1 using System;
2 using UnityEngine;
3
4 // This class implements simple ghosting type Motion Blur.
5 // If Extra Blur is selected, the scene will allways be a little blurred,
6 // as it is scaled to a smaller resolution.
7 // The effect works by accumulating the previous frames in an accumulation
8 // texture.
9 namespace UnityStandardAssets.ImageEffects
10 {
11 [ExecuteInEditMode]
12 [AddComponentMenu("Image Effects/Blur/Motion Blur (Color Accumulation)")]
13 [RequireComponent(typeof(Camera))]
14 public class MotionBlur : ImageEffectBase
15 {
16 [Range(0.0f, 0.92f)]
17 public float blurAmount = 0.8f;
18 public bool extraBlur = false;
19
20 private RenderTexture accumTexture;
21
22 override protected void Start()
23 {
24 if (!SystemInfo.supportsRenderTextures)
25 {
26 enabled = false;
27 return;
28 }
29 base.Start();
30 }
31
32 override protected void OnDisable()
33 {
34 base.OnDisable();
35 DestroyImmediate(accumTexture);
36 }
37
38 // Called by camera to apply image effect
39 void OnRenderImage (RenderTexture source, RenderTexture destination)
40 {
41 // Create the accumulation texture
42 if (accumTexture == null || accumTexture.width != source.width || accumTexture.height != source.height)
43 {
44 DestroyImmediate(accumTexture);
45 accumTexture = new RenderTexture(source.width, source.height, 0);
46 accumTexture.hideFlags = HideFlags.HideAndDontSave;
47 Graphics.Blit( source, accumTexture );
48 }
49
50 // If Extra Blur is selected, downscale the texture to 4x4 smaller resolution.
51 if (extraBlur)
52 {
53 RenderTexture blurbuffer = RenderTexture.GetTemporary(source.width/4, source.height/4, 0);
54 accumTexture.MarkRestoreExpected();
55 Graphics.Blit(accumTexture, blurbuffer);
56 Graphics.Blit(blurbuffer,accumTexture);
57 RenderTexture.ReleaseTemporary(blurbuffer);
58 }
59
60 // Clamp the motion blur variable, so it can never leave permanent trails in the image
61 blurAmount = Mathf.Clamp( blurAmount, 0.0f, 0.92f );
62
63 // Setup the texture and floating point values in the shader
64 material.SetTexture("_MainTex", accumTexture);
65 material.SetFloat("_AccumOrig", 1.0F-blurAmount);
66
67 // We are accumulating motion over frames without clear/discard
68 // by design, so silence any performance warnings from Unity
69 accumTexture.MarkRestoreExpected();
70
71 // Render the image using the motion blur shader
72 Graphics.Blit (source, accumTexture, material);
73 Graphics.Blit (accumTexture, destination);
74 }
75 }
76 }
