1. Chap 2 Write a Simple OpenGL Program

2. Preparing 1/2 environment ： Microsoft Visual C++ 6.0 、 Microsoft Visual C++.Net Also need ： GLUT http://www.xmission.com/~nate/glut.html

3. Preparing 2/2 On Microsoft Visual C++ 6.0 Put glut.h into /include/GL/ Put glut.lib into /lib/ Put glut32.dll into /System32/ On Microsoft Visual C++.Net Put glut.h into /platformSDK/include/GL/ Put glut.lib into /platformSDK/lib/ Put glut32.dll into /System32/

4. Books OpenGL Programming Guide (Red-book) OpenGL Reference Manual (Blue-book) OpenGL SuperBible

5. OpenGL Utility Toolkit (GLUT) A window system-independent toolkit to hide the complexity of differing window system APIs. Providing following operations: Initializing and creating window Handling window and input events Drawing basic 3D objects Running the program Use the prefix of glut (ex: glutCreateWindow)

6. Write an OpenGL Program 1/7 Microsoft Visual C++ 6.0 Step 1: create a Win32 Console Application project

7. Write an OpenGL Program 2/7 Step 2:Press Alt-F7 ， brings “ Project Settings ” ， select “ Link ”

8. Write an OpenGL Program 3/7 Step 3:add opengl32.lib glu32.lib glut32.lib into Object/library modules: Step 4:write your code Step 5:compile

9. Write an OpenGL Program 4/7 Microsoft Visual C++.Net Step 1:create Win32 console project

10. Write an OpenGL Program 5/7 Step 2: check “ empty project ”

11. Write an OpenGL Program 6/7 Step 3:select project / property … / linker / input Step 4: add opengl32.lib glu32.lib glut32.lib

12. Write an OpenGL Program 7/7 Step 5: add a new C++ source file Step 6:write your code Step 7:compile

13. A simple OpenGL program 1/2 #include void GL_display(){ glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glColor3f(1.0f, 1.0f, 1.0f); glutSolidCube(1.0); glFlush(); } void GL_reshape(GLsizei w, GLsizei h){ glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-2.0f, 2.0f, -2.0f, 2.0f, -2.0f, 2.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); }

14. A simple OpenGL program 2/2 void main(int argc, char** argv){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutCreateWindow("sample"); glutDisplayFunc(GL_display); glutReshapeFunc(GL_reshape); glutMainLoop(); }

15. OpenGL command Syntax 1/2 OpenGL commands use the prefix gl and initial capital letters for each word ex: glClearColor OpenGL defined constants begin with GL_, use all capital letters and underscores to separate words ex: GL_COLOR_BUFFER_BIT

16. OpenGL command Syntax 2/2

17. State management 1/2 OpenGL is a state machine You put it into various states (or modes) that then remain in effect until you change them. Each state variable or mode has a default value, and at any point can query the system for each variable ’ s current value.

18. State management 2/2 glEnable(GLenum), glDisable(GLenum) Enable and disable some state. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_3l5x.asp glIsEnable(GLenum) Query if the specific state is enabled. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc03_7pgk.asp glGetBooleanv(), glGetIntegerv(), glGetFloatv(), glGetDoublev(), glGetPointerv() Query the specific state value http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc02_5ub8.asp

19. Program detail 1/5 Initializing and creating a window void glutInit(int *, char**) Initializing the GLUT library. Should be called before any other GLUT routine. http://www.opengl.org/resources/libraries/glut/spec3/node10.html void glutInitDisplayMode(unsigned int) Specify a display mode for windows created. GLUT_RGB / GLUT_RGBA / GLUT_INDEX GLUT_SINGLE / GLUT_DOUBLE GLUT_DEPTH / GLUT_STENCIL / GLUT_ACCUM http://www.opengl.org/resources/libraries/glut/spec3/node12.html

20. Program detail 2/5 void glutInitWindowPosition(int, int) void glutInitWindowSize(int, int) Initializing the window position and size when created. http://www.opengl.org/resources/libraries/glut/spec3/node11.html int glutCreateWindow(char*) Open a window with previous settings. http://www.opengl.org/resources/libraries/glut/spec3/node16.html#383

21. Program detail 3/5 Handling window and input events void glutDisplayFunc(void (*func)(void)) Called whenever the contents of the windows need to be redrawn. Put whatever you wish to draw on screen here. Use glutPostRedisplay() to manually ask GLUT to recall this display function. http://www.opengl.org/resources/libraries/glut/spec3/node46.html void glutReshapeFunc(void (*func)(void)) Called whenever the window is resized or moved. You should always call glViewport() here to resize your viewport. http://www.opengl.org/resources/libraries/glut/spec3/node48.html

22. Program detail 4/5 Other call back functions void glutKeyboardFunc(void (*func)(unsigned char key, int x, int y)); http://www.opengl.org/resources/libraries/glut/spec3/node49.html void glutMouseFunc(void (*func)(int button, int state, int x, int y)); http://www.opengl.org/resources/libraries/glut/spec3/node50.html void glutMotionFunc(void (*func)(int x, int y)); http://www.opengl.org/resources/libraries/glut/spec3/node51.html void glutIdleFunc(void (*func)(void)); http://www.opengl.org/resources/libraries/glut/spec3/node63.html See OpenGL Programming Guide: Appendix D for more detail.

23. Program detail 5/5 Running the program void glutMainLoop(void); Enter the GLUT processing loop and never return.

24. GLUT objects GLUT provides the follow objects: Sphere, cube, torus, icosahedron, ocrtahedron, tetrahedron, teapot, dodecahedron, cone. Both wireframe and solid Ex: glutSolidSphere(1.0, 24, 24) Ex: glutWireCube(1.0) http://www.opengl.org/resources/libraries/glut/spec3/node80.html#SECTION000120000000000000000

25. OpenGL program -2 1/2 #include void GL_display(){ glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_POLYGON); glColor3d(1.0f, 1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, 0.0f); glColor3d(1.0f, 0.0f, 0.0f); glVertex3f(1.0f, -1.0f, 0.0f); glColor3d(0.0f, 1.0f, 0.0f); glVertex3f(1.0f, 1.0f, 0.0f); glColor3d(0.0f, 0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.0f); glEnd(); glFlush(); }

26. OpenGL program -2 2/2 void GL_reshape(GLsizei w, GLsizei h){ glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-2.0f, 2.0f, -2.0f, 2.0f, -2.0f, 2.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void main(int argc, char** argv){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(250, 250); glutInitWindowPosition(100, 100); glutCreateWindow("Drawing sample"); glutDisplayFunc(GL_display); glutReshapeFunc(GL_reshape); glutMainLoop(); }

27. Data type

28. Clear the buffers 1/2 void glClearColor(GLclampf, GLclampf, GLclampf, GLclampf ) Set the current values for use in cleaning color buffers in RGBA mode. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_0rhu.asp void glClearDepth(GLclampd) Set the current values for use in cleaning depth buffer. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_4j1k.asp

29. Clear the buffers 2/2 void glClear(GLbitfield) Clear the specified buffers to their current clearing values. GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT GL_ACCUM_BUFFER_BIT GL_STENCIL_BUFFER_BIT http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_8koi.asp

30. Color representation RGBA: red, green, blue, alpha Each channel has intensity from 0.0~1.0 Values outside this interval will be clamp to 0.0 or 1.0 Alpha is used in blending and transparency Specify a color: glColor{34}{sifd}[v]( … ) http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_62b6.asp

31. Points, Lines and Polygons 1/5 Describe points, lines, polygons void glBegin(GLenum) Marks the beginning of a vertex-data list The mode can be any of the values in next page void glEnd() Marks the end of a vertex-data list http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc01_9u3y.asp

32. Points, Lines and Polygons 2/5

33. Points, Lines and Polygons 3/5

34. Points, Lines and Polygons 4/5 Specifying the vertices glVertex{234}{sifd}[v]( … ) Specifies a vertex for use in describing a geometric object Can only effective between a glBegin() and glEnd() pair http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc03_2kag.asp

35. Points, Lines and Polygons 5/5 Specifying others … glNormal*(), glColor*(), glIndex*(), glTexCoord*(), glMaterial*() … These commands should always be called before glVertex*()

36. Completion of drawing 1/2 void glFlush() Forces previously issued OpenGL commands to begin execution. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc02_8sa0.asp void glFinish() Forces previous issued OpenGL commands to complete. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/glfunc02_3aqw.asp

37. Completion of drawing 2/2 void glutSwapBuffers() Swap front and back buffers. http://www.opengl.org/resources/libraries/glut/spec3/node21.html