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using System.IO; |
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using UnityEngine; |
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using UnityEditor; |
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public class GenerateTextures : MonoBehaviour |
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{ |
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private static readonly int kTextureSize = 1024; |
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private static readonly float kQuadraticFac = 25.0f; |
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private static readonly float kToZeroFadeStart = 0.8f * 0.8f; |
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private static readonly string kSavePath = "Assets/ScriptableRenderPipeline/LightweightPipeline/Textures/LightweightLightAttenuation.png"; |
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[MenuItem("RenderPipeline/LightweightPipeline/GenerateLightFalloffTexture")] |
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public static void GenerateLightFalloffTexture() |
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{ |
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Texture2D tex = new Texture2D(kTextureSize, 4, TextureFormat.Alpha8, false, true); |
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tex.wrapMode = TextureWrapMode.Clamp; |
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byte[] bytes = new byte[kTextureSize * 4]; |
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for (int x = 0; x < kTextureSize; ++x) |
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{ |
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float sqrRange = (float) x/(float) kTextureSize; |
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byte atten = LightAttenuationNormalized(sqrRange); |
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bytes[x] = atten; |
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bytes[x + kTextureSize] = atten; |
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bytes[x + kTextureSize * 2] = atten; |
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bytes[x + kTextureSize * 3] = atten; |
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} |
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tex.LoadRawTextureData(bytes); |
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tex.Apply(false); |
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SaveTexture(tex); |
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} |
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public static void SaveTexture(Texture2D tex) |
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{ |
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byte[] bytes = tex.EncodeToPNG(); |
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File.WriteAllBytes(kSavePath, bytes); |
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} |
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public static byte LightAttenuationNormalized(float distSqr) |
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{ |
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// 1 / 1.0 + quadAtten * distSqr attenuation function
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float atten = 1.0f / (1.0f + CalculateLightQuadFac(1.0f) * distSqr); |
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// however the above does not falloff to zero at light range.
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// Start fading from ktoZeroFadeStart to light range
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float fadeMultiplier = Mathf.Clamp01((distSqr - 1.0f) / (kToZeroFadeStart - 1.0f)); |
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atten *= fadeMultiplier; |
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//return atten;
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return (byte)Mathf.RoundToInt(atten * (float)byte.MaxValue); |
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} |
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public static float CalculateLightQuadFac(float range) |
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{ |
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return kQuadraticFac / (range * range); |
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} |
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} |
Felipe Lira