In Review
Prev | Chapter 7. World in Motion | Next

## In Review

In this tutorial, you have learned the following:

- World space is an intermediate space between model space and camera space. All objects are transformed into it, and the position/orientation of the camera is specified relative to it.

- OpenGL can processes a sequence of vertex data as triangles in different ways. It can process the vertices as a list of triangles, a triangle fan, or a triangle strip. Each of these has its own way of building triangles from a sequence of vertices.

- Uniform data can be stored in buffer objects, so that multiple programs can share the same uniform. Changing the buffer object data will automatically change the data the programs get.

- It is usually not a good idea to have vertex positions in an explicit world space. Doing so can lead to numerical precision problems if the vertex positions are sufficiently far from 0.

### Further Study

Play around with the world space tutorials in the following ways:

- In the World Space tutorial, we use 3 matrices. This requires an extra matrix multiply, which is a wasteful per-vertex cost. Fold the camera matrix into the perspective transformation matrix, so that only two matrices are used. Any time parameters change to one matrix, make sure to recompute both and combine them together before uploading the combined world-to-clip-space matrix.

- Instead of folding the world-to-camera transform into the perspective matrix, fold it into the model-to-world matrix instead. Simply push it onto the same stack as everything else. The function MatrixStack::ApplyMatrix can right-multiply an arbitrary matrix with the current matrix.

### OpenGL Functions of Note

glGetUniformBlockIndex

  Retrieves the uniform block index for a particular uniform block name from a program.

glUniformBlockBinding

  Sets the uniform buffer binding index used by a particular uniform block in a given program.

glBindBufferRange

  Binds a buffer object to a particular indexed location, as well as binding it to the given. When used with GL_UNIFORM_BUFFER, it binds the buffer object to a particular uniform buffer binding point. It has range parameters that can be used to effectively bind part of the buffer object to an indexed location.

Prev | Up | Next
The Perils of World Space | Home | Glossary