/// <summary>
/// Get model matrix that transform this renderer from model space to world space.
/// </summary>
/// <returns></returns>
public MarkableStruct<mat4> GetModelMatrix()
{
if (this.modelMatrixRecord.IsMarked())// this model matrix is updated.
{
// get matrix representing transform relative to parent node.
mat4 matrix = IModelSpaceHelper.GetModelMatrix(this);
this.modelMatrixRecord.CancelMark();
// cascade parent's model matrix.
SceneObject obj = this.BindingSceneObject;
if (obj != null)
{
ITreeNode<SceneObject> parent = obj.Parent;
if (parent != null)
{
RendererBase parentRenderer = parent.Content.Renderer;
if (parentRenderer != null)
{
// get parent's matrix representing transform relative to world space coordinate.
MarkableStruct<mat4> parentMatrix = parentRenderer.GetModelMatrix();
// get matrix means transform relative to world space coordinate for this renderer.
matrix = parentMatrix.Value * matrix;
}
}
}
// update this renderer's transform matrix relative to world space coordinate.
this.modelMatrix.Value = matrix;
}
else // this model matrix is not updated.
{
SceneObject obj = this.BindingSceneObject;
if (obj != null)
{
SceneObject parent = obj.Parent.Content;
if (parent != null)
{
RendererBase parentRenderer = parent.Renderer;
if (parentRenderer != null)
{
// get parent's matrix representing transform relative to world space coordinate.
MarkableStruct<mat4> parentMatrix = parentRenderer.GetModelMatrix();
long ticks = parentMatrix.UpdateTicks;
if (this.parentMatrixTicks != ticks) // parent's model matrix is updated.
{
mat4 matrix = IModelSpaceHelper.GetModelMatrix(this);
this.modelMatrix.Value = parentMatrix.Value * matrix;
this.parentMatrixTicks = ticks;
}
}
}
}
}
return this.modelMatrix;
}
