add MTIHighlightShadowFilter

.gitignore

@@ -1,6 +1,7 @@
 # Xcode
 #
 # gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
+.DS_Store
 
 ## User settings
 xcuserdata/

MetalPetalHighlightShadow.podspec

@@ -0,0 +1,19 @@
+Pod::Spec.new do |s|
+  s.name             = 'MetalPetalHighlightShadow'
+  s.version          = '0.1.0'
+  s.summary          = 'Highlight and shadow adjust filter for MetalPetal'
+  s.description      = 'Highlight and shadow adjust filter for MetalPetal'
+
+  s.homepage         = 'https://github.com/MetalPetal/HighlightShadow'
+  s.license          = { :type => 'GPLv3', :file => 'LICENSE' }
+  s.author           = { 'yuao' => '[email protected]' }
+  s.source           = { :git => 'https://github.com/MetalPetal/HighlightShadow.git', :tag => s.version.to_s }
+
+  s.ios.deployment_target = '10.0'
+  s.macos.deployment_target = '10.13'
+
+  s.source_files = 'Sources/**/*'
+
+  s.dependency 'MetalPetal'
+
+end

Sources/MTIHighlightShadowFilter.h

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+//
+//  MTIHighlightShadowFilter.h
+//  MetalPetal
+//
+//  Created by YuAo on 2020/8/9.
+//
+
+#import <Foundation/Foundation.h>
+#import <MetalPetal/MetalPetal.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MTIHighlightShadowFilter : NSObject <MTIUnaryFilter>
+
+@property (nonatomic) float radius;
+
+/// Amount for shadow adjustment, -1.0 to 1.0
+@property (nonatomic) float shadow;
+
+/// Amount for highlight adjustment, -1.0 to 1.0
+@property (nonatomic) float highlight;
+
+@end
+
+NS_ASSUME_NONNULL_END

Sources/MTIHighlightShadowFilter.m

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+//
+//  MTIHighlightShadowFilter.m
+//  MetalPetal
+//
+//  Created by YuAo on 2020/8/9.
+//
+
+#import "MTIHighlightShadowFilter.h"
+
+@interface MTIHighlightShadowFilter()
+
+@property (nonatomic, strong) MTIMPSGaussianBlurFilter *blurFilter;
+
+@end
+
+@implementation MTIHighlightShadowFilter
+@synthesize inputImage = _inputImage;
+@synthesize outputPixelFormat = _outputPixelFormat;
+
++ (MTIRenderPipelineKernel *)kernel {
+    return [[MTIRenderPipelineKernel alloc] initWithVertexFunctionDescriptor:[[MTIFunctionDescriptor alloc] initWithName:MTIFilterPassthroughVertexFunctionName]
+                                                  fragmentFunctionDescriptor:[[MTIFunctionDescriptor alloc] initWithName:@"shadowHighlightAdjust" libraryURL:MTIDefaultLibraryURLForBundle([NSBundle bundleForClass:self])]];
+}
+
+- (instancetype)init {
+    if (self = [super init]) {
+        _radius = 30;
+        _blurFilter = [[MTIMPSGaussianBlurFilter alloc] init];
+        _blurFilter.radius = _radius;
+    }
+    return self;
+}
+
+- (MTIImage *)outputImage {
+    if (!self.inputImage) {
+        return nil;
+    }
+    self.blurFilter.radius = self.radius;
+    self.blurFilter.inputImage = self.inputImage;
+    MTIImage *blurredImage = self.blurFilter.outputImage;
+    return [MTIHighlightShadowFilter.kernel applyToInputImages:@[self.inputImage, blurredImage]
+                                                       parameters:@{@"shadow": @(self.shadow),
+                                                                    @"highlight": @(self.highlight)}
+                                          outputTextureDimensions:self.inputImage.dimensions
+                                                outputPixelFormat:self.outputPixelFormat];
+}
+
+@end

Sources/MTIHighlightShadowFilter.metal

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+//
+//  MTIHighlightShadowFilter.metal
+//  MetalPetal
+//
+//  Created by YuAo on 2020/8/9.
+//
+
+#include <metal_stdlib>
+using namespace metal;
+
+namespace metalpetalshadowhighlight {
+
+    static float4 convertFromRGBToYIQ(float4 src) {
+        float3 pix2;
+        float4 pix = src;
+        pix.xyz = sqrt(fmax(pix.xyz, 0.000000e+00f));
+        pix2 = ((pix.x* float3(2.990000e-01f, 5.960000e-01f, 2.120000e-01f))+ (pix.y* float3(5.870000e-01f, -2.755000e-01f, -5.230000e-01f)))+ (pix.z* float3(1.140000e-01f, -3.210000e-01f, 3.110000e-01f));
+        return float4(pix2, pix.w);
+    }
+
+    static float4 convertFromYIQToRGB(float4 src) {
+        float4 color, pix;
+        pix = src;
+        color.xyz = ((pix.x* float3(1.000480e+00f, 9.998640e-01f, 9.994460e-01f))+ (pix.y* float3(9.555580e-01f, -2.715450e-01f, -1.108030e+00f)))+ (pix.z* float3(6.195490e-01f, -6.467860e-01f, 1.705420e+00f));
+        color.xyz = fmax(color.xyz, float3(0.000000e+00f));
+        color.xyz = color.xyz* color.xyz;
+        color.w = pix.w;
+        return color;
+    }
+
+    typedef struct {
+        float4 position [[ position ]];
+        float2 textureCoordinate;
+    } MTIDefaultVertexOut;
+
+    fragment float4 shadowHighlightAdjust(MTIDefaultVertexOut vertexIn [[stage_in]],
+                                          texture2d<float, access::sample> sourceTexture [[texture(0)]],
+                                          texture2d<float, access::sample> blurTexture [[texture(1)]],
+                                          sampler sourceSampler [[sampler(0)]],
+                                          sampler blurSampler [[sampler(1)]],
+                                          constant float &shadow [[buffer(0)]],
+                                          constant float &highlight [[buffer(1)]]) {
+        float4 source = sourceTexture.sample(sourceSampler, vertexIn.textureCoordinate);
+        float4 blur = blurTexture.sample(blurSampler, vertexIn.textureCoordinate);
+        float4 sourceYIQ = convertFromRGBToYIQ(source);
+        float4 blurYIQ = convertFromRGBToYIQ(blur);
+        float highlights_sign_negated = copysign(1.0, -highlight);
+        float shadows_sign = copysign(1.0f, shadow);
+        //constexpr float whitepoint = 1.0;
+        constexpr float compress = 0.5;
+        constexpr float low_approximation = 0.01f;
+        constexpr float shadowColor = 1.0;
+        constexpr float highlightColor = 1.0;
+        float tb0 = 1.0 - blurYIQ.x;
+        if (tb0 < 1.0 - compress) {
+            float highlights2 = highlight * highlight;
+            float highlights_xform = min(1.0f - tb0 / (1.0f - compress), 1.0f);
+            while (highlights2 > 0.0f) {
+                float lref, href;
+                float chunk, optrans;
+
+                float la = sourceYIQ.x;
+                float la_abs;
+                float la_inverted = 1.0f - la;
+                float la_inverted_abs;
+                float lb = (tb0 - 0.5f) * highlights_sign_negated * sign(la_inverted) + 0.5f;
+
+                la_abs = abs(la);
+                lref = copysign(la_abs > low_approximation ? 1.0f / la_abs : 1.0f / low_approximation, la);
+
+                la_inverted_abs = abs(la_inverted);
+                href = copysign(la_inverted_abs > low_approximation ? 1.0f / la_inverted_abs : 1.0f / low_approximation, la_inverted);
+
+                chunk = highlights2 > 1.0f ? 1.0f : highlights2;
+                optrans = chunk * highlights_xform;
+                highlights2 -= 1.0f;
+
+                sourceYIQ.x = la * (1.0 - optrans) + (la > 0.5f ? 1.0f - (1.0f - 2.0f * (la - 0.5f)) * (1.0f - lb) : 2.0f * la * lb) * optrans;
+
+                sourceYIQ.y = sourceYIQ.y * (1.0f - optrans)
+                + sourceYIQ.y * (sourceYIQ.x * lref * (1.0f - highlightColor)
+                                 + (1.0f - sourceYIQ.x) * href * highlightColor) * optrans;
+
+                sourceYIQ.z = sourceYIQ.z * (1.0f - optrans)
+                + sourceYIQ.z * (sourceYIQ.x * lref * (1.0f - highlightColor)
+                                 + (1.0f - sourceYIQ.x) * href * highlightColor) * optrans;
+            }
+        }
+        if (tb0 > compress) {
+            float shadows2 = shadow * shadow;
+            float shadows_xform = min(tb0 / (1.0f - compress) - compress / (1.0f - compress), 1.0f);
+
+            while (shadows2 > 0.0f) {
+                float lref, href;
+                float chunk, optrans;
+
+                float la = sourceYIQ.x;
+                float la_abs;
+                float la_inverted = 1.0f - la;
+                float la_inverted_abs;
+                float lb = (tb0 - 0.5f) * shadows_sign * sign(la_inverted) + 0.5f;
+
+                la_abs = abs(la);
+                lref = copysign(la_abs > low_approximation ? 1.0f / la_abs : 1.0f / low_approximation, la);
+
+                la_inverted_abs = abs(la_inverted);
+                href = copysign(la_inverted_abs > low_approximation ? 1.0f / la_inverted_abs : 1.0f / low_approximation,
+                                la_inverted);
+
+                chunk = shadows2 > 1.0f ? 1.0f : shadows2;
+                optrans = chunk * shadows_xform;
+                shadows2 -= 1.0f;
+
+                sourceYIQ.x = la * (1.0 - optrans)
+                + (la > 0.5f ? 1.0f - (1.0f - 2.0f * (la - 0.5f)) * (1.0f - lb) : 2.0f * la * lb) * optrans;
+
+                sourceYIQ.y = sourceYIQ.y * (1.0f - optrans)
+                + sourceYIQ.y * (sourceYIQ.x * lref * shadowColor
+                                 + (1.0f - sourceYIQ.x) * href * (1.0f - shadowColor)) * optrans;
+
+                sourceYIQ.z = sourceYIQ.z * (1.0f - optrans)
+                + sourceYIQ.z * (sourceYIQ.x * lref * shadowColor
+                                 + (1.0f - sourceYIQ.x) * href * (1.0f - shadowColor)) * optrans;
+            }
+        }
+        return convertFromYIQToRGB(sourceYIQ);
+    }
+}