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406 行
17 KiB
406 行
17 KiB
// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
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Shader "BoatAttack/Procedural Sky" {
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Properties {
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[KeywordEnum(None, Simple, High Quality)] _SunDisk ("Sun", Int) = 2
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_SunSize ("Sun Size", Range(0,1)) = 0.04
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_SunSizeConvergence("Sun Size Convergence", Range(1,10)) = 5
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_AtmosphereThickness ("Atmosphere Thickness", Range(0,5)) = 1.0
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_SkyTint ("Sky Tint", Color) = (.5, .5, .5, 1)
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_GroundColor ("Ground", Color) = (.369, .349, .341, 1)
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_Exposure("Exposure", Range(0, 8)) = 1.3
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}
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SubShader {
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Tags { "Queue"="Background" "RenderType"="Background" "PreviewType"="Skybox" }
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Cull Off ZWrite Off
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Pass {
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HLSLPROGRAM
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#pragma vertex vert
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#pragma fragment frag
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
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#pragma multi_compile_local _SUNDISK_NONE _SUNDISK_SIMPLE _SUNDISK_HIGH_QUALITY
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uniform half _Exposure; // HDR exposure
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uniform half3 _GroundColor;
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uniform half _SunSize;
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uniform half _SunSizeConvergence;
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uniform half3 _SkyTint;
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uniform half _AtmosphereThickness;
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#if defined(UNITY_COLORSPACE_GAMMA)
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#define GAMMA 2
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#define COLOR_2_GAMMA(color) color
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#define COLOR_2_LINEAR(color) color*color
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#define LINEAR_2_OUTPUT(color) sqrt(color)
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#else
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#define GAMMA 2.2
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// HACK: to get gfx-tests in Gamma mode to agree until UNITY_ACTIVE_COLORSPACE_IS_GAMMA is working properly
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#define COLOR_2_GAMMA(color) pow(color,1.0/GAMMA)
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#define COLOR_2_LINEAR(color) color
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#define LINEAR_2_LINEAR(color) color
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#endif
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// RGB wavelengths
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// .35 (.62=158), .43 (.68=174), .525 (.75=190)
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static const float3 kDefaultScatteringWavelength = float3(.65, .57, .475);
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static const float3 kVariableRangeForScatteringWavelength = float3(.15, .15, .15);
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#define OUTER_RADIUS 1.025
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static const float kOuterRadius = OUTER_RADIUS;
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static const float kOuterRadius2 = OUTER_RADIUS*OUTER_RADIUS;
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static const float kInnerRadius = 1.0;
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static const float kInnerRadius2 = 1.0;
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static const float kCameraHeight = 0.0001;
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#define kRAYLEIGH (lerp(0.0, 0.0025, pow(abs(_AtmosphereThickness),2.5))) // Rayleigh constant
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#define kMIE 0.0010 // Mie constant
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#define kSUN_BRIGHTNESS 20.0 // Sun brightness
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#define kMAX_SCATTER 50.0 // Maximum scattering value, to prevent math overflows on Adrenos
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static const half kHDSundiskIntensityFactor = 15.0;
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static const half kSimpleSundiskIntensityFactor = 27.0;
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static const half kSunScale = 400.0 * kSUN_BRIGHTNESS;
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static const float kKmESun = kMIE * kSUN_BRIGHTNESS;
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static const float kKm4PI = kMIE * 4.0 * 3.14159265;
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static const float kScale = 1.0 / (OUTER_RADIUS - 1.0);
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static const float kScaleDepth = 0.25;
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static const float kScaleOverScaleDepth = (1.0 / (OUTER_RADIUS - 1.0)) / 0.25;
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static const float kSamples = 2.0; // THIS IS UNROLLED MANUALLY, DON'T TOUCH
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#define MIE_G (-0.990)
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#define MIE_G2 0.9801
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#define SKY_GROUND_THRESHOLD 0.02
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// fine tuning of performance. You can override defines here if you want some specific setup
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// or keep as is and allow later code to set it according to target api
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// if set vprog will output color in final color space (instead of linear always)
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// in case of rendering in gamma mode that means that we will do lerps in gamma mode too, so there will be tiny difference around horizon
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// #define SKYBOX_COLOR_IN_TARGET_COLOR_SPACE 0
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// sun disk rendering:
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// no sun disk - the fastest option
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#define SKYBOX_SUNDISK_NONE 0
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// simplistic sun disk - without mie phase function
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#define SKYBOX_SUNDISK_SIMPLE 1
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// full calculation - uses mie phase function
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#define SKYBOX_SUNDISK_HQ 2
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// uncomment this line and change SKYBOX_SUNDISK_SIMPLE to override material settings
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// #define SKYBOX_SUNDISK SKYBOX_SUNDISK_SIMPLE
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#ifndef SKYBOX_SUNDISK
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#if defined(_SUNDISK_NONE)
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#define SKYBOX_SUNDISK SKYBOX_SUNDISK_NONE
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#elif defined(_SUNDISK_SIMPLE)
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#define SKYBOX_SUNDISK SKYBOX_SUNDISK_SIMPLE
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#else
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#define SKYBOX_SUNDISK SKYBOX_SUNDISK_HQ
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#endif
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#endif
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#ifndef SKYBOX_COLOR_IN_TARGET_COLOR_SPACE
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#if defined(SHADER_API_MOBILE)
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#define SKYBOX_COLOR_IN_TARGET_COLOR_SPACE 1
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#else
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#define SKYBOX_COLOR_IN_TARGET_COLOR_SPACE 0
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#endif
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#endif
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// Calculates the Rayleigh phase function
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half getRayleighPhase(half eyeCos2)
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{
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return 0.75 + 0.75*eyeCos2;
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}
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half getRayleighPhase(half3 light, half3 ray)
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{
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half eyeCos = dot(light, ray);
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return getRayleighPhase(eyeCos * eyeCos);
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}
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struct appdata_t
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{
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float4 vertex : POSITION;
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UNITY_VERTEX_INPUT_INSTANCE_ID
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};
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struct v2f
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{
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float4 pos : SV_POSITION;
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#if SKYBOX_SUNDISK == SKYBOX_SUNDISK_HQ
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// for HQ sun disk, we need vertex itself to calculate ray-dir per-pixel
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float3 vertex : TEXCOORD0;
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#elif SKYBOX_SUNDISK == SKYBOX_SUNDISK_SIMPLE
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half3 rayDir : TEXCOORD0;
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#else
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// as we dont need sun disk we need just rayDir.y (sky/ground threshold)
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half skyGroundFactor : TEXCOORD0;
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#endif
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// calculate sky colors in vprog
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half3 groundColor : TEXCOORD1;
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half3 skyColor : TEXCOORD2;
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#if SKYBOX_SUNDISK != SKYBOX_SUNDISK_NONE
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half3 sunColor : TEXCOORD3;
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#endif
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UNITY_VERTEX_OUTPUT_STEREO
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};
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float scale(float inCos)
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{
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float x = 1.0 - inCos;
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return 0.25 * exp(-0.00287 + x*(0.459 + x*(3.83 + x*(-6.80 + x*5.25))));
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}
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v2f vert (appdata_t v)
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{
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v2f OUT;
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UNITY_SETUP_INSTANCE_ID(v);
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UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
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VertexPositionInputs vertexPositions = GetVertexPositionInputs(v.vertex.xyz);
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OUT.pos = vertexPositions.positionCS;
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float3 kSkyTintInGammaSpace = COLOR_2_GAMMA(abs(_SkyTint)); // convert tint from Linear back to Gamma
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float3 kScatteringWavelength = lerp (
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kDefaultScatteringWavelength-kVariableRangeForScatteringWavelength,
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kDefaultScatteringWavelength+kVariableRangeForScatteringWavelength,
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half3(1,1,1) - kSkyTintInGammaSpace); // using Tint in sRGB gamma allows for more visually linear interpolation and to keep (.5) at (128, gray in sRGB) point
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float3 kInvWavelength = 1.0 / pow(kScatteringWavelength, 4);
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float kKrESun = kRAYLEIGH * kSUN_BRIGHTNESS;
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float kKr4PI = kRAYLEIGH * 4.0 * 3.14159265;
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float3 cameraPos = float3(0,kInnerRadius + kCameraHeight,0); // The camera's current position
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// Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere)
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float3 eyeRay = normalize(mul((float3x3)unity_ObjectToWorld, v.vertex.xyz));
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float far = 0.0;
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half3 cIn, cOut;
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Light mainLight = GetMainLight();
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if(eyeRay.y >= 0.0)
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{
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// Sky
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// Calculate the length of the "atmosphere"
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far = sqrt(kOuterRadius2 + kInnerRadius2 * eyeRay.y * eyeRay.y - kInnerRadius2) - kInnerRadius * eyeRay.y;
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float3 pos = cameraPos + far * eyeRay;
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// Calculate the ray's starting position, then calculate its scattering offset
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float height = kInnerRadius + kCameraHeight;
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float depth = exp(kScaleOverScaleDepth * (-kCameraHeight));
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float startAngle = dot(eyeRay, cameraPos) / height;
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float startOffset = depth*scale(startAngle);
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// Initialize the scattering loop variables
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float sampleLength = far / kSamples;
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float scaledLength = sampleLength * kScale;
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float3 sampleRay = eyeRay * sampleLength;
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float3 samplePoint = cameraPos + sampleRay * 0.5;
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// Now loop through the sample rays
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float3 frontColor = float3(0.0, 0.0, 0.0);
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// Weird workaround: WP8 and desktop FL_9_3 do not like the for loop here
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// (but an almost identical loop is perfectly fine in the ground calculations below)
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// Just unrolling this manually seems to make everything fine again.
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// for(int i=0; i<int(kSamples); i++)
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{
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float height = length(samplePoint);
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float depth = exp(kScaleOverScaleDepth * (kInnerRadius - height));
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float lightAngle = dot(mainLight.direction, samplePoint) / height;
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float cameraAngle = dot(eyeRay, samplePoint) / height;
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float scatter = (startOffset + depth*(scale(lightAngle) - scale(cameraAngle)));
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float3 attenuate = exp(-clamp(scatter, 0.0, kMAX_SCATTER) * (kInvWavelength * kKr4PI + kKm4PI));
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frontColor += attenuate * (depth * scaledLength);
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samplePoint += sampleRay;
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}
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{
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float height = length(samplePoint);
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float depth = exp(kScaleOverScaleDepth * (kInnerRadius - height));
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float lightAngle = dot(mainLight.direction, samplePoint) / height;
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float cameraAngle = dot(eyeRay, samplePoint) / height;
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float scatter = (startOffset + depth*(scale(lightAngle) - scale(cameraAngle)));
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float3 attenuate = exp(-clamp(scatter, 0.0, kMAX_SCATTER) * (kInvWavelength * kKr4PI + kKm4PI));
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frontColor += attenuate * (depth * scaledLength);
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samplePoint += sampleRay;
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}
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// Finally, scale the Mie and Rayleigh colors and set up the varying variables for the pixel shader
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cIn = frontColor * (kInvWavelength * kKrESun);
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cOut = frontColor * kKmESun;
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}
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else
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{
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// Ground
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far = (-kCameraHeight) / (min(-0.001, eyeRay.y));
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float3 pos = cameraPos + far * eyeRay;
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// Calculate the ray's starting position, then calculate its scattering offset
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float depth = exp((-kCameraHeight) * (1.0/kScaleDepth));
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float cameraAngle = dot(-eyeRay, pos);
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float lightAngle = dot(mainLight.direction, pos);
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float cameraScale = scale(cameraAngle);
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float lightScale = scale(lightAngle);
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float cameraOffset = depth*cameraScale;
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float temp = (lightScale + cameraScale);
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// Initialize the scattering loop variables
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float sampleLength = far / kSamples;
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float scaledLength = sampleLength * kScale;
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float3 sampleRay = eyeRay * sampleLength;
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float3 samplePoint = cameraPos + sampleRay * 0.5;
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// Now loop through the sample rays
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float3 frontColor = float3(0.0, 0.0, 0.0);
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float3 attenuate;
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// for(int i=0; i<int(kSamples); i++) // Loop removed because we kept hitting SM2.0 temp variable limits. Doesn't affect the image too much.
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{
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float height = length(samplePoint);
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float depth = exp(kScaleOverScaleDepth * (kInnerRadius - height));
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float scatter = depth*temp - cameraOffset;
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attenuate = exp(-clamp(scatter, 0.0, kMAX_SCATTER) * (kInvWavelength * kKr4PI + kKm4PI));
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frontColor += attenuate * (depth * scaledLength);
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samplePoint += sampleRay;
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}
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cIn = frontColor * (kInvWavelength * kKrESun + kKmESun);
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cOut = clamp(attenuate, 0.0, 1.0);
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}
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#if SKYBOX_SUNDISK == SKYBOX_SUNDISK_HQ
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OUT.vertex = -v.vertex;
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#elif SKYBOX_SUNDISK == SKYBOX_SUNDISK_SIMPLE
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OUT.rayDir = half3(-eyeRay);
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#else
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OUT.skyGroundFactor = -eyeRay.y / SKY_GROUND_THRESHOLD;
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#endif
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// if we want to calculate color in vprog:
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// 1. in case of linear: multiply by _Exposure in here (even in case of lerp it will be common multiplier, so we can skip mul in fshader)
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// 2. in case of gamma and SKYBOX_COLOR_IN_TARGET_COLOR_SPACE: do sqrt right away instead of doing that in fshader
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OUT.groundColor = _Exposure * (cIn + COLOR_2_LINEAR(_GroundColor) * cOut);
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OUT.skyColor = _Exposure * (cIn * getRayleighPhase(mainLight.direction, -eyeRay));
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#if SKYBOX_SUNDISK != SKYBOX_SUNDISK_NONE
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// The sun should have a stable intensity in its course in the sky. Moreover it should match the highlight of a purely specular material.
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// This matching was done using the standard shader BRDF1 on the 5/31/2017
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// Finally we want the sun to be always bright even in LDR thus the normalization of the lightColor for low intensity.
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half lightColorIntensity = clamp(length(mainLight.color), 0.25, 1);
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#if SKYBOX_SUNDISK == SKYBOX_SUNDISK_SIMPLE
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OUT.sunColor = kSimpleSundiskIntensityFactor * saturate(cOut * kSunScale) * mainLight.color / lightColorIntensity;
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#else // SKYBOX_SUNDISK_HQ
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OUT.sunColor = kHDSundiskIntensityFactor * saturate(cOut) * mainLight.color / lightColorIntensity;
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#endif
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#endif
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#if defined(UNITY_COLORSPACE_GAMMA) && SKYBOX_COLOR_IN_TARGET_COLOR_SPACE
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OUT.groundColor = sqrt(OUT.groundColor);
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OUT.skyColor = sqrt(OUT.skyColor);
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#if SKYBOX_SUNDISK != SKYBOX_SUNDISK_NONE
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OUT.sunColor= sqrt(OUT.sunColor);
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#endif
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#endif
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return OUT;
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}
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// Calculates the Mie phase function
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half getMiePhase(half eyeCos, half eyeCos2)
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{
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half temp = 1.0 + MIE_G2 - 2.0 * MIE_G * eyeCos;
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temp = pow(temp, pow(_SunSize,0.65) * 10);
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temp = max(temp,1.0e-4); // prevent division by zero, esp. in half precision
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temp = 1.5 * ((1.0 - MIE_G2) / (2.0 + MIE_G2)) * (1.0 + eyeCos2) / temp;
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#if defined(UNITY_COLORSPACE_GAMMA) && SKYBOX_COLOR_IN_TARGET_COLOR_SPACE
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temp = pow(temp, .454545);
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#endif
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return temp;
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}
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// Calculates the sun shape
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half calcSunAttenuation(half3 lightPos, half3 ray)
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{
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#if SKYBOX_SUNDISK == SKYBOX_SUNDISK_SIMPLE
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half3 delta = lightPos - ray;
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half dist = length(delta);
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half spot = 1.0 - smoothstep(0.0, _SunSize, dist);
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return spot * spot;
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#else // SKYBOX_SUNDISK_HQ
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half focusedEyeCos = pow(saturate(dot(lightPos, ray)), _SunSizeConvergence);
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return getMiePhase(-focusedEyeCos, focusedEyeCos * focusedEyeCos);
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#endif
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}
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half4 frag (v2f IN) : SV_Target
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{
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half3 col = half3(0.0, 0.0, 0.0);
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Light mainLight = GetMainLight();
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// if y > 1 [eyeRay.y < -SKY_GROUND_THRESHOLD] - ground
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// if y >= 0 and < 1 [eyeRay.y <= 0 and > -SKY_GROUND_THRESHOLD] - horizon
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// if y < 0 [eyeRay.y > 0] - sky
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#if SKYBOX_SUNDISK == SKYBOX_SUNDISK_HQ
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half3 ray = normalize(mul((float3x3)unity_ObjectToWorld, IN.vertex));
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half y = ray.y / SKY_GROUND_THRESHOLD;
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#elif SKYBOX_SUNDISK == SKYBOX_SUNDISK_SIMPLE
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half3 ray = IN.rayDir.xyz;
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half y = ray.y / SKY_GROUND_THRESHOLD;
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#else
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half y = IN.skyGroundFactor;
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#endif
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// if we did precalculate color in vprog: just do lerp between them
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col = lerp(IN.skyColor, IN.groundColor, saturate(y));
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#if SKYBOX_SUNDISK != SKYBOX_SUNDISK_NONE
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if(y < 0.0)
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{
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col += IN.sunColor * calcSunAttenuation(mainLight.direction, -ray);
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}
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#endif
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#if defined(UNITY_COLORSPACE_GAMMA) && !SKYBOX_COLOR_IN_TARGET_COLOR_SPACE
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col = LINEAR_2_OUTPUT(col);
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#endif
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return half4(clamp(col, 0, 25),1.0);
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}
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ENDHLSL
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}
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}
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Fallback Off
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CustomEditor "SkyboxProceduralShaderGUI"
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}
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