godot/servers/rendering/renderer_rd/shaders/tonemap.glsl
Hugo Locurcio 57451f132f
Clamp negative colors regardless of the tonemapper to avoid artifacts
Color artifacts could be visible when using negative lights with the
Filmic and ACES tonemapping operators, as these did not clamp negative
colors.
2021-08-09 17:01:07 +02:00

436 lines
14 KiB
GLSL

#[vertex]
#version 450
#VERSION_DEFINES
#ifdef MULTIVIEW
#ifdef has_VK_KHR_multiview
#extension GL_EXT_multiview : enable
#endif
#endif
layout(location = 0) out vec2 uv_interp;
void main() {
vec2 base_arr[4] = vec2[](vec2(0.0, 0.0), vec2(0.0, 1.0), vec2(1.0, 1.0), vec2(1.0, 0.0));
uv_interp = base_arr[gl_VertexIndex];
gl_Position = vec4(uv_interp * 2.0 - 1.0, 0.0, 1.0);
}
#[fragment]
#version 450
#VERSION_DEFINES
#ifdef MULTIVIEW
#ifdef has_VK_KHR_multiview
#extension GL_EXT_multiview : enable
#define ViewIndex gl_ViewIndex
#else // has_VK_KHR_multiview
#define ViewIndex 0
#endif // has_VK_KHR_multiview
#endif //MULTIVIEW
layout(location = 0) in vec2 uv_interp;
#ifdef SUBPASS
layout(input_attachment_index = 0, set = 0, binding = 0) uniform subpassInput input_color;
#else
#if MULTIVIEW
layout(set = 0, binding = 0) uniform sampler2DArray source_color;
#else
layout(set = 0, binding = 0) uniform sampler2D source_color;
#endif
#endif
layout(set = 1, binding = 0) uniform sampler2D source_auto_exposure;
layout(set = 2, binding = 0) uniform sampler2D source_glow;
#ifdef USE_1D_LUT
layout(set = 3, binding = 0) uniform sampler2D source_color_correction;
#else
layout(set = 3, binding = 0) uniform sampler3D source_color_correction;
#endif
layout(push_constant, binding = 1, std430) uniform Params {
vec3 bcs;
bool use_bcs;
bool use_glow;
bool use_auto_exposure;
bool use_color_correction;
uint tonemapper;
uvec2 glow_texture_size;
float glow_intensity;
uint pad3;
uint glow_mode;
float glow_levels[7];
float exposure;
float white;
float auto_exposure_grey;
uint pad2;
vec2 pixel_size;
bool use_fxaa;
bool use_debanding;
}
params;
layout(location = 0) out vec4 frag_color;
#ifdef USE_GLOW_FILTER_BICUBIC
// w0, w1, w2, and w3 are the four cubic B-spline basis functions
float w0(float a) {
return (1.0f / 6.0f) * (a * (a * (-a + 3.0f) - 3.0f) + 1.0f);
}
float w1(float a) {
return (1.0f / 6.0f) * (a * a * (3.0f * a - 6.0f) + 4.0f);
}
float w2(float a) {
return (1.0f / 6.0f) * (a * (a * (-3.0f * a + 3.0f) + 3.0f) + 1.0f);
}
float w3(float a) {
return (1.0f / 6.0f) * (a * a * a);
}
// g0 and g1 are the two amplitude functions
float g0(float a) {
return w0(a) + w1(a);
}
float g1(float a) {
return w2(a) + w3(a);
}
// h0 and h1 are the two offset functions
float h0(float a) {
return -1.0f + w1(a) / (w0(a) + w1(a));
}
float h1(float a) {
return 1.0f + w3(a) / (w2(a) + w3(a));
}
vec4 texture2D_bicubic(sampler2D tex, vec2 uv, int p_lod) {
float lod = float(p_lod);
vec2 tex_size = vec2(params.glow_texture_size >> p_lod);
vec2 pixel_size = vec2(1.0f) / tex_size;
uv = uv * tex_size + vec2(0.5f);
vec2 iuv = floor(uv);
vec2 fuv = fract(uv);
float g0x = g0(fuv.x);
float g1x = g1(fuv.x);
float h0x = h0(fuv.x);
float h1x = h1(fuv.x);
float h0y = h0(fuv.y);
float h1y = h1(fuv.y);
vec2 p0 = (vec2(iuv.x + h0x, iuv.y + h0y) - vec2(0.5f)) * pixel_size;
vec2 p1 = (vec2(iuv.x + h1x, iuv.y + h0y) - vec2(0.5f)) * pixel_size;
vec2 p2 = (vec2(iuv.x + h0x, iuv.y + h1y) - vec2(0.5f)) * pixel_size;
vec2 p3 = (vec2(iuv.x + h1x, iuv.y + h1y) - vec2(0.5f)) * pixel_size;
return (g0(fuv.y) * (g0x * textureLod(tex, p0, lod) + g1x * textureLod(tex, p1, lod))) +
(g1(fuv.y) * (g0x * textureLod(tex, p2, lod) + g1x * textureLod(tex, p3, lod)));
}
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) texture2D_bicubic(m_tex, m_uv, m_lod)
#else
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) textureLod(m_tex, m_uv, float(m_lod))
#endif
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)
// has no effect on the curve's general shape or visual properties
const float exposure_bias = 2.0f;
const float A = 0.22f * exposure_bias * exposure_bias; // bias baked into constants for performance
const float B = 0.30f * exposure_bias;
const float C = 0.10f;
const float D = 0.20f;
const float E = 0.01f;
const float F = 0.30f;
vec3 color_tonemapped = ((color * (A * color + C * B) + D * E) / (color * (A * color + B) + D * F)) - E / F;
float white_tonemapped = ((white * (A * white + C * B) + D * E) / (white * (A * white + B) + D * F)) - E / F;
return color_tonemapped / white_tonemapped;
}
vec3 tonemap_aces(vec3 color, float white) {
const float exposure_bias = 0.85f;
const float A = 2.51f * exposure_bias * exposure_bias;
const float B = 0.03f * exposure_bias;
const float C = 2.43f * exposure_bias * exposure_bias;
const float D = 0.59f * exposure_bias;
const float E = 0.14f;
vec3 color_tonemapped = (color * (A * color + B)) / (color * (C * color + D) + E);
float white_tonemapped = (white * (A * white + B)) / (white * (C * white + D) + E);
return color_tonemapped / white_tonemapped;
}
vec3 tonemap_reinhard(vec3 color, float white) {
return (white * color + color) / (color * white + white);
}
vec3 linear_to_srgb(vec3 color) {
//if going to srgb, clamp from 0 to 1.
color = clamp(color, vec3(0.0), vec3(1.0));
const vec3 a = vec3(0.055f);
return mix((vec3(1.0f) + a) * pow(color.rgb, vec3(1.0f / 2.4f)) - a, 12.92f * color.rgb, lessThan(color.rgb, vec3(0.0031308f)));
}
#define TONEMAPPER_LINEAR 0
#define TONEMAPPER_REINHARD 1
#define TONEMAPPER_FILMIC 2
#define TONEMAPPER_ACES 3
vec3 apply_tonemapping(vec3 color, float white) { // inputs are LINEAR, always outputs clamped [0;1] color
if (params.tonemapper == TONEMAPPER_LINEAR) {
return color;
} else if (params.tonemapper == TONEMAPPER_REINHARD) {
return tonemap_reinhard(color, white);
} else if (params.tonemapper == TONEMAPPER_FILMIC) {
return tonemap_filmic(color, white);
} else { // TONEMAPPER_ACES
return tonemap_aces(color, white);
}
}
vec3 gather_glow(sampler2D tex, vec2 uv) { // sample all selected glow levels
vec3 glow = vec3(0.0f);
if (params.glow_levels[0] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 0).rgb * params.glow_levels[0];
}
if (params.glow_levels[1] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 1).rgb * params.glow_levels[1];
}
if (params.glow_levels[2] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 2).rgb * params.glow_levels[2];
}
if (params.glow_levels[3] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 3).rgb * params.glow_levels[3];
}
if (params.glow_levels[4] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 4).rgb * params.glow_levels[4];
}
if (params.glow_levels[5] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 5).rgb * params.glow_levels[5];
}
if (params.glow_levels[6] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 6).rgb * params.glow_levels[6];
}
return glow;
}
#define GLOW_MODE_ADD 0
#define GLOW_MODE_SCREEN 1
#define GLOW_MODE_SOFTLIGHT 2
#define GLOW_MODE_REPLACE 3
#define GLOW_MODE_MIX 4
vec3 apply_glow(vec3 color, vec3 glow) { // apply glow using the selected blending mode
if (params.glow_mode == GLOW_MODE_ADD) {
return color + glow;
} else if (params.glow_mode == GLOW_MODE_SCREEN) {
//need color clamping
return max((color + glow) - (color * glow), vec3(0.0));
} else if (params.glow_mode == GLOW_MODE_SOFTLIGHT) {
//need color clamping
glow = glow * vec3(0.5f) + vec3(0.5f);
color.r = (glow.r <= 0.5f) ? (color.r - (1.0f - 2.0f * glow.r) * color.r * (1.0f - color.r)) : (((glow.r > 0.5f) && (color.r <= 0.25f)) ? (color.r + (2.0f * glow.r - 1.0f) * (4.0f * color.r * (4.0f * color.r + 1.0f) * (color.r - 1.0f) + 7.0f * color.r)) : (color.r + (2.0f * glow.r - 1.0f) * (sqrt(color.r) - color.r)));
color.g = (glow.g <= 0.5f) ? (color.g - (1.0f - 2.0f * glow.g) * color.g * (1.0f - color.g)) : (((glow.g > 0.5f) && (color.g <= 0.25f)) ? (color.g + (2.0f * glow.g - 1.0f) * (4.0f * color.g * (4.0f * color.g + 1.0f) * (color.g - 1.0f) + 7.0f * color.g)) : (color.g + (2.0f * glow.g - 1.0f) * (sqrt(color.g) - color.g)));
color.b = (glow.b <= 0.5f) ? (color.b - (1.0f - 2.0f * glow.b) * color.b * (1.0f - color.b)) : (((glow.b > 0.5f) && (color.b <= 0.25f)) ? (color.b + (2.0f * glow.b - 1.0f) * (4.0f * color.b * (4.0f * color.b + 1.0f) * (color.b - 1.0f) + 7.0f * color.b)) : (color.b + (2.0f * glow.b - 1.0f) * (sqrt(color.b) - color.b)));
return color;
} else { //replace
return glow;
}
}
vec3 apply_bcs(vec3 color, vec3 bcs) {
color = mix(vec3(0.0f), color, bcs.x);
color = mix(vec3(0.5f), color, bcs.y);
color = mix(vec3(dot(vec3(1.0f), color) * 0.33333f), color, bcs.z);
return color;
}
#ifdef USE_1D_LUT
vec3 apply_color_correction(vec3 color) {
color.r = texture(source_color_correction, vec2(color.r, 0.0f)).r;
color.g = texture(source_color_correction, vec2(color.g, 0.0f)).g;
color.b = texture(source_color_correction, vec2(color.b, 0.0f)).b;
return color;
}
#else
vec3 apply_color_correction(vec3 color) {
return textureLod(source_color_correction, color, 0.0).rgb;
}
#endif
#ifndef SUBPASS
vec3 do_fxaa(vec3 color, float exposure, vec2 uv_interp) {
const float FXAA_REDUCE_MIN = (1.0 / 128.0);
const float FXAA_REDUCE_MUL = (1.0 / 8.0);
const float FXAA_SPAN_MAX = 8.0;
#ifdef MULTIVIEW
vec3 rgbNW = textureLod(source_color, vec3(uv_interp + vec2(-1.0, -1.0) * params.pixel_size, ViewIndex), 0.0).xyz * exposure;
vec3 rgbNE = textureLod(source_color, vec3(uv_interp + vec2(1.0, -1.0) * params.pixel_size, ViewIndex), 0.0).xyz * exposure;
vec3 rgbSW = textureLod(source_color, vec3(uv_interp + vec2(-1.0, 1.0) * params.pixel_size, ViewIndex), 0.0).xyz * exposure;
vec3 rgbSE = textureLod(source_color, vec3(uv_interp + vec2(1.0, 1.0) * params.pixel_size, ViewIndex), 0.0).xyz * exposure;
#else
vec3 rgbNW = textureLod(source_color, uv_interp + vec2(-1.0, -1.0) * params.pixel_size, 0.0).xyz * exposure;
vec3 rgbNE = textureLod(source_color, uv_interp + vec2(1.0, -1.0) * params.pixel_size, 0.0).xyz * exposure;
vec3 rgbSW = textureLod(source_color, uv_interp + vec2(-1.0, 1.0) * params.pixel_size, 0.0).xyz * exposure;
vec3 rgbSE = textureLod(source_color, uv_interp + vec2(1.0, 1.0) * params.pixel_size, 0.0).xyz * exposure;
#endif
vec3 rgbM = color;
vec3 luma = vec3(0.299, 0.587, 0.114);
float lumaNW = dot(rgbNW, luma);
float lumaNE = dot(rgbNE, luma);
float lumaSW = dot(rgbSW, luma);
float lumaSE = dot(rgbSE, luma);
float lumaM = dot(rgbM, luma);
float lumaMin = min(lumaM, min(min(lumaNW, lumaNE), min(lumaSW, lumaSE)));
float lumaMax = max(lumaM, max(max(lumaNW, lumaNE), max(lumaSW, lumaSE)));
vec2 dir;
dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
dir.y = ((lumaNW + lumaSW) - (lumaNE + lumaSE));
float dirReduce = max((lumaNW + lumaNE + lumaSW + lumaSE) *
(0.25 * FXAA_REDUCE_MUL),
FXAA_REDUCE_MIN);
float rcpDirMin = 1.0 / (min(abs(dir.x), abs(dir.y)) + dirReduce);
dir = min(vec2(FXAA_SPAN_MAX, FXAA_SPAN_MAX),
max(vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),
dir * rcpDirMin)) *
params.pixel_size;
#ifdef MULTIVIEW
vec3 rgbA = 0.5 * exposure * (textureLod(source_color, vec3(uv_interp + dir * (1.0 / 3.0 - 0.5), ViewIndex), 0.0).xyz + textureLod(source_color, vec3(uv_interp + dir * (2.0 / 3.0 - 0.5), ViewIndex), 0.0).xyz);
vec3 rgbB = rgbA * 0.5 + 0.25 * exposure * (textureLod(source_color, vec3(uv_interp + dir * -0.5, ViewIndex), 0.0).xyz + textureLod(source_color, vec3(uv_interp + dir * 0.5, ViewIndex), 0.0).xyz);
#else
vec3 rgbA = 0.5 * exposure * (textureLod(source_color, uv_interp + dir * (1.0 / 3.0 - 0.5), 0.0).xyz + textureLod(source_color, uv_interp + dir * (2.0 / 3.0 - 0.5), 0.0).xyz);
vec3 rgbB = rgbA * 0.5 + 0.25 * exposure * (textureLod(source_color, uv_interp + dir * -0.5, 0.0).xyz + textureLod(source_color, uv_interp + dir * 0.5, 0.0).xyz);
#endif
float lumaB = dot(rgbB, luma);
if ((lumaB < lumaMin) || (lumaB > lumaMax)) {
return rgbA;
} else {
return rgbB;
}
}
#endif // !SUBPASS
// From http://alex.vlachos.com/graphics/Alex_Vlachos_Advanced_VR_Rendering_GDC2015.pdf
// and https://www.shadertoy.com/view/MslGR8 (5th one starting from the bottom)
// NOTE: `frag_coord` is in pixels (i.e. not normalized UV).
vec3 screen_space_dither(vec2 frag_coord) {
// Iestyn's RGB dither (7 asm instructions) from Portal 2 X360, slightly modified for VR.
vec3 dither = vec3(dot(vec2(171.0, 231.0), frag_coord));
dither.rgb = fract(dither.rgb / vec3(103.0, 71.0, 97.0));
// Subtract 0.5 to avoid slightly brightening the whole viewport.
return (dither.rgb - 0.5) / 255.0;
}
void main() {
#ifdef SUBPASS
// SUBPASS and MULTIVIEW can be combined but in that case we're already reading from the correct layer
vec3 color = subpassLoad(input_color).rgb;
#elif MULTIVIEW
vec3 color = textureLod(source_color, vec3(uv_interp, ViewIndex), 0.0f).rgb;
#else
vec3 color = textureLod(source_color, uv_interp, 0.0f).rgb;
#endif
// Exposure
float exposure = params.exposure;
#ifndef SUBPASS
if (params.use_auto_exposure) {
exposure *= 1.0 / (texelFetch(source_auto_exposure, ivec2(0, 0), 0).r / params.auto_exposure_grey);
}
#endif
color *= exposure;
// Early Tonemap & SRGB Conversion
#ifndef SUBPASS
if (params.use_glow && params.glow_mode == GLOW_MODE_MIX) {
vec3 glow = gather_glow(source_glow, uv_interp);
color.rgb = mix(color.rgb, glow, params.glow_intensity);
}
if (params.use_fxaa) {
color = do_fxaa(color, exposure, uv_interp);
}
#endif
if (params.use_debanding) {
// For best results, debanding should be done before tonemapping.
// Otherwise, we're adding noise to an already-quantized image.
color += screen_space_dither(gl_FragCoord.xy);
}
// Ensure color values passed to tonemappers are positive.
// They can be negative in the case of negative lights, which leads to undesired behavior.
color = apply_tonemapping(max(vec3(0.0), color), params.white);
color = linear_to_srgb(color); // regular linear -> SRGB conversion
#ifndef SUBPASS
// Glow
if (params.use_glow && params.glow_mode != GLOW_MODE_MIX) {
vec3 glow = gather_glow(source_glow, uv_interp) * params.glow_intensity;
// high dynamic range -> SRGB
glow = apply_tonemapping(glow, params.white);
glow = linear_to_srgb(glow);
color = apply_glow(color, glow);
}
#endif
// Additional effects
if (params.use_bcs) {
color = apply_bcs(color, params.bcs);
}
if (params.use_color_correction) {
color = apply_color_correction(color);
}
frag_color = vec4(color, 1.0f);
}