Physical Simulation Language : P S L

Physical Simulation Language:PSL John Hamer John Rodriguez Danian Martinez Taino Ortiz hamer jr534 djm188 tjo22

Background Info • PSL is a language intended for the convenient analysis of motion and objects in a 2D 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(n2) algorithm

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

Compiler • ANTLR v2.7.2 was used to develop PslParser and PslLexer via our language-specific 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 x1, double y1, double x2, double y2) • Line • Line(double x1, double y1, double x2, double y2)

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 – OpenGL! • 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++/OpenGL • PslEnvironment = the rendering environment • PslPolygon, PslSquare, 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 circle1 Circle(3, 3, 3);//Creates a circle circle1.color(255, 0, 0);//Sets color to red circle1.points(20); def poly1 Polygon(-5, -5, 3, -5);//Creats a square Poly1.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.windowSize(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

Physical Simulation Language : P S L