Add AgX tonemapper

NEW_RELEASE_NOTES.md

@@ -10,3 +10,4 @@ appropriate header in [RELEASE_NOTES.md](./RELEASE_NOTES.md).
 
 - engine: Added parameter for configuring JobSystem thread count
 - engine: In Java, introduce Engine.Builder
+- engine: New tone mapper: `AgXTonemapper`.

android/filament-android/src/main/cpp/ToneMapper.cpp

@@ -47,6 +47,11 @@ Java_com_google_android_filament_ToneMapper_nCreateFilmicToneMapper(JNIEnv*, jcl
     return (jlong) new FilmicToneMapper();
 }
 
+extern "C" JNIEXPORT jlong JNICALL
+Java_com_google_android_filament_ToneMapper_nCreateAgxToneMapper(JNIEnv*, jclass, jint look) {
+    return (jlong) new AgxToneMapper(AgxToneMapper::AgxLook(look));
+}
+
 extern "C" JNIEXPORT jlong JNICALL
 Java_com_google_android_filament_ToneMapper_nCreateGenericToneMapper(JNIEnv*, jclass,
         jfloat contrast, jfloat midGrayIn, jfloat midGrayOut, jfloat hdrMax) {

android/filament-android/src/main/java/com/google/android/filament/ToneMapper.java

@@ -100,6 +100,45 @@ public Filmic() {
         }
     }
 
+    /**
+     * AgX tone mapping operator.
+     */
+    public static class Agx extends ToneMapper {
+
+        public enum AgxLook {
+            /**
+             * Base contrast with no look applied
+             */
+            NONE,
+
+            /**
+             * A punchy and more chroma laden look for sRGB displays
+             */
+            PUNCHY,
+
+            /**
+             * A golden tinted, slightly washed look for BT.1886 displays
+             */
+            GOLDEN
+        }
+
+        /**
+         * Builds a new AgX tone mapper with no look applied.
+         */
+        public Agx() {
+            this(AgxLook.NONE);
+        }
+
+        /**
+         * Builds a new AgX tone mapper.
+         *
+         * @param look: an optional creative adjustment to contrast and saturation
+         */
+        public Agx(AgxLook look) {
+            super(nCreateAgxToneMapper(look.ordinal()));
+        }
+    }
+
     /**
      * Generic tone mapping operator that gives control over the tone mapping
      * curve. This operator can be used to control the aesthetics of the final
@@ -194,6 +233,7 @@ public void setHdrMax(float hdrMax) {
     private static native long nCreateACESToneMapper();
     private static native long nCreateACESLegacyToneMapper();
     private static native long nCreateFilmicToneMapper();
+    private static native long nCreateAgxToneMapper(int look);
     private static native long nCreateGenericToneMapper(
             float contrast, float midGrayIn, float midGrayOut, float hdrMax);
 

filament/include/filament/ToneMapper.h

@@ -115,6 +115,30 @@ struct UTILS_PUBLIC FilmicToneMapper final : public ToneMapper {
     math::float3 operator()(math::float3 x) const noexcept override;
 };
 
+/**
+ * AgX tone mapping operator.
+ */
+struct UTILS_PUBLIC AgxToneMapper final : public ToneMapper {
+
+    enum class AgxLook : uint8_t {
+        NONE = 0,   //!< Base contrast with no look applied
+        PUNCHY,     //!< A punchy and more chroma laden look for sRGB displays
+        GOLDEN      //!< A golden tinted, slightly washed look for BT.1886 displays
+    };
+
+    /**
+     * Builds a new AgX tone mapper.
+     *
+     * @param look an optional creative adjustment to contrast and saturation
+     */
+    explicit AgxToneMapper(AgxLook look = AgxLook::NONE) noexcept;
+    ~AgxToneMapper() noexcept final;
+
+    math::float3 operator()(math::float3 x) const noexcept override;
+
+    AgxLook look;
+};
+
 /**
  * Generic tone mapping operator that gives control over the tone mapping
  * curve. This operator can be used to control the aesthetics of the final

filament/src/ToneMapper.cpp

@@ -230,6 +230,106 @@ float3 FilmicToneMapper::operator()(math::float3 x) const noexcept {
     return (x * (a * x + b)) / (x * (c * x + d) + e);
 }
 
+//------------------------------------------------------------------------------
+// AgX tone mapper
+//------------------------------------------------------------------------------
+
+AgxToneMapper::AgxToneMapper(AgxToneMapper::AgxLook look) noexcept : look(look) {}
+AgxToneMapper::~AgxToneMapper() noexcept = default;
+
+// These matrices taken from Blender's implementation of AgX, which works with Rec.2020 primaries.
+// https://github.com/EaryChow/AgX_LUT_Gen/blob/main/AgXBaseRec2020.py
+constexpr mat3f AgXInsetMatrix {
+    0.856627153315983, 0.137318972929847, 0.11189821299995,
+    0.0951212405381588, 0.761241990602591, 0.0767994186031903,
+    0.0482516061458583, 0.101439036467562, 0.811302368396859
+};
+constexpr mat3f AgXOutsetMatrixInv {
+    0.899796955911611, 0.11142098895748, 0.11142098895748,
+    0.0871996192028351, 0.875575586156966, 0.0871996192028349,
+    0.013003424885555, 0.0130034248855548, 0.801379391839686
+};
+constexpr mat3f AgXOutsetMatrix { inverse(AgXOutsetMatrixInv) };
+
+// LOG2_MIN      = -10.0
+// LOG2_MAX      =  +6.5
+// MIDDLE_GRAY   =  0.18
+const float AgxMinEv = -12.47393f;      // log2(pow(2, LOG2_MIN) * MIDDLE_GRAY)
+const float AgxMaxEv = 4.026069f;       // log2(pow(2, LOG2_MAX) * MIDDLE_GRAY)
+
+// Adapted from https://iolite-engine.com/blog_posts/minimal_agx_implementation
+float3 agxDefaultContrastApprox(float3 x) {
+    float3 x2 = x * x;
+    float3 x4 = x2 * x2;
+    float3 x6 = x4 * x2;
+    return  - 17.86     * x6 * x
+            + 78.01     * x6
+            - 126.7     * x4 * x
+            + 92.06     * x4
+            - 28.72     * x2 * x
+            + 4.361     * x2
+            - 0.1718    * x
+            + 0.002857;
+}
+
+// Adapted from https://iolite-engine.com/blog_posts/minimal_agx_implementation
+float3 agxLook(float3 val, AgxToneMapper::AgxLook look) {
+    if (look == AgxToneMapper::AgxLook::NONE) {
+        return val;
+    }
+
+    const float3 lw = float3(0.2126, 0.7152, 0.0722);
+    float luma = dot(val, lw);
+
+    // Default
+    float3 offset = float3(0.0);
+    float3 slope = float3(1.0);
+    float3 power = float3(1.0);
+    float sat = 1.0;
+
+    if (look == AgxToneMapper::AgxLook::GOLDEN) {
+        slope = float3(1.0, 0.9, 0.5);
+        power = float3(0.8);
+        sat = 1.3;
+    }
+    if (look == AgxToneMapper::AgxLook::PUNCHY) {
+        slope = float3(1.0);
+        power = float3(1.35, 1.35, 1.35);
+        sat = 1.4;
+    }
+
+    // ASC CDL
+    val = pow(val * slope + offset, power);
+    return luma + sat * (val - luma);
+}
+
+float3 AgxToneMapper::operator()(float3 v) const noexcept {
+    // Ensure no negative values
+    v = max(float3(0.0), v);
+
+    v = AgXInsetMatrix * v;
+
+    // Log2 encoding
+    v = max(v, 1E-10); // avoid 0 or negative numbers for log2
+    v = log2(v);
+    v = (v - AgxMinEv) / (AgxMaxEv - AgxMinEv);
+
+    v = clamp(v, 0, 1);
+
+    // Apply sigmoid
+    v = agxDefaultContrastApprox(v);
+
+    // Apply AgX look
+    v = agxLook(v, look);
+
+    v = AgXOutsetMatrix * v;
+
+    // Linearize
+    v = pow(max(float3(0.0), v), 2.2);
+
+    return v;
+}
+
 //------------------------------------------------------------------------------
 // Display range tone mapper
 //------------------------------------------------------------------------------

libs/viewer/include/viewer/Settings.h

@@ -57,8 +57,9 @@ enum class ToneMapping : uint8_t {
     ACES_LEGACY   = 1,
     ACES          = 2,
     FILMIC        = 3,
-    GENERIC       = 4,
-    DISPLAY_RANGE = 5,
+    AGX           = 4,
+    GENERIC       = 5,
+    DISPLAY_RANGE = 6,
 };
 
 using AmbientOcclusionOptions = filament::View::AmbientOcclusionOptions;
@@ -114,8 +115,14 @@ struct GenericToneMapperSettings {
     float midGrayIn = 0.18f;
     float midGrayOut = 0.215f;
     float hdrMax = 10.0f;
-    bool operator!=(const GenericToneMapperSettings &rhs) const { return !(rhs == *this); }
-    bool operator==(const GenericToneMapperSettings &rhs) const;
+    bool operator!=(const GenericToneMapperSettings& rhs) const { return !(rhs == *this); }
+    bool operator==(const GenericToneMapperSettings& rhs) const;
+};
+
+struct AgxToneMapperSettings {
+    AgxToneMapper::AgxLook look = AgxToneMapper::AgxLook::NONE;
+    bool operator!=(const AgxToneMapperSettings& rhs) const { return !(rhs == *this); }
+    bool operator==(const AgxToneMapperSettings& rhs) const;
 };
 
 struct ColorGradingSettings {
@@ -127,7 +134,7 @@ struct ColorGradingSettings {
     filament::ColorGrading::QualityLevel quality = filament::ColorGrading::QualityLevel::MEDIUM;
     ToneMapping toneMapping = ToneMapping::ACES_LEGACY;
     bool padding0{};
-    bool padding1{};
+    AgxToneMapperSettings agxToneMapper;
     color::ColorSpace colorspace = Rec709-sRGB-D65;
     GenericToneMapperSettings genericToneMapper;
     math::float4 shadows{1.0f, 1.0f, 1.0f, 0.0f};

libs/viewer/src/Settings.cpp

@@ -86,6 +86,7 @@ static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, ToneMapp
     else if (0 == compare(tokens[i], jsonChunk, "ACES_LEGACY")) { *out = ToneMapping::ACES_LEGACY; }
     else if (0 == compare(tokens[i], jsonChunk, "ACES")) { *out = ToneMapping::ACES; }
     else if (0 == compare(tokens[i], jsonChunk, "FILMIC")) { *out = ToneMapping::FILMIC; }
+    else if (0 == compare(tokens[i], jsonChunk, "AGX")) { *out = ToneMapping::AGX; }
     else if (0 == compare(tokens[i], jsonChunk, "GENERIC")) { *out = ToneMapping::GENERIC; }
     else if (0 == compare(tokens[i], jsonChunk, "DISPLAY_RANGE")) { *out = ToneMapping::DISPLAY_RANGE; }
     else {
@@ -130,6 +131,36 @@ static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, GenericT
     return i;
 }
 
+static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, AgxToneMapper::AgxLook* out) {
+    if (0 == compare(tokens[i], jsonChunk, "NONE")) { *out = AgxToneMapper::AgxLook::NONE; }
+    else if (0 == compare(tokens[i], jsonChunk, "PUNCHY")) { *out = AgxToneMapper::AgxLook::PUNCHY; }
+    else if (0 == compare(tokens[i], jsonChunk, "GOLDEN")) { *out = AgxToneMapper::AgxLook::GOLDEN; }
+    else {
+        slog.w << "Invalid AgxLook: '" << STR(tokens[i], jsonChunk) << "'" << io::endl;
+    }
+    return i + 1;
+}
+
+static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, AgxToneMapperSettings* out) {
+    CHECK_TOKTYPE(tokens[i], JSMN_OBJECT);
+    int size = tokens[i++].size;
+    for (int j = 0; j < size; ++j) {
+        const jsmntok_t tok = tokens[i];
+        CHECK_KEY(tok);
+        if (compare(tok, jsonChunk, "look") == 0) {
+            i = parse(tokens, i + 1, jsonChunk, &out->look);
+        } else {
+            slog.w << "Invalid AgX tone mapper key: '" << STR(tok, jsonChunk) << "'" << io::endl;
+            i = parse(tokens, i + 1);
+        }
+        if (i < 0) {
+            slog.e << "Invalid AgX tone mapper value: '" << STR(tok, jsonChunk) << "'" << io::endl;
+            return i;
+        }
+    }
+    return i;
+}
+
 static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, ColorGradingSettings* out) {
     CHECK_TOKTYPE(tokens[i], JSMN_OBJECT);
     int size = tokens[i++].size;
@@ -146,6 +177,8 @@ static int parse(jsmntok_t const* tokens, int i, const char* jsonChunk, ColorGra
             i = parse(tokens, i + 1, jsonChunk, &out->toneMapping);
         } else if (compare(tok, jsonChunk, "genericToneMapper") == 0) {
             i = parse(tokens, i + 1, jsonChunk, &out->genericToneMapper);
+        } else if (compare(tok, jsonChunk, "agxToneMapper") == 0) {
+            i = parse(tokens, i + 1, jsonChunk, &out->agxToneMapper);
         } else if (compare(tok, jsonChunk, "luminanceScaling") == 0) {
             i = parse(tokens, i + 1, jsonChunk, &out->luminanceScaling);
         } else if (compare(tok, jsonChunk, "gamutMapping") == 0) {
@@ -619,6 +652,7 @@ constexpr ToneMapper* createToneMapper(const ColorGradingSettings& settings) noe
         case ToneMapping::ACES_LEGACY: return new ACESLegacyToneMapper;
         case ToneMapping::ACES: return new ACESToneMapper;
         case ToneMapping::FILMIC: return new FilmicToneMapper;
+        case ToneMapping::AGX: return new AgxToneMapper(settings.agxToneMapper.look);
         case ToneMapping::GENERIC: return new GenericToneMapper(
                     settings.genericToneMapper.contrast,
                     settings.genericToneMapper.midGrayIn,
@@ -673,6 +707,7 @@ static std::ostream& operator<<(std::ostream& out, ToneMapping in) {
         case ToneMapping::ACES_LEGACY: return out << "\"ACES_LEGACY\"";
         case ToneMapping::ACES: return out << "\"ACES\"";
         case ToneMapping::FILMIC: return out << "\"FILMIC\"";
+        case ToneMapping::AGX: return out << "\"AGX\"";
         case ToneMapping::GENERIC: return out << "\"GENERIC\"";
         case ToneMapping::DISPLAY_RANGE: return out << "\"DISPLAY_RANGE\"";
     }
@@ -688,13 +723,29 @@ static std::ostream& operator<<(std::ostream& out, const GenericToneMapperSettin
        << "}";
 }
 
+static std::ostream& operator<<(std::ostream& out, AgxToneMapper::AgxLook in) {
+    switch (in) {
+        case AgxToneMapper::AgxLook::NONE: return out << "\"NONE\"";
+        case AgxToneMapper::AgxLook::PUNCHY: return out << "\"PUNCHY\"";
+        case AgxToneMapper::AgxLook::GOLDEN: return out << "\"GOLDEN\"";
+    }
+    return out << "\"INVALID\"";
+}
+
+static std::ostream& operator<<(std::ostream& out, const AgxToneMapperSettings& in) {
+    return out << "{\n"
+               << "\"look\": " << (in.look) << ",\n"
+               << "}";
+}
+
 static std::ostream& operator<<(std::ostream& out, const ColorGradingSettings& in) {
     return out << "{\n"
         << "\"enabled\": " << to_string(in.enabled) << ",\n"
         << "\"colorspace\": " << to_string(in.colorspace) << ",\n"
         << "\"quality\": " << (in.quality) << ",\n"
         << "\"toneMapping\": " << (in.toneMapping) << ",\n"
         << "\"genericToneMapper\": " << (in.genericToneMapper) << ",\n"
+        << "\"agxToneMapper\": " << (in.agxToneMapper) << ",\n"
         << "\"luminanceScaling\": " << to_string(in.luminanceScaling) << ",\n"
         << "\"gamutMapping\": " << to_string(in.gamutMapping) << ",\n"
         << "\"exposure\": " << (in.exposure) << ",\n"
@@ -854,15 +905,20 @@ static std::ostream& operator<<(std::ostream& out, const Settings& in) {
         << "}";
 }
 
-bool GenericToneMapperSettings::operator==(const GenericToneMapperSettings &rhs) const {
+bool GenericToneMapperSettings::operator==(const GenericToneMapperSettings& rhs) const {
     static_assert(sizeof(GenericToneMapperSettings) == 16, "Please update Settings.cpp");
     return contrast == rhs.contrast &&
            midGrayIn == rhs.midGrayIn &&
            midGrayOut == rhs.midGrayOut &&
            hdrMax == rhs.hdrMax;
 }
 
-bool ColorGradingSettings::operator==(const ColorGradingSettings &rhs) const {
+bool AgxToneMapperSettings::operator==(const AgxToneMapperSettings& rhs) const {
+    static_assert(sizeof(AgxToneMapperSettings) == 1, "Please update Settings.cpp");
+    return look == rhs.look;
+}
+
+bool ColorGradingSettings::operator==(const ColorGradingSettings& rhs) const {
     // If you had to fix the following codeline, then you likely also need to update the
     // implementation of operator==.
     static_assert(sizeof(ColorGradingSettings) == 312, "Please update Settings.cpp");
@@ -871,6 +927,7 @@ bool ColorGradingSettings::operator==(const ColorGradingSettings &rhs) const {
             quality == rhs.quality &&
             toneMapping == rhs.toneMapping &&
             genericToneMapper == rhs.genericToneMapper &&
+            agxToneMapper == rhs.agxToneMapper &&
             luminanceScaling == rhs.luminanceScaling &&
             gamutMapping == rhs.gamutMapping &&
             exposure == rhs.exposure &&