//-----------------------------------------------------------------------------
// Copyright (c) 2012 GarageGames, LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//-----------------------------------------------------------------------------

#include "core/rendering/shaders/postFX/postFx.hlsl"
#include "core/rendering/shaders/torque.hlsl"


TORQUE_UNIFORM_SAMPLER2D(inputTex, 0);
TORQUE_UNIFORM_SAMPLER2D(luminanceTex, 1);
uniform float2 oneOverTargetSize;
uniform float brightPassThreshold;
uniform float g_fMiddleGray;

static const float3 LUMINANCE_VECTOR = float3(0.3125f, 0.6154f, 0.0721f);


static float2 gTapOffsets[4] = 
{
   { -0.5, 0.5 },  { 0.5, -0.5 },
   { -0.5, -0.5 }, { 0.5, 0.5 }
};

float4 main( PFXVertToPix IN ) : TORQUE_TARGET0
{
   float4 average = { 0.0f, 0.0f, 0.0f, 0.0f };      

   // Combine and average 4 samples from the source HDR texture.
   for( int i = 0; i < 4; i++ )
      average += hdrDecode( TORQUE_TEX2D( inputTex, IN.uv0 + ( gTapOffsets[i] * oneOverTargetSize ) ) );
   average *= 0.25f;

   // Determine the brightness of this particular pixel.   
   float adaptedLum = TORQUE_TEX2D( luminanceTex, float2( 0.5f, 0.5f ) ).r;
   float lum = (g_fMiddleGray / (adaptedLum + 0.0001)) * hdrLuminance( average.rgb );
   //float lum = hdrLuminance( average.rgb );
   
   // Determine whether this pixel passes the test...
   if ( lum < brightPassThreshold )
      average = float4( 0.0f, 0.0f, 0.0f, 1.0f );

   // Write the colour to the bright-pass render target
   return hdrEncode( average );
}
