本案例的目的是理解如何用Metal實現圖像包裝效果濾鏡,用於圖像處理色彩丟失和模糊效果;
效果圖
Demo
實操代碼
// 色彩丟失和模糊效果
let filter = C7ColorPacking.init(horizontalTexel: 2.5, verticalTexel: 5)
// 方案1:
let dest = BoxxIO.init(element: originImage, filter: filter)
ImageView.image = try? dest.output()
dest.filters.forEach {
NSLog("%@", "\($0.parameterDescription)")
}
// 方案2:
ImageView.image = try? originImage.make(filter: filter)
// 方案3:
ImageView.image = originImage ->> filter
實現原理
- 過濾器
這款濾鏡採用並行計算編碼器設計.compute(kernel: "C7ColorPacking")
,參數因子[horizontalTexel, verticalTexel]
對外開放參數
-
horizontalTexel
: 橫向偏移,越大綠色輪廓虛影向右偏移越多; -
verticalTexel
: 縱向偏移,越大藍色輪廓虛影向下偏移越多;
/// 色彩丟失/模糊效果
public struct C7ColorPacking: C7FilterProtocol {
/// The larger the transverse offset, the more the green contour shadow offset to the right.
public var horizontalTexel: Float
/// The larger the vertical offset, the more the blue contour shadow offset downward.
public var verticalTexel: Float
public var modifier: Modifier {
return .compute(kernel: "C7ColorPacking")
}
public var factors: [Float] {
return [horizontalTexel, verticalTexel]
}
public init(horizontalTexel: Float = 0, verticalTexel: Float = 0) {
self.horizontalTexel = horizontalTexel
self.verticalTexel = verticalTexel
}
}
- 着色器
紋理座標和偏移均歸一化處理,然後獲取到上下左右4個紋理偏移座標,取出對應的紋理紅色值,最後得到像素值;
kernel void C7ColorPacking(texture2d<half, access::write> outputTexture [[texture(0)]],
texture2d<half, access::sample> inputTexture [[texture(1)]],
device float *texelWidthPointer [[buffer(0)]],
device float *texelHeightPointer [[buffer(1)]],
uint2 grid [[thread_position_in_grid]]) {
constexpr sampler quadSampler(mag_filter::linear, min_filter::linear);
const float width = outputTexture.get_width();
const float height = outputTexture.get_height();
const float texelWidth = float(*texelWidthPointer / width);
const float texelHeight = float(*texelHeightPointer / height);
const float2 textureCoordinate = float2(float(grid.x) / width, float(grid.y) / height);
const float2 upperLeftTextureCoordinate = textureCoordinate + float2(-texelWidth, -texelHeight);
const float2 upperRightTextureCoordinate = textureCoordinate + float2(texelWidth, -texelHeight);
const float2 lowerLeftTextureCoordinate = textureCoordinate + float2(-texelWidth, texelHeight);
const float2 lowerRightTextureCoordinate = textureCoordinate + float2(texelWidth, texelHeight);
half upperLeftIntensity = inputTexture.sample(quadSampler, upperLeftTextureCoordinate).r;
half upperRightIntensity = inputTexture.sample(quadSampler, upperRightTextureCoordinate).r;
half lowerLeftIntensity = inputTexture.sample(quadSampler, lowerLeftTextureCoordinate).r;
half lowerRightIntensity = inputTexture.sample(quadSampler, lowerRightTextureCoordinate).r;
const half4 outColor = half4(upperLeftIntensity, upperRightIntensity, lowerLeftIntensity, lowerRightIntensity);
outputTexture.write(outColor, grid);
}
效果圖
橫行縱向偏移 | 橫向偏移 | 縱向偏移 |
---|---|---|
Harbeth功能清單
- 支持ios系統和macOS系統
- 支持運算符函數式操作
- 支持多種模式數據源 UIImage, CIImage, CGImage, CMSampleBuffer, CVPixelBuffer.
- 支持快速設計濾鏡
- 支持合併多種濾鏡效果
- 支持輸出源的快速擴展
- 支持相機採集特效
- 支持視頻添加濾鏡特效
- 支持矩陣卷積
- 支持使用系統 MetalPerformanceShaders.
- 支持兼容 CoreImage.
- 濾鏡部分大致分爲以下幾個模塊:
最後
- 慢慢再補充其他相關濾鏡,喜歡就給我點個星🌟吧。
-
濾鏡Demo地址,目前包含
100+
種濾鏡,同時也支持CoreImage混合使用。 - 再附上一個開發加速庫KJCategoriesDemo地址
- 再附上一個網絡基礎庫RxNetworksDemo地址
- 喜歡的老闆們可以點個星🌟,謝謝各位老闆!!!
✌️.