High Performance Visualization I

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High Performance Visualization I

• Instructors
• Dr. James Sochacki
• Dr. Ramon Mata-Toledo
• Lab Instructors
• Joshua Blake
• Justin Creasy

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Introduction

• HPV I
• Introduction to OpenGL and Scientific
  Visualization
• HPV II
• Introduction to the Immersive Visualization
  System
• http//ivs.cs.jmu.edu/
• HPV III (proposed for Spring 05)
• Projects on IVS

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Immersive Visualization System
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Course Overview

• OpenGL
• 3D graphics API standard
• Cross-platform
• Hardware accelerated (i.e. GeForceFX 5950 Ultra)
• DirectX / Direct3D
• Windows only
• Maya / 3dStudio / Blender
• Create 3D Models
• NOT an API
• NOT the subject of this course

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Course Overview

• Scientific Visualization
• Visualization of scientific data
• Sources Measured, estimated, computed
• We will focus on computed
• Visualize in order to make data understandable
• Complex and high-dimensional data (5 or 6
  dimensions) is hard to understand!

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OpenGL History

• OpenGL Open Graphics Library
• Single Vendor-independent API for 2D and 3D
  graphics applications
• Adapted from SGI Iris GL library in 1992
• Industry review board
• Recently released OpenGL 2.0 spec
• No license needed!

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WTF is OpenGL?

• According to The Redbook (SGI)
• Construct shapes from geometric primitives,
  thereby creating mathematical descriptions of
  objects. (OpenGL considers points, lines,
  polygons, images, and bitmaps to be primitives.)

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• Arrange the objects in three-dimensional space
  and select the desired vantage point for viewing
  the composed scene.

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• Calculate the color of all the objects. The
  color might be explicitly assigned by the
  application, determined from specified lighting
  conditions, obtained by pasting a texture onto
  the object, or some combination of these three
  actions.

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• Convert the mathematical description of objects
  and their associated color information to pixels
  on the screen. This process is called
  rasterization.
• Also
• No commands for performing windowing tasks or
  obtaining user input are included in OpenGL
  instead, you must work through whatever windowing
  system controls the particular hardware youre
  using.

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OpenGL Programming Environment

• OpenGL spec contains 150 commands
• Other libraries add to functionality
• GLUT GL Utility Toolkit
• Handles windowing, input/output
• Cross-platform, Windows and Linux and more

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Setting up GLUT on VS.Net 2003

• Download GLUT
• http//www.xmission.com/nate/glut/glut-3.7.6-bin.
  zip
• Copy files to appropriate directories
• glut.h -gt C\Program Files\Microsoft Visual
  Studio .NET 2003\Vc7\PlatformSDK\Include\gl
• glut32.lib -gt \PlatformSDK\Lib
• Glut32.dll -gt C\Windows\System
• Glut32.dll must be on any computer that runs a
  glut program, so distribute it with your program

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Creating a Project in VS.Net 2003

• Create New Project (Select Visual C Projects,
  Win32, Win32 Console Project), give it a name,
  and press OK

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Creating a Project in VS.Net 2003

• Click Application Settings and check Empty
  Project

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Creating a Project in VS.Net 2003

• Add source files, compile, and run!
• Creating a project reference
• http//helpdesk.cs.tamu.edu/docs/glut_Visual_Studi
  o2003

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First Program

• include ltgl/glut.hgt
• void renderScene(void)
• glClear(GL_COLOR_BUFFER_BIT)
• glBegin(GL_TRIANGLES)
• glVertex3f(-0.5,-0.5,0.0)
• glVertex3f(0.5,0.0,0.0)
• glVertex3f(0.0,0.5,0.0)
• glEnd()
• glFlush()

• void main(int argc, char argv)
• glutInit(argc, argv)
• glutInitDisplayMode(GLUT_DEPTH GLUT_SINGLE
  GLUT_RGBA)
• glutInitWindowPosition(100,100)
• glutInitWindowSize(320,320)
• glutCreateWindow("3D Tech- GLUT Tutorial")
• glutDisplayFunc(renderScene)
• glutMainLoop()

Source http//www.lighthouse3d.com/opengl/glut/in
dex.php3?2
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Draw with Points, Quads, Triangles

• glBegin(GL_TRIANGLES)
• Begins a vertex list, and specifies how to
  process the vertices. Vertex list ends with
  glEnd() below.
• glVertex3f(-0.5,-0.5,0.0)
• glVertex3f(0.5,0.0,0.0)
• glVertex3f(0.0,0.5,0.0)
• The vertex list. We can also have colors,
  normals, and other appropriate commands here
• glColor3f(1.0, 0.0, 0.0)
• glVertex3f(-1.5,-0.5,0.0)
• glColor3f(0.0, 1.0, 0.0)
• glVertex3f(-0.5,0.0,0.0)
• glColor3f(0.0, 0.0, 1.0)
• glVertex3f(-1.0,0.5,0.0)
• glEnd()

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Draw with Points, Quads, Triangles
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Callbacks

• Give GLUT function pointers to our functions
• void renderScene(void)
• glutDisplayFunc(renderScene)
• GLUT calls the function as needed, according to
  the purpose.

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Input

• void keyboard(unsigned char key, int x, int y)
• glutKeyboardFunc(keyboard)
• Keyboard input (characters plus escape key) are
  sent to this callback
• X and Y are mouse position in window coordinates
  when key is pressed

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Animation!

• void timer(int num)
• int milliseconds 10, num 1
• glutTimerFunc(milliseconds, timer, num)
• Sets a timer and the specified function is called
  at minimum 10 ms (in this case) with a value of
  1.
• void idle()
• glutIdleFunc(idle)
• Calls the idle function whenever GLUT isnt doing
  anything else

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Program State

• Anything that determines what is displayed is
  called the program state.
• In a game would be game state
• For smooth animation, the state should be updated
  only in the timer function.
• User input should change HOW the timer function
  changes the state (i.e. change the rate of
  change/velocity)
• Timer function can do small bits of computation

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Reference

• www.opengl.org
• www.sgi.com/products/software/opengl
• www.gatetutorials.com/Tutorials/tutorials.htm
• www.gamedev.net (The Redbook)

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Homework

• Write name in 2D using Quads and/or Triangles
• Make it animated in a cool way.