COMP 5822M: High Performance Graphics
May 20-22, 2020
This question paper consists
of 2 printed pages each
of which is identified by the Code COMP5821M
ý UNIVERSITY OF LEEDS
School of Computing
May 2020
COMP5822M: High Performance Graphics
Answer all questions. There are 40 marks in total.
Submit a single PDF document with your answers.
Aids: You may use any reference materials you wish, including internet searches. You may use a calculator. You may use code that you have developed yourself or been provided by the instructor, if that helps you with the answer.
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Time allowed: 48 hours
COMP 5822M: High Performance Graphics May 20-22, 2020
Question 1: Vulkan Pipeline Design [4 marks]
Describe one design choice in Vulkan that you think was particularly well done, and one that you think was particularly poorly done. Explain why you think so.
Question 2: Rasterisation [4 marks]
Of all the stages in the render pipeline, the rasterisation stage has not yet been opened up for shader programming. Can you identify one good reason why it should be, and another why it should not be?
Question 3: Building a Raytracing Pipeline [6 marks]
Suppose you were asked to design a brand new pipeline for raytracing based on parallel hardware similar to a modern GPU. Draw a diagram for a suitable raytracing pipeline, and describe what each stage would do.
Question 4: Coordinate Systems [6 marks]
In the fixed function pipeline, transformation matrices are applied to convert primitives from the World Coordinate System (WCS) to the Device Coordinate System (DCS), allowing rasterisation and fragment processing to use image coordinates. As rendering has become more sophisticated, some techniques rely on using the WCS in the fragment shader. Give two examples of where this has been done, and explain why.
Question 5: Coordinate Systems [6 marks]
For some techniques, we need to know a coordinate system with respect to a given point on the surface. Give two examples of when this is useful (two variations on the same idea do not count), and explain how to find such a coordinate system.
Question 6: Indirect Lighting [8 marks]
Blinn-Phong does a poor job of simulating indirect lighting, but is simple and efficient in practice. Recursive raytracing is much better, but still to expensive. What techniques would you choose to improve indirect lighting for each of the following, and why?
a) A landscape in a flight simulator
b) A jungle landscape in a first person shooter
c) The interior of an office building with many glass windows
d) The interior of a dark cavern with flickering light sources
Question 7: God Rays
[6 marks]
A “god ray” is a shaft of light coming down through the lights and reflecting off aerosol particles beneath the clouds towards the viewer. How would you add this to a render, and what problems would you anticipate as a result?
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