state *osd,
+                               bool legacy)
 {
     GLint max_texture_size;
     gl->GetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
@@ -66,10 +72,12 @@ struct mpgl_osd *mpgl_osd_init(GL *gl, struct mp_log *log, struct osd_state *osd
         .scratch = talloc_zero_size(ctx, 1),
     };
 
-    if (gl->es >= 300) {
+    if (legacy) {
+        ctx->fmt_table = osd_to_gl_legacy_formats;
+    } else if (gl->es >= 300) {
         ctx->fmt_table = osd_to_gles3_formats;
     } else if (!(gl->mpgl_caps & MPGL_CAP_TEX_RG)) {
-        ctx->fmt_table = osd_to_gl_legacy_formats;
+        ctx->fmt_table = osd_to_gl2_formats;
     }
 
     for (int n = 0; n < MAX_OSD_PARTS; n++) {