70 lines
2.1 KiB
HLSL
70 lines
2.1 KiB
HLSL
//UNITY_SHADER_NO_UPGRADE
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#ifndef WIND_ANIM
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#define WIND_ANIM
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// SmoothTriangleWave function
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inline float SmoothTriangleWave(float x)
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{
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// 将输入值限制在 [0, 1] 范围内，使用 frac 函数保证值是周期性的
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x = frac(x);
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// 使用三角函数生成平滑的波形，注意：frac(x) 生成的是 [0, 1] 之间的值
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return 1.0 - abs(2.0 * x - 1.0); // 生成平滑的三角波
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}
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// SmoothTriangleWave function for a 4-component vector
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inline float4 SmoothTriangleWave(float4 x)
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{
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return float4(SmoothTriangleWave(x.x), SmoothTriangleWave(x.y), SmoothTriangleWave(x.z), SmoothTriangleWave(x.w));
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}
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inline void WindVert_float(float4 pos, float3 normal, float3 vertColor, float4 wind, float speed, float amplitude, out float4 aniPos)
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{
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// animParams.x = branch phase
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// animParams.y = edge flutter factor
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// animParams.z = primary factor
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// animParams.w = secondary factor
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float bendingFact = 1 - vertColor.b;
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//wind.xyz = TransformWorldToObject(wind.xyz);
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//wind.z = wind.z * bendingFact;
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float4 animParams = float4(0, amplitude, bendingFact.xx);
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float time = _Time.y * float2(speed, 1);
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float fDetailAmp = 0.1f;
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float fBranchAmp = 0.3f;
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// Phases (object, vertex, branch)
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float fObjPhase = dot(unity_ObjectToWorld[3].xyz, 1);
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float fBranchPhase = fObjPhase + animParams.x;
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float fVtxPhase = dot(pos.xyz, animParams.y + fBranchPhase);
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// x is used for edges; y is used for branches
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float2 vWavesIn = time + float2(fVtxPhase, fBranchPhase );
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// 1.975, 0.793, 0.375, 0.193 are good frequencies
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float4 vWaves = (frac( vWavesIn.xxyy * float4(1.975, 0.793, 0.375, 0.193) ) * 2.0 - 1.0);
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vWaves = SmoothTriangleWave( vWaves );
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float2 vWavesSum = vWaves.xz + vWaves.yw;
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// Edge (xz) and branch bending (y)
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float3 bend = animParams.y * fDetailAmp * normal.xyz;
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bend.y = animParams.w * fBranchAmp;
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pos.xyz += ((vWavesSum.xyx * bend)*wind.w + (wind.xyz * vWavesSum.y * animParams.w)) * wind.w;
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// Primary bending
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// Displace position
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pos.xyz += animParams.z * wind.xyz;
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aniPos = pos;
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}
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#endif
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