// 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.

#include "Common.ogsfh"

// The source texture
uniform texture2D gSourceTex : LeftSourceTexture;

// Sampler of source texture
uniform sampler2D gSourceSamp = sampler_state
{
    Texture = <gSourceTex>;
};

// The 2nd source texture
uniform texture2D gSourceTex2 : RightSourceTexture;

// Sampler of 2nd source texture
uniform sampler2D gSourceSamp2 = sampler_state
{
    Texture = <gSourceTex2>;
};

uniform vec4 gUVTransform : RelativeViewportDimensions;
uniform vec2 gViewportSizePixels = { 0.0, 0.0 };
uniform vec2 gSourceSizePixels = { 0.0, 0.0 };
uniform float  gBorderSizePixels = 10.0;
uniform vec4 gBorderColor = { 0, 0, 0, 1 };
uniform vec4 gBackgroundColor = { 0.1, 0.1, 0.1, 1 };


// uniform vec4 PS_FreeView(VS_TO_PS_ScreenQuad In) : COLOR0
GLSLShader PS_FreeView
{
    float inRect( vec2 inp, vec2 wh )
    {
        float val = (inp.x >= 0.0 && inp.x < wh.x && inp.y >= 0.0 && inp.y < wh.y) ? 1.0 : 0.0;
        return val;
    }

    void main()
    {
        // scale the incoming uvs to reflect a smaller than full raster viewport
        vec2 vpScale = gSourceSizePixels.xy / gViewportSizePixels.xy;
        vec2 UV = (VSUV * gUVTransform.zw + gUVTransform.xy) * vpScale;

        // how much do we scale the sources to fit the given viewport
        float sourceScale = (gScreenSize[0] - gBorderSizePixels) / (2.0 * gSourceSizePixels.x);
        // find width & height in UV space
        vec2 wh = sourceScale * gSourceSizePixels / gScreenSize;
        // find L0, R0 & B0 in UV space. they are the origins of the left eye vp, the right eye vp & the border rectangle
        vec2 L0 = vec2( 0, (1.0 - wh.y)/2.0 );
        vec2 R0 = vec2( wh.x + gBorderSizePixels/gScreenSize[0], L0.y );
        vec2 B0 = vec2( 0, L0.y - gBorderSizePixels/gScreenSize[1] );

        vec2 Luv = UV - L0;
        vec2 Ruv = UV - R0;

        float xL = inRect( Luv, wh );
        float xR = inRect( Ruv, wh );
        float xB = (1.0-xL) * (1.0-xR) * inRect( UV - B0, vec2( 1.0, 1.0-2.0*B0.y ) );

        vec4 leftEye = texture2D(gSourceSamp, Luv/(wh*vpScale) );
        vec4 rightEye = texture2D(gSourceSamp2, Ruv/(wh*vpScale) );

        vec4 result = (1.0 - (xB+xR+xL))*gBackgroundColor + xB * gBorderColor + xR * rightEye + xL * leftEye;

        colorOut = result;
    }
}


technique Main
{
    pass p0
    {
        VertexShader (in VS_INPUT_ScreenQuad, out VS_TO_PS_ScreenQuad) = VS_ScreenQuad;
        PixelShader (in VS_TO_PS_ScreenQuad, out pixelOut) = PS_FreeView;
    }
}