This is a helper for drawing simple geometric shapes including texture coordinates and surface normals.
For exception safety, it is recommended you make use of the C++ RAII pattern and use a std::unique_ptr.
The draw method accepts an optional texture parameter, wireframe flag, and a callback function which can be used to override the default rendering state:
This makes use of a BasicEffect shared by all geometric primitives drawn on that device context.
This takes an optional parameter for enabling alpha-blending, wireframe, and a callback function which can be used to override the default rendering state.
http://msdn.microsoft.com/en-us/library/windows/desktop/ff476892.aspx
http://blogs.msdn.com/b/chuckw/archive/2012/06/20/direct3d-feature-levels.aspx
http://en.wikipedia.org/wiki/Cube
http://en.wikipedia.org/wiki/Hexahedron
http://en.wikipedia.org/wiki/Sphere
http://en.wikipedia.org/wiki/Cylinder_(geometry)
http://en.wikipedia.org/wiki/Cone
http://en.wikipedia.org/wiki/Torus
http://en.wikipedia.org/wiki/Tetrahedron
http://en.wikipedia.org/wiki/Octahedron
http://en.wikipedia.org/wiki/Dodecahedron
http://en.wikipedia.org/wiki/Icosahedron
http://en.wikipedia.org/wiki/Utah_teapot
- Cube (aka hexahedron)
- Sphere
- Geodesic Sphere
- Cylinder
- Cone
- Torus
- Tetrahedron
- Octahedron
- Dodecahedron
- Icosahedron
- Teapot
Initialization
The GeometryPrimitive class must be created from a factory method which takes the Direct3D 11 device context.std::unique_ptr<GeometricPrimitive> shape( GeometricPrimitive::CreateTeapot(deviceContext) );
- CreateCube( deviceContext, float size = 1)
- CreateSphere( deviceContext, float diameter = 1, size_t tessellation = 16)
- CreateGeoSphere( deviceContext, float diameter = 1, size_t tessellation = 3)
- CreateCylinder( deviceContext, float height = 1, float diameter = 1, size_t tessellation = 32)
- CreateCone( deviceContext, float diameter = 1, float height = 1, size_t tessellation = 32)
- CreateTorus( deviceContext, float diameter = 1, float thickness = 0.333f, size_t tessellation = 32)
- CreateTetrahedron ( deviceContext, float size = 1)
- CreateOctahedron ( deviceContext, float size = 1)
- CreateDodecahedron ( deviceContext, float size = 1)
- CreateIcosahedron ( deviceContext, float size = 1)
- CreateTeapot( deviceContext, float size = 1, size_t tessellation = 8)
Simple drawing
shape->Draw(world, view, projection, Colors::CornflowerBlue);
shape->Draw(world, view, projection, Colors::White, catTexture, false, [=]
{
deviceContext->OMSetBlendState(...);
});Advanced drawing
This form of drawing makes use of a custom Effects instance. The caller is responsible for using an input layout that matches the effect.IEffect* myeffect = ... Microsoft::WRL::ComPtr<ID3D11InputLayout> inputLayout; shape->CreateInputLayout( myeffect, &inputLayout ); shape->Draw( myeffect, inputLayout.Get() );
Coordinate systems
These geometric primitives (based on the XNA Game Studio conventions) use right-handed coordinates. They can be used with left-handed coordinates by setting the rhcoords parameter on the factory methods to 'false' to reverse the winding ordering (the parameter defaults to 'true').
std::unique_ptr<GeometricPrimitive> shape(
GeometricPrimitive::CreateTeapot( deviceContext, 1.f, 8, false ) );Alpha blending
Alpha blending defaults to using premultiplied alpha. To make use of 'straight' alpha textures, override the blending mode via the optional callback:CommonStates states(deviceContext); shape->Draw(world, view, projection, Colors::White, catTexture, false, [=] { deviceContext->OMSetBlendState( states.NonPremultiplied(), nullptr, 0xFFFFFFFF); });
Feature Level Notes
In order to support all feature levels, the GeometricPrimitive implementation make use of 16-bit indices (DXGI_FORMAT_R16_UINT) which limits to a maximum of 65535 vertices. Feature Level 9.1 is limited to a maximum of 65535 primitives in a single draw.Threading model
Each GeometricPrimitive instance only supports drawing from one thread at a time, but you can simultaneously submit primitives on multiple threads if you create a separate GeometricPrimitive instance per Direct3D 11 deferred context.http://msdn.microsoft.com/en-us/library/windows/desktop/ff476892.aspx
Further Reading
http://msdn.microsoft.com/en-us/library/windows/desktop/ff476876.aspxhttp://blogs.msdn.com/b/chuckw/archive/2012/06/20/direct3d-feature-levels.aspx
http://en.wikipedia.org/wiki/Cube
http://en.wikipedia.org/wiki/Hexahedron
http://en.wikipedia.org/wiki/Sphere
http://en.wikipedia.org/wiki/Cylinder_(geometry)
http://en.wikipedia.org/wiki/Cone
http://en.wikipedia.org/wiki/Torus
http://en.wikipedia.org/wiki/Tetrahedron
http://en.wikipedia.org/wiki/Octahedron
http://en.wikipedia.org/wiki/Dodecahedron
http://en.wikipedia.org/wiki/Icosahedron
http://en.wikipedia.org/wiki/Utah_teapot