CAP4730: Assignment 4

Compare Ray-Tracing to OpenGL

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Assigned: Friday, March 21^st, 2008
Due: Monday, April 14^th, 2008

Objective: For a given scene:

1) render it OpenGL

2) ray-trace it (you can enhance the ray-trace scene to make it as realistic/artistic as possible)

Analyze the differences.

Step 1: Create a scene.

Step 2: Download, install, and go through the tutorials for povray (http://www.povray.org/). If you know how to use another ray-tracer, please feel free to use it.

Step 3: If you want to convert models from 3ds, .obj, or other file formats, download poseray (http://mysite.verizon.net/sfg0000/index.htm)

Step 4: Render the scene in OpenGL.

Step 5: Save a screenshot (on a PC, use Alt-PrintScreen to copy the current window’s contents to the clipboard, then go into a program like Paint to paste and save it out)

Your ray-traced scene should contain at least:

Lighting: point light source, area light source, objects that emit light

Objects: Surfaces that reflect, surfaces that refract, constructive solid geometry, textures

Render the scene in PovRay with a global_settings {max_trace_ray }setting of 1, 5, and 10.

Understandably, you can not do everything the same between OpenGL and ray-tracing, just do the best you can.

Report (Maximum 2 pages, 1 page of pictures/screen shots)

· Your report should have the following sections

· Performance

1. Plot the time to ray-trace as you increase the # of lights (from 1- to at least 4) (5 points)

2. Estimate the # of rays fired to render your scene. Write how you came up with that estimate (5 points)

· Differences

1. Lighting differences between the OpenGL and ray traced image of your scene (5 points)

2. Geometry differences between the OpenGL and ray traced image of your scene (5 points)

3. Visual differences between the OpenGL and ray traced image of your scene (5 points)

4. What types of objects can you do easily with ray-tracing you can not do easily with OpenGL? (5 points)

Turn in:

• Web page including links to:
• .pov file of your scene
• .doc or .pdf of your report
• and images of:
• Screenshot of your pov-ray image
• Screenshot of your OpenGL image (lined up somewhat closely to the pov-ray image)

Extra credit:

Best scene (artistic) – 10 points. (aesthetics)

Best scene (technical) – 10 points. (complexity)

Grading:
OpenGL Rendering (10 points)

Ray-traced scene (60 points)

1. 15 points each for:

1. Point Light source, Area Light source, Emissive objects

2. Reflective surfaces, refractive surfaces

3. constructive solid geometry

4. Textures

2. Report (30 points)