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using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[ExecuteInEditMode]
public class ReflectionCamera : MonoBehaviour {
public GameObject Mirror;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
}
static Matrix4x4 PerspectiveOffCenter(float left, float right, float bottom, float top, float near, float far)
{
float x = 2.0F * near / (right - left);
float y = 2.0F * near / (top - bottom);
float a = (right + left) / (right - left);
float b = (top + bottom) / (top - bottom);
float c = -(far + near) / (far - near);
float d = -(2.0F * far * near) / (far - near);
float e = -1.0F;
Matrix4x4 m = new Matrix4x4();
m[0, 0] = x;
m[0, 1] = 0;
m[0, 2] = a;
m[0, 3] = 0;
m[1, 0] = 0;
m[1, 1] = y;
m[1, 2] = b;
m[1, 3] = 0;
m[2, 0] = 0;
m[2, 1] = 0;
m[2, 2] = c;
m[2, 3] = d;
m[3, 0] = 0;
m[3, 1] = 0;
m[3, 2] = e;
m[3, 3] = 0;
return m;
}
void LateUpdate() {
Camera mainCamera = Camera.main;
Camera camera = GetComponent<Camera>();
Transform mirrorTransform = Mirror.transform;
Vector3 reflectionPos = mirrorTransform.position;
Vector3 reflectionDir = mirrorTransform.forward;
Vector3 mainCameraPos = mainCamera.transform.position;
Vector3 reflectedCameraPos = mainCameraPos - 2 * Vector3.Dot(reflectionDir, mainCameraPos - reflectionPos) * reflectionDir;
transform.position = reflectedCameraPos;
// https://en.wikibooks.org/wiki/Cg_Programming/Unity/Projection_for_Virtual_Reality
// lower left corner in world coordinates
Vector3 pa = Mirror.transform.TransformPoint( new Vector3(-0.5f, -0.5f, 0.0f) );
// lower right corner
Vector3 pb = Mirror.transform.TransformPoint( new Vector3( 0.5f, -0.5f, 0.0f) );
// upper left corner
Vector3 pc = Mirror.transform.TransformPoint( new Vector3(-0.5f, 0.5f, 0.0f) );
// eye position
Vector3 pe = reflectedCameraPos;
// distance of near clipping plane
float n = camera.nearClipPlane;
// distance of far clipping plane
float f = camera.farClipPlane;
Vector3 va = pa - pe; // from pe to pa
Vector3 vb = pb - pe; // from pe to pb
Vector3 vc = pc - pe; // from pe to pc
Vector3 vr = pb - pa; // right axis of screen
Vector3 vu = pc - pa; // up axis of screen
Vector3 vn; // normal vector of screen
float l; // distance to left screen edge
float r; // distance to right screen edge
float b; // distance to bottom screen edge
float t; // distance to top screen edge
float d; // distance from eye to screen
// are we looking at the backface of the plane object?
if (Vector3.Dot(-Vector3.Cross(va, vc), vb) < 0.0)
{
// mirror points along the z axis (most users
// probably expect the x axis to stay fixed)
vu = -vu;
pa = pc;
pb = pa + vr;
pc = pa + vu;
va = pa - pe;
vb = pb - pe;
vc = pc - pe;
}
vr.Normalize();
vu.Normalize();
vn = -Vector3.Cross(vr, vu);
// we need the minus sign because Unity
// uses a left-handed coordinate system
vn.Normalize();
d = -Vector3.Dot(va, vn);
//if (setNearClipPlane)
//{
// n = d + nearClipDistanceOffset;
// cameraComponent.nearClipPlane = n;
//}
l = Vector3.Dot(vr, va) * n / d;
r = Vector3.Dot(vr, vb) * n / d;
b = Vector3.Dot(vu, va) * n / d;
t = Vector3.Dot(vu, vc) * n / d;
// Flip top and bottom
camera.projectionMatrix = PerspectiveOffCenter(l,r, b,t, n, f);
Matrix4x4 rm = new Matrix4x4(); // rotation matrix;
rm[0, 0] = vr.x;
rm[0, 1] = vr.y;
rm[0, 2] = vr.z;
rm[0, 3] = 0.0f;
rm[1, 0] = vu.x;
rm[1, 1] = vu.y;
rm[1, 2] = vu.z;
rm[1, 3] = 0.0f;
rm[2, 0] = vn.x;
rm[2, 1] = vn.y;
rm[2, 2] = vn.z;
rm[2, 3] = 0.0f;
rm[3, 0] = 0.0f;
rm[3, 1] = 0.0f;
rm[3, 2] = 0.0f;
rm[3, 3] = 1.0f;
Matrix4x4 tm = new Matrix4x4(); // translation matrix;
tm[0, 0] = 1.0f;
tm[0, 1] = 0.0f;
tm[0, 2] = 0.0f;
tm[0, 3] = -pe.x;
tm[1, 0] = 0.0f;
tm[1, 1] = 1.0f;
tm[1, 2] = 0.0f;
tm[1, 3] = -pe.y;
tm[2, 0] = 0.0f;
tm[2, 1] = 0.0f;
tm[2, 2] = 1.0f;
tm[2, 3] = -pe.z;
tm[3, 0] = 0.0f;
tm[3, 1] = 0.0f;
tm[3, 2] = 0.0f;
tm[3, 3] = 1.0f;
// set matrices
camera.worldToCameraMatrix = rm * tm;
// The original paper puts everything into the projection
// matrix (i.e. sets it to p * rm * tm and the other
// matrix to the identity), but this doesn't appear to
// work with Unity's shadow maps.
bool estimateViewFrustum = true;
if (estimateViewFrustum)
{
// rotate camera to screen for culling to work
Quaternion q = new Quaternion();
q.SetLookRotation((0.5f * (pb + pc) - pe), vu);
// look at center of screen
camera.transform.rotation = q;
// set fieldOfView to a conservative estimate
// to make frustum tall enough
if (camera.aspect >= 1.0)
{
camera.fieldOfView = Mathf.Rad2Deg * Mathf.Atan(((pb - pa).magnitude + (pc - pa).magnitude) / va.magnitude);
}
else
{
// take the camera aspect into account to
// make the frustum wide enough
camera.fieldOfView = Mathf.Rad2Deg / camera.aspect * Mathf.Atan(((pb - pa).magnitude + (pc - pa).magnitude) / va.magnitude);
}
}
}
}
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