176 lines
6.3 KiB
HLSL
176 lines
6.3 KiB
HLSL
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/*
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--------------------------------------------------------------------------------
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This source file is part of SkyX.
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Visit http://www.paradise-studios.net/products/skyx/
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Copyright (C) 2009-2012 Xavier Vergu<EFBFBD>n Gonz<EFBFBD>lez <xavyiy@gmail.com>
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA, or go to
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http://www.gnu.org/copyleft/lesser.txt.
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--------------------------------------------------------------------------------
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*/
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// --------------------- SkyX skydome material ------------------------
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float scale(float cos, float uScaleDepth)
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{
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float x = 1.0 - cos;
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return uScaleDepth * exp(-0.00287 + x*(0.459 + x*(3.83 + x*(-6.80 + x*5.25))));
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}
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void main_vp(
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// IN
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float4 iPosition : POSITION,
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float3 iNPosition : TEXCOORD0,
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float2 iUV : TEXCOORD1,
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float iOpacity : TEXCOORD2,
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// OUT
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out float4 oPosition : POSITION,
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out float2 oUV : TEXCOORD0,
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out float3 oRayleighColor : TEXCOORD1,
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out float3 oMieColor : TEXCOORD2,
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out float3 oDirection : TEXCOORD3,
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out float oOpacity : TEXCOORD4,
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out float oHeight : TEXCOORD5,
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// UNIFORM
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uniform float4x4 uWorldViewProj,
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// Global information
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uniform float3 uLightDir,
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// Position information
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uniform float3 uCameraPos,
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uniform float3 uInvWaveLength,
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uniform float uInnerRadius,
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// Scattering parameters
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uniform float uKrESun, // Kr * ESun
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uniform float uKmESun, // Km * ESun
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uniform float uKr4PI, // Kr * 4 * PI
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uniform float uKm4PI, // Km * 4 * PI
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// Atmosphere properties
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uniform float uScale, // 1 / (outerRadius - innerRadius)
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uniform float uScaleDepth, // Where the average atmosphere density is found
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uniform float uScaleOverScaleDepth, // Scale / ScaleDepth
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// Number of samples
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uniform int uNumberOfSamples,
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uniform float uSamples)
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{
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// Clip space position
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oPosition = mul(uWorldViewProj, iPosition);
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float3 v3Pos = iNPosition;
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v3Pos.y += uInnerRadius;
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float3 v3Ray = v3Pos - uCameraPos;
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float fFar = length(v3Ray);
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v3Ray /= fFar;
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// Calculate the ray's starting position, then calculate its scattering offset
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float3 v3Start = uCameraPos;
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float fHeight = uCameraPos.y;
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float fStartAngle = dot(v3Ray, v3Start) / fHeight;
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// NOTE: fDepth is not pased as parameter(like a constant) to avoid the little precission issue (Apreciable)
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float fDepth = exp(uScaleOverScaleDepth * (uInnerRadius - uCameraPos.y));
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float fStartOffset = fDepth * scale(fStartAngle, uScaleDepth);
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// Init loop variables
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float fSampleLength = fFar / uSamples;
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float fScaledLength = fSampleLength * uScale;
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float3 v3SampleRay = v3Ray * fSampleLength;
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float3 v3SamplePoint = v3Start + v3SampleRay * 0.5f;
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// Loop the ray
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float3 color = float3(0,0,0);
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for (int i = 0; i < uNumberOfSamples; i++)
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{
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float fHeight = length(v3SamplePoint);
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float fDepth = exp(uScaleOverScaleDepth * (uInnerRadius-fHeight));
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float fLightAngle = dot(uLightDir, v3SamplePoint) / fHeight;
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float fCameraAngle = dot(v3Ray, v3SamplePoint) / fHeight;
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float fScatter = (fStartOffset + fDepth*(scale(fLightAngle, uScaleDepth) - scale(fCameraAngle, uScaleDepth)));
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float3 v3Attenuate = exp(-fScatter * (uInvWaveLength * uKr4PI + uKm4PI)); // <<< TODO
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// Accumulate color
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v3Attenuate *= (fDepth * fScaledLength);
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color += v3Attenuate;
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// Next sample point
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v3SamplePoint += v3SampleRay;
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}
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// Outputs
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oRayleighColor = color * (uInvWaveLength * uKrESun); // TODO <--- parameter
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oMieColor = color * uKmESun; // TODO <--- *uInvMieWaveLength
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oDirection = uCameraPos - v3Pos;
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oUV = iUV;
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oOpacity = iOpacity;
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oHeight = 1-iNPosition.y;
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}
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void main_fp(
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// IN
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float2 iUV : TEXCOORD0,
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float3 iRayleighColor : TEXCOORD1,
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float3 iMieColor : TEXCOORD2,
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float3 iDirection : TEXCOORD3,
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float iOpacity : TEXCOORD4,
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float iHeight : TEXCOORD5,
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// OUT
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out float4 oColor : COLOR,
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// UNIFORM
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#ifdef STARFIELD
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uniform float uTime,
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#endif // STARFIELD
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uniform float3 uLightDir,
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// Phase function
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uniform float uG,
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uniform float uG2,
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uniform float uExposure
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#ifdef STARFIELD
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,
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uniform sampler2D uStarfield : register(s0)
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#endif // STARFIELD
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)
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{
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float cos = dot(uLightDir, iDirection) / length(iDirection);
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float cos2 = cos*cos;
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float rayleighPhase = 0.75 * (1.0 + 0.5*cos2);
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float miePhase = 1.5f * ((1.0f - uG2) / (2.0f + uG2)) * // <<< TODO
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(1.0f + cos2) / pow(1.0f + uG2 - 2.0f * uG * cos, 1.5f);
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#ifdef LDR
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oColor = float4((1 - exp(-uExposure * (rayleighPhase * iRayleighColor + miePhase * iMieColor))), iOpacity);
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#else // HDR
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oColor = float4(uExposure * (rayleighPhase * iRayleighColor + miePhase * iMieColor), iOpacity);
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#endif // LDR
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// For night rendering
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float nightmult = saturate(1 - max(oColor.x, max(oColor.y, oColor.z))*10);
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#ifdef STARFIELD
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#ifdef LDR
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oColor.xyz += nightmult *(float3(0.05, 0.05, 0.1)*(2-0.75*saturate(-uLightDir.y))*pow(iHeight,3) + tex2D(uStarfield, iUV+uTime)*(0.35f + saturate(-uLightDir.y*0.45f)));
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#else // HDR (Linear pipeline -> Gamma correction)
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oColor.xyz += nightmult *(pow(float3(0.05, 0.05, 0.1)*(2-0.75*saturate(-uLightDir.y))*pow(iHeight,3),2.2) + tex2D(uStarfield, iUV+uTime)*(0.35f + saturate(-uLightDir.y*0.45f)));
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#endif // LDR
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#else // NO STARFIELD
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#ifdef LDR
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oColor.xyz += nightmult *(float3(0.05, 0.05, 0.1)*(2-0.75*saturate(-uLightDir.y))*pow(iHeight,3));
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#else // HDR (Linear pipeline -> Gamma correction)
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oColor.xyz += nightmult * pow(float3(0.05, 0.05, 0.1)*(2-0.75*saturate(-uLightDir.y))*pow(iHeight,3), 2.2);
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#endif // LDR
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#endif // STARFIELD
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}
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