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V0.1.2, Updated and added some dithering algorithms to the program

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ewen 2026-01-14 09:56:07 +01:00
parent bee56ff8ae
commit 8382078eb4
2 changed files with 99 additions and 32 deletions
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113
Sources/iDither/Resources/Shaders.metal
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@ -5,10 +5,24 @@ struct RenderParameters {
float brightness;
float contrast;
float pixelScale;
int algorithm; // 0: None, 1: Bayer 8x8, 2: Bayer 4x4
int algorithm; // 0: None, 1: Bayer 2x2, 2: Bayer 4x4, 3: Bayer 8x8, 4: Cluster 4x4, 5: Cluster 8x8, 6: Blue Noise
int isGrayscale;
};
// Bayer 2x2 Matrix
constant float bayer2x2[2][2] = {
{0.0/4.0, 2.0/4.0},
{3.0/4.0, 1.0/4.0}
};
// Bayer 4x4 Matrix
constant float bayer4x4[4][4] = {
{ 0.0/16.0, 8.0/16.0, 2.0/16.0, 10.0/16.0 },
{12.0/16.0, 4.0/16.0, 14.0/16.0, 6.0/16.0 },
{ 3.0/16.0, 11.0/16.0, 1.0/16.0, 9.0/16.0 },
{15.0/16.0, 7.0/16.0, 13.0/16.0, 5.0/16.0 }
};
// Bayer 8x8 Matrix
constant float bayer8x8[8][8] = {
{ 0.0/64.0, 32.0/64.0, 8.0/64.0, 40.0/64.0, 2.0/64.0, 34.0/64.0, 10.0/64.0, 42.0/64.0 },
@ -21,12 +35,36 @@ constant float bayer8x8[8][8] = {
{63.0/64.0, 31.0/64.0, 55.0/64.0, 23.0/64.0, 61.0/64.0, 29.0/64.0, 53.0/64.0, 21.0/64.0 }
};
// Bayer 4x4 Matrix
constant float bayer4x4[4][4] = {
{ 0.0/16.0, 8.0/16.0, 2.0/16.0, 10.0/16.0 },
{12.0/16.0, 4.0/16.0, 14.0/16.0, 6.0/16.0 },
{ 3.0/16.0, 11.0/16.0, 1.0/16.0, 9.0/16.0 },
{15.0/16.0, 7.0/16.0, 13.0/16.0, 5.0/16.0 }
// Cluster 4x4 Matrix
constant float cluster4x4[4][4] = {
{12.0/16.0, 5.0/16.0, 6.0/16.0, 13.0/16.0},
{ 4.0/16.0, 0.0/16.0, 1.0/16.0, 7.0/16.0},
{11.0/16.0, 3.0/16.0, 2.0/16.0, 8.0/16.0},
{15.0/16.0, 10.0/16.0, 9.0/16.0, 14.0/16.0}
};
// Cluster 8x8 Matrix
constant float cluster8x8[8][8] = {
{24.0/64.0, 10.0/64.0, 12.0/64.0, 26.0/64.0, 35.0/64.0, 47.0/64.0, 49.0/64.0, 37.0/64.0},
{ 8.0/64.0, 0.0/64.0, 2.0/64.0, 14.0/64.0, 45.0/64.0, 59.0/64.0, 61.0/64.0, 51.0/64.0},
{22.0/64.0, 6.0/64.0, 4.0/64.0, 20.0/64.0, 43.0/64.0, 57.0/64.0, 63.0/64.0, 53.0/64.0},
{30.0/64.0, 18.0/64.0, 16.0/64.0, 28.0/64.0, 33.0/64.0, 41.0/64.0, 55.0/64.0, 39.0/64.0},
{34.0/64.0, 46.0/64.0, 48.0/64.0, 36.0/64.0, 25.0/64.0, 11.0/64.0, 13.0/64.0, 27.0/64.0},
{44.0/64.0, 58.0/64.0, 60.0/64.0, 50.0/64.0, 9.0/64.0, 1.0/64.0, 3.0/64.0, 15.0/64.0},
{42.0/64.0, 56.0/64.0, 62.0/64.0, 52.0/64.0, 23.0/64.0, 7.0/64.0, 5.0/64.0, 21.0/64.0},
{32.0/64.0, 40.0/64.0, 54.0/64.0, 38.0/64.0, 31.0/64.0, 19.0/64.0, 17.0/64.0, 29.0/64.0}
};
// Blue Noise 8x8 (Approx)
constant float blueNoise8x8[8][8] = {
{52.0/64.0, 21.0/64.0, 58.0/64.0, 10.0/64.0, 45.0/64.0, 33.0/64.0, 56.0/64.0, 17.0/64.0},
{ 4.0/64.0, 38.0/64.0, 28.0/64.0, 51.0/64.0, 5.0/64.0, 22.0/64.0, 40.0/64.0, 62.0/64.0},
{61.0/64.0, 12.0/64.0, 48.0/64.0, 14.0/64.0, 55.0/64.0, 36.0/64.0, 7.0/64.0, 31.0/64.0},
{32.0/64.0, 43.0/64.0, 2.0/64.0, 46.0/64.0, 25.0/64.0, 63.0/64.0, 19.0/64.0, 50.0/64.0},
{16.0/64.0, 53.0/64.0, 23.0/64.0, 60.0/64.0, 9.0/64.0, 47.0/64.0, 29.0/64.0, 6.0/64.0},
{44.0/64.0, 27.0/64.0, 39.0/64.0, 34.0/64.0, 54.0/64.0, 13.0/64.0, 59.0/64.0, 26.0/64.0},
{ 8.0/64.0, 57.0/64.0, 18.0/64.0, 1.0/64.0, 42.0/64.0, 30.0/64.0, 3.0/64.0, 49.0/64.0},
{35.0/64.0, 24.0/64.0, 0.0/64.0, 41.0/64.0, 15.0/64.0, 52.0/64.0, 20.0/64.0, 37.0/64.0}
};
kernel void ditherShader(texture2d<float, access::read> inputTexture [[texture(0)]],
@ -38,22 +76,21 @@ kernel void ditherShader(texture2d<float, access::read> inputTexture [[texture(0
return;
}
// 1. Pixelation (Downsampling)
// 1. Pixelation
float scale = max(1.0, params.pixelScale);
uint2 sourceCoord = uint2(floor(float(gid.x) / scale) * scale, floor(float(gid.y) / scale) * scale);
// Clamp to texture bounds
sourceCoord.x = min(sourceCoord.x, inputTexture.get_width() - 1);
sourceCoord.y = min(sourceCoord.y, inputTexture.get_height() - 1);
float4 color = inputTexture.read(sourceCoord);
// 2. Color Adjustment (Brightness & Contrast)
// 2. Color Adjustment
float3 rgb = color.rgb;
rgb = rgb + params.brightness;
rgb = (rgb - 0.5) * params.contrast + 0.5;
// Grayscale conversion (Luma)
// Grayscale
float luma = dot(rgb, float3(0.299, 0.587, 0.114));
if (params.isGrayscale > 0) {
@ -61,24 +98,46 @@ kernel void ditherShader(texture2d<float, access::read> inputTexture [[texture(0
}
// 3. Dithering
if (params.algorithm == 1) { // Bayer 8x8
// Map current pixel to matrix coordinates
// We use the original gid (screen coordinates) for the matrix pattern to keep it stable across pixelation blocks?
// OR we use the sourceCoord (pixelated coordinates) to make the dither pattern scale with the pixels?
// Usually, dither is applied at screen resolution, but for "retro pixel art" look, the dither pattern usually matches the "big pixel" size.
// Let's try using the scaled coordinate index: sourceCoord / scale
float threshold = 0.5;
bool shouldDither = (params.algorithm > 0);
uint x = uint(sourceCoord.x / scale) % 8;
uint y = uint(sourceCoord.y / scale) % 8;
float threshold = bayer8x8[y][x];
if (shouldDither) {
uint x, y;
// Apply threshold
rgb = (luma > threshold) ? float3(1.0) : float3(0.0);
} else if (params.algorithm == 2) { // Bayer 4x4
uint x = uint(sourceCoord.x / scale) % 4;
uint y = uint(sourceCoord.y / scale) % 4;
float threshold = bayer4x4[y][x];
switch (params.algorithm) {
case 1: // Bayer 2x2
x = uint(sourceCoord.x / scale) % 2;
y = uint(sourceCoord.y / scale) % 2;
threshold = bayer2x2[y][x];
break;
case 2: // Bayer 4x4
x = uint(sourceCoord.x / scale) % 4;
y = uint(sourceCoord.y / scale) % 4;
threshold = bayer4x4[y][x];
break;
case 3: // Bayer 8x8
x = uint(sourceCoord.x / scale) % 8;
y = uint(sourceCoord.y / scale) % 8;
threshold = bayer8x8[y][x];
break;
case 4: // Cluster 4x4
x = uint(sourceCoord.x / scale) % 4;
y = uint(sourceCoord.y / scale) % 4;
threshold = cluster4x4[y][x];
break;
case 5: // Cluster 8x8
x = uint(sourceCoord.x / scale) % 8;
y = uint(sourceCoord.y / scale) % 8;
threshold = cluster8x8[y][x];
break;
case 6: // Blue Noise 8x8
x = uint(sourceCoord.x / scale) % 8;
y = uint(sourceCoord.y / scale) % 8;
threshold = blueNoise8x8[y][x];
break;
default:
break;
}
rgb = (luma > threshold) ? float3(1.0) : float3(0.0);
}

16
Sources/iDither/ViewModel/DitherViewModel.swift
View file

@ -4,16 +4,24 @@ import ImageIO
enum DitherAlgorithm: Int, CaseIterable, Identifiable {
case noDither = 0
case bayer8x8 = 1
case bayer2x2 = 1
case bayer4x4 = 2
case bayer8x8 = 3
case cluster4x4 = 4
case cluster8x8 = 5
case blueNoise = 6
var id: Int { rawValue }
var name: String {
switch self {
case .noDither: return "No Dither"
case .bayer8x8: return "Bayer 8x8"
case .bayer4x4: return "Bayer 4x4"
case .bayer2x2: return "Bayer 2x2 (Retro)"
case .bayer4x4: return "Bayer 4x4 (Balanced)"
case .bayer8x8: return "Bayer 8x8 (Smooth)"
case .cluster4x4: return "Cluster 4x4 (Vintage)"
case .cluster8x8: return "Cluster 8x8 (Soft)"
case .blueNoise: return "Blue Noise / Organic (Best Quality)"
}
}
}
@ -29,7 +37,7 @@ class DitherViewModel {
var brightness: Double = 0.0
var contrast: Double = 1.0
var pixelScale: Double = 4.0
var selectedAlgorithm: DitherAlgorithm = .bayer8x8
var selectedAlgorithm: DitherAlgorithm = .bayer4x4 // Default to Balanced
var isGrayscale: Bool = false
private let renderer = MetalImageRenderer()