单相机做分屏混合

　　做了一个单相机实现分屏混合的功能, 需求大概就是在同一视角下, 相机通过不同的CullingMask获取不同的渲染图片RenderTexture之后, 通过某种方式一起显示在界面的功能. 其实核心逻辑就是怎样用一个相机渲染不同的图片罢了, 直接上代码:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[ExecuteInEditMode]
public class BlendRenderTexture : MonoBehaviour
{
    public enum BlendDirection
    {
        Horizontal = 0,
        Vertical = 1
    }

    [SerializeField]
    [Range(0, 1)]
    public float blend = 0.5f;
    [SerializeField]
    public BlendDirection blendDirection = BlendDirection.Horizontal;
    [SerializeField]
    public LayerMask tagLayerMask;
    [SerializeField]
    public RenderingTools.BlendRenderTextureTarget blendRenderTextureTarget;

    private bool m_grabbing = false;

    private void OnEnable()
    {
        if(blendRenderTextureTarget == null)
        {
            blendRenderTextureTarget = new RenderingTools.BlendRenderTextureTarget("Unlit/BlendRenderTexture");
        }
    }
    private void OnDisable()
    {
        if(blendRenderTextureTarget != null)
        {
            blendRenderTextureTarget.Release();
        }
    }

    void OnRenderImage(RenderTexture src, RenderTexture dest)
    {
        if(m_grabbing)
        {
            m_grabbing = false;
            Graphics.Blit(src, dest);
            return;
        }
        if(blendRenderTextureTarget.renderTexture && blendRenderTextureTarget.material)
        {
            blendRenderTextureTarget.material.SetTexture("_Left", src);
            blendRenderTextureTarget.material.SetTexture("_Right", blendRenderTextureTarget.renderTexture);
            blendRenderTextureTarget.material.SetFloat("_Blend", Mathf.Clamp01(blend));
            blendRenderTextureTarget.material.SetInt("_Direction", (int)blendDirection);
            Graphics.Blit(src, dest, blendRenderTextureTarget.material);
        }
        else
        {
            Graphics.Blit(src, dest);
        }
    }

    private void LateUpdate()
    {
        RenderTargetTexture();
    }
    
    public void RenderTargetTexture()
    {
        var material = blendRenderTextureTarget.GetMaterial();
        if (m_grabbing = material)
        {
            var lastMask = Camera.main.cullingMask;
            var lastTex = Camera.main.targetTexture;
            Camera.main.cullingMask = tagLayerMask;
            Camera.main.targetTexture = blendRenderTextureTarget.GetRenderTexture();
            Camera.main.Render();
            Camera.main.cullingMask = lastMask;
            Camera.main.targetTexture = lastTex;
        }      
    }
}

　　在LateUpdate中请求目标图片渲染, 标记了m_grabbing之后, 调用到OnRenderImage, 直接就把目标渲染图片输出到我们的临时RenderTexture上了, 然后再通过正常渲染时调用OnRenderImage之后, 就会通过Material进行混合了.

BlendRenderTextureTarget 只是一个资源的封装:

using System.Collections;using System.Collections.Generic;using UnityEngine;public static class RenderingTools{    [System.Serializable]    public class BlendRenderTextureTarget    {        [SerializeField]        public Material material = null;        [SerializeField]        public string shaderName = string.Empty;        public RenderTexture renderTexture { get; set; }        public BlendRenderTextureTarget(string shaderName)        {            this.shaderName = shaderName;        }        public Material GetMaterial()        {            if(material == false)            {                var shader = Shader.Find(shaderName);                if(shader)                {                    material = new Material(shader);                    material.hideFlags = HideFlags.DontSave;                }            }            return material;        }        public RenderTexture GetRenderTexture()        {            if(renderTexture)            {                if(renderTexture.width != Screen.width || renderTexture.height != Screen.height)                {                    RenderTexture.ReleaseTemporary(renderTexture);                    renderTexture = null;                }            }            if(renderTexture == false)            {                renderTexture = RenderTexture.GetTemporary(Screen.width, Screen.height, 24, RenderTextureFormat.ARGB32);                renderTexture.hideFlags = HideFlags.DontSave;            }            return renderTexture;        }        public void Release()        {            if(renderTexture)            {                RenderTexture.ReleaseTemporary(renderTexture);                renderTexture = null;            }            if(material)            {                material = null;            }        }    }}