Welcome to the Laser 2.0 Raytracer!
To use the raytracer, you first need to make sure a Laser scene description is entered in the text box at the top of the raytracer window. If you are unfamiliar with Laser, the easiest thing to do is use one of our sample scenes. You can use a sample scene by typing
in the text box, where scenename is the name of the scene you would like to use. Alternatively, you can visit the URL and paste the code into the Laser text box. (The URL connection has been known to timeout and/or fail). To find a list of the available sample scenes, visit http://web.mit.edu/morganm/Public/lsr/scenelist.html. Also, you can get a quick sampling of what the raytracer does by rendering the default scene,(include "http://web.mit.edu/morganm/Public/lsr/scenename.lsr")
which is a sphere at the origin lit by a directional light coming from the upper left.(list (sphere) (directional-light))
If a scene is entered in the text box, you can push the Render button to have the program raytrace your scene. The raytraced scene will appear in the black box in the bottom part of the window. Be warned: it will take a long time for the final picture to show up, so please be patient! Also, please note that the picture will show up all at once after the program has completely calculated everything it needs to, rather than showing up incrementally.
To get an idea of what the program is doing, you can open the Netscape Java Console by choosing Show Java Console under the Options menu. The raytracer prints out all sorts of useful information here. For example, open up the Java Console when the default scene is entered in the text box. Then push the Evaluate button. In the Console, you will see the program's evaluation of the Laser code for the default scene. Now push the Render button. The Console shows what objects the program found, and whether or not they were added to the scene. It also shows the transformation matrices of some of the objects. In addition, it gives some useful information on the rendering status. While the last thing in the console is
the program is calculating everything it needs to in order to render the scene. When the console displaysRendering Universe:
the program has finished calculating and has drawn the image into the picture box.called paint
If your Laser scene discription has a syntax error, the Java Console will display it. Usually errors are caused by mismatched parantheses, so be careful! Errors can also be caused by using the wrong argument names for objects, or incorrect syntax for a Scheme operation, such as addition. To find out the correct syntax, see the Laser Language 2.0 Graphics API.
To save a picture you have rendered, you need to use the Screen Capture utility on your computer. This utility varies depending on what operating system you are using, so look it up in your operating system documentation.
We hope you enjoy using the Laser 2.0 Raytracer! Please direct comments and questions to the authors of the program, Laura Wollstadt and Morgan McGuire.
While the Laser 2.0 Raytracer is a functioning raytracer and Laser interpreter (and Scheme interpreter), there are doubtlessly many bugs which will take take time to find and correct. Send buglists to the authors. Some known bugs (the cause of which, of course, being unknown) are include and runtime, the Scheme and Java runtime linkers for laser malfunctioning. Cone, Spot-light and Rightcylinder are not fully debugged either.
LBW 12/09/96