Stickydots

[jaclyn.bill]

Dear users,

A while ago there was a post suggesting a vizard plugin available called stickydots (available at http://mirror.optusnet.com.au/sourceforge/v/vi/vizard/)

I can no longer find anything at this link. Does anyone know of any more recent plugins? Or, another method of creating some random dot motions in vizard?

Many thanks.

JB

[farshizzo]

I've attached the most recent version of the plug-in, including a sample script. Hope this helps.

[jaclyn.bill]

Dear Farshizzo,

Thank you for this, although I don't think I'll be able to do what I want with this plugin looking at it.

I want to create a circular patch at a certain point on the screen filled with 500 dots. I want these dots to then move randomly in direction for 300ms at a certain speed and then disappear. This a control condition for an experiment which contains structured dot balls, so I need to make sure this particular condition has no decipherable structure and the movement appears random.

I could create lots of dots separately, but this I presume is going to be too computationally demanding. Could you offer any advice as to the best route to take with this sort of problem?

Many thanks.

JB

[farshizzo]

You can create an On-The-Fly object that renders points and modify the position of each point every frame. If you are concerned about performance, then you can create a vertex shader that performs all the animating of the points directly on the GPU. If you are only rendering 500 points, then you could get away with just using an On-The-Fly object, depending on how fast your computer is.

Have a look at the example for creating On-The-Fly geometry and let me know if you have any more questions.

[jaclyn.bill]

Hi,

Thanks, this has been really useful. I was just wondering however, if there is some command which resets to the orignal vertex values in the code.

The relevant section is here


# for backward trials
if Mot_sel < 2:
R_spd = 0.0
Z_spd = 0.0
L_spd = 0.0
ball1.clearAttribute(viz.ATTR_VERTEXPROGRAM,op=viz .OP_OVERRIDE)
# # for rotation trial
if Mot_sel == 2:
Z_spd = 0.0
L_spd = 0.0
B_spd = 0.0
Z_st = Z_pos[0,0]
X_off = Side_id*X_offset[0,0]
####Create random dot motion
ball1.dynamic()
def mytimer(num):
#Change the position of a vertex
for i in range (0, NUM_DOTS):
x = random.random() - 0.5
y = random.random() - 0.5
z = random.random() - 0
length = math.sqrt(x*x + y*y + z*z)
x = x / length * RADIUS
y = y / length * RADIUS
z = z / length * RADIUS
ball1.setVertex(i,x,y,z)
viz.callback(viz.TIMER_EVENT,mytimer)
viz.starttimer(0,0.2,viz.FOREVER)



So for mot_sel == 2 trials I have managed to create randomly moving dots withing a flatten ball (setting z to 0) for the mot_sel < 2 trails I want to reset the balls back to being spherical. Inserting the orignal dotball code at this point gives me a timing error for my trails. Is there a less computationally demanding way of doing this. I've tried some clearAttribute functions but not sure if I'm selecting the right command as I can't find much on these in the vizard help section.

My entire code is too long to post. Let me know if this would be useful for you.

Thank you.

Best, JB

[farshizzo]

There is no command that will reset each vertex position to its original value. You will need to save the original values in a list and then manually apply them to each vertex when you need to reset them.