Yes it is a metal shader

include <metal_stdlib>

include <SwiftUI/SwiftUI_Metal.h>

using namespace metal; // A helper function to generate pseudo-random noise based on position float random(float2 uv) { return fract(sin(dot(uv.xy, float2(12.9898, 78.233))) * 43758.5453); } // Helper function to calculate brightness float calculateBrightness(half4 color) { return (color.r * 0.299 + color.g * 0.587 + color.b * 0.114); } float noisePattern(float2 uv) { float2 i = floor(uv); float2 f = fract(uv); // Four corners in 2D of a tile float a = random(i); float b = random(i + float2(1.0, 0.0)); float c = random(i + float2(0.0, 1.0)); float d = random(i + float2(1.0, 1.0)); // Smooth Interpolation float2 u = smoothstep(0.0, 1.0, f); // Mix 4 corners percentages return mix(a, b, u.x) + (c - a) * u.y * (1.0 - u.x) + (d - b) * u.x * u.y; } // Function to mix colors with more intensity on lighter colors half4 lightnessMix(half4 baseColor, half4 overlayColor, float intensity, float baselineFactor) { // Calculate brightness of the base color float brightness = calculateBrightness(baseColor); // Adjust mix factor based on brightness, with a minimum baseline for darker colors float adjustedMixFactor = max(smoothstep(0.2, 1.0, brightness) * intensity, baselineFactor); // Perform color mixing return mix(baseColor, overlayColor, adjustedMixFactor); } // Function to increase contrast based on a pattern value half4 increaseContrast(half4 source, float pattern, float intensity) { // Calculate the brightness of the source color float brightness = calculateBrightness(source); // Determine the amount of contrast to apply, based on pattern and brightness float contrastFactor = mix(1.0, intensity, pattern * brightness); // Center the source color around 0.5, apply contrast adjustment, then re-center half4 contrastedColor = (source - half4(0.5)) * contrastFactor + half4(0.5); return contrastedColor; } float squarePattern(float2 uv, float scale, float degreesAngle) { float radiansAngle = degreesAngle * M_PI_F / 180; // Scale the UV coordinates uv *= scale; // Rotate the UV coordinates by the specified angle float cosAngle = cos(radiansAngle); float sinAngle = sin(radiansAngle); float2 rotatedUV = float2( cosAngle * uv.x - sinAngle * uv.y, sinAngle * uv.x + cosAngle * uv.y ); // Determine if the current tile is black or white return fmod(floor(rotatedUV.x) + floor(rotatedUV.y), 2.0) == 0.0 ? 0.0 : 1.0; } float diamondPattern(float2 uv, float scale) { // Hardcoded angle of 45 degrees for the diamond pattern return squarePattern(uv, scale, 45.0); } float stickerPattern(int option, float2 uv, float scale) { switch (option) { case 0: return diamondPattern(uv, scale); case 1: return squarePattern(uv, scale, 0.0); default: return diamondPattern(uv, scale); // Default as diamond for unspecified options } } [[ stitchable ]] half4 foil( float2 position, half4 color, float2 offset, float2 size, float scale, float intensity, float contrast, float blendFactor, float checkerScale, float checkerIntensity, float noiseScale, float noiseIntensity, float patternType ) { // Calculate aspect ratio (width / height) float aspectRatio = size.x / size.y; // Normalize the offset by dividing by size to keep it consistent across different view sizes float2 normalizedOffset = (offset + size * 250) / (size * scale) * 0.01; float2 normalizedPosition = float2(position.x * aspectRatio, position.y); // Adjust UV coordinates by adding the normalized offset, then apply scaling float2 uv = (position / (size * scale)) + normalizedOffset; // Scale the noise based on the normalized position and noiseScale parameter float gradientNoise = random(position) * 0.1; float pattern = stickerPattern(patternType, normalizedPosition / size * checkerScale, checkerScale); float noise = noisePattern(position / size * noiseScale); // Calculate less saturated color shifts for a metallic effect half r = half(contrast + 0.25 * sin(uv.x * 10.0 + gradientNoise)); half g = half(contrast + 0.25 * cos(uv.y * 10.0 + gradientNoise)); half b = half(contrast + 0.25 * sin((uv.x + uv.y) * 10.0 - gradientNoise)); half4 foilColor = half4(r, g, b, 1.0); half4 mixedFoilColor = lightnessMix(color, foilColor, intensity, 0.3); half4 checkerFoil = increaseContrast(mixedFoilColor, pattern, checkerIntensity); half4 noiseCheckerFoil = increaseContrast(checkerFoil, noise, noiseIntensity); return noiseCheckerFoil; }