Metal每日分享，分镜滤镜效果

// 分成两行两列
let filter = C7Storyboard.init(ranks: 2)
// 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

/// 分镜滤镜
public struct C7Storyboard: C7FilterProtocol {
    /// 分为`N x N`个屏幕
    public var N: Int = 2
    public var modifier: Modifier {
        return .compute(kernel: "C7Storyboard")
    }
    public var factors: [Float] {
        return [Float(N)]
    }
    public init(ranks: Int = 2) {
        self.N = ranks
    }
}

kernel void C7Storyboard(texture2d<half, access::write> outputTexture [[texture(0)]],
                         texture2d<half, access::sample> inputTexture [[texture(1)]],
                         constant float *few [[buffer(0)]],
                         uint2 grid [[thread_position_in_grid]]) {
    constexpr sampler quadSampler(mag_filter::linear, min_filter::linear);
    const float x = float(grid.x) / outputTexture.get_width();
    const float y = float(grid.y) / outputTexture.get_height();
    const float2 textureCoordinate = float2(x, y);
    const int N = int(*few);
    const float2 uv = fmod(textureCoordinate, 1.0 / N) * N;
    const half4 outColor = inputTexture.sample(quadSampler, uv);
    outputTexture.write(outColor, grid);
}

/// 1.转换成BGRA
let filter1 = C7ColorConvert(with: C7ColorConvert.ColorType.bgra)
/// 2.调整颗粒度
var filter2 = C7Granularity()
filter2.grain = 0.8
/// 3.调整白平衡
var filter3 = C7WhiteBalance()
filter3.temperature = 5555
/// 4.调整高光阴影
var filter4 = C7HighlightShadow()
filter4.shadows = 0.4
filter4.highlights = 0.5
/// 5.组合操作，获取结果
filterImageView.image = originImage ->> filter1 ->> filter2 ->> filter3 ->> filter4

/// 1.转换成RBGA
let filter1 = C7ColorConvert(with: C7ColorConvert.ColorType.rbga)
/// 2.调整颗粒度
var filter2 = C7Granularity()
filter2.grain = 0.8
/// 3.配置灵魂效果
var filter3 = C7SoulOut()
filter3.soul = 0.7
/// 4.组合操作
let group: [C7FilterProtocol] = [filter1, filter2, filter3]
/// 5.获取结果
filterImageView.image = try? originImage.makeGroup(filters: group)