vo_opengl: enable fancy-downscaling by default for opengl-hq

DOCS/man/vo.rst

@@ -609,7 +609,7 @@ Available video output drivers are:
 
     This is equivalent to::
 
-        --vo=opengl:lscale=spline36:dither-depth=auto:fbo-format=rgba16
+        --vo=opengl:lscale=spline36:dither-depth=auto:fbo-format=rgba16:fancy-downscaling
 
     Note that some cheaper LCDs do dithering that gravely interferes with
     ``opengl``'s dithering. Disabling dithering with ``dither-depth=no`` helps.

video/out/gl_video.c

@@ -302,6 +302,7 @@ const struct gl_video_opts gl_video_opts_hq_def = {
     .dither_size = 6,
     .fbo_format = GL_RGBA16,
     .scale_sep = 1,
+    .fancy_downscaling = 1,
     .scalers = { "spline36", "bilinear" },
     .scaler_params = {{NAN, NAN}, {NAN, NAN}},
     .scaler_radius = {NAN, NAN},