import Metal

// BT.601, which is the standard for SDTV.
public let colorConversionMatrix601Default = Matrix3x3(rowMajorValues:[
    1.164,  1.164, 1.164,
    0.0, -0.392, 2.017,
    1.596, -0.813,   0.0
])

// BT.601 full range (ref: http://www.equasys.de/colorconversion.html)
public let colorConversionMatrix601FullRangeDefault = Matrix3x3(rowMajorValues:[
    1.0,    1.0,    1.0,
    0.0,    -0.343, 1.765,
    1.4,    -0.711, 0.0,
])

// BT.709, which is the standard for HDTV.
public let colorConversionMatrix709Default = Matrix3x3(rowMajorValues:[
    1.164,  1.164, 1.164,
    0.0, -0.213, 2.112,
    1.793, -0.533,   0.0,
])

public func convertYUVToRGB(pipelineState:MTLRenderPipelineState, uniformSettings:ShaderUniformSettings, luminanceTexture:Texture, chrominanceTexture:Texture, secondChrominanceTexture:Texture? = nil, resultTexture:Texture, colorConversionMatrix:Matrix3x3) {
    uniformSettings["colorConversionMatrix"] = colorConversionMatrix
    
    guard let commandBuffer = sharedMetalRenderingDevice.commandQueue.makeCommandBuffer() else {return}
    
    let inputTextures:[UInt:Texture]
    if let secondChrominanceTexture = secondChrominanceTexture {
        inputTextures = [0:luminanceTexture, 1:chrominanceTexture, 2:secondChrominanceTexture]
    } else {
        inputTextures = [0:luminanceTexture, 1:chrominanceTexture]
    }
    
    commandBuffer.renderQuad(pipelineState:pipelineState, uniformSettings:uniformSettings, inputTextures:inputTextures, useNormalizedTextureCoordinates:true, outputTexture:resultTexture)
    commandBuffer.commit()
}
