//-----------------------------------------------------------------------------
// Copyright 2014-2018 RenderHeads Ltd.  All rights reserved.
//-----------------------------------------------------------------------------

// Each #kernel tells which function to compile; you can have many kernels
#pragma kernel RGBX10_to_RGBA

// Create a RenderTexture with enableRandomWrite flag and set it
// with cs.SetTexture
Texture2D<uint> input;
RWTexture2D<float4> result;

struct Parameters{
	uint width;
	uint height;
	uint bufferWidth;
	uint bigEndian;
	uint leading;
	bool isLinear;
	bool flipX;
	bool flipY;
};

RWStructuredBuffer<Parameters> constBuffer;

[numthreads(8,8,1)]
void RGBX10_to_RGBA(uint3 id : SV_DispatchThreadID)
{
	if (id.x >= constBuffer[0].width || id.y >= constBuffer[0].height) {
		return;
	}
	
	int3 extractedRGB;

	uint rgb10Val = input[id.xy];

	if (constBuffer[0].bigEndian) {
		uint mask = 1023;
		
		extractedRGB.r = rgb10Val >> 22;
		extractedRGB.g = (rgb10Val >> 12) & mask;
		extractedRGB.b = (rgb10Val >> 2) & mask;
	}
	else{
		uint bytes[4];

		for (uint shift = 0U; shift < 32U; shift += 8U) {
			bytes[shift / 8U] = (rgb10Val >> shift) & 255U;
		}
		
		extractedRGB.r = ((bytes[0] << 8) | bytes[1]) >> 6;
		extractedRGB.g = (((bytes[1] << 8) | bytes[2]) >> 4) & 1023U;
		extractedRGB.b = (((bytes[2] << 8) | bytes[3]) >> 2) & 1023U;
	}
	
	
	result[id.xy] = float4((float)extractedRGB.r / 1023.0, (float)extractedRGB.g / 1023.0, (float)extractedRGB.b / 1023.0, 1.0);
}