111 lines
4.2 KiB
C#
111 lines
4.2 KiB
C#
using UnityEngine;
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namespace AwesomeTechnologies.Utility
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{
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public class ShadowUtility
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{
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/// <summary>
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/// Check for shadow visibility, send minimum terrain height in worldspace as planeOrigin
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/// </summary>
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/// <param name="objectBounds"></param>
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/// <param name="lightDirection"></param>
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/// <param name="planeOrigin"></param>
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/// <param name="frustumPlanes"></param>
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/// <returns></returns>
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public static bool IsShadowVisible(Bounds objectBounds, Vector3 lightDirection, Vector3 planeOrigin, Plane[] frustumPlanes)
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{
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bool hitPlane;
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Bounds shadowBounds = GetShadowBounds(objectBounds, lightDirection, planeOrigin, out hitPlane);
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//return hitPlane && GeometryUtility.TestPlanesAABB(frustumPlanes, shadowBounds);
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return hitPlane && BoundsIntersectsFrustum(frustumPlanes, shadowBounds);
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}
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/// <summary>
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/// Test for bounds visible in frustum
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/// </summary>
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/// <param name="planes"></param>
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/// <param name="bounds"></param>
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/// <returns></returns>
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public static bool BoundsIntersectsFrustum(Plane[] planes, Bounds bounds)
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{
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var center = bounds.center;
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var extents = bounds.extents;
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for (int i = 0; i <= planes.Length -1; i++)
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{
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Vector3 planeNormal = planes[i].normal;
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float planeDistance = planes[i].distance;
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Vector3 abs = new Vector3(Mathf.Abs(planeNormal.x), Mathf.Abs(planeNormal.y), Mathf.Abs(planeNormal.z));
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float r = extents.x * abs.x + extents.y * abs.y + extents.z * abs.z;
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float s = planeNormal.x * center.x + planeNormal.y * center.y + planeNormal.z * center.z;
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if (s + r < -planeDistance)
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{
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return false;
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}
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}
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return true;
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}
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/// <summary>
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/// Get the projected bounds of the shadow of an object
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/// </summary>
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/// <param name="objectBounds"></param>
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/// <param name="lightDirection"></param>
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/// <param name="planeOrigin"></param>
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/// <param name="hitPlane"></param>
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/// <returns></returns>
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public static Bounds GetShadowBounds(Bounds objectBounds, Vector3 lightDirection, Vector3 planeOrigin, out bool hitPlane)
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{
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Ray p0 = new Ray(new Vector3(objectBounds.min.x, objectBounds.max.y, objectBounds.min.z), lightDirection);
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Ray p1 = new Ray(new Vector3(objectBounds.min.x, objectBounds.max.y, objectBounds.max.z), lightDirection);
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Ray p2 = new Ray(new Vector3(objectBounds.max.x, objectBounds.max.y, objectBounds.min.z), lightDirection);
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Ray p3 = new Ray(objectBounds.max, lightDirection);
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Vector3 hitPoint;
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hitPlane = false;
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if (IntersectPlane(p0, planeOrigin, out hitPoint))
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{
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objectBounds.Encapsulate(hitPoint);
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hitPlane = true;
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}
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if (IntersectPlane(p1, planeOrigin, out hitPoint))
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{
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objectBounds.Encapsulate(hitPoint);
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hitPlane = true;
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}
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if (IntersectPlane(p2, planeOrigin, out hitPoint))
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{
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objectBounds.Encapsulate(hitPoint);
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hitPlane = true;
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}
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if (IntersectPlane(p3, planeOrigin, out hitPoint))
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{
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objectBounds.Encapsulate(hitPoint);
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hitPlane = true;
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}
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return objectBounds;
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}
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public static bool IntersectPlane(Ray ray, Vector3 planeOrigin, out Vector3 hitPoint)
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{
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Vector3 planeNormal = -Vector3.up;
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float denominator = Vector3.Dot(ray.direction, planeNormal);
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if (denominator > 0.00001f)
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{
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float t = Vector3.Dot(planeOrigin - ray.origin, planeNormal) / denominator;
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hitPoint = ray.origin + ray.direction * t;
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return true;
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}
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hitPoint = Vector3.zero;
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return false;
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}
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}
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}
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