Xamarin.iOS GPUImage :如何在Xamarin.iOS中使用自定义着色器文件创建GPUImageTwoInputFilter

Question

我想在xamarin.iOS中创建一个带有自定义着色器文件的GPUImageTwoInputFilter。我正在使用GPUImage组件。

var stillCamera = new GPUImageStillCamera ();
var filter1 = new GPUImageTwoInputFilter();
stillCamera.AddTarget(filter1);
var internalSourcePicture1 = new GPUImagePicture(UIImage.FromFile("image.png").CGImage,true);
internalSourcePicture1.AddTarget(filter1);
internalSourcePicture1.ProcessImage();

但是不知道如何在GPUImageTwoInputFilter中传递着色器文件

Answer 1

将自定义片段着色器(.fsh)添加到Xamarin.iOS应用程序包中，作为BundleResource的构建类型。

然后通过GPUImageFilter.FromFragmentShaderFile加载它

注意:请勿包含文件扩展名，否则将在应用程序输出/日志中显示"Failed to load vertex shader“

var filter = GPUImageFilter.FromFragmentShaderFile ("StackOverflowShader");

或将片段着色器作为字符串嵌入：

    fragShaderString = @"
 varying highp vec2 textureCoordinate;
 varying highp vec2 textureCoordinate2;

 uniform sampler2D inputImageTexture;
 uniform sampler2D inputImageTexture2;

 void main()
 {
    lowp vec4 base = texture2D(inputImageTexture, textureCoordinate);
    lowp vec4 overlayer = texture2D(inputImageTexture2, textureCoordinate2);

    gl_FragColor = vec4(min(overlayer.rgb * base.a, base.rgb * overlayer.a) + overlayer.rgb * (1.0 - base.a) + base.rgb * (1.0 - overlayer.a), 1.0);
 }

";

并通过FromFragmentShaderString加载它

var filter = GPUImageFilter.FromFragmentShaderString(fragShaderString);