1 files changed, 75 insertions, 0 deletions
diff --git a/src/shaders/film_grain.h b/src/shaders/film_grain.h
new file mode 100644
index 0000000..f6498c1
--- /dev/null
+++ b/src/shaders/film_grain.h
@@ -0,0 +1,75 @@
+/*
+ * This file is part of libplacebo.
+ *
+ * libplacebo is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * libplacebo is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with libplacebo. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "common.h"
+
+#include <libplacebo/shaders/film_grain.h>
+
+bool pl_needs_fg_av1(const struct pl_film_grain_params *);
+bool pl_needs_fg_h274(const struct pl_film_grain_params *);
+
+bool pl_shader_fg_av1(pl_shader, pl_shader_obj *, const struct pl_film_grain_params *);
+bool pl_shader_fg_h274(pl_shader, pl_shader_obj *, const struct pl_film_grain_params *);
+
+// Common helper function
+static inline enum pl_channel channel_map(int i, const struct pl_film_grain_params *params)
+{
+    static const enum pl_channel map_rgb[3] = {
+        [PL_CHANNEL_G] = PL_CHANNEL_Y,
+        [PL_CHANNEL_B] = PL_CHANNEL_CB,
+        [PL_CHANNEL_R] = PL_CHANNEL_CR,
+    };
+
+    static const enum pl_channel map_xyz[3] = {
+        [1] = PL_CHANNEL_Y,  // Y
+        [2] = PL_CHANNEL_CB, // Z
+        [0] = PL_CHANNEL_CR, // X
+    };
+
+    if (i >= params->components)
+        return PL_CHANNEL_NONE;
+
+    int comp = params->component_mapping[i];
+    if (comp < 0 || comp > 2)
+        return PL_CHANNEL_NONE;
+
+    switch (params->repr->sys) {
+    case PL_COLOR_SYSTEM_UNKNOWN:
+    case PL_COLOR_SYSTEM_RGB:
+        return map_rgb[comp];
+    case PL_COLOR_SYSTEM_XYZ:
+        return map_xyz[comp];
+
+    case PL_COLOR_SYSTEM_BT_601:
+    case PL_COLOR_SYSTEM_BT_709:
+    case PL_COLOR_SYSTEM_SMPTE_240M:
+    case PL_COLOR_SYSTEM_BT_2020_NC:
+    case PL_COLOR_SYSTEM_BT_2020_C:
+    case PL_COLOR_SYSTEM_BT_2100_PQ:
+    case PL_COLOR_SYSTEM_BT_2100_HLG:
+    case PL_COLOR_SYSTEM_DOLBYVISION:
+    case PL_COLOR_SYSTEM_YCGCO:
+        return comp;
+
+    case PL_COLOR_SYSTEM_COUNT:
+        break;
+    }
+
+    pl_unreachable();
+}