HLSL Create Vertices

[Jeff Hegedus]

Is it possible for an effect or shader to return more vertices than were
passed to it or is it always 1 for 1?

[legalize+ (Richard [Microsoft Direct3D MVP])]

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Post by Jeff Hegedus
Is it possible for an effect or shader to return more vertices than were
passed to it or is it always 1 for 1?

In D3D11, hull and domain shaders can be used in conjunction with the
tessellator unit to generate new vertices.

In D3D10 (and 11), the geometry shader can be used to generate new
vertices.

A vertex shader can never introduce new vertices. However, a vertex
shader can appear to introduce new vertices by transforming the
vertices of a degenerate triangle and creating a non-degenerate
triangle. In reality, no vertices were created or removed, but
degenerate triangles are discarded by the pipeline.