/// <summary>
///
/// </summary>
/// <param name="arg"></param>
/// <param name="lastVertexId"></param>
/// <param name="picker"></param>
/// <returns></returns>
internal override uint[] Search(PickingEventArgs arg,
uint lastVertexId, ZeroIndexPicker picker)
{
OneIndexBuffer buffer = GLBuffer.Create(IndexBufferElementType.UInt, 6, DrawMode.Lines, BufferUsage.StaticDraw);
unsafe
{
var array = (uint *)buffer.MapBuffer(MapBufferAccess.WriteOnly);
array[0] = 0; array[1] = lastVertexId - 1;
array[2] = lastVertexId - 1; array[3] = lastVertexId - 0;
array[4] = lastVertexId - 0; array[5] = 0;
buffer.UnmapBuffer();
}
picker.Renderer.Render4InnerPicking(arg, buffer);
uint id = ColorCodedPicking.ReadStageVertexId(arg.X, arg.Y);
buffer.Dispose();
if (id + 1 == lastVertexId)
{
return(new uint[] { 0, lastVertexId - 1, });
}
else if (id == lastVertexId)
{
return(new uint[] { lastVertexId - 1, lastVertexId - 0, });
}
else if (id == 0)
{
return(new uint[] { lastVertexId - 0, 0, });
}
else
{
throw new Exception("This should not happen!");
}
}
/// <summary>
///
/// </summary>
/// <param name="arg"></param>
/// <param name="lastVertexId"></param>
/// <param name="picker"></param>
/// <returns></returns>
internal override uint Search(PickingEventArgs arg, uint lastVertexId, ZeroIndexPicker picker)
{
OneIndexBuffer buffer = GLBuffer.Create(IndexBufferElementType.UInt, 4, DrawMode.Points, BufferUsage.StaticDraw);
unsafe
{
var array = (uint *)buffer.MapBuffer(MapBufferAccess.WriteOnly);
array[0] = lastVertexId - 0;
array[1] = lastVertexId - 1;
array[2] = lastVertexId - 2;
array[3] = lastVertexId - 3;
buffer.UnmapBuffer();
}
picker.Renderer.Render4InnerPicking(arg, buffer);
uint id = ColorCodedPicking.ReadStageVertexId(arg.X, arg.Y);
buffer.Dispose();
if (lastVertexId - 3 <= id && id <= lastVertexId - 0)
{
return(id);
}
else
{
throw new Exception("This should not happen!");
}
}
/// <summary>
/// 在三角形图元中拾取指定位置的Point
/// </summary>
/// <param name="arg">渲染参数</param>
/// <param name="lastVertexId">三角形图元的最后一个顶点</param>
/// <param name="picker">目标Renderer</param>
/// <returns></returns>
internal override uint Search(PickingEventArgs arg, uint lastVertexId, ZeroIndexPicker picker)
{
// 创建临时索引
OneIndexBuffer buffer = GLBuffer.Create(IndexBufferElementType.UInt, 3, DrawMode.Points, BufferUsage.StaticDraw);
unsafe
{
var array = (uint *)buffer.MapBuffer(MapBufferAccess.WriteOnly);
array[0] = lastVertexId - 0;
array[1] = lastVertexId - 1;
array[2] = lastVertexId - 2;
buffer.UnmapBuffer();
}
// 用临时索引渲染此三角形图元（仅渲染此三角形图元）
picker.Node.Render4InnerPicking(arg, buffer);
// id是拾取到的Line的Last Vertex Id
uint id = ColorCodedPicking.ReadStageVertexId(arg.X, arg.Y);
buffer.Dispose();
// 对比临时索引，找到那个Line
if (lastVertexId - 2 <= id && id <= lastVertexId - 0)
{
return(id);
}
else
{
throw new Exception("This should not happen!");
}
}
/// <summary>
///
/// </summary>
/// <param name="arg"></param>
/// <param name="lastVertexId"></param>
/// <param name="picker"></param>
/// <returns></returns>
internal override uint Search(PickingEventArgs arg,
uint lastVertexId, ZeroIndexPicker picker)
{
var zeroIndexBuffer = picker.Node.PickingRenderUnit.VertexArrayObject.IndexBuffer as ZeroIndexBuffer;
// when the temp index buffer could be long, it's no longer needed.
// what a great OpenGL API design!
ZeroIndexBuffer indexBuffer = ZeroIndexBuffer.Create(DrawMode.Points, zeroIndexBuffer.FirstVertex, zeroIndexBuffer.RenderingVertexCount, zeroIndexBuffer.InstanceCount);
picker.Node.Render4InnerPicking(arg, indexBuffer);
uint id = ColorCodedPicking.ReadStageVertexId(arg.X, arg.Y);
indexBuffer.Dispose();
if (zeroIndexBuffer.FirstVertex <= id &&
id < zeroIndexBuffer.FirstVertex + zeroIndexBuffer.RenderingVertexCount)
{
return(id);
}
else
{
throw new Exception("This should not happen!");
}
}