vo_opengl: support HDR peak detection

This is done via compute shaders. As a consequence, the tone mapping
algorithms had to be rewritten to compute their known constants in GLSL
(ahead of time), instead of doing it once. Didn't affect performance.

Using shmem/SSBO atomics in this way is extremely fast on nvidia, but it
might be slow on other platforms. Needs testing.

Unfortunately, setting up the SSBO still requires OpenGL calls, which
means I can't have it in video_shaders.c, where it belongs. But I'll
defer worrying about that until the backend refactor, since then I'll be
breaking up the video/video_shaders structure anyway.

1 files changed, 5 insertions, 0 deletions

diff --git a/video/out/opengl/common.c b/video/out/opengl/common.c
index b9536b6c59..9af21856ab 100644
--- a/video/out/opengl/common.c
+++ b/video/out/opengl/common.c
@@ -346,6 +346,11 @@ static const struct gl_functions gl_functions[] = {
     },
     {
         .ver_core = 430,
+        .extension = "GL_ARB_shader_storage_buffer_object",
+        .provides = MPGL_CAP_SSBO,
+    },
+    {
+        .ver_core = 430,
         .extension = "GL_ARB_compute_shader",
         .functions = (const struct gl_function[]) {
             DEF_FN(DispatchCompute),