//**************************************************************************/
// Copyright 2012 Autodesk, Inc.  
// All rights reserved.
// Use of this software is subject to the terms of the Autodesk license 
// agreement provided at the time of installation or download, or which 
// otherwise accompanies this software in either electronic or hard copy form.   
//**************************************************************************/
//
// Sample shader useful for rendering a "depth" pass.
//
// World-view-projection transformation.
uniform mat4 gWVPXf : WorldViewProjection 
<
    string UIWidget = "None"; 
    bool rowMajor = true;
>;

// Depth priority, which shifts the model a bit forward in the z-buffer
uniform float gDepthPriority : DepthPriority
<
    string UIName =  "Depth Priority";
    string UIWidget = "Slider";
    float UIMin = -16/1048576.0f;    // divide by 2^24/16 by default
    float UIMax = 16/1048576.0f;
    float UIStep = 1/1048576.0f;
> = 0.0f;

// Vertex shader input structure.
attribute VS_INPUT
{
    vec3 Pos : POSITION;
};

// Vertex shader output structure.
attribute VS_TO_PS
{
	// None
};

// Pixel shader output structure.
attribute pixelOut
{
    vec4 colorOut : COLOR0;
}

// Vertex shader.
GLSLShader VS_Depth
{
	void main()
	{
		// Transform the position from object space to clip space for output.
		vec4 HPos = gWVPXf*vec4(Pos, 1.0);
		
		// modify the HPos a bit by biasing the Z a bit forward, based on depth priority
		HPos.z -= HPos.w*gDepthPriority;

		gl_Position = HPos;
	}
}

// Pixel shader.
GLSLShader PS_Depth
{
	void main()
	{
    	colorOut = vec4(0.0, 0.0, 0.0, 0.0);
	}
}

// The main technique.
technique Main
{
    pass P0
    {
        VertexShader (in VS_INPUT, out VS_TO_PS) = VS_Depth;
        PixelShader (in VS_TO_PS, out pixelOut) = PS_Depth;
    }
}