protected void UpdateRemoveDeadSections()
{
int lastDeadSectionIndex = -1;
float minLiveBirthTime = Time.time - LifeTime;
for (int iSection = 0; iSection < m_Sections.Count; iSection++)
{
hwmTrailSection iterSection = m_Sections[iSection];
if (iterSection.BirthTime > minLiveBirthTime)
{
lastDeadSectionIndex = iSection - 1;
break;
}
}
if (lastDeadSectionIndex > -1) // 说明有过期的Section
{
/* 断裂效果说明：例
* 下图第一行是Section Index 第二行中"*"是Section "----"是画出来的Trail
* 0 1 2 3 4
*----*----*----*----*
* 当有2个Section过期时，如果移除两个Section，结果如下图
* 2 3 4
* ----*----*----*
* ↑这里断裂
* 为了避免断裂效果，我们只移除1个Section（iLastOutdateSection = 1）
* 1 2 3 4
*----*----*----*
*/
m_Sections.RemoveRange(0, lastDeadSectionIndex + 1 == m_Sections.Count
? m_Sections.Count // 所有的都过期了，我们可以彻底移除了
: lastDeadSectionIndex); // 只要不是全部过期了就保留一个过期的Section，避免断裂效果
}
}
/// <summary>
/// 用于更新条带段的属性。自定制的特殊动画、过渡等逻辑请写在这个方法的重载中。（见osPlaneTrail范例中如何实现的“自定制曲线的条带颜色变化”）
/// </summary>
protected void UpdateSections()
{
for (int iSection = 0; iSection < m_Sections.Count; iSection++)
{
hwmTrailSection currentSection = m_Sections[iSection];
currentSection.NormalizedAge = Mathf.Clamp01((Time.time - currentSection.BirthTime) / LifeTime);
currentSection.Color = Color.Lerp(StartColor, EndColor, currentSection.NormalizedAge);
currentSection.HalfWidth = Mathf.Lerp(StartHalfWidth, EndHalfWidth, currentSection.NormalizedAge);
}
}
/// <summary>
/// 计算Trail世界空间的包围球
/// 如果当前没有Section，则返回中心为发射器的位置，大小为0的Bounds
/// TODO 优化计算方式，降低计算频率
/// 这种计算方式更适合处理一直朝某方向飞的条带
/// 遍历所有的Section计算Bounds太废了，又不可能实现通用且高效的算法
/// 考虑让子类重载，根据不同情况去优化计算
/// </summary>
protected Bounds CaculateBounds()
{
Bounds bounds = new Bounds(transform.position, Vector3.zero);
if (m_Sections.Count > 0)
{
hwmTrailSection centerSection = m_Sections[m_Sections.Count / 2];
hwmTrailSection lastSection = m_Sections[m_Sections.Count - 1];
bounds.Encapsulate(centerSection.Position);
bounds.Encapsulate(lastSection.Position);
}
return(bounds);
}
protected void UpdateAutoEmitting()
{
if (!m_IsEmitting ||
m_IsManualEmit)
{
return;
}
if (!(m_Me2CameraDistanceSqr < AutoEmittingWhenMe2CameraDistanceSqrIsLessThan &&
(EnableAutoEmittingWhenMeOutOfCamera ||
IsInRendererCamera(transform.position))))
{
return;
}
Vector3 emitterPosition_RendererSpace = Quaternion.Inverse(m_TrailRenderer.transform.rotation) * (transform.position - m_TrailRenderer.transform.position);
Quaternion emitterRotation_RendererSpace = transform.rotation * Quaternion.Inverse(m_TrailRenderer.transform.rotation);
if (m_Sections.Count == 0)
{
// 在发射器上一帧的位置添加一个Section
TryAddSection(emitterPosition_RendererSpace, emitterRotation_RendererSpace);
// 在发射器当前位置添加一个Section作为HeadSection,
TryAddSection(emitterPosition_RendererSpace, emitterRotation_RendererSpace);
}
else
{
#region 判断是否需要新的Section
// TDOO 如果FOV不经常变动，可以把这个结果Cache下来。或者把这个值放在相机的管理中每帧计算
float cameraHalfTanFOV = Mathf.Tan(RendererCamera.fieldOfView * 0.5f * Mathf.Deg2Rad);
// 把需要发射新Section的发射器在屏幕上移动的距离换算成世界空间的距离
float minMeMoveDistanceSqr = cameraHalfTanFOV * AutoEmittingAddSectionWhenMeMoveDistanceInScreenSpaceGreaterThen;
minMeMoveDistanceSqr *= minMeMoveDistanceSqr;
minMeMoveDistanceSqr *= m_Me2CameraDistanceSqr;
// 需要同时满足世界空间距离和屏幕空间距离
minMeMoveDistanceSqr = Mathf.Max(AutoEmittingAddSectionWhenMeMoveDistanceSqrInWorldSpcaeGreaterThen, minMeMoveDistanceSqr);
bool needAddSection = (transform.position - m_Sections[m_Sections.Count - 2].Position).sqrMagnitude > minMeMoveDistanceSqr;
#endregion
if (needAddSection)
{
TryAddSection(emitterPosition_RendererSpace, emitterRotation_RendererSpace);
}
else
{
// 将HeadSection挪到发射器的位置
hwmTrailSection headSection = m_Sections[m_Sections.Count - 1];
SetupSection(headSection, emitterPosition_RendererSpace, emitterRotation_RendererSpace, m_Sections.Count - 2);
}
}
}
/// <summary>
/// 如果希望在发射新的条带段时，能够对这个新产生的段上的数据做一些特殊处理（例如随机颜色），或者对自己扩展的变量进行初始化赋值时，重载本方法
/// </summary>
protected void SetupSection(hwmTrailSection section, Vector3 position, Quaternion rotation, int previousSectionIndex)
{
bool isHeadSection = previousSectionIndex < 0;
section.Position = position;
section.BirthTime = Time.time;
section.RightDirection = rotation * Vector3.right;
section.NormalizedAge = 0;
section.HalfWidth = StartHalfWidth;
section.Color = StartColor;
section.TexcoordU = isHeadSection
? 0
: (position - m_Sections[previousSectionIndex].Position).magnitude * WorldToTexcoordU + m_Sections[previousSectionIndex].TexcoordU;
}
/// <summary>
/// 当前Section数量超过<see cref="MaxSectionCount"/>时不会添加Section
/// </summary>
protected hwmTrailSection TryAddSection(Vector3 position, Quaternion rotation)
{
// TODO 不能添加Section会导致条带发射器终止发射，暂时的解决方法是把MaxSectionCount配的很大。预计以后顶点数可以动态改变
if (m_Sections.Count == MaxSectionCount - 1)
{
return(null);
}
hwmTrailSection newSection = new hwmTrailSection();
m_Sections.Add(newSection);
SetupSection(newSection, position, rotation, m_Sections.Count - 2);
return(newSection);
}
/// <summary>
/// 用于将条带的Section转换为用于渲染的顶点、索引缓冲
/// 可以重载这个方法实现特定的填充策略，例如：
/// 可断裂的条带
/// 更高性能的填充策略
/// 定向Billboard
/// </summary>
protected void UpdateBuffers()
{
// UNDONE 这里有点蒙蔽啊。懒得看了，直接问祝锐把
for (int iSection = 0; iSection < m_Sections.Count; iSection++)
{
hwmTrailSection iterSection = m_Sections[iSection];
// Generate vertices
Vector3 vHalfWidth = iterSection.RightDirection * iterSection.HalfWidth;
m_PositionBuffer[iSection * 4 + 0] = iterSection.Position - vHalfWidth;
m_PositionBuffer[iSection * 4 + 1] = iterSection.Position + vHalfWidth;
// fade colors out over time
m_ColorBuffer[iSection * 4 + 0] = iterSection.Color;
m_ColorBuffer[iSection * 4 + 1] = iterSection.Color;
m_UVBuffer[iSection * 4 + 0] = new Vector2(iterSection.TexcoordU, 0);
m_UVBuffer[iSection * 4 + 1] = new Vector2(iterSection.TexcoordU, 1);
}
for (int iSection = 0; iSection < m_Sections.Count - 1; iSection++)
{
hwmTrailSection iterSection = m_Sections[iSection + 1];
// TODO 就这里不懂，找祝锐
m_PositionBuffer[iSection * 4 + 2] = m_PositionBuffer[iSection * 4 + Mathf.Min(iSection, 1) * 4];
m_PositionBuffer[iSection * 4 + 3] = m_PositionBuffer[iSection * 4 + Mathf.Min(iSection, 1) * 5];
// fade colors out over time
m_ColorBuffer[iSection * 4 + 2] = m_ColorBuffer[iSection * 4 + 4];
m_ColorBuffer[iSection * 4 + 3] = m_ColorBuffer[iSection * 4 + 5];
m_UVBuffer[iSection * 4 + 2] = m_UVBuffer[iSection * 4 + 4];
m_UVBuffer[iSection * 4 + 3] = m_UVBuffer[iSection * 4 + 5];
}
for (int iSection = (m_Sections.Count - 1) * 4; iSection < m_PositionBuffer.Length; ++iSection)
{
// TODO 这里也不懂。这样为什么不会渲染出从最后一个Section到这个位置的Trail？是被裁剪掉了么。不是会把一个三角形切开，然后渲染在屏幕中的部分么。为什么全裁掉了
m_PositionBuffer[iSection] = new Vector3(0, -100000.0f, 0);
}
}
protected void OnDrawGizmosSelected()
{
if (!Application.isPlaying || !DEBUG_DrawGizmos)
{
return;
}
GUIStyle guiStyle = new GUIStyle();
guiStyle.fontSize = 15;
guiStyle.normal.textColor = Color.green;
for (int iSection = 0; iSection < m_Sections.Count; ++iSection)
{
hwmTrailSection iterSection = m_Sections[iSection];
Gizmos.color = iSection == 0
? new Color(1.0f, 0, 0, 0.5f)
: new Color(1.0f, 1.0f, 1.0f, 0.5f);
float radius = Mathf.Lerp(StartHalfWidth, EndHalfWidth, iterSection.NormalizedAge);
Gizmos.DrawWireSphere(iterSection.Position, radius);
UnityEditor.Handles.Label(iterSection.Position, (iSection).ToString(), guiStyle);
}
for (int i = 0; i < m_PositionBuffer.Length; i++)
{
if (i % 2 == 0)
{
Vector3 start = m_PositionBuffer[i];
Vector3 end = m_PositionBuffer[i + 1];
Gizmos.color = Color.yellow;
Gizmos.DrawLine(start, end);
if (i % 4 == 0)
{
Gizmos.color = Color.green;
guiStyle.normal.textColor = Color.green;
Gizmos.DrawSphere(start, 0.05f);
UnityEditor.Handles.Label(start + Vector3.right * .2f, i.ToString(), guiStyle);
Gizmos.color = Color.red;
guiStyle.normal.textColor = Color.red;
Gizmos.DrawSphere(end, 0.05f);
UnityEditor.Handles.Label(end - Vector3.right * .2f, (i + 1).ToString(), guiStyle);
}
else
{
Gizmos.color = Color.green;
guiStyle.normal.textColor = Color.green;
Gizmos.DrawSphere(start, 0.05f);
UnityEditor.Handles.Label(start + Vector3.right * .2f + Vector3.forward * .2f, i.ToString(), guiStyle);
Gizmos.color = Color.red;
guiStyle.normal.textColor = Color.red;
Gizmos.DrawSphere(end, 0.05f);
UnityEditor.Handles.Label(end - Vector3.right * .2f + Vector3.forward * .2f, (i + 1).ToString(), guiStyle);
}
}
}
Bounds bounds = m_TrailRenderer._MeshRenderer.bounds;
Gizmos.color = Color.white;
Gizmos.DrawWireSphere(bounds.center, bounds.extents.magnitude);
}