117 lines
3.7 KiB
HLSL
117 lines
3.7 KiB
HLSL
#ifndef UNIVERSAL_WAVING_GRASS_INPUT_INCLUDED
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#define UNIVERSAL_WAVING_GRASS_INPUT_INCLUDED
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/SurfaceInput.hlsl"
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/DebugMipmapStreamingMacros.hlsl"
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CBUFFER_START(UnityPerMaterial)
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float4 _MainTex_ST;
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half4 _BaseColor;
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half4 _SpecColor;
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half4 _EmissionColor;
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half _Cutoff;
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half _Shininess;
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CBUFFER_END
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#define _Surface 0.0 // Grass is always opaque
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// Terrain engine shader helpers
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CBUFFER_START(TerrainGrass)
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half4 _WavingTint;
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float4 _WaveAndDistance; // wind speed, wave size, wind amount, max sqr distance
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float4 _CameraPosition; // .xyz = camera position, .w = 1 / (max sqr distance)
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float3 _CameraRight, _CameraUp;
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CBUFFER_END
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TEXTURE2D(_MainTex);
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SAMPLER(sampler_MainTex);
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float4 _MainTex_TexelSize;
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UNITY_TEXTURE_STREAMING_DEBUG_VARS_FOR_TEX(_MainTex);
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// ---- Grass helpers
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// Calculate a 4 fast sine-cosine pairs
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// val: the 4 input values - each must be in the range (0 to 1)
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// s: The sine of each of the 4 values
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// c: The cosine of each of the 4 values
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void FastSinCos (float4 val, out float4 s, out float4 c) {
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val = val * 6.408849 - 3.1415927;
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// powers for taylor series
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float4 r5 = val * val; // wavevec ^ 2
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float4 r6 = r5 * r5; // wavevec ^ 4;
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float4 r7 = r6 * r5; // wavevec ^ 6;
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float4 r8 = r6 * r5; // wavevec ^ 8;
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float4 r1 = r5 * val; // wavevec ^ 3
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float4 r2 = r1 * r5; // wavevec ^ 5;
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float4 r3 = r2 * r5; // wavevec ^ 7;
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//Vectors for taylor's series expansion of sin and cos
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float4 sin7 = {1, -0.16161616, 0.0083333, -0.00019841};
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float4 cos8 = {-0.5, 0.041666666, -0.0013888889, 0.000024801587};
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// sin
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s = val + r1 * sin7.y + r2 * sin7.z + r3 * sin7.w;
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// cos
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c = 1 + r5 * cos8.x + r6 * cos8.y + r7 * cos8.z + r8 * cos8.w;
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}
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half4 TerrainWaveGrass (inout float4 vertex, float waveAmount, half4 color)
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{
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half4 _waveXSize = half4(0.012, 0.02, 0.06, 0.024) * _WaveAndDistance.y;
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half4 _waveZSize = half4 (0.006, .02, 0.02, 0.05) * _WaveAndDistance.y;
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half4 waveSpeed = half4 (1.2, 2, 1.6, 4.8);
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half4 _waveXmove = half4(0.024, 0.04, -0.12, 0.096);
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half4 _waveZmove = half4 (0.006, .02, -0.02, 0.1);
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float4 waves;
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waves = vertex.x * _waveXSize;
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waves += vertex.z * _waveZSize;
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// Add in time to model them over time
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waves += _WaveAndDistance.x * waveSpeed;
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float4 s, c;
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waves = frac (waves);
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FastSinCos (waves, s,c);
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s = s * s;
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s = s * s;
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half lighting = dot (s, normalize (half4 (1,1,.4,.2))) * 0.7;
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s = s * waveAmount;
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half3 waveMove = 0;
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waveMove.x = dot (s, _waveXmove);
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waveMove.z = dot (s, _waveZmove);
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vertex.xz -= waveMove.xz * _WaveAndDistance.z;
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// apply color animation
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half3 waveColor = lerp (real3(0.5, 0.5, 0.5), _WavingTint.rgb, lighting);
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// Fade the grass out before detail distance.
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// Saturate because Radeon HD drivers on OS X 10.4.10 don't saturate vertex colors properly.
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half3 offset = vertex.xyz - _CameraPosition.xyz;
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color.a = saturate (2 * (_WaveAndDistance.w - dot (offset, offset)) * _CameraPosition.w);
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return half4(2 * waveColor * color.rgb, color.a);
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}
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void TerrainBillboardGrass( inout float4 pos, float2 offset )
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{
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float3 grasspos = pos.xyz - _CameraPosition.xyz;
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if (dot(grasspos, grasspos) > _WaveAndDistance.w)
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offset = 0.0;
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pos.xyz += offset.x * _CameraRight.xyz;
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pos.y += offset.y;
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}
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#endif
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