CS 381 Fall 2012
Quiz Topics Before the Midterm

Below are all of the possible quiz topics that were posted on the class webpage prior to the Midterm Exam.

• Determine the official name of function, constant, or type. Examples: A core OpenGL function is called GL-draw-something. Give the actual name of the function. What would the name be if it were a constant? A type?
• What is an “event”?
• What is a “rendering context”?
• What happens in the “rasterization” section of the rendering pipeline?
• What is a “framebuffer”?
• List the ten OpenGL general geometry primitives.
• Given a primitive and some vertices, with order specified, indicate what will be drawn.
• The glVertex* command does two things. What are they?
• What is an “event”?
• What is the model/view transformation used for?
• What is “double buffering”, and what problem does it help with?
• Your instructor says that an object should always be drawn with its natural center at the origin. What if we want the object to appear somewhere else? What do we do?
• Draw a block diagram of the rendering pipeline, showing all the detail we have covered so far.
• Compute a linearly interpolated value. Example: We are mapping the interval \([2,4]\) to \([1,5]\). Given the value \(2.3\), lying in the first interval, use linear interpolation to find the corresponding value in the second interval.
• GLUT uses events to return the mouse position. Why might this be a poor choice?
• What is the OpenGL “viewport”?
• Draw a block diagram of the rendering pipeline, showing all the detail we have covered so far.
• What is “picking”?
• What is the “extent” of an object?
• What is a “scalar”?
• What are the components of the vector \(\langle 3,-4,2 \rangle\)? (Or a very similar question.)
• Given a matrix, find its transpose.
• Compute a simple matrix-vector product.
• Given two matrices, indicate whether their product is defined.
• Write down a \(3\times 3\) identity matrix. (Or a very similar question.)
• What do we mean by the “inverse” of a matrix?
• Perform simple matrix multiplication.
• How does OpenGL store transformations? (Note: To be precise, I am asking how OpenGL behaves, not how data are actually stored internally.)
• If a vertex (say \(\langle 1,-2,3 \rangle\)) enters the rendering pipeline, what is it converted to?
• If a 4-D vector (say \(\langle 1,-2,3,4 \rangle\)) represents a vertex inside the Vertex Processing portion of the pipeline, what is this vector converted to as it exits?
• We discussed the Painter’s Algorithm and the Reverse Painter’s Algorithm. For each of these, give one advantage it has over the other.
• Explain the difference between “object coordinates” and “world coordinates”.
• OpenGL only has facilities for multiplying on the right side of a matrix. Sometimes we need to multiply on the left. How do we do it?
• How can we rotate (or translate or whatever) an object in world coordinates?
• Explain the difference between “object coordinates”, “world coordinates”, and “camera coordinates”.
• “Camera transformations are done backwards and in reverse order.” Explain.
• Given a vector, find its length.
• Given a vector, find a unit vector in the same direction.
• Given two vectors, find their dot product.
• Explain how the dot product can be used to compute a cosine.
• What is a “shader”?
• Explain the meanings of the GLSL qualfiers attribute, uniform, varying.