Untitled

using System.Collections.Generic;
using UnityEngine;

namespace UnityStandardAssets.Water
{
    [ExecuteInEditMode]
    public class Water : MonoBehaviour
    {
        public enum WaterMode
        {
            Simple = 0,
            Reflective = 1,
            Refractive = 2,
        }

        public WaterMode waterMode = WaterMode.Refractive;
        public bool disablePixelLights = true;
        public int textureSize = 256;
        public float clipPlaneOffset = 0.07f;
        public LayerMask reflectLayers = -1;
        public LayerMask refractLayers = -1;

        private Dictionary<Camera, Camera> m_ReflectionCameras = new Dictionary<Camera, Camera>();
        private Dictionary<Camera, Camera> m_RefractionCameras = new Dictionary<Camera, Camera>();
        private RenderTexture m_ReflectionTexture;
        private RenderTexture m_RefractionTexture;
        private WaterMode m_HardwareWaterSupport = WaterMode.Refractive;
        private int m_OldReflectionTextureSize;
        private int m_OldRefractionTextureSize;
        private static bool s_InsideWater;

        public void OnWillRenderObject()
        {
            if (!enabled || !GetComponent<Renderer>() || !GetComponent<Renderer>().sharedMaterial || !GetComponent<Renderer>().enabled)
                return;

            Camera cam = Camera.current;
            if (!cam)
                return;

            if (s_InsideWater)
                return;

            // Frustum check
            Plane[] cameraFrustumPlanes = GeometryUtility.CalculateFrustumPlanes(cam);
            if (!GeometryUtility.TestPlanesAABB(cameraFrustumPlanes, GetComponent<Renderer>().bounds))
                return;

            // Check camera position distance from water
            float distanceToWater = Vector3.Distance(cam.transform.position, transform.position);
            if (distanceToWater > 500f) // Adjust this value based on your scene scale
                return;

            s_InsideWater = true;

            m_HardwareWaterSupport = FindHardwareWaterSupport();
            WaterMode mode = GetWaterMode();

            Camera reflectionCamera, refractionCamera;
            CreateWaterObjects(cam, out reflectionCamera, out refractionCamera);

            Vector3 pos = transform.position;
            Vector3 normal = transform.up;

            int oldPixelLightCount = QualitySettings.pixelLightCount;
            if (disablePixelLights)
            {
                QualitySettings.pixelLightCount = 0;
            }

            UpdateCameraModes(cam, reflectionCamera);
            UpdateCameraModes(cam, refractionCamera);

            // Render Reflection
            if (mode >= WaterMode.Reflective)
            {
                RenderReflection(cam, reflectionCamera, pos, normal);
            }

            // Render Refraction
            if (mode >= WaterMode.Refractive)
            {
                RenderRefraction(cam, refractionCamera, pos, normal);
            }

            if (disablePixelLights)
            {
                QualitySettings.pixelLightCount = oldPixelLightCount;
            }

            SetWaterModeKeywords(mode);

            s_InsideWater = false;
        }

        void RenderReflection(Camera cam, Camera reflectionCamera, Vector3 pos, Vector3 normal)
        {
            float d = -Vector3.Dot(normal, pos) - clipPlaneOffset;
            Vector4 reflectionPlane = new Vector4(normal.x, normal.y, normal.z, d);

            Matrix4x4 reflection = Matrix4x4.zero;
            CalculateReflectionMatrix(ref reflection, reflectionPlane);
            Vector3 oldpos = cam.transform.position;
            Vector3 newpos = reflection.MultiplyPoint(oldpos);
            reflectionCamera.worldToCameraMatrix = cam.worldToCameraMatrix * reflection;

            Vector4 clipPlane = CameraSpacePlane(reflectionCamera, pos, normal, 1.0f);
            reflectionCamera.projectionMatrix = cam.CalculateObliqueMatrix(clipPlane);

            reflectionCamera.cullingMask = ~(1 << 4) & reflectLayers.value;
            reflectionCamera.targetTexture = m_ReflectionTexture;

            GL.invertCulling = true;
            reflectionCamera.transform.position = newpos;
            Vector3 euler = cam.transform.eulerAngles;
            reflectionCamera.transform.eulerAngles = new Vector3(-euler.x, euler.y, euler.z);
            reflectionCamera.Render();
            reflectionCamera.transform.position = oldpos;
            GL.invertCulling = false;
            GetComponent<Renderer>().sharedMaterial.SetTexture("_ReflectionTex", m_ReflectionTexture);
        }

        void RenderRefraction(Camera cam, Camera refractionCamera, Vector3 pos, Vector3 normal)
        {
            refractionCamera.worldToCameraMatrix = cam.worldToCameraMatrix;

            Vector4 clipPlane = CameraSpacePlane(refractionCamera, pos, normal, -1.0f);
            refractionCamera.projectionMatrix = cam.CalculateObliqueMatrix(clipPlane);

            refractionCamera.cullingMask = ~(1 << 4) & refractLayers.value;
            refractionCamera.targetTexture = m_RefractionTexture;

            refractionCamera.transform.position = cam.transform.position;
            refractionCamera.transform.rotation = cam.transform.rotation;
            refractionCamera.Render();
            GetComponent<Renderer>().sharedMaterial.SetTexture("_RefractionTex", m_RefractionTexture);
        }

        void UpdateCameraModes(Camera src, Camera dest)
        {
            if (dest == null)
                return;

            dest.clearFlags = src.clearFlags;
            dest.backgroundColor = src.backgroundColor;

            if (src.clearFlags == CameraClearFlags.Skybox)
            {
                Skybox sky = src.GetComponent<Skybox>();
                Skybox mysky = dest.GetComponent<Skybox>();
                if (!sky || !sky.material)
                {
                    mysky.enabled = false;
                }
                else
                {
                    mysky.enabled = true;
                    mysky.material = sky.material;
                }
            }

            dest.farClipPlane = src.farClipPlane;
            dest.nearClipPlane = src.nearClipPlane;
            dest.orthographic = src.orthographic;
            dest.fieldOfView = src.fieldOfView;
            dest.aspect = src.aspect;
            dest.orthographicSize = src.orthographicSize;
        }

        void CreateWaterObjects(Camera currentCamera, out Camera reflectionCamera, out Camera refractionCamera)
        {
            WaterMode mode = GetWaterMode();

            reflectionCamera = null;
            refractionCamera = null;

            if (mode >= WaterMode.Reflective)
            {
                if (!m_ReflectionTexture || m_OldReflectionTextureSize != textureSize)
                {
                    if (m_ReflectionTexture)
                        DestroyImmediate(m_ReflectionTexture);

                    m_ReflectionTexture = new RenderTexture(textureSize, textureSize, 16);
                    m_ReflectionTexture.name = "__WaterReflection" + GetInstanceID();
                    m_ReflectionTexture.isPowerOfTwo = true;
                    m_ReflectionTexture.hideFlags = HideFlags.DontSave;
                    m_OldReflectionTextureSize = textureSize;
                }

                m_ReflectionCameras.TryGetValue(currentCamera, out reflectionCamera);
                if (!reflectionCamera)
                {
                    GameObject go = new GameObject("Water Refl Camera id" + GetInstanceID() + " for " + currentCamera.GetInstanceID(), typeof(Camera), typeof(Skybox));
                    reflectionCamera = go.GetComponent<Camera>();
                    reflectionCamera.enabled = false;
                    reflectionCamera.transform.position = transform.position;
                    reflectionCamera.transform.rotation = transform.rotation;
                    reflectionCamera.gameObject.AddComponent<FlareLayer>();
                    go.hideFlags = HideFlags.HideAndDontSave;
                    m_ReflectionCameras[currentCamera] = reflectionCamera;
                }
            }

            if (mode >= WaterMode.Refractive)
            {
                if (!m_RefractionTexture || m_OldRefractionTextureSize != textureSize)
                {
                    if (m_RefractionTexture)
                        DestroyImmediate(m_RefractionTexture);

                    m_RefractionTexture = new RenderTexture(textureSize, textureSize, 16);
                    m_RefractionTexture.name = "__WaterRefraction" + GetInstanceID();
                    m_RefractionTexture.isPowerOfTwo = true;
                    m_RefractionTexture.hideFlags = HideFlags.DontSave;
                    m_OldRefractionTextureSize = textureSize;
                }

                m_RefractionCameras.TryGetValue(currentCamera, out refractionCamera);
                if (!refractionCamera)
                {
                    GameObject go = new GameObject("Water Refr Camera id" + GetInstanceID() + " for " + currentCamera.GetInstanceID(), typeof(Camera), typeof(Skybox));
                    refractionCamera = go.GetComponent<Camera>();
                    refractionCamera.enabled = false;
                    refractionCamera.transform.position = transform.position;
                    refractionCamera.transform.rotation = transform.rotation;
                    refractionCamera.gameObject.AddComponent<FlareLayer>();
                    go.hideFlags = HideFlags.HideAndDontSave;
                    m_RefractionCameras[currentCamera] = refractionCamera;
                }
            }
        }

        WaterMode GetWaterMode()
        {
            if (m_HardwareWaterSupport < waterMode)
                return m_HardwareWaterSupport;
            return waterMode;
        }

        WaterMode FindHardwareWaterSupport()
        {
            if (!SystemInfo.supportsRenderTextures || !GetComponent<Renderer>())
                return WaterMode.Simple;

            Material mat = GetComponent<Renderer>().sharedMaterial;
            if (!mat)
                return WaterMode.Simple;

            string mode = mat.GetTag("WATERMODE", false);
            if (mode == "Refractive")
                return WaterMode.Refractive;
            if (mode == "Reflective")
                return WaterMode.Reflective;

            return WaterMode.Simple;
        }

        Vector4 CameraSpacePlane(Camera cam, Vector3 pos, Vector3 normal, float sideSign)
        {
            Vector3 offsetPos = pos + normal * clipPlaneOffset;
            Matrix4x4 m = cam.worldToCameraMatrix;
            Vector3 cpos = m.MultiplyPoint(offsetPos);
            Vector3 cnormal = m.MultiplyVector(normal).normalized * sideSign;
            return new Vector4(cnormal.x, cnormal.y, cnormal.z, -Vector3.Dot(cpos, cnormal));
        }

        static void CalculateReflectionMatrix(ref Matrix4x4 reflectionMat, Vector4 plane)
        {
            reflectionMat.m00 = (1F - 2F * plane[0] * plane[0]);
            reflectionMat.m01 = (-2F * plane[0] * plane[1]);
            reflectionMat.m02 = (-2F * plane[0] * plane[2]);
            reflectionMat.m03 = (-2F * plane[3] * plane[0]);

            reflectionMat.m10 = (-2F * plane[1] * plane[0]);
            reflectionMat.m11 = (1F - 2F * plane[1] * plane[1]);
            reflectionMat.m12 = (-2F * plane[1] * plane[2]);
            reflectionMat.m13 = (-2F * plane[3] * plane[1]);

            reflectionMat.m20 = (-2F * plane[2] * plane[0]);
            reflectionMat.m21 = (-2F * plane[2] * plane[1]);
            reflectionMat.m22 = (1F - 2F * plane[2] * plane[2]);
            reflectionMat.m23 = (-2F * plane[3] * plane[2]);

            reflectionMat.m30 = 0F;
            reflectionMat.m31 = 0F;
            reflectionMat.m32 = 0F;
            reflectionMat.m33 = 1F;
        }

        void SetWaterModeKeywords(WaterMode mode)
        {
            if (mode == WaterMode.Simple)
            {
                Shader.DisableKeyword("WATER_REFLECTIVE");
                Shader.DisableKeyword("WATER_REFRACTIVE");
            }
            else if (mode == WaterMode.Reflective)
            {
                Shader.EnableKeyword("WATER_REFLECTIVE");
                Shader.DisableKeyword("WATER_REFRACTIVE");
            }
            else if (mode == WaterMode.Refractive)
            {
                Shader.EnableKeyword("WATER_REFLECTIVE");
                Shader.EnableKeyword("WATER_REFRACTIVE");
            }
        }
    }
}