Gerard Pace - 2007528V

Interactive 3D Graphics and Animation

Crazy Ants

User Guide

Installation

• At prompt type "make" to compile program.
• Once compiled type "./prog" to run program.

Included files

• Main directory contains makefile, .cpp files and .h files.
• "/textures" directory contains ppm file for texture maps.
• "/keyframes" directory contains keyframe data files.

Key Bindings

In standard mode:

• p - play/pause
• < - select previous ant
• > - select next ant
• h - toggle between focusing on an ant or on the ant mound
• a - increas ant speed
• z - decrease ant speed
• f - toggle fog
• TAB - toggle wireframe, flat shading and smooth shading
• ESC - Exit
• m - enter modify keyframe mode

In modify keyframe mode:

• Down(On numpad with numlock on) - modify child joint
• Up(On numpad with numlock on) - modify parent joint
• Left(On numpad with numlock on) - modify previous sibling joint
• Right(On numpad with numlock on) - modify next sibling joint
• Center(On numpad with numlock on) - modify other axis on current joint
• + - Increase angle by 5 degrees
• - - Decrease angle by 5 degrees
• ] - Increase angle by 1 degree
• [ - Decrease angle by 1 degree
• n - next keyframe(while animation is paused)
• b - previous keyframe(while animation is paused)
• w - write keyframes to file

Mouse Bindings

• Left Button and Drag - Rotate around selected ant
• Middle Button and Drag - Zoom In/Out
• Right Button and Drag - Change focus point on ant

Features

Interactive Editing of Keyframes with input and output to files

All keyframes for my ant model are read in from a data file when the program begins. Also when an ant changes modes, for example from walking to carrying, a key frame file is read to update the keyframes for the new mode. The keyframe files are found in the /keyframes directory.

While the program is being run, keyframes can be modified by pressing "m". The user can then navigate through the data structure (see below for more details on the Hierachical Data Structure) with the number pad, view individual key frames and modify any joint in the structure. When a joint is selected, a trasparent yellow sphere encases the joint. A yellow arrow coming out of the joint indicates the axis of rotation, and the amount of rotation can be modifyed. If there are two axis' of rotation on one joint, the second axis will be white and can be switch to by pressing 5 on the number pad, causing this axis to turn yellow.

Once the user is satified with the changes made to the keyframes, the file can be saved by pressing "w". The next time the program runs, all the keyframes will be updated.

Hierachical Data Structure

The basis of my design was the structure of each indidual ant. Below shows a diagram of the data structure.

   
   RearThorax
       |
       |
      Tail----FrontThorax----RRLS0----LRLS0----RMLS0----LMLS0
                   |           |        |        |       |
                   |         RRLS1    LRLS1    RMLS1    LMLS1 
                   |           |        |        |       |
                   |         RRLS2    LRLS2    RMLS2    LMLS2 
                   |           |        |        |       |
                   |         RRLS3    LRLS3    RMLS3    LMLS3 
                   |           |        |        |       |
                   |         RRLS4    LRLS4    RMLS4    LMLS4 
                   |
                   |
                 Head----RFLS0----LFLS0
                   |       |        |
                   |     RFLS1    LFLS1
                   |       |        |  
                   |     RFLS2    LFLS2
                   |       |        |  
                   |     RFLS3    LFLS3
                   |       |        |  
                   |     RFLS4    LFLS4
                   |
                   |
           LowerRightAntenna----LowerLeftAntenna
                   |                   |
           UpperRightAntenna    UpperLeftAntenna

Note: 
RRLS0 = Right Rear Leg Segment 0
RRLS1 = Right Rear Leg Segment 1
etc...
   
   

In the diagram, if a node (A) is below another node (B), then A is B's child and B is A's parent. If a node (C) is to the left another node (D), then C is D's previous sibling and D is C's next sibling.

Polygon Meshes

My design ustilises polygon meshes for the head and tail of the ant. Implementing the verticies of these meshes was reasonably easy, but implementing the normals was much more dificult as it involved differentiation and much fiddling before it worked properly.

Fog

My design implemented fog. It can be accessed by pressing "f". Much work was needed to implement this feature. Luckily, it wasn't on my part ;)

Textures

My design implemented texturemapping on multiple objects:

• The floor of the world which is a tiled greenish ppm image.
• The skybox, which is a ppm image of clouds and grass. The skybox stays in the same position no matter where the camera is creating the effect of a horizen that can never be reached
• The ant mound, a texture mapped hemisphere.
• The sugar cubes, a texture mapped cube with a whitish ppm image.

Behaviour

The ants are very simple creatures with a few goals in life:

• Dont wonder too far away from the ant mound.
• Try their best not to run into any other innocent ants.
• If they find food, pick it up and take it back to the ant mound.
• Be happy! (notice the smiles on their faces)

Not getting to far away from the mound is implemented by the ants checking that their position is not greater than a predifined amount, if it is they turn around.

Trying not to run into each other is implemented by each ant scanning each other and finding which is the closest. If the other closest ant is too close, then turn away from it.

Picking up food is implemented by scanning each sugar cube and seeing if it within a predifined distance. If it is, rotate towards it, walk towards it, pick it up, rotate towards the ant mound, walk towards the ant mound then once at the ant mound drop it off.