i think you guys are confusing Geometry TESSELLATION with GEOMETRY INSTANCING.
GEOMETRY INSTANCING From Wikipedia:
"In real-time computer graphics, geometry instancing refers to the practice of rendering multiple copies of the same mesh in a scene at once. This technique is primarily used for objects such as trees, grass, or buildings which can be represented as repeated geometry without appearing unduly repetitive, but may also be used for characters.
Although vertex data is duplicated across all instanced meshes, each instance may have other differentiating parameters (such as color, or skeletal animation pose) changed in order to reduce the appearance of repetition. By factoring out common data between instances to achieve lower memory usage, this technique is an example of the flyweight design pattern."
Geometry TESSELLATION From ExtremeTech:
The hull shader takes control points for a patch as an input. Note that this is the first appearance of patch-based data used in DirectX. The output of the hull shader essentially tells the tessellator stage how much to tessellate. The tessellator itself is a fixed function unit, taking the outputs from the hull shader and generating the added geometry. The domain shader calculates the vertex positions from the tessellation data, which is passed to the geometry shader.
It's important to recognize that the key primitive used in the tessellator is no longer a triangle: It's a patch. A patch represents a curve or region, and can be represented by a triangle, but the more common representation is a quad, used in many 3D authoring applications.
What all this means is that fully compliant DirectX 11 hardware can procedurally generate complex geometry out of relatively sparse data sets, improving bandwidth and storage requirements. This also affects animation, as changes in the control points of the patch can affect the final output in each frame.
The cool thing about hardware tessellation is that it's scalable. It's possible that low end hardware would simply generate less complex models than high-end hardware, while the actual data fed into the GPUs remains the same.
much more efficient.
Shiny Entertainment did geometry sub-division in their engine for "Messiah" and "sacrifice". it was all software done by the engine.
now we get it hardware accelerated as part of the DirectX API
N.B.
i may be a little off on some parts, so anyone more knowledgeable feel free to set things straight for the greater good
