Physical Simulation Language PSL John Hamer hamer John

Physical Simulation Language: PSL John Hamer hamer John Rodriguez jr 534 Danian Martinez djm 188 Taino Ortiz tjo 22

Background Info • PSL is a language intended for the convenient analysis of motion and objects in a 2 D space. • Other languages, such as Direct X, make even the simplest simulation a bother. – Window management issues – Efficient memory handling, message queueing

Purpose • PSL was created for two reasons: – To facilitate the creation of simple polygonal shapes using a simple language. – To feature interaction among these objects for the demonstration of physical principles.

Key Features • Key Features of PSL – Graphical Display • Immediate response to what he programmed in PSL – Collision Detection and Reaction • Attempts to simulate how real world objects handle collisions in the environment • Slightly costly – O(n 2) algorithm

PSL Data Flow This diagram shows the process a. PSL file is put through to become an executable

Compiler • ANTLR v 2. 7. 2 was used to develop Psl. Parser and Psl. Lexer via our languagespecific CFG • We decided to implement our own treewalker, which assisted ANTLR in performing semantic analysis of the resultant ASTs

PSL Objects • Possible objects in PSL – Circle • Circle(double center_x, double center_y, double radius) – Rectangle • Rectangle(double x, double y, double length, double width) – Square • Square(double x, double y, double length) – Polygon – convex AND concave • Poly(double x 1, double y 1, double x 2, double y 2) – Line • Line(double x 1, double y 1, double x 2, double y 2)

Abstract Syntax Tree • Each statement is composed of a subtree known as a child with the first token as the root and all proceeding tokens its children • Value list become children of the Object that is being created of altered. • The AST that ANTLR generates is read as a list and using the API provided by their AST files they are processed one child at a time.

Intermediate Code Generator • Takes in – One vector of all objects – All global variables defined • Abides by PSL-specific C++ template to generate appropriate environment and object specifications • Writes the corresponding C++ source file – PSL “bytecode”

Backend • Graphics programming already has a commonly-used API – Open. GL! • Often complicated and error prone – Complicates the simplest demo – Not for rookies… • PSL implements its powerful capabilities while eliminating the learning curve

Backend (continued) • The backend of the PSL language implemented a carefully structured OO environment using C++/Open. GL – Psl. Environment = the rendering environment – Psl. Polygon, Psl. Square, etc… • For windowing, the GLUT toolkit was used on Windows XP, Mesa on Redhat Linux. – Set using PSL Global setter methods

Design of Backend

Simple. psl def circle 1 Circle(3, 3, 3); //Creates a circle 1. color(255, 0, 0); //Sets color to red circle 1. points(20); def poly 1 Polygon(-5, 3, -5); //Creats a square Poly 1. addpoint(-2. 5, -2. 5) poly. color(0, 0, 255); //Sets color to blue Global. zoom(15); //Set the camera zoom /* Sets window size */ Global. window. Size(300, 300);

Simple. psx

Testing Plan • Modular Testing – Tested each module before integrating • Regression Testing – Tested new modules to verify that they worked with the other modules • Integration Testing – Integration of front and Backend • This Test verified that the language worked • Error Testing – Used to verify that the compiler threw errors for incorrect syntax and/or semantics

Conclusion • PSL is a valuable asset – To the graphics designer, executive, or engineer who must incorporate graphical displays into their everyday assignments. – A lecture given by a high school physics professor will be much more effective with PSL -designed presentations in his or her arsenal.

Lessons • Three very important properties of a good team – Trust – Communication – Commitment