Unity3D手游开发日记(8)

2D游戏的残影很简单,美术做序列帧图片就行了,那么3D游戏的残影美术做不了,得靠程序员动态创建模型来处理.

实现原理也很简单:

1.间隔一定时间创建一个残影模型

GameObject go = GameObject.Instantiate(origin, pos, dir) as GameObject;

2.对残影模型采用特殊的shader,要简单高效

public class MotionGhost
{
    public GameObject m_GameObject;
    public List<Material> m_Materials;
    public float m_DurationTime;
    public float m_FadeTime;
    public float m_Time;

    public MotionGhost(GameObject go, Color color, float durationTime, float fadeTime)
    {
        m_GameObject = go;
        m_DurationTime = durationTime;
        m_FadeTime = fadeTime;
        m_Time = durationTime;

        if (MotionGhostMgr.Instance.m_MaterialMotionGhost == null)
            MotionGhostMgr.Instance.m_MaterialMotionGhost = Resources.Load("Material/MotionGhost");

        m_Materials = new List<Material>();
        foreach (Renderer renderer in go.GetComponentsInChildren<Renderer>())
        {
            if (renderer as MeshRenderer || renderer as SkinnedMeshRenderer)
            {
                // 身体和武器
                Material[] newMaterials = new Material[1];
                newMaterials[0] = GameObject.Instantiate(MotionGhostMgr.Instance.m_MaterialMotionGhost) as Material;
                if (newMaterials[0].HasProperty("_RimColor"))
                    newMaterials[0].SetColor("_RimColor", color);
                renderer.materials = newMaterials;

                m_Materials.Add(renderer.material);
            }
            else
            {
                // 隐藏粒子
                renderer.enabled = false;
            }
        }
    }
}

3.残影淡入淡出的处理

public void Tick()
{
    for (int i = m_MotionGhosts.Count - 1; i >= 0; --i)
    {
        m_MotionGhosts[i].m_Time -= Time.deltaTime;

        // 时间到了删除掉
        if (m_MotionGhosts[i].m_Time <= 0)
        {
            GameObject.Destroy(m_MotionGhosts[i].m_GameObject);
            m_MotionGhosts.RemoveAt(i);
            --m_Counter;
            continue;
        }

        // 开始材质渐变
        if (m_MotionGhosts[i].m_Time < m_MotionGhosts[i].m_FadeTime)
        {
            float alpha = m_MotionGhosts[i].m_Time / m_MotionGhosts[i].m_FadeTime;
            foreach (Material material in m_MotionGhosts[i].m_Materials)
            {
                if (material.HasProperty("_RimColor"))
                {
                    Color color = material.GetColor("_RimColor");
                    color *= alpha;
                    material.SetColor("_RimColor", color);
                }
            }
        }
    }
}

残影+扭曲的效果:

残影效果: