77 lines
2.6 KiB
Markdown
77 lines
2.6 KiB
Markdown
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# Simple Noise node
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The Simple Noise node generates a pseudo-random value, also known as value noise, for each UV coordinate in the input **UV**.
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## Ports
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| **Name** | **Direction** | **Type** | **Binding** | **Description** |
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|:------------ |:-------------|:-----|:---|:---|
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| **UV** | Input | Vector 2 | UV | The UV coordinates to input. For example UV coordinates, refer to [UV Nodes](UV-Nodes.md). |
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| **Scale** | Input | Float | None | How much to scale the size of the output. A higher value zooms out so there are more noise values in the same space. The default is 500. |
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| **Out** | Output | Float | None | The simple noise. The range of each value is between 0 and 1. |
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## Hash Type
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The **Hash Type** dropdown determines the hash function Unity uses to generate random numbers for the noise generation.
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| **Option** | **Description** |
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| **Deterministic** | Uses a hash function that generates the same noise across different platforms. This is the default option. |
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| **Legacy Sine** | Uses a sine-based hash function. For most uses, **Deterministic** replaces **Legacy Sine**. |
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## Generated code example
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The following example code represents one possible outcome of this node.
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```
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inline float unity_noise_randomValue (float2 uv)
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{
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return frac(sin(dot(uv, float2(12.9898, 78.233)))*43758.5453);
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}
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inline float unity_noise_interpolate (float a, float b, float t)
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{
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return (1.0-t)*a + (t*b);
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}
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inline float unity_valueNoise (float2 uv)
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{
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float2 i = floor(uv);
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float2 f = frac(uv);
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f = f * f * (3.0 - 2.0 * f);
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uv = abs(frac(uv) - 0.5);
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float2 c0 = i + float2(0.0, 0.0);
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float2 c1 = i + float2(1.0, 0.0);
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float2 c2 = i + float2(0.0, 1.0);
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float2 c3 = i + float2(1.0, 1.0);
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float r0 = unity_noise_randomValue(c0);
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float r1 = unity_noise_randomValue(c1);
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float r2 = unity_noise_randomValue(c2);
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float r3 = unity_noise_randomValue(c3);
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float bottomOfGrid = unity_noise_interpolate(r0, r1, f.x);
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float topOfGrid = unity_noise_interpolate(r2, r3, f.x);
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float t = unity_noise_interpolate(bottomOfGrid, topOfGrid, f.y);
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return t;
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}
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void Unity_SimpleNoise_float(float2 UV, float Scale, out float Out)
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{
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float t = 0.0;
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float freq = pow(2.0, float(0));
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float amp = pow(0.5, float(3-0));
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t += unity_valueNoise(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;
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freq = pow(2.0, float(1));
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amp = pow(0.5, float(3-1));
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t += unity_valueNoise(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;
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freq = pow(2.0, float(2));
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amp = pow(0.5, float(3-2));
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t += unity_valueNoise(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;
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Out = t;
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}
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```
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