/trunk/Hieroglyph3/Applications/Data/Shaders/Lights.hlsl
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Possible License(s): MIT
- //--------------------------------------------------------------------------------
- // Lights
- //
- // Vertex shaders and pixel shaders for performing the lighting pass of a
- // classic deferred renderer
- //--------------------------------------------------------------------------------
-
- //-------------------------------------------------------------------------------------------------
- // Constants
- //-------------------------------------------------------------------------------------------------
- cbuffer LightParams
- {
- float3 LightPos;
- float3 LightColor;
- float3 LightDirection;
- float2 SpotlightAngles;
- float4 LightRange;
- };
-
- cbuffer CameraParams
- {
- float3 CameraPos;
- matrix ProjMatrix;
- matrix InvProjMatrix;
- }
-
- cbuffer Transforms
- {
- matrix WorldMatrix;
- matrix WorldViewMatrix;
- matrix WorldViewProjMatrix;
- };
-
- // This macro indicates whether we're currently rendering a volume
- #define VOLUMERENDERING ( ( POINTLIGHT || SPOTLIGHT ) && LIGHTVOLUMES )
-
- // This indicates the number of MSAA samples
- #if MSAA
- #define NUMSUBSAMPLES 4
- #else
- #define NUMSUBSAMPLES 1
- #endif
-
- //-------------------------------------------------------------------------------------------------
- // Input/output structs
- //-------------------------------------------------------------------------------------------------
- struct VSInput
- {
- float4 Position : POSITION;
- };
-
- struct VSOutput
- {
- float4 PositionCS : SV_Position;
- float3 ViewRay : VIEWRAY;
- };
-
- struct PSOutput
- {
- float4 Color : SV_Target0;
- };
-
- //-------------------------------------------------------------------------------------------------
- // Textures
- //-------------------------------------------------------------------------------------------------
- #if MSAA
- Texture2DMS<float4, 4> NormalTexture : register( t0 );
- Texture2DMS<float4, 4> DiffuseAlbedoTexture : register( t1 );
- Texture2DMS<float4, 4> SpecularAlbedoTexture : register( t2 );
- Texture2DMS<float4, 4> PositionTexture : register( t3 );
- Texture2DMS<float, 4> DepthTexture : register( t3 );
- #else
- Texture2D NormalTexture : register( t0 );
- Texture2D DiffuseAlbedoTexture : register( t1 );
- Texture2D SpecularAlbedoTexture : register( t2 );
- Texture2D PositionTexture : register( t3 );
- Texture2D DepthTexture : register( t3 );
- #endif
-
- //-------------------------------------------------------------------------------------------------
- // Vertex shader entry point
- //-------------------------------------------------------------------------------------------------
- VSOutput VSMain( in VSInput input )
- {
- VSOutput output;
-
- #if VOLUMERENDERING
- // Apply the world * view * projection
- output.PositionCS = mul( input.Position, WorldViewProjMatrix );
-
- // Calculate the view space vertex position, and output that as the view ray
- float3 positionVS = mul( input.Position, WorldViewMatrix ).xyz;
- output.ViewRay = positionVS;
- #else
- // Just copy the position
- output.PositionCS = input.Position;
-
- // For a quad we can clamp in the vertex shader, since we only interpolate in the XY direction
- float3 positionVS = mul( input.Position, InvProjMatrix ).xyz;
- output.ViewRay = float3( positionVS.xy / positionVS.z, 1.0f );
- #endif
-
- return output;
- }
-
- //-------------------------------------------------------------------------------------------------
- // Decodes a spheremap-encoded normal
- //-------------------------------------------------------------------------------------------------
- float3 SpheremapDecode( float2 encoded )
- {
- float4 nn = float4( encoded, 1, -1 );
- float l = dot( nn.xyz, -nn.xyw );
- nn.z = l;
- nn.xy *= sqrt( l );
- return nn.xyz * 2 + float3( 0, 0, -1 );
- }
-
- //-------------------------------------------------------------------------------------------------
- // Converts a depth buffer value to view-space position
- //-------------------------------------------------------------------------------------------------
- float3 PositionFromDepth( in float zBufferDepth, in float3 viewRay )
- {
- #if VOLUMERENDERING
- // Clamp the view space position to the plane at Z = 1
- viewRay = float3( viewRay.xy / viewRay.z, 1.0f );
- #else
- // For a quad we already clamped in the vertex shader
- viewRay = viewRay.xyz;
- #endif
-
- // Convert to a linear depth value using the projection matrix
- float linearDepth = ProjMatrix[3][2] / ( zBufferDepth - ProjMatrix[2][2] );
- return viewRay * linearDepth;
- }
-
- //-------------------------------------------------------------------------------------------------
- // Helper function for extracting G-Buffer attributes
- //-------------------------------------------------------------------------------------------------
- void GetGBufferAttributes( in float2 screenPos, in float3 viewRay, in int subSampleIndex, out float3 normal,
- out float3 position, out float3 diffuseAlbedo, out float3 specularAlbedo,
- out float specularPower )
- {
- // Determine our coordinate for sampling the texture based on the current screen position
- int3 sampleCoord = int3( screenPos.xy, 0 );
-
- #if GBUFFEROPTIMIZATIONS
- #if MSAA
- diffuseAlbedo = DiffuseAlbedoTexture.Load( sampleCoord.xy, subSampleIndex ).xyz;
- normal = SpheremapDecode( NormalTexture.Load( sampleCoord.xy, subSampleIndex ).xy );
- float4 spec = SpecularAlbedoTexture.Load( sampleCoord.xy, subSampleIndex );
- position = PositionFromDepth( DepthTexture.Load( sampleCoord.xy, subSampleIndex ).x, viewRay );
- #else
- normal = SpheremapDecode( NormalTexture.Load( sampleCoord ).xy );
- diffuseAlbedo = DiffuseAlbedoTexture.Load( sampleCoord ).xyz;
- float4 spec = SpecularAlbedoTexture.Load( sampleCoord );
- position = PositionFromDepth( DepthTexture.Load( sampleCoord ).x, viewRay );
- #endif
-
- specularAlbedo = spec.xyz;
- specularPower = spec.w * 255.0f;
- #else
- #if MSAA
- normal = NormalTexture.Load( sampleCoord.xy, subSampleIndex ).xyz;
- position = PositionTexture.Load( sampleCoord.xy, subSampleIndex ).xyz;
- diffuseAlbedo = DiffuseAlbedoTexture.Load( sampleCoord.xy, subSampleIndex ).xyz;
- float4 spec = SpecularAlbedoTexture.Load( sampleCoord.xy, subSampleIndex );
- #else
- normal = NormalTexture.Load( sampleCoord ).xyz;
- position = PositionTexture.Load( sampleCoord ).xyz;
- diffuseAlbedo = DiffuseAlbedoTexture.Load( sampleCoord ).xyz;
- float4 spec = SpecularAlbedoTexture.Load( sampleCoord );
- #endif
-
- specularAlbedo = spec.xyz;
- specularPower = spec.w;
- #endif
- }
-
- //-------------------------------------------------------------------------------------------------
- // Calculates the lighting term for a single G-Buffer texel
- //-------------------------------------------------------------------------------------------------
- float3 CalcLighting( in float3 normal, in float3 position, in float3 diffuseAlbedo,
- in float3 specularAlbedo, in float specularPower )
- {
- // Calculate the diffuse term
- float3 L = 0;
- float attenuation = 1.0f;
- #if POINTLIGHT || SPOTLIGHT
- // Base the the light vector on the light position
- L = LightPos - position;
-
- // Calculate attenuation based on distance from the light source
- float dist = length( L );
- attenuation = max( 0, 1.0f - ( dist / LightRange.x ) );
-
- L /= dist;
- #elif DIRECTIONALLIGHT
- // Light direction is explicit for directional lights
- L = -LightDirection;
- #endif
-
- #if SPOTLIGHT
- // Also add in the spotlight attenuation factor
- float3 L2 = LightDirection;
- float rho = dot( -L, L2 );
- attenuation *= saturate( ( rho - SpotlightAngles.y ) / ( SpotlightAngles.x - SpotlightAngles.y ) );
- #endif
-
- const float DiffuseNormalizationFactor = 1.0f / 3.14159265f;
- float nDotL = saturate( dot( normal, L ) );
- float3 diffuse = nDotL * LightColor * diffuseAlbedo * DiffuseNormalizationFactor;
-
- #if GBUFFEROPTIMIZATIONS
- // In view space camera position is (0, 0, 0)
- float3 camPos = 0.0f;
- #else
- float3 camPos = CameraPos;
- #endif
-
- // Calculate the specular term
- float3 V = camPos - position;
- float3 H = normalize( L + V );
- float specNormalizationFactor = ( ( specularPower + 8.0f ) / ( 8.0f * 3.14159265f ) );
- float3 specular = pow( saturate( dot( normal, H ) ), specularPower ) * specNormalizationFactor * LightColor * specularAlbedo.xyz * nDotL;
-
- // Final value is the sum of the albedo and diffuse with attenuation applied
- return ( diffuse + specular ) * attenuation;
- }
-
- //-------------------------------------------------------------------------------------------------
- // Light pixel shader
- //-------------------------------------------------------------------------------------------------
- PSOutput PSMain( in VSOutput input, in float4 screenPos : SV_Position, in uint coverage : SV_Coverage )
- {
- PSOutput output;
- float3 lighting = 0;
- float3 normal;
- float3 position;
- float3 diffuseAlbedo;
- float3 specularAlbedo;
- float specularPower;
-
- #if MSAA
- // Calculate lighting for MSAA samples
- float numSamplesApplied = 0.0f;
- for ( int i = 0; i < NUMSUBSAMPLES; ++i )
- {
- // We only want to calculate lighting for a sample if the light volume is covered.
- // We determine this using the input coverage mask.
- if ( coverage & ( 1 << i ) )
- {
- GetGBufferAttributes( screenPos.xy, input.ViewRay, i, normal, position, diffuseAlbedo,
- specularAlbedo, specularPower );
- lighting += CalcLighting( normal, position, diffuseAlbedo, specularAlbedo, specularPower );
- ++numSamplesApplied;
- }
- }
-
- lighting /= numSamplesApplied;
- #else
- // Calculate lighting for a single G-Buffer sample
- GetGBufferAttributes( screenPos.xy, input.ViewRay, 0, normal, position, diffuseAlbedo,
- specularAlbedo, specularPower );
- lighting = CalcLighting( normal, position, diffuseAlbedo, specularAlbedo, specularPower );
- #endif
-
- output.Color = float4( lighting, 1.0f );
-
- return output;
- }
-
-
-