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Where are vertex and index data stored in Direct3D?
Vertex data is stored in vertex buffers, and index data is stored in index buffers. Listed below are a few common scenarios for drawing primitives using vertex and index buffers. These examples compare the use of IDirect3DDevice9::DrawPrimitive and IDirect3DDevice9::DrawIndexedPrimitive
What are Uvs and how do they relate to geometry?
UVs are two-dimensional texture coordinates that correspond with the vertex information for your geometry. UVs are vital because they provide the link between a surface mesh and how an image texture gets applied onto that surface. They are basically marker points that control which pixels on the texture corresponds to which vertex on the 3D mesh.
Are there different types of Uvs for 3D?
The concept is the same, except in a 3D application there are typically several different UV projection types available to you. These are based off of simple geometric shapes and often times are a great starting point when beginning to layout UVs for a single object.
When to draw from vertex and index buffers?
This technique can also be used when drawing multiple instances of a mesh using a single index buffer; for example, if the vertex buffer contained two meshes with identical draw order but slightly different vertices (perhaps different diffuse colors or texture coordinates), both meshes could be drawn by using different values for BaseVertexIndex.
How many vertices are needed to draw a triangle?
Even though only three vertices are required to draw the triangle, those three vertices are spread across four adjacent locations in the vertex buffer; the number of locations within the contiguous block of vertex buffer memory required for the drawing call is called NumVertices, and will be set to 4 in this call.
Why does the vertex buffer contain duplicate data?
As you’ll notice, the vertex buffer contains duplicate data in locations 0 and 4, 2 and 5. That makes sense because the two triangles share two common vertices. This duplicate data is wasteful, and the vertex buffer can be compressed by using an index buffer.