// Copyright 2014 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.
//
// Simple shader to output some vertex attributes to different output targets
// For now will write out 2 outputs: position and normals in world space.
//

#include "Common.ogsfh"

// Vertex input structure
attribute VS_INPUT
{
    vec3 Pm : POSITION;
    vec3 Nm : NORMAL;
}

// Vertex output structure
attribute VS_TO_PS
{
    vec3 Pw : TEXCOORD0;
    vec3 Nw : TEXCOORD1;
}


// Globals
uniform mat4 WorldIT : worldinversetranspose;
uniform mat4 World : world;
uniform float DepthPriority : depthpriority;
uniform mat4 WorldViewProj : worldviewprojection;


//  Vertex shader fragments

GLSLShader VS_GeometryAttributes
{
    vec3 iNw( vec3 nm, mat4 worldITC )
    {
        return ( worldITC * vec4(nm,0) ).xyz;
    }

    vec3 iPw( vec3 pm, mat4 world )
    {
        return ( world * vec4(pm, 1.0) ).xyz;
    }

    // vec3 iVw( vec3 Pm, vec3 Ew, mat4 world  )
    // {
    //     vec4 Pw = world * vec4(Pm,1);
    //     return Ew - Pw.xyz;
    // }

    vec4 iPcPriority( vec3 pm, float depthPriority, mat4 worldViewProjectionC )
    {
        vec4 P = worldViewProjectionC * vec4(pm,1);
        P.z -= P.w * 2.0 * depthPriority;
        return P;
    }

    void main()
    {
        Nw = iNw( Nm, WorldIT );
        Pw = iPw( Pm, World );
        gl_Position= iPcPriority ( Pm, DepthPriority, WorldViewProj );
    }
}


// Pixel shader output structure.
attribute PS_OUT
{
    vec4 colorOut[2];
}

// Pixel shader.
GLSLShader PS_GeometryAttributes
{
    void main()
    {
        colorOut[0] = vec4( Pw, 1.0);
        colorOut[1] = vec4((normalize(Nw) + 1.0) * 0.5, 1.0);
    }
}

// Technique.
technique Main
{
    pass p0
    {
        VertexShader (in VS_INPUT, out VS_TO_PS) = VS_GeometryAttributes;
        PixelShader (in VS_TO_PS, out PS_OUT) = PS_GeometryAttributes;
    }
}