vo_opengl: fall back to ordered dither instead of blowing up

In GLES 2 mode, we can do dither, but "fruit" dithering is still out of
the question, because it does not support any high depth textures.
(Actually we probably could use an 8 bit texture too for this, at least
with small matrix sizes, but it's still too much of a pain to convert
the data, so why bother.)

This is actually a regression; before this, forcibly enabling dumb mode
due to low GL caps actually happened to avoid this case.

Fixes #4519.

1 files changed, 9 insertions, 4 deletions

diff --git a/video/out/opengl/video.c b/video/out/opengl/video.c
index f4695b1333..51d484d078 100644
--- a/video/out/opengl/video.c
+++ b/video/out/opengl/video.c
@@ -2192,14 +2192,19 @@ static void pass_dither(struct gl_video *p)
             const struct gl_format *fmt = gl_find_unorm_format(gl, 2, 1);
             if (!fmt || gl->es)
                 fmt = gl_find_float16_format(gl, 1);
-            tex_size = size;
             if (fmt) {
+                tex_size = size;
                 tex_iformat = fmt->internal_format;
                 tex_format = fmt->format;
+                tex_type = GL_FLOAT;
+                tex_data = p->last_dither_matrix;
+            } else {
+                MP_VERBOSE(p, "GL too old. Falling back to ordered dither.\n");
+                p->opts.dither_algo = DITHER_ORDERED;
             }
-            tex_type = GL_FLOAT;
-            tex_data = p->last_dither_matrix;
-        } else {
+        }
+
+        if (p->opts.dither_algo == DITHER_ORDERED) {
             assert(sizeof(temp) >= 8 * 8);
             mp_make_ordered_dither_matrix(temp, 8);