Ios 将图像边缘压缩为自定义内核不会产生预期的结果

我开发了一个定制的

CIWarpKernel

，它是我的数字模型设计的换位，如下所示：

kernel vec2 panoramaDistortion (vec2 center) {
    float pi = 3.141592653589793;
    vec2 t = destCoord();
    float x = t.x / center.x - 1.0;         // x ∈ -1...1
    float y = t.y / center.y - 1.0;         // y ∈ -1...1

    float rx = x;
    float delta = 50.0;
    float siny = sin(y * pi / 2.0);

    // See my model in Numbers: Aladdin PanoramPinch CIKernel file where $a2 = x and b$1 = y

    // sin($a2×pi()÷2)×(−cos(b$1×pi())×($a2+1)÷$w$3+sin($a2 ×pi()÷$w$5))
    // sin(y×pi()÷2)×(−cos(x×pi())×(y+1)÷$w$3+sin(y×pi()÷2))

    // sin($a22×pi()÷2)×(−cos(b$1×pi())×abs(1−$a22)÷$w$3−sin($a22 ×pi()÷$w$5))

    float ry =
      y >= 0.0 ?
        siny * (-cos(x * pi) * (y + 1.0) / delta + siny)
      : siny * (-cos(x * pi) * (1.0 - y) / delta - siny)
    ;

    return vec2(center.x * (rx + 1.0), center.y * (ry + 1.0));
}

阳性

y

的单元格为：

SIN（$A2×PI（）÷2）×个(−COS（B$1×PI（））×（$A2+1）÷$W$3+SIN（$A2×PI（）÷2））

其中，

$A2

是

y

，

B$1

是

x

，

$W$3

是中心拉伸因子

代码如下：

kernel vec2 panoramaDistortion (vec2 center) {
    float pi = 3.141592653589793;
    vec2 t = destCoord();
    float x = t.x / center.x - 1.0;         // x ∈ -1...1
    float y = t.y / center.y - 1.0;         // y ∈ -1...1

    float rx = x;
    float delta = 50.0;
    float siny = sin(y * pi / 2.0);

    // See my model in Numbers: Aladdin PanoramPinch CIKernel file where $a2 = x and b$1 = y

    // sin($a2×pi()÷2)×(−cos(b$1×pi())×($a2+1)÷$w$3+sin($a2 ×pi()÷$w$5))
    // sin(y×pi()÷2)×(−cos(x×pi())×(y+1)÷$w$3+sin(y×pi()÷2))

    // sin($a22×pi()÷2)×(−cos(b$1×pi())×abs(1−$a22)÷$w$3−sin($a22 ×pi()÷$w$5))

    float ry =
      y >= 0.0 ?
        siny * (-cos(x * pi) * (y + 1.0) / delta + siny)
      : siny * (-cos(x * pi) * (1.0 - y) / delta - siny)
    ;

    return vec2(center.x * (rx + 1.0), center.y * (ry + 1.0));
}

我的问题是，虽然换位是100%精确的，但我没有得到与我的模型相同的结果。请参见生成的平铺图像扭曲：

它是怎么来的，在中心y=0，在上边和下边有膨胀的

有关信息，我的平铺图像如下所示：

kernel vec2 panoramaDistortion (vec2 center) {
    float pi = 3.141592653589793;
    vec2 t = destCoord();
    float x = t.x / center.x - 1.0;         // x ∈ -1...1
    float y = t.y / center.y - 1.0;         // y ∈ -1...1

    float rx = x;
    float delta = 50.0;
    float siny = sin(y * pi / 2.0);

    // See my model in Numbers: Aladdin PanoramPinch CIKernel file where $a2 = x and b$1 = y

    // sin($a2×pi()÷2)×(−cos(b$1×pi())×($a2+1)÷$w$3+sin($a2 ×pi()÷$w$5))
    // sin(y×pi()÷2)×(−cos(x×pi())×(y+1)÷$w$3+sin(y×pi()÷2))

    // sin($a22×pi()÷2)×(−cos(b$1×pi())×abs(1−$a22)÷$w$3−sin($a22 ×pi()÷$w$5))

    float ry =
      y >= 0.0 ?
        siny * (-cos(x * pi) * (y + 1.0) / delta + siny)
      : siny * (-cos(x * pi) * (1.0 - y) / delta - siny)
    ;

    return vec2(center.x * (rx + 1.0), center.y * (ry + 1.0));
}