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| Original file line number | Diff line number | Diff line change |
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| // | ||
| // MTAntiLuxFilter.metal | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
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| #include <metal_stdlib> | ||
| #include "MTIShaderLib.h" | ||
| #include "../Filters/IFShaderLib.h" | ||
| using namespace metalpetal; | ||
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| // see: http://en.wikipedia.org/wiki/Adaptive_histogram_equalization | ||
| // return the point when the CDF crosses 0.5, the center of mass of the histogram. | ||
| // we'll adjust contrast around this point as the center. | ||
| float histogramCenter(texture2d<float, access::sample> cdfTexture, float2 coordinate, float brightness) { | ||
| const float xHalfPix = 0.001953125; // (1.0/256.0)/2.0; | ||
| const float yHalfPix = .03125; // (1.0/16.0)/2.0; | ||
| constexpr sampler s(coord::normalized, address::clamp_to_edge, filter::linear); | ||
| brightness = brightness + xHalfPix; | ||
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| // find the coordinate within the interpolation mesh | ||
| coordinate = clamp(coordinate, 0.125, 1.0 - 0.125001) - 0.125; | ||
| coordinate = coordinate * (3.0 / (1.0-0.125*2.0)); | ||
| float2 weight = fract(coordinate); // the fractional part are our interpolation weights | ||
| coordinate = floor(coordinate); // floor to get the top-right corner | ||
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| // compute the 4 corners of the mesh we'll be interpolating | ||
| // tl = top-left, tr = top-right etc | ||
| float tl = float(coordinate.y*4.0 + coordinate.x)/16.0 + yHalfPix; | ||
| float tr = float(coordinate.y*4.0 + coordinate.x + 1.0)/16.0 + yHalfPix; | ||
| float bl = float((coordinate.y + 1.0)*4.0 + coordinate.x)/16.0 + yHalfPix; | ||
| float br = float((coordinate.y + 1.0)*4.0 + coordinate.x + 1.0)/16.0 + yHalfPix; | ||
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| // obtain the cdf center values of the 4 corners | ||
| float4 b1 = cdfTexture.sample(s, float2(1.0, tl)); | ||
| float4 b2 = cdfTexture.sample(s, float2(1.0, tr)); | ||
| float4 b3 = cdfTexture.sample(s, float2(1.0, bl)); | ||
| float4 b4 = cdfTexture.sample(s, float2(1.0, br)); | ||
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| // the fourth channel, "a", is the histogram midpoint | ||
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| // linearly interpolate to obtain the final brightness | ||
| float c1_2 = mix(b1.a, b2.a, weight.x); | ||
| float c3_4 = mix(b3.a, b4.a, weight.x); | ||
| return mix(c1_2, c3_4, weight.y); | ||
| } | ||
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| fragment float4 MTAntiLuxFilterFragment(VertexOut vertexIn [[ stage_in ]], | ||
| texture2d<float, access::sample> inputTexture [[ texture(0) ]], | ||
| texture2d<float, access::sample> blurred [[ texture(1) ]], | ||
| texture2d<float, access::sample> cdf [[ texture(2) ]], | ||
| constant float & filterStrength [[ buffer(0) ]], | ||
| sampler textureSampler [[ sampler(0) ]]) | ||
| { | ||
| constexpr sampler s(coord::normalized, address::clamp_to_edge, filter::linear); | ||
| float4 texel = inputTexture.sample(s, vertexIn.textureCoordinate); | ||
| float3 hsv = rgb_to_hsv(texel.rgb); | ||
| float3 blurredTexel = blurred.sample(s, vertexIn.textureCoordinate).rgb; | ||
| float blurredLum = (blurredTexel.r + blurredTexel.g + blurredTexel.b)/3.0; | ||
| // boost highlights and shadows | ||
| // first with a mask over regions, don't boost a bright pixel in a shadow region or a dark pixel in a highlight region | ||
| float shadowMask = smoothstep(0.5, 0.0, blurredLum); // mask for "shadow areas" | ||
| float highlightMask = smoothstep(0.5, 1.0, blurredLum); // mask for "highlight areas" | ||
|
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| // then adjust the luminace curve | ||
| float srcDarkness = smoothstep(0.0, 0.25, hsv.z) * smoothstep(0.5, 0.25, hsv.z); // lerp on how dark this pixel is | ||
| float srcHighlightness = smoothstep(0.50, 0.85, hsv.z); // lery on how bright this pixel is | ||
| hsv.z = hsv.z + srcDarkness * 0.14 * shadowMask; | ||
| hsv.z = hsv.z + srcHighlightness * 0.14 * highlightMask; | ||
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| // adjust saturation | ||
| hsv.y = min(hsv.y * 0.825, 1.0); | ||
| // adjust contrast centered around the CDF | ||
| float flatBright = histogramCenter(cdf, vertexIn.textureCoordinate, hsv.z); | ||
| hsv.z = mix(hsv.z, flatBright, 0.175); | ||
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| float3 newRgb = hsv_to_rgb(hsv); | ||
| // fade in a recycled paper gray colored overlay, the max is for a "lighten" blend mode | ||
| newRgb = mix(newRgb, max(newRgb, float3(0.651, 0.615, 0.580)), 0.18); | ||
| texel.rgb = mix(texel.rgb, newRgb, filterStrength); | ||
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| return texel; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,9 @@ | ||
| // | ||
| // MTAntiLuxFilter.swift | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
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| import Foundation |
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| // | ||
| // MTLuxBlendFilter.metal | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
|
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| #include <metal_stdlib> | ||
| #include "MTIShaderLib.h" | ||
| using namespace metalpetal; | ||
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| fragment float4 MTLuxBlendFilterFragment(VertexOut vertexIn [[ stage_in ]], | ||
| texture2d<float, access::sample> inputTexture [[ texture(0) ]], | ||
| texture2d<float, access::sample> antilux [[ texture(1) ]], | ||
| texture2d<float, access::sample> starlight [[ texture(2) ]], | ||
| constant float & luxBlendAmount [[ buffer(0) ]], | ||
| sampler textureSampler [[ sampler(0) ]]) | ||
| { | ||
| constexpr sampler s(coord::normalized, address::clamp_to_edge, filter::linear); | ||
| float4 texel = inputTexture.sample(s, vertexIn.textureCoordinate); | ||
| if (luxBlendAmount >= 0.0) { | ||
| texel = mix(texel, starlight.sample(s, vertexIn.textureCoordinate), luxBlendAmount); | ||
| } else { | ||
| texel = mix(texel, antilux.sample(s, vertexIn.textureCoordinate), -luxBlendAmount); | ||
| } | ||
| return texel; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,18 @@ | ||
| // | ||
| // MTLuxBlendFilter.swift | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
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| import Foundation | ||
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| class MTLuxBlendFilter: MTFilter { | ||
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| var luxBlendAmount: Float = 0 | ||
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| override var parameters: [String : Any] { | ||
| return ["luxBlendAmount": luxBlendAmount] | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,69 @@ | ||
| // | ||
| // MTStarlightFilter.metal | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
|
|
||
| #include <metal_stdlib> | ||
| #include "MTIShaderLib.h" | ||
| #include "../Filters/IFShaderLib.h" | ||
| using namespace metalpetal; | ||
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||
| // see: http://en.wikipedia.org/wiki/Adaptive_histogram_equalization | ||
| float clahe2D(texture2d<float, access::sample> cdfTexture, float2 coordinate, float brightness) { | ||
| const float xHalfPix = 0.001953125; // (1.0/256.0)/2.0; | ||
| const float yHalfPix = .03125; // (1.0/16.0)/2.0; | ||
| constexpr sampler s(coord::normalized, address::clamp_to_edge, filter::linear); | ||
| brightness = brightness + xHalfPix; | ||
|
|
||
| // find the coordinate within the interpolation mesh | ||
| coordinate = clamp(coordinate, 0.125, 1.0 - 0.125001) - 0.125; | ||
| coordinate = coordinate * (3.0 / (1.0-0.125*2.0)); | ||
| float2 weight = fract(coordinate); // the fractional part are our interpolation weights | ||
| coordinate = floor(coordinate); // floor to get the top-right corner | ||
|
|
||
| // compute the 4 corners of the mesh we'll be interpolating | ||
| // tl = top-left, tr = top-right etc | ||
| float tl = float(coordinate.y*4.0 + coordinate.x)/16.0 + yHalfPix; | ||
| float tr = float(coordinate.y*4.0 + coordinate.x + 1.0)/16.0 + yHalfPix; | ||
| float bl = float((coordinate.y + 1.0)*4.0 + coordinate.x)/16.0 + yHalfPix; | ||
| float br = float((coordinate.y + 1.0)*4.0 + coordinate.x + 1.0)/16.0 + yHalfPix; | ||
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| // obtain the cdf values of the 4 corners | ||
| float4 b1 = cdfTexture.sample(s, float2(brightness, tl)); | ||
| float4 b2 = cdfTexture.sample(s, float2(brightness, tr)); | ||
| float4 b3 = cdfTexture.sample(s, float2(brightness, bl)); | ||
| float4 b4 = cdfTexture.sample(s, float2(brightness, br)); | ||
|
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| // Commented out for efficiency and subbed in | ||
| //float cdf = cdfColor.r; | ||
| //float cdfMin = cdfColor.b; | ||
|
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| // FIXME: this looks wrong! | ||
| float c1 = ((b1.r - b1.b) / (1.0 - b1.b)); | ||
| float c2 = ((b2.r - b2.b) / (1.0 - b2.b)); | ||
| float c3 = ((b3.r - b3.b) / (1.0 - b3.b)); | ||
| float c4 = ((b4.r - b4.b) / (1.0 - b4.b)); | ||
|
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| // linearly interpolate to obtain the final brightness | ||
| float c1_2 = mix(c1, c2, weight.x); | ||
| float c3_4 = mix(c3, c4, weight.x); | ||
| return mix(c1_2, c3_4, weight.y); | ||
| } | ||
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| fragment float4 MTStarlightFilterFragment(VertexOut vertexIn [[ stage_in ]], | ||
| texture2d<float, access::sample> inputTexture [[ texture(0) ]], | ||
| texture2d<float, access::sample> cdf [[ texture(1) ]], | ||
| constant float & filterStrength [[ buffer(0) ]], | ||
| sampler textureSampler [[ sampler(0) ]]) | ||
| { | ||
| constexpr sampler s(coord::normalized, address::clamp_to_edge, filter::linear); | ||
| float4 texel = inputTexture.sample(s, vertexIn.textureCoordinate); | ||
| float3 hsv = rgb_to_hsv(texel.rgb); | ||
| hsv.z = clahe2D(cdf, vertexIn.textureCoordinate, hsv.z); | ||
| hsv.y = min(hsv.y*1.2, 1.0); | ||
| texel.rgb = mix(texel.rgb, hsv_to_rgb(hsv), filterStrength); | ||
| return texel; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,13 @@ | ||
| // | ||
| // MTStarlightFilter.swift | ||
| // MetalFilters | ||
| // | ||
| // Created by xu.shuifeng on 2018/6/13. | ||
| // Copyright © 2018 shuifeng.me. All rights reserved. | ||
| // | ||
|
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| import Foundation | ||
|
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| class MTStarlightFilter: MTFilter { | ||
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| } |