//-----------------------------------------------------------------------------
// Copyright (c) 2008 dhpoware. All Rights Reserved.
//
// 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.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// Globals.
//-----------------------------------------------------------------------------

float4x4 world;
float4x4 view;
float4x4 projection;
float4x4 lightViewProjection;
float4x4 textureScaleBias;

float3 lightDir;
float4 lightColor;
float4 materialAmbient;
float4 materialDiffuse;

float depthBias;
float texelSize;

//-----------------------------------------------------------------------------
// Textures.
//-----------------------------------------------------------------------------

texture shadowMap;
sampler shadowMapSampler = sampler_state
{
    Texture = <shadowMap>;
    MinFilter = Point;
    MagFilter = Point;
    MipFilter = None;
    AddressU = Clamp;
    AddressV = Clamp;
};

//-----------------------------------------------------------------------------
// Vertex shaders.
//-----------------------------------------------------------------------------

void VS_Lambert(in  float4 inPosition  : POSITION,
void VS_LambertWithShadows(in  float4 inPosition        : POSITION,
	                       in  float2 inTexCoord        : TEXCOORD,
	                       in  float3 inNormal          : NORMAL,
			               out float4 outPosition       : POSITION,
			               out float4 outLightSpacePos  : TEXCOORD0,
			               out float2 outShadowTexCoord : TEXCOORD1,
			               out float2 outTexCoord       : TEXCOORD2,
				           out float3 outNormal         : TEXCOORD3,
				           out float3 outLightDir       : TEXCOORD4)
{
	float4x4 worldViewProjection = mul(mul(world, view), projection);
	float4 lightSpacePos = mul(mul(inPosition, world), lightViewProjection);
	float4 shadowCoord = mul(lightSpacePos, textureScaleBias);
					
	outPosition = mul(inPosition, worldViewProjection);
	outLightSpacePos = lightSpacePos;
	outShadowTexCoord = shadowCoord.xy / shadowCoord.w;
	outTexCoord = inTexCoord;
	outNormal = mul(inNormal, (float3x3)world);
	outLightDir = -lightDir;
}

//-----------------------------------------------------------------------------
// Pixel shaders.
//-----------------------------------------------------------------------------

float PS_ShadowMapLookup(sampler shadowMap, float2 texCoord, float depth)
{
	return (tex2D(shadowMap, texCoord).r + 0.1 < depth) ? 0.0f : 1.0f;
}

void PS_LambertWithShadows(in  float4 inLightSpacePos  : TEXCOORD0,
                           in  float2 inShadowTexCoord : TEXCOORD1,
                           in  float2 inTexCoord       : TEXCOORD2,
                           in  float3 inNormal         : TEXCOORD3,
                           in  float3 inLightDir       : TEXCOORD4,
				           out float4 outColor         : COLOR)
{
	float3 l = normalize(inLightDir);
	float3 n = normalize(inNormal);
	float nDotL = saturate(dot(n, l));
	
	float depth = inLightSpacePos.z / inLightSpacePos.w;
    float shadowOcclusion = PS_ShadowMapLookup(shadowMapSampler, inShadowTexCoord, depth);
    
    outColor = (materialAmbient * lightColor) +
	           (materialDiffuse * lightColor * nDotL) * shadowOcclusion;
}


technique LambertWithShadows
{
    pass
    {
        VertexShader = compile vs_2_0 VS_LambertWithShadows();
        PixelShader = compile ps_2_0 PS_LambertWithShadows();
    }
}