/// <summary>
/// Perform material modification in this function.
/// 获取修改后的材质
/// 默认的实现为替换材质，根据是否父物体为 Mask 组件，修改 Stencil 值，通过shader 的模板功能实现遮罩
/// </summary>
public virtual Material GetModifiedMaterial(Material baseMaterial)
{
var toUse = baseMaterial;
if (m_ShouldRecalculateStencil)
{
var rootCanvas = MaskUtilities.FindRootSortOverrideCanvas(transform);
m_StencilValue = maskable ?
MaskUtilities.GetStencilDepth(transform, rootCanvas) : 0;
m_ShouldRecalculateStencil = false;
}
// if we have a enabled Mask component then it will
// generate the mask material. This is an optimisation
// it adds some coupling between components though :(
Mask maskComponent = GetComponent <Mask>();
if (m_StencilValue > 0 &&
(maskComponent == null || !maskComponent.IsActive()))
{
var maskMat = StencilMaterial.Add(toUse,
(1 << m_StencilValue) - 1,
StencilOp.Keep,
CompareFunction.Equal,
ColorWriteMask.All,
(1 << m_StencilValue) - 1,
0);
StencilMaterial.Remove(m_MaskMaterial);
m_MaskMaterial = maskMat;
toUse = m_MaskMaterial;
}
return(toUse);
}
protected override void OnEnable()
{
base.OnEnable();
m_ShouldRecalculateClipRects = true;
ClipperRegistry.Register(this);
MaskUtilities.Notify2DMaskStateChanged(this);
}
public virtual void PerformClipping()
{
// if the parents are changed
// or something similar we
// do a recalculate here
if (m_ShouldRecalculateClipRects)
{
MaskUtilities.GetRectMasksForClip(this, m_Clippers);
m_ShouldRecalculateClipRects = false;
}
// get the compound rects from
// the clippers that are valid
bool validRect = true;
Rect clipRect = Clipping.FindCullAndClipWorldRect(m_Clippers, out validRect);
if (clipRect != m_LastClipRectCanvasSpace)
{
for (int i = 0; i < m_ClipTargets.Count; ++i)
{
m_ClipTargets[i].SetClipRect(clipRect, validRect);
}
m_LastClipRectCanvasSpace = clipRect;
m_LastClipRectValid = validRect;
}
for (int i = 0; i < m_ClipTargets.Count; ++i)
{
m_ClipTargets[i].Cull(m_LastClipRectCanvasSpace, m_LastClipRectValid);
}
}
protected override void OnEnable()
{
base.OnEnable();
if (graphic != null)
{
graphic.canvasRenderer.hasPopInstruction = true;
graphic.SetMaterialDirty();
}
MaskUtilities.NotifyStencilStateChanged(this);
}
protected override void OnValidate()
{
base.OnValidate();
m_ShouldRecalculateClipRects = true;
if (!IsActive())
{
return;
}
MaskUtilities.Notify2DMaskStateChanged(this);
}
protected override void OnDisable()
{
// we call base OnDisable first here
// as we need to have the IsActive return the
// correct value when we notify the children
// that the mask state has changed.
base.OnDisable();
m_ClipTargets.Clear();
m_Clippers.Clear();
ClipperRegistry.Unregister(this);
MaskUtilities.Notify2DMaskStateChanged(this);
}
/// Stencil calculation time!
public virtual Material GetModifiedMaterial(Material baseMaterial)
{
if (graphic == null)
{
return(baseMaterial);
}
var rootSortCanvas = MaskUtilities.FindRootSortOverrideCanvas(transform);
var stencilDepth = MaskUtilities.GetStencilDepth(transform, rootSortCanvas);
if (stencilDepth >= 8)
{
Debug.LogError("Attempting to use a stencil mask with depth > 8", gameObject);
return(baseMaterial);
}
int desiredStencilBit = 1 << stencilDepth;
// if we are at the first level...
// we want to destroy what is there
if (desiredStencilBit == 1)
{
var maskMaterial = StencilMaterial.Add(baseMaterial, 1, StencilOp.Replace, CompareFunction.Always, m_ShowMaskGraphic ? ColorWriteMask.All : 0);
StencilMaterial.Remove(m_MaskMaterial);
m_MaskMaterial = maskMaterial;
var unmaskMaterial = StencilMaterial.Add(baseMaterial, 1, StencilOp.Zero, CompareFunction.Always, 0);
StencilMaterial.Remove(m_UnmaskMaterial);
m_UnmaskMaterial = unmaskMaterial;
graphic.canvasRenderer.popMaterialCount = 1;
graphic.canvasRenderer.SetPopMaterial(m_UnmaskMaterial, 0);
return(m_MaskMaterial);
}
//otherwise we need to be a bit smarter and set some read / write masks
var maskMaterial2 = StencilMaterial.Add(baseMaterial, desiredStencilBit | (desiredStencilBit - 1), StencilOp.Replace, CompareFunction.Equal, m_ShowMaskGraphic ? ColorWriteMask.All : 0, desiredStencilBit - 1, desiredStencilBit | (desiredStencilBit - 1));
StencilMaterial.Remove(m_MaskMaterial);
m_MaskMaterial = maskMaterial2;
graphic.canvasRenderer.hasPopInstruction = true;
var unmaskMaterial2 = StencilMaterial.Add(baseMaterial, desiredStencilBit - 1, StencilOp.Replace, CompareFunction.Equal, 0, desiredStencilBit - 1, desiredStencilBit | (desiredStencilBit - 1));
StencilMaterial.Remove(m_UnmaskMaterial);
m_UnmaskMaterial = unmaskMaterial2;
graphic.canvasRenderer.popMaterialCount = 1;
graphic.canvasRenderer.SetPopMaterial(m_UnmaskMaterial, 0);
return(m_MaskMaterial);
}
protected override void OnDisable()
{
base.OnDisable();
m_ShouldRecalculateStencil = true;
SetMaterialDirty();
UpdateClipParent();
StencilMaterial.Remove(m_MaskMaterial);
m_MaskMaterial = null;
if (GetComponent <Mask>() != null)
{
MaskUtilities.NotifyStencilStateChanged(this);
}
}
protected override void OnValidate()
{
base.OnValidate();
if (!IsActive())
{
return;
}
if (graphic != null)
{
graphic.SetMaterialDirty();
}
MaskUtilities.NotifyStencilStateChanged(this);
}
private void UpdateClipParent()
{
var newParent = (maskable && IsActive()) ?
MaskUtilities.GetRectMaskForClippable(this) : null;
// if the new parent is different OR is now inactive
// 移出旧遮罩父物体的控制
if (m_ParentMask != null &&
(newParent != m_ParentMask || !newParent.IsActive()))
{
m_ParentMask.RemoveClippable(this);
UpdateCull(false);
}
if (newParent != null && newParent.IsActive())
{
newParent.AddClippable(this);
}
m_ParentMask = newParent;
}
protected override void OnDisable()
{
// we call base OnDisable first here
// as we need to have the IsActive return the
// correct value when we notify the children
// that the mask state has changed.
base.OnDisable();
if (graphic != null)
{
graphic.SetMaterialDirty();
graphic.canvasRenderer.hasPopInstruction = false;
graphic.canvasRenderer.popMaterialCount = 0;
}
StencilMaterial.Remove(m_MaskMaterial);
m_MaskMaterial = null;
StencilMaterial.Remove(m_UnmaskMaterial);
m_UnmaskMaterial = null;
MaskUtilities.NotifyStencilStateChanged(this);
}