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Tonemapper AGX
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DanielSnd committed Feb 6, 2024
1 parent 86105fd commit a97807e
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Showing 6 changed files with 170 additions and 8 deletions.
83 changes: 80 additions & 3 deletions drivers/gles3/shaders/tonemap_inc.glsl
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,10 @@ vec3 apply_color_correction(vec3 color) {
#endif
#endif

vec3 tonemap_reinhard(vec3 color, float p_white) {
return (p_white * color + color) / (color * p_white + p_white);
}

vec3 tonemap_filmic(vec3 color, float p_white) {
// exposure bias: input scale (color *= bias, white *= bias) to make the brightness consistent with other tonemappers
// also useful to scale the input to the range that the tonemapper is designed for (some require very high input values)
Expand Down Expand Up @@ -88,8 +92,75 @@ vec3 tonemap_aces(vec3 color, float p_white) {
return color_tonemapped / p_white_tonemapped;
}

vec3 tonemap_reinhard(vec3 color, float p_white) {
return (p_white * color + color) / (color * p_white + p_white);
// Mean error^2: 3.6705141e-06
vec3 agx_default_contrast_approx(vec3 x) {
vec3 x2 = x * x;
vec3 x4 = x2 * x2;

return +15.5 * x4 * x2 - 40.14 * x4 * x + 31.96 * x4 - 6.868 * x2 * x + 0.4298 * x2 + 0.1191 * x - 0.00232;
}

vec3 agx(vec3 val, float white) {
const mat3 agx_mat = mat3(
0.842479062253094, 0.0423282422610123, 0.0423756549057051,
0.0784335999999992, 0.878468636469772, 0.0784336,
0.0792237451477643, 0.0791661274605434, 0.879142973793104);

const float min_ev = -12.47393f;
float max_ev = log2(white);

// Input transform (inset).
val = agx_mat * val;

// Log2 space encoding.
val = clamp(log2(val), min_ev, max_ev);
val = (val - min_ev) / (max_ev - min_ev);

// Apply sigmoid function approximation.
val = agx_default_contrast_approx(val);

return val;
}

vec3 agx_eotf(vec3 val) {
const mat3 agx_mat_inv = mat3(
1.19687900512017, -0.0528968517574562, -0.0529716355144438,
-0.0980208811401368, 1.15190312990417, -0.0980434501171241,
-0.0990297440797205, -0.0989611768448433, 1.15107367264116);

// Inverse input transform (outset).
val = agx_mat_inv * val;

// sRGB IEC 61966-2-1 2.2 Exponent Reference EOTF Display
// NOTE: We're linearizing the output here. Comment/adjust when
// *not* using a sRGB render target.
val = pow(val, vec3(2.2));

return val;
}

vec3 agx_look_punchy(vec3 val) {
const vec3 lw = vec3(0.2126, 0.7152, 0.0722);
float luma = dot(val, lw);

vec3 offset = vec3(0.0);
vec3 slope = vec3(1.0);
vec3 power = vec3(1.35, 1.35, 1.35);
float sat = 1.4;

// ASC CDL.
val = pow(val * slope + offset, power);
return luma + sat * (val - luma);
}

// Adapted from https://iolite-engine.com/blog_posts/minimal_agx_implementation
vec3 tonemap_agx(vec3 color, float white, bool punchy) {
color = agx(color, white);
if (punchy) {
color = agx_look_punchy(color);
}
color = agx_eotf(color);
return color;
}

// This expects 0-1 range input.
Expand All @@ -111,6 +182,8 @@ vec3 srgb_to_linear(vec3 color) {
#define TONEMAPPER_REINHARD 1
#define TONEMAPPER_FILMIC 2
#define TONEMAPPER_ACES 3
#define TONEMAPPER_AGX 4
#define TONEMAPPER_AGX_PUNCHY 5

vec3 apply_tonemapping(vec3 color, float p_white) { // inputs are LINEAR, always outputs clamped [0;1] color
// Ensure color values passed to tonemappers are positive.
Expand All @@ -121,7 +194,11 @@ vec3 apply_tonemapping(vec3 color, float p_white) { // inputs are LINEAR, always
return tonemap_reinhard(max(vec3(0.0f), color), p_white);
} else if (tonemapper == TONEMAPPER_FILMIC) {
return tonemap_filmic(max(vec3(0.0f), color), p_white);
} else { // TONEMAPPER_ACES
} else if (tonemapper == TONEMAPPER_ACES) {
return tonemap_aces(max(vec3(0.0f), color), p_white);
} else if (tonemapper == TONEMAPPER_AGX) {
return tonemap_agx(max(vec3(0.0f), color), p_white, false);
} else { // TONEMAPPER_AGX_PUNCHY
return tonemap_agx(max(vec3(0.0f), color), p_white, true);
}
}
4 changes: 3 additions & 1 deletion scene/resources/environment.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1206,7 +1206,7 @@ void Environment::_bind_methods() {
ClassDB::bind_method(D_METHOD("get_tonemap_white"), &Environment::get_tonemap_white);

ADD_GROUP("Tonemap", "tonemap_");
ADD_PROPERTY(PropertyInfo(Variant::INT, "tonemap_mode", PROPERTY_HINT_ENUM, "Linear,Reinhard,Filmic,ACES"), "set_tonemapper", "get_tonemapper");
ADD_PROPERTY(PropertyInfo(Variant::INT, "tonemap_mode", PROPERTY_HINT_ENUM, "Linear,Reinhard,Filmic,ACES,AgX,AgX Punchy"), "set_tonemapper", "get_tonemapper");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "tonemap_exposure", PROPERTY_HINT_RANGE, "0,16,0.01"), "set_tonemap_exposure", "get_tonemap_exposure");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "tonemap_white", PROPERTY_HINT_RANGE, "0,16,0.01"), "set_tonemap_white", "get_tonemap_white");

Expand Down Expand Up @@ -1497,6 +1497,8 @@ void Environment::_bind_methods() {
BIND_ENUM_CONSTANT(TONE_MAPPER_REINHARDT);
BIND_ENUM_CONSTANT(TONE_MAPPER_FILMIC);
BIND_ENUM_CONSTANT(TONE_MAPPER_ACES);
BIND_ENUM_CONSTANT(TONE_MAPPER_AGX);
BIND_ENUM_CONSTANT(TONE_MAPPER_AGX_PUNCHY);

BIND_ENUM_CONSTANT(GLOW_BLEND_MODE_ADDITIVE);
BIND_ENUM_CONSTANT(GLOW_BLEND_MODE_SCREEN);
Expand Down
2 changes: 2 additions & 0 deletions scene/resources/environment.h
Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,8 @@ class Environment : public Resource {
TONE_MAPPER_REINHARDT,
TONE_MAPPER_FILMIC,
TONE_MAPPER_ACES,
TONE_MAPPER_AGX,
TONE_MAPPER_AGX_PUNCHY,
};

enum SDFGIYScale {
Expand Down
83 changes: 80 additions & 3 deletions servers/rendering/renderer_rd/shaders/effects/tonemap.glsl
Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,10 @@ vec4 texture2D_bicubic(sampler2D tex, vec2 uv, int p_lod) {

#endif // !USE_GLOW_FILTER_BICUBIC

vec3 tonemap_reinhard(vec3 color, float white) {
return (white * color + color) / (color * white + white);
}

vec3 tonemap_filmic(vec3 color, float white) {
// exposure bias: input scale (color *= bias, white *= bias) to make the brightness consistent with other tonemappers
// also useful to scale the input to the range that the tonemapper is designed for (some require very high input values)
Expand Down Expand Up @@ -243,8 +247,75 @@ vec3 tonemap_aces(vec3 color, float white) {
return color_tonemapped / white_tonemapped;
}

vec3 tonemap_reinhard(vec3 color, float white) {
return (white * color + color) / (color * white + white);
// Mean error^2: 3.6705141e-06
vec3 agx_default_contrast_approx(vec3 x) {
vec3 x2 = x * x;
vec3 x4 = x2 * x2;

return +15.5 * x4 * x2 - 40.14 * x4 * x + 31.96 * x4 - 6.868 * x2 * x + 0.4298 * x2 + 0.1191 * x - 0.00232;
}

vec3 agx(vec3 val, float white) {
const mat3 agx_mat = mat3(
0.842479062253094, 0.0423282422610123, 0.0423756549057051,
0.0784335999999992, 0.878468636469772, 0.0784336,
0.0792237451477643, 0.0791661274605434, 0.879142973793104);

const float min_ev = -12.47393f;
float max_ev = log2(white);

// Input transform (inset).
val = agx_mat * val;

// Log2 space encoding.
val = clamp(log2(val), min_ev, max_ev);
val = (val - min_ev) / (max_ev - min_ev);

// Apply sigmoid function approximation.
val = agx_default_contrast_approx(val);

return val;
}

vec3 agx_eotf(vec3 val) {
const mat3 agx_mat_inv = mat3(
1.19687900512017, -0.0528968517574562, -0.0529716355144438,
-0.0980208811401368, 1.15190312990417, -0.0980434501171241,
-0.0990297440797205, -0.0989611768448433, 1.15107367264116);

// Inverse input transform (outset).
val = agx_mat_inv * val;

// sRGB IEC 61966-2-1 2.2 Exponent Reference EOTF Display
// NOTE: We're linearizing the output here. Comment/adjust when
// *not* using a sRGB render target.
val = pow(val, vec3(2.2));

return val;
}

vec3 agx_look_punchy(vec3 val) {
const vec3 lw = vec3(0.2126, 0.7152, 0.0722);
float luma = dot(val, lw);

vec3 offset = vec3(0.0);
vec3 slope = vec3(1.0);
vec3 power = vec3(1.35, 1.35, 1.35);
float sat = 1.4;

// ASC CDL.
val = pow(val * slope + offset, power);
return luma + sat * (val - luma);
}

// Adapted from https://iolite-engine.com/blog_posts/minimal_agx_implementation
vec3 tonemap_agx(vec3 color, float white, bool punchy) {
color = agx(color, white);
if (punchy) {
color = agx_look_punchy(color);
}
color = agx_eotf(color);
return color;
}

vec3 linear_to_srgb(vec3 color) {
Expand All @@ -258,6 +329,8 @@ vec3 linear_to_srgb(vec3 color) {
#define TONEMAPPER_REINHARD 1
#define TONEMAPPER_FILMIC 2
#define TONEMAPPER_ACES 3
#define TONEMAPPER_AGX 4
#define TONEMAPPER_AGX_PUNCHY 5

vec3 apply_tonemapping(vec3 color, float white) { // inputs are LINEAR, always outputs clamped [0;1] color
// Ensure color values passed to tonemappers are positive.
Expand All @@ -268,8 +341,12 @@ vec3 apply_tonemapping(vec3 color, float white) { // inputs are LINEAR, always o
return tonemap_reinhard(max(vec3(0.0f), color), white);
} else if (params.tonemapper == TONEMAPPER_FILMIC) {
return tonemap_filmic(max(vec3(0.0f), color), white);
} else { // TONEMAPPER_ACES
} else if (params.tonemapper == TONEMAPPER_ACES) {
return tonemap_aces(max(vec3(0.0f), color), white);
} else if (params.tonemapper == TONEMAPPER_AGX) {
return tonemap_agx(max(vec3(0.0f), color), white, false);
} else { // TONEMAPPER_AGX_PUNCHY
return tonemap_agx(max(vec3(0.0f), color), white, true);
}
}

Expand Down
2 changes: 2 additions & 0 deletions servers/rendering_server.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -2969,6 +2969,8 @@ void RenderingServer::_bind_methods() {
BIND_ENUM_CONSTANT(ENV_TONE_MAPPER_REINHARD);
BIND_ENUM_CONSTANT(ENV_TONE_MAPPER_FILMIC);
BIND_ENUM_CONSTANT(ENV_TONE_MAPPER_ACES);
BIND_ENUM_CONSTANT(ENV_TONE_MAPPER_AGX);
BIND_ENUM_CONSTANT(ENV_TONE_MAPPER_AGX_PUNCHY);

BIND_ENUM_CONSTANT(ENV_SSR_ROUGHNESS_QUALITY_DISABLED);
BIND_ENUM_CONSTANT(ENV_SSR_ROUGHNESS_QUALITY_LOW);
Expand Down
4 changes: 3 additions & 1 deletion servers/rendering_server.h
Original file line number Diff line number Diff line change
Expand Up @@ -1087,7 +1087,9 @@ class RenderingServer : public Object {
ENV_TONE_MAPPER_LINEAR,
ENV_TONE_MAPPER_REINHARD,
ENV_TONE_MAPPER_FILMIC,
ENV_TONE_MAPPER_ACES
ENV_TONE_MAPPER_ACES,
ENV_TONE_MAPPER_AGX,
ENV_TONE_MAPPER_AGX_PUNCHY,
};

virtual void environment_set_tonemap(RID p_env, EnvironmentToneMapper p_tone_mapper, float p_exposure, float p_white) = 0;
Expand Down

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