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我参考了 github 上的OBS Studio 20.1.0 文档和chroma_key_filter.effect。最近自制的 obs-studio 过滤器有问题。我想不出如何解决它。在这里想请教大家，希望能得到一些建议或答案。

第一个问题是，当捕捉到power point演示文稿时，背景设置为红色（图1），然后我可以用我自己的边缘检测内核得到文本的边缘，但是通常的绿色（或蓝色）颜色会不会显示效果（图2）？（OBS-studio资源为了方便看效果使用了白色背景）在 此输入图片说明 图1。

在此处输入图像描述 图 2。

第二个问题是过滤器已更改为其他内核。相反，参数化的水平滚动条没有任何作用。是否需要调整位置才能使全罩工作（图 3）？ 在此处输入图像描述 图 3。

代码展示如下（其编程语言使用HLSL或GLSL语言）：

uniform float4x4 ViewProj;
uniform texture2d image;

uniform float4x4 yuv_mat = { 0.182586,  0.614231,  0.062007, 0.062745,
                            -0.100644, -0.338572,  0.439216, 0.501961,
                             0.439216, -0.398942, -0.040274, 0.501961,
                             0.000000,  0.000000,  0.000000, 1.000000};

uniform float4 color;
uniform float contrast;
uniform float brightness;
uniform float gamma;

uniform float2 chroma_key;
uniform float4 key_rgb;
uniform float2 pixel_size;
uniform float similarity;
uniform float smoothness;
uniform float spill;

// 3x3 kernel for convolution edge detection.
uniform float3 kernel1  = { -1.0, -1.0, -1.0};
uniform float3 kernel2    = {-1.0, 8.0, -1.0};
uniform float3 kernel3    = {-1.0, -1.0, -1.0 };

sampler_state textureSampler {
    Filter    = Linear;
    AddressU  = Clamp;
    AddressV  = Clamp;
};

struct VertData {
    float4 pos : POSITION;
    float2 uv  : TEXCOORD0; //Texture coordinates.
};

VertData VSDefault(VertData v_in)
{
    VertData vert_out;
    vert_out.pos = mul(float4(v_in.pos.xyz, 1.0), ViewProj);
    vert_out.uv  = v_in.uv;
    return vert_out;
}

float4 CalcColor(float4 rgba)
{
    return float4(pow(rgba.rgb, float3(gamma, gamma, gamma)) * contrast + brightness, rgba.a);
}

float GetChromaDist(float3 rgb)
{
    float4 yuvx = mul(float4(rgb.rgb, 1.0), yuv_mat); //rgb to yuv
    return distance(chroma_key, yuvx.yz);             // Take the distance scalar value of two vectors.
}

float4 SampleTexture(float2 uv)
{
    return image.Sample(textureSampler, uv); 
}

//  3x3 filter of Edge detection
float GetEdgeDetectionFilteredChromaDist(float3 rgb, float2 texCoord)
{
    float distVal = SampleTexture(-texCoord-pixel_size).rgb * kernel1[0];                        // Top left
    distVal += SampleTexture(texCoord-pixel_size).rgb * kernel1[1];                             // Top center
    distVal += SampleTexture(texCoord-float2(pixel_size.x, 0.0)).rgb * kernel1[2];              // Top right

    distVal += SampleTexture(texCoord-float2(pixel_size.x, -pixel_size.y)).rgb * kernel2[0];    // Middle left
    distVal += SampleTexture(texCoord-float2(0.0, pixel_size.y)).rgb * kernel2[1];              // Current pixel
    distVal += SampleTexture(texCoord+float2(0.0, pixel_size.y)).rgb * kernel2[2];              // Middle right

    distVal += SampleTexture(texCoord+float2(pixel_size.x, -pixel_size.y)).rgb * kernel3[0];    // Bottom left
    distVal += SampleTexture(texCoord+float2(pixel_size.x, 0.0)).rgb * kernel3[1];              // Bottom center
    distVal += SampleTexture(texCoord+pixel_size).rgb * kernel3[2];                             // Bottom right

    return distVal;
}


float4 ProcessChromaKey(float4 rgba, VertData v_in)
{
    float chromaDist = GetEdgeDetectionFilteredChromaDist(rgba.rgb, v_in.uv);//Edge detection filter function.

    float baseMask = chromaDist - similarity;
    float fullMask = pow(saturate(baseMask / smoothness), 1.5);
    float spillVal = pow(saturate(baseMask / spill), 1.5);

    rgba.rgba *= color;
    rgba.a *= fullMask;

    float desat = (rgba.r * 0.2126 + rgba.g * 0.7152 + rgba.b * 0.0722);
    rgba.rgb = saturate(float3(desat, desat, desat)) * (1.0 - spillVal) + rgba.rgb * spillVal;

    return CalcColor(rgba);
}

float4 PSChromaKeyRGBA(VertData v_in) : TARGET
{
    float4 rgba = image.Sample(textureSampler, v_in.uv);
    return ProcessChromaKey(rgba, v_in);
}

technique Draw
{
    pass
    {
        vertex_shader = VSDefault(v_in);
        pixel_shader  = PSChromaKeyRGBA(v_in);
    }
}

谢谢！

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