Accelerometer and Open GL
Upcoming SlideShare
Loading in...5
×
 

Like this? Share it with your network

Share

Accelerometer and Open GL

on

  • 2,590 views

Jon Liang - Accelerometer and Open GL. 360|iDev San Jose '09

Jon Liang - Accelerometer and Open GL. 360|iDev San Jose '09

Statistics

Views

Total Views
2,590
Views on SlideShare
2,576
Embed Views
14

Actions

Likes
1
Downloads
32
Comments
0

1 Embed 14

http://www.slideshare.net 14

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Accelerometer and Open GL Presentation Transcript

  • 1. Introduction to Accelerometers and OpenGL ES on the iPhone Jon Liang ● Mobility Lead – Mobclix ● http://www.mobclix.com ● Jeff LaMarche ● Author - Beginning iPhone Development: Exploring ● the iPhone SDK http://iphonedevelopment.blogspot.com/ ●
  • 2. Introduction to Accelerometers and OpenGL ES on the iPhone OpenGL ES ● Accelerometer ● More OpenGL ●
  • 3. OpenGL ES 1.1 - Open Graphics Library for Embedded Systems
  • 4. OpenGL Source:http://www.cs.unc.edu/~walk/pap//fig1.gif
  • 5. OpenGL (continued) Platform independent ● Input ● Points, Lines, Polygons ● Transforms ● Textures ● Transparency ● Lighting ●
  • 6. OpenGL Pipeline Source: Apple
  • 7. Code: Hello World
  • 8. Quartz 2D vs. OpenGL for 2D Quartz 2D ● Higher Level API ● Compatible with – CoreAnimation Easier to Display Text – Inverted y-axis ● OpenGL ● Low Level API ● More Control – Source: Apple Less Overhead – 3D ●
  • 9. iPhone Limitations 24 MB of Memory for textures and surfaces. ● The maximum texture size is 1024 x 1024. ● 2D texture targets are supported; other texture ● targets are not. Stencil buffers aren’t available. ● More Info: ● http://developer.apple.com/iphone/library/documentation/i – Phone/Conceptual/iPhoneOSProgrammingGuide/Graphi csandDrawing/chapter_6_section_5.html#//apple_ref/doc /uid/TP40007072-CH10-SW18
  • 10. Open GL → OpenGL ES Removed glBegin() and glEnd() ● Use glDrawArrays() or glDrawElements() ● Added Fixed Point data types ● Embedded systems often don't have FPU's. ● Removed convenience functions ● More lightweight implementation. ●
  • 11. Questions?
  • 12. Accelerometer
  • 13. Accelerometer Hardware ● 3-Axis MEMS Accelerometer ● Part Number: LIS302DL – Max Sample Rate: 400 Hz – Max Acceleration: ± 8g – No Gyroscope ● Implications ● No Direct Angular Acceleration Data ● Zeroed at Free Fall ● Limited Amplitude (± 4g per axis) ●
  • 14. Basic Tasks: Signal Processing Isolating Large Movements ● Low-Pass Filter: ● xn = xn-1/2 + x/2 Isolating Small Movements ● High-Pass Filter: ● xn = x - xn-1 Sournce: http://jp.physoc.org/content/vol550/issue3/fulltext/873/Figures/HiRes/873-F2.gif
  • 15. Basic Tasks: Ground Angle 2 Dimensions: ● Θ = atan(y/x) Axis-Plane: ● Θ = atan(z/sqrt(x2+y2)) Source: http://www.forestgumpsays.com/wp-content/uploads/2008/03/3iphoneaxes.jpg
  • 16. Basic Tasks: Simple Gestures Swipe ● Positive-Negative Spike Shake ● Oscillating Wave Rotations ● 2-Axis Change
  • 17. Classes UIAccelerometer UIAcceleration Methods Properties + sharedAccelerometer UIAccelerationValue x Properties UIAccelerationValue y updateInterval UIAccelerationValue z delegate NSTimeInterval timestamp MyClass <UIAccelerationDelegate> Methods - (void) accelerometer:(UIAccelerometer*) accelerometer didAccelerate:(UIAcceleration*) acceleration MyOtherClass
  • 18. Code: Hello World (continued)
  • 19. Questions?
  • 20. More Open GL
  • 21. Apple Sample Code Accelerometer Graph ● Crash Landing ● GLGravity ● GLPaint ● GLSprite ● Touchfighter II ●
  • 22. Additional Resources Open GL ● http://www.khronos.org/opengles/sdk/1.1/docs/man/ ● http://www.glprogramming.com/red/ ● Accelerometer ● www.st.com/stonline/products/literature/ds/12726.p ● df http://squallchua.blogspot.com/2008/12/wiimote-gesture ● http://ifiddling.blogspot.com/2009/01/dummy2.html ●
  • 23. Additional Resources (continued) Collision Models ● http://www.metanetsoftware.com/technique/tutorialA ● .html http://www.metanetsoftware.com/technique/tutorialB ● .html http://www.euclideanspace.com/physics/dynamics/c ● ollision/index.htm