1. Lecture 2 Review OpenGL Libraries Graphics Overview Rendering Pipeline OpenGL command structure

2. Lecture 2 OpenGL Libraries and Compilation GLUT Window initialization commands Color Drawing 2-D Primitives

3. OpenGL Libraries GLUT(OpenGL Utility Toolkit): Implements a simple windowing API for OpenGL. GLU(OpenGL Utility Library): Set of functions to create textures from base images, drawing quadratic surfaces, etc. More Details about libraries: http://www.opengl.org/resources/libraries/

4. Compilation Overview: Compiling Linking Running In Microsoft Visual Studio C++ http://csf11.acs.uwosh.edu/cs371/visualstudio/ In MinGW C http://www.transmissionzero.co.uk/computing/using-glut-with-mingw/

5. GLUT Window Initialization What is Buffer? Clearing the Window glClearColor(R, G, B, A) glClearColor(GL_COLOR_BUFFER_BIT) glClearDepth() glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

6. GLUT Window Initialization glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) Vs. glClear(GL_COLOR_BUFFER_BIT) glClear(GL_DEPTH_BUFFER_BIT)

7. OpenGL Buffers

8. Color glColor3f(R, G, B) glColor3f(0.0, 0.0, 0.0) : Black glColor3f(1.0, 0.0, 0.0) : Red glColor3f(0.0, 1.0, 0.0) : Green glColor3f(0.0, 0.0, 1.0) : Blue

9. Forcing Completion of Drawing void glFlush(void) void glFinish(void)

10. Structure of an OpenGL code Sample Code Reshape Function void reshape (int w, int h) { glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); glLoadIdentity (); gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h); }

11. Point (Vertex) Mathematical Representation OpenGL representation Homogeneous Coordinate System (Optional)

12. Line Mathematical Line Line Segment: Used in OpenGL

13. Polygon Mathematical Definitions. Convex Polygon (Used in OpenGL) What is the simplest Polygon?

14. Polygon Invalid Polygons in OpenGL

15. Polygon

20. Specifying Vertices OpenGL command: void glVertex{234}{sifd}[v](TYPEcoords); Example: glVertex2s(2, 3); glVertex3d(0.0, 0.0, 3.1415926535898); glVertex4f(2.3, 1.0, -2.2, 2.0); GLdouble dvect[3] = {5.0, 9.0, 1992.0}; glVertex3dv(dvect);

21. Specifying Lines, Polygons Specifying a set of vertices glBegin(GLenum_mode); glVertex2f(0.0, 0.0); glVertex2f(0.0, 3.0); glVertex2f(4.0, 3.0); glVertex2f(6.0, 1.5); glVertex2f(4.0, 0.0); glEnd();

22. Specifying Lines, Polygons

23. glBegin(parameters)

24. Stippled Lines Definition Command: glLineStipple(GLint factor, GLushort pattern) glEnable(GL_LINE_STIPPLE)

25. QUESTIONS?

26. Next Session Interactive Programming with GLUT Callback Registration Keyboard, Mouse Callbacks Animation Double Buffering