vo_gpu: add --tone-mapping-mode

This merges the old desaturation control options into a single
enumeration, with the goal of both simplifying how these options work
and also making this list more extensible (including, notably, new
options only supported by vo_gpu_next).

For the hybrid option, I decided to port the (slightly tweaked) values
from libplacebo's pre-refactor defaults, rather than the old values we
had in mpv, to more visually match the look of the vo_gpu_next hybrid.

4 files changed, 56 insertions, 19 deletions

diff --git a/video/out/gpu/video.c b/video/out/gpu/video.c
index 8236a7b43f..d0d0509792 100644
--- a/video/out/gpu/video.c
+++ b/video/out/gpu/video.c
@@ -329,8 +329,6 @@ static const struct gl_video_opts gl_video_opts_def = {
         .decay_rate = 100.0,
         .scene_threshold_low = 5.5,
         .scene_threshold_high = 10.0,
-        .desat = 0.75,
-        .desat_exp = 1.5,
     },
     .early_flush = -1,
     .hwdec_interop = "auto",
@@ -394,9 +392,12 @@ const struct m_sub_options gl_video_conf = {
             M_RANGE(0.0, 0.3)},
         {"tone-mapping-max-boost", OPT_FLOAT(tone_map.max_boost),
             M_RANGE(1.0, 10.0)},
-        {"tone-mapping-desaturate", OPT_FLOAT(tone_map.desat)},
-        {"tone-mapping-desaturate-exponent", OPT_FLOAT(tone_map.desat_exp),
-            M_RANGE(0.0, 20.0)},
+        {"tone-mapping-mode", OPT_CHOICE(tone_map.mode,
+            {"auto",        TONE_MAP_MODE_AUTO},
+            {"rgb",         TONE_MAP_MODE_RGB},
+            {"max",         TONE_MAP_MODE_MAX},
+            {"hybrid",      TONE_MAP_MODE_HYBRID},
+            {"luma",        TONE_MAP_MODE_LUMA})},
         {"gamut-mapping-mode", OPT_CHOICE(tone_map.gamut_mode,
             {"auto",        GAMUT_AUTO},
             {"clip",        GAMUT_CLIP},
@@ -479,6 +480,8 @@ const struct m_sub_options gl_video_conf = {
                                         "--linear-downscaling")},
         {"gamut-warning", OPT_REMOVED("Replaced by --gamut-mapping-mode=warn")},
         {"gamut-clipping", OPT_REMOVED("Replaced by --gamut-mapping-mode=desaturate")},
+        {"tone-mapping-desaturate", OPT_REMOVED("Replaced by --tone-mapping-mode")},
+        {"tone-mapping-desaturate-exponent", OPT_REMOVED("Replaced by --tone-mapping-mode")},
         {0}
     },
     .size = sizeof(struct gl_video_opts),
@@ -2644,6 +2647,18 @@ static void pass_colormanage(struct gl_video *p, struct mp_colorspace src,
         break;
     }
 
+    switch (p->opts.tone_map.mode) {
+    case TONE_MAP_MODE_AUTO:
+    case TONE_MAP_MODE_RGB:
+    case TONE_MAP_MODE_MAX:
+    case TONE_MAP_MODE_HYBRID:
+        break;
+    default:
+        MP_WARN(p, "Tone mapping mode unsupported by vo_gpu, falling back.\n");
+        p->opts.tone_map.mode = TONE_MAP_MODE_AUTO;
+        break;
+    }
+
     switch (p->opts.tone_map.gamut_mode) {
     case GAMUT_AUTO:
     case GAMUT_WARN:
diff --git a/video/out/gpu/video.h b/video/out/gpu/video.h
index adeadaba65..0bb180e514 100644
--- a/video/out/gpu/video.h
+++ b/video/out/gpu/video.h
@@ -100,6 +100,14 @@ enum tone_mapping {
     TONE_MAPPING_BT_2446A,
 };
 
+enum tone_mapping_mode {
+    TONE_MAP_MODE_AUTO,
+    TONE_MAP_MODE_RGB,
+    TONE_MAP_MODE_MAX,
+    TONE_MAP_MODE_HYBRID,
+    TONE_MAP_MODE_LUMA,
+};
+
 enum gamut_mode {
     GAMUT_AUTO,
     GAMUT_CLIP,
@@ -114,12 +122,11 @@ struct gl_tone_map_opts {
     float max_boost;
     int inverse;
     float crosstalk;
+    int mode;
     int compute_peak;
     float decay_rate;
     float scene_threshold_low;
     float scene_threshold_high;
-    float desat;
-    float desat_exp;
     int gamut_mode;
 };
 
diff --git a/video/out/gpu/video_shaders.c b/video/out/gpu/video_shaders.c
index 6dcef77fa0..9628274b19 100644
--- a/video/out/gpu/video_shaders.c
+++ b/video/out/gpu/video_shaders.c
@@ -809,18 +809,24 @@ static void pass_tone_map(struct gl_shader_cache *sc,
         abort();
     }
 
-    GLSL(vec3 sig_lin = color.rgb * (sig[sig_idx] / sig_orig);)
-
-    // Mix between the per-channel tone mapped and the linear tone mapped
-    // signal based on the desaturation strength
-    if (opts->desat > 0) {
-        float base = 0.18 * dst_scale;
-        GLSLF("float coeff = max(sig[sig_idx] - %f, 1e-6) / "
-              "              max(sig[sig_idx], 1.0);\n", base);
-        GLSLF("coeff = %f * pow(coeff, %f);\n", opts->desat, opts->desat_exp);
-        GLSLF("color.rgb = mix(sig_lin, %f * sig, coeff);\n", dst_scale);
-    } else {
-        GLSL(color.rgb = sig_lin;)
+    switch (opts->mode) {
+    case TONE_MAP_MODE_RGB:
+        GLSL(color.rgb = sig;)
+        break;
+    case TONE_MAP_MODE_MAX:
+        GLSL(color.rgb *= sig[sig_idx] / sig_orig;)
+        break;
+    case TONE_MAP_MODE_AUTO:
+    case TONE_MAP_MODE_HYBRID:
+        GLSLF("float coeff = max(sig[sig_idx] - %f, 1e-6) / \n"
+              "              max(sig[sig_idx], 1.0);        \n"
+              "coeff = %f * pow(coeff / %f, %f);            \n"
+              "color.rgb *= sig[sig_idx] / sig_orig;        \n"
+              "color.rgb = mix(color.rgb, %f * sig, coeff); \n",
+              0.18 / dst_scale, 0.90, dst_scale, 0.20, dst_scale);
+        break;
+    default:
+        abort();
     }
 }
 
diff --git a/video/out/vo_gpu_next.c b/video/out/vo_gpu_next.c
index 390852ff71..9bbb58101f 100644
--- a/video/out/vo_gpu_next.c
+++ b/video/out/vo_gpu_next.c
@@ -1406,12 +1406,21 @@ static void update_render_options(struct priv *p)
         [GAMUT_DARKEN]          = PL_GAMUT_DARKEN,
     };
 
+    static const enum pl_tone_map_mode tone_map_modes[] = {
+        [TONE_MAP_MODE_AUTO]    = PL_TONE_MAP_AUTO,
+        [TONE_MAP_MODE_RGB]     = PL_TONE_MAP_RGB,
+        [TONE_MAP_MODE_MAX]     = PL_TONE_MAP_MAX,
+        [TONE_MAP_MODE_HYBRID]  = PL_TONE_MAP_HYBRID,
+        [TONE_MAP_MODE_LUMA]    = PL_TONE_MAP_LUMA,
+    };
+
     p->color_map = pl_color_map_default_params;
     p->color_map.intent = opts->icc_opts->intent;
     p->color_map.tone_mapping_function = tone_map_funs[opts->tone_map.curve];
     p->color_map.tone_mapping_param = opts->tone_map.curve_param;
     p->color_map.inverse_tone_mapping = opts->tone_map.inverse;
     p->color_map.tone_mapping_crosstalk = opts->tone_map.crosstalk;
+    p->color_map.tone_mapping_mode = tone_map_modes[opts->tone_map.mode];
     if (isnan(p->color_map.tone_mapping_param)) // vo_gpu compatibility
         p->color_map.tone_mapping_param = 0.0;
     if (opts->tone_map.gamut_mode != GAMUT_AUTO)