//**************************************************************************/
// Copyright (c) 2010 Autodesk, Inc.
// All rights reserved.
// 
// These coded instructions, statements, and computer programs contain
// unpublished proprietary information written by Autodesk, Inc., and are
// protected by Federal copyright law. They may not be disclosed to third
// parties or copied or duplicated in any form, in whole or in part, without
// the prior written consent of Autodesk, Inc.
//**************************************************************************/
// DESCRIPTION:  Spread the influence of DOF to neighboring pixels.
// AUTHOR:  Kells Elmquist
// CREATED: November 2010
//**************************************************************************/

#include "Common.cgh"    

/////////////////////////////////////////////////////////////////////////////
//
//	Spread DOF circles of confusion to affected pixels
//
// The  source image texure to be blurred
uniform texture source;
uniform sampler2D sourceSamp = sampler_state
{
    Texture = <source>;
};
// the coc/depth texture is a float2 texture that has no-abs coc in .x & linear depth in .y
uniform texture cocDepth;
uniform sampler2D cocDepthSamp = sampler_state
{
    Texture = <cocDepth>;
};

uniform int		searchRadius = 8;   // in pixels, radius 4 = 9x9 samples; 8 = 17x17; side=2*radius+1
uniform float2	searchDirection;	// (0,1) for V pass or (1,0) for H pass
uniform int		sampleSpacing = 1;	// stride between pixel samples in motion spreading, 1x1 default
uniform float	acceptThreshold = 0.01f;	// similarity threshold to accept neighbor 


// filter kernel, return value of kernel of radius r at a distance x from the filter center
// both x & r must be positive, r must be > 0
float filter( float r, float x )
{
	// box kernel
	//return 1;
	// linear (triangle) kernel
	return saturate( 1.0f - x/r );
	// gaussian kernel
	//return 0.79788f * exp( -x*x/(0.375 * r*r) ) / r;
}

// DOF Pixel shader. 2 pass (H&V) filter, pass controlled by searchDirection
// NOTE: This expects the common screen quad vertex shader output in common.cgh.
float4 visualizeDOFBlur( VS_TO_PS_ScreenQuad In ) : COLOR0
{
    // Compute the offset between samples in uv space
    float2 offset = (float)sampleSpacing * searchDirection * gTexelSize;
    
	// center pixel
    //float4 s0 = tex2D(sourceSamp, In.UV); 
    float4 c0 = tex2D(cocDepthSamp, In.UV); 

	const float nearOffset = 0.0f;
	const float cocScale = 25.0f;

	float coc = abs( c0.x );
	float z = c0.y / (20.0f + c0.y);
	float isNear = (c0.x < nearOffset)? 0.4f : 0.0f;

    float4 clrSum = float4( cocScale * coc, 0.4f * z, isNear, 1.0f );

		
    return clrSum; 
}

// shader for either pass of the 2 pass h/v spreading technique.
technique spreadDOFPass
{
    pass p0
    {
        VertexShader = compile glslv VS_ScreenQuad();
        PixelShader  = compile glslf visualizeDOFBlur();
    }
}