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OpenGL Programming

OpenGL Programming. Adam Hewgill MSc Computer Science ta480@cis.uoguelph.ca http://teachweb.cis.uoguelph.ca/cs4800. Special Thanks to:. What is OpenGL?. Open Graphics Library Computer Graphics API Production Quality Interfaces with Graphics Hardware Multi-platform library

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OpenGL Programming

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  1. OpenGL Programming Adam Hewgill MSc Computer Science ta480@cis.uoguelph.ca http://teachweb.cis.uoguelph.ca/cs4800 Special Thanks to:

  2. What is OpenGL? • Open Graphics Library • Computer Graphics API • Production Quality • Interfaces with Graphics Hardware • Multi-platform library • Originally created by SGI in the early 90’s • Controlled by the ARB since 1992 • 3D Labs, Apple, ATI, Dell, IBM, Intel, NVIDIA, SGI, and Sun Microsystems

  3. OpenGL In-depth • OpenGL 1.3 • Released on August 14th, 2001 • My first view of OpenGL as a programmer • Basic Shape Drawing • Lighting • Color Blending (Transparency) • Vertex Arrays and Display Lists • Texture Mapping (2D and 3D) • Texture LOD Mapping (Mip-mapping) • Anti-aliasing • Multi-texturing • DOT3 Environment Mapping (Early Bump Mapping) • Behind Direct3D 8 due to Pixel and Vertex Programs • Demise predicted by many on the Direct3D side

  4. OpenGL 1.4 • Released on July 24th, 2002 • Vertex and Fragment (Pixel) Program Support • ARB Extension • Mipmap Auto Generation • Depth Texturing (Better Bump Mapping) • Fog • Various advances to other more specialized functions • Behind Direct3D 9 due to Pixel and Vertex Shaders • Most Graphics cards specialized for DirectX now

  5. OpenGL 1.5 • Released on July 29th, 2003 • Vertex and Fragment (Pixel) Shader Support • ARB Extension • Buffer Objects • Occlusion Queries • Improved texture comparison for shadow mapping

  6. OpenGL 2.0 • Released on September 7th, 2004 • Vertex and Fragment (Pixel) Shader Support • OpenGL Shading Language (GLslang) • Non-power of two textures • Point sprites (for particles) • Separate Stencil (shadow volumes) • Now includes full support of GPUs • However no GPU yet supports all of OpenGL 2.0 • Now comparable to Direct3D • Still more stuff for Direct3D as seen on both the ATI and NVIDIA SDK sites, most games still use DirectX • http://www.opengl.org/documentation/specs/version2.0/glspec20.pdf

  7. What is GLUT? • OpenGL Utility Toolkit • GUI Windowing and Control API • Event-Driven System • Creates windows to display OpenGL view port • Handles Keyboard, Mouse, etc. events • May only be available for Windows and Linux however source is on-line for porting • Windows http://www.xmission.com/~nate/glut.html • Linux http://www.opengl.org/resources/libraries/glut.html • Other alternatives • http://www.opengl.org/resources/libraries/windowtoolkits.html

  8. How do we get started? • Linux • GLUT uses XWindows libraries • Check for /usr/include/gl/glut.h and gl.h • GCC is generally used to compile • OpenGL is either MESA (Software) or provided by your graphics card (Hardware) • Implementations of open specs • Program using any editor you like • Include <gl\gl.h> and <gl\glut.h> • gcc filename.c -o outputname -I/usr/X11R6/include/ -L/usr/X11R6/lib -lX11 -lXi -lXmu -lglut -lGL -lGLU -lm

  9. Windows • MinGW, MSYS • Visual Studio [ X | .NET | 200X ] Y Edition • Borland C/C++ Builder • DJGPP • etc.

  10. Visual Studio 2005 Express Edition Beta • http://lab.msdn.microsoft.com/express/visualc/ • Microsoft Platform SDK • http://www.microsoft.com/msdownload/platformsdk/sdkupdate/ • Install Visual Studio then Platform SDK • Install Glut for Win32 • Copy glut32.lib into lib directory • Copy glut.h into include directory • Copy glut32.dll into C:\Windows\system32 • Open Visual Studio • Create New Project (Win32, Console Application) • Click Project in Solution Explorer (on right side) • Click Project -> Project Properties … • Select General under C/C++ • Add C:\Program Files\Microsoft SDK\include • Select General under Linker • Add C:\Program Files\Microsoft SDK\lib • Add .cpp file to project • Include <windows.h> <gl/gl.h>

  11. MAC • Sorry never done it before • http://developer.apple.com/graphicsimaging/opengl/index.html

  12. Hello World #include <gl/gl.h> #include <gl/glut.h> void draw () { glClear(GL_COLOR_BUFFER_BIT); glFlush(); } int main (int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE); glutInitWindowSize(100, 100); glutCreateWindow(“Hello World”); glutDisplayFunc(draw); glutMainLoop(); return 0; }

  13. Hello World Analysis • Result 100x100 Blank Black Windows • glutInit(int *argcp, char **argv) • Sets up GLUT • glutInitDisplayMode(unsigned int mode) • Color Mode • GLUT_INDEX Indexed Color Mode :o( • GLUT_RGB Red, Green, Blue Mode :o) • GLUT_RGBA RGB + Alpha Mode :oD • Buffer Mode • GLUT_SINGLE Single Drawing Buffer • GLUT_DOUBLE Two Buffer Drawing • Extra Buffers • GLUT_DEPTH Allow space for Depth Buffer • … • glutInitWindowSize(int width, int height) • glutCreateWindow(char *title)

  14. glutDisplayFunc(void (*func)(void)) • Parameter is name of function for all *Func()’s • glutMainLoop() • Never Exits • Starts the Event Driven GLUT Engine • Round-Robin thru Callbacks registers • glClear(GLbitfield mask) • GL_COLOR_BUFFER_BIT Color Part of Buffer • GL_DEPTH_BUFFER_BIT Depth Part of Buffer • glFlush() • Forces processing of buffered commands • Just in case

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