Final project for CR31 module Computer Graphics for University of Leeds.

See the Screenshots section for examples of the scenes this experimental raytracer program can render.

Raytracing:

• Casting rays through each pixel
• Sphere and triangle intersections
• Surface colours and textures

Advanced Raytracing:

• Local illumination with own implementation of Phong lighting
• Multiple light sources possible
• Reflection and refraction rays
• Shadows cast
• Multisampling (uniform/grid and random)

Terrain Rendering:

• Loading heightfield from image file (uses intensity of red for height)
• Uses central differencing to compute surface normals
• Uses layered, blended textures to provide detailed/varying surfaces based on height (the higher the terrain, the more rocky the surface becomes, for example)

Geometric Optimisation:

• Octree structure used to optimise terrain rendering
• Octree is dynamically constructed by simply adding more
• shapes to the Octree, with subdivisons being created as necessary
• Visualisation of Octree regions possible. Parameters for good visualisation of Octrees is below: Sampling: Uniform Multisampling with 2 Samples Dimensions: 200 x 200 All effects disabled Terrain: Low/Shallow Viewpoint: Camera 2 Octree enabled and visible

Other features:

• Save rendered images to files
• Configure different parameters of the scene

This program demonstrates the basic raytracing and terrain engine I developed through a demo scene. This scene consists of four spheres, terrain and a sky box. The four spheres consist of:

• one purely reflective
• one a mixture of refraction/felection
• one slightly reflection (yellow)
• one purely opaque

The terrain can be varied between three types - varied, shallow and high peaks. These demonstrate the effects the different structures have one equations.

There are two lights - one far away in the sky and one which is on the yellow sphere. These can be enabled/disabled using the check boxes on the right.

Since the terrain is wrapped in an Octree structure to increase rendering times, it is possible to enable/disable this acceleration structure using the check box "Use Octree". It is possible to see how the Octree has split the space up into regions by checking "Show Octree". Bear in mind doing this will drasticly reduce rendering times.

# Generate makefile and run it
./qt-build project

# Subsequent builds (don't need to run 'project' command,
# since makefile is already generated)
./qt-build

# Running the build executable will open up a GUI which can render a 
# number of scenes with configurable parameters (e.g. camera location)
./raytracer-experiments

Note that the Qt4 development libraries must be installed in a place the compiler will be able to pick up the required headers and static libraries. the qt4-qmake command line tool must also be installed to generate the project's makefile.

On Ubuntu, the required Qt4 packages can be installed using the following command:

sudo apt-get install \
    libqt4-dev \
    libqt4-dev-bin \
    libqt4-opengl-dev \
    libqtwebkit-dev \
    qt4-linguist-tools \
    qt4-qmake \

Credit goes to the following sources for the invaluable help they gave:

• Realistic Raytracing (Peter Shirley, R. Keith Morley)
• http://steve.hollasch.net/cgindex/render/refraction.txt
• http://www.catalinzima.com/xna/tutorials/4-uses-of-vtf/terrain-rendering-using-heightmaps/
• http://www.cs.jhu.edu/~cohen/RendTech99/Lectures/Ray_Tracing.bw.pdf
• https://github.com/jelmervdl/raytracer/blob/master/scene.cpp