/// <summary>
/// Wraps glDrawArrays(uint mode, int first, int count).
/// </summary>
/// <param name="mode">用哪种方式渲染各个顶点？（OpenGL.GL_TRIANGLES etc.）</param>
/// <param name="firstVertex">要渲染的第一个顶点的位置。<para>Index of first vertex to be rendered.</para></param>
/// <param name="vertexCount">要渲染多少个元素？<para>How many vertexes to be rendered?</para></param>
/// <param name="primCount">primCount in instanced rendering.</param>
internal ZeroIndexBufferPtr(DrawMode mode, int firstVertex, int vertexCount, int primCount = 1)
: base(mode, 0, vertexCount, vertexCount * sizeof(uint), primCount)
{
if (glDrawArraysInstanced == null)
{
glDrawArraysInstanced = OpenGL.GetDelegateFor <OpenGL.glDrawArraysInstanced>();
}
this.FirstVertex = firstVertex;
this.VertexCount = vertexCount;
this.OriginalVertexCount = vertexCount;
}
/// <summary>
///
/// </summary>
/// <param name="arg"></param>
public override void Render(RenderEventArgs arg)
{
uint mode = 0;
if (arg.PickingGeometryType == PickingGeometryType.Point &&
this.Mode.ToGeometryType() == PickingGeometryType.Line) // picking point from a line
{
// this maybe render points that should not appear.
// so need to select by another picking.
mode = (uint)DrawMode.Points;
}
else
{
mode = (uint)this.Mode;
}
int primCount = this.PrimCount;
if (primCount < 1)
{
throw new Exception("error: primCount is less than 1.");
}
else if (primCount == 1)
{
OpenGL.DrawArrays(mode, this.FirstVertex, this.RenderingVertexCount);
}
else
{
if (glDrawArraysInstanced == null)
{
glDrawArraysInstanced = OpenGL.GetDelegateFor <OpenGL.glDrawArraysInstanced>();
}
glDrawArraysInstanced(mode, this.FirstVertex, this.RenderingVertexCount, primCount);
}
}
/// <summary>
///
/// </summary>
public override void Render()
{
uint mode = (uint)this.Mode;
int primCount = this.PrimCount;
if (primCount < 1)
{
throw new Exception("error: primCount is less than 1.");
}
else if (primCount == 1)
{
OpenGL.DrawArrays(mode, this.FirstVertex, this.RenderingVertexCount);
}
else
{
if (glDrawArraysInstanced == null)
{
glDrawArraysInstanced = OpenGL.GetDelegateFor <OpenGL.glDrawArraysInstanced>();
}
glDrawArraysInstanced(mode, this.FirstVertex, this.RenderingVertexCount, primCount);
}
}
/// <summary>
///
/// </summary>
/// <param name="arg"></param>
public override void Render(RenderEventArgs arg)
{
uint mode = 0;
if (arg.PickingGeometryType == PickingGeometryType.Point
&& this.Mode.ToGeometryType() == PickingGeometryType.Line)// picking point from a line
{
// this maybe render points that should not appear.
// so need to select by another picking.
mode = (uint)DrawMode.Points;
}
else
{
mode = (uint)this.Mode;
}
int primCount = this.PrimCount;
if (primCount < 1) { throw new Exception("error: primCount is less than 1."); }
else if (primCount == 1)
{
OpenGL.DrawArrays(mode, this.FirstVertex, this.RenderingVertexCount);
}
else
{
if (glDrawArraysInstanced == null)
{ glDrawArraysInstanced = OpenGL.GetDelegateFor<OpenGL.glDrawArraysInstanced>(); }
glDrawArraysInstanced(mode, this.FirstVertex, this.RenderingVertexCount, primCount);
}
}
