每日读码1 Unity GL

最新推荐文章于 2025-05-12 15:46:44 发布

原创最新推荐文章于 2025-05-12 15:46:44 发布 · 3.9k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#unity

每日读码专栏收录该内容

1 篇文章

订阅专栏

这篇博客详细讲解了如何在Unity中利用OnRenderImage()和OnPostRender()函数进行相机后处理和图像渲染，通过设置材质和Shader实现自定义屏幕效果。作者提供了具体的代码示例，适合想要掌握Unity后期处理技巧的开发者。

//一般在渲染函数里实现，比如：OnPostRender()/*相机后处理*/,OnRenderImage()/*图像处理*/
void OnRenderImage(RenderTexture src, RenderTexture dst)
    {
        Vector3 toRight = cameraTransform.right * halfHeight * aspect;
        Vector3 toTop = cameraTransform.up * halfHeight;

        Vector3 topLeft = (myCamera.transform.forward - toRight + toTop);
        float scale = topLeft.magnitude / near;

        Vector3 topRight = cameraTransform.forward * near + toRight + toTop;
        topRight.Normalize();
        topRight *= scale;

        Vector3 bottomLeft = cameraTransform.forward * near - toTop - toRight;
        bottomLeft.Normalize();
        bottomLeft *= scale;

        Vector3 bottomRight = cameraTransform.forward * near + toRight - toTop;
        bottomRight.Normalize();
        bottomRight *= scale;

        // Custom Blit, encoding Frustum Corners as additional Texture Coordinates
        RenderTexture.active = dst;

        mat.SetTexture("_MainTex", src);

        GL.PushMatrix();
        GL.LoadOrtho();
        
        //必须设置material pass通道，不然无法生效
        mat.SetPass(0);

        GL.Begin(GL.QUADS);

        GL.MultiTexCoord2(0, 0.0f, 0.0f);
        GL.MultiTexCoord(1, bottomLeft);
        GL.Vertex3(0.0f, 0.0f, 0.0f);

        GL.MultiTexCoord2(0, 1.0f, 0.0f);
        GL.MultiTexCoord(1, bottomRight);
        GL.Vertex3(1.0f, 0.0f, 0.0f);

        GL.MultiTexCoord2(0, 1.0f, 1.0f);
        GL.MultiTexCoord(1, topRight);
        GL.Vertex3(1.0f, 1.0f, 0.0f);

        GL.MultiTexCoord2(0, 0.0f, 1.0f);
        GL.MultiTexCoord(1, topLeft);
        GL.Vertex3(0.0f, 1.0f, 0.0f);

        GL.End();
        GL.PopMatrix();
    }

官方脚本UnityEngine.GL - Unity 脚本 API

using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    // When added to an object, draws colored rays from the
    // transform position.
    public int lineCount = 100;
    public float radius = 3.0f;

    static Material lineMaterial;
    static void CreateLineMaterial()
    {
        if (!lineMaterial)
        {
            // Unity has a built-in shader that is useful for drawing
            // simple colored things.
            Shader shader = Shader.Find("Hidden/Internal-Colored");
            lineMaterial = new Material(shader);
            lineMaterial.hideFlags = HideFlags.HideAndDontSave;
            // Turn on alpha blending
            lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
            lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            // Turn backface culling off
            lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
            // Turn off depth writes
            lineMaterial.SetInt("_ZWrite", 0);
        }
    }

    // Will be called after all regular rendering is done
    public void OnRenderObject()
    {
        CreateLineMaterial();
        // Apply the line material
        lineMaterial.SetPass(0);

        GL.PushMatrix();
        // Set transformation matrix for drawing to
        // match our transform
        GL.MultMatrix(transform.localToWorldMatrix);

        // Draw lines
        GL.Begin(GL.LINES);
        for (int i = 0; i < lineCount; ++i)
        {
            float a = i / (float)lineCount;
            float angle = a * Mathf.PI * 2;
            // Vertex colors change from red to green
            GL.Color(new Color(a, 1 - a, 0, 0.8F));
            // One vertex at transform position
            GL.Vertex3(0, 0, 0);
            // Another vertex at edge of circle
            GL.Vertex3(Mathf.Cos(angle) * radius, Mathf.Sin(angle) * radius, 0);
        }
        GL.End();
        GL.PopMatrix();
    }
}

调用示例：

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    void OnPostRender()
    {
        // Set your materials
        GL.PushMatrix();
        // yourMaterial.SetPass( );
        // Draw your stuff
        GL.PopMatrix();
    }
}

简而言之使用方法就是：

挂一个脚本在camera上，重写OnRenderImg()/OnPostRender(),设置material 绑定 shader, 实现屏幕后效果