rotation

Giving images inside an iteration patch a time limit

Mangenta's picture

Hello Kineme,

I am reasonably new to quartz, and still quite a novice to the programmers language.

I am trying to build a MIDI visualizer. I had a lot of success building an over complicated version, which had a network of patches assigned directly to every single MIDI note. this i thought was using too much CPU. now i am trying to streamline things.

My question is, How does one give "iterations" a time limit, relative to the time that they are first triggered? instead of only being visible while the signal is being sent, I would like each sprite to last for a predetermined time.

I want to trigger sprites that rotate around a fixed axis. The color, and distance to the center depends on the MIDI note data. So being inside an iteration (or replicate in space) patch all the iterations change color and position, but i would like them to maintain this information and accumulate until their time is up.

I hope that makes sense, if not i can send screen caps or draw a diagram.

Best

Mangenta.

Euler rotation

sorenknud's picture

Hi there, i had a smilar post a couple of weeks ago, but i have been reading a bit since then.

I found, that the way you rotate an object in ex. After effects or Maya 3D is Euler. The x-axis of an object follows, when you rotate z and y axis, and the other way around too.

Now, i don't understand the argument why we DON'T rotate objects that way in quartz composer. It seems far more logic to humans.

Could it be, that it would be posible to make a "Euler-Sprite" or is there anyone who has figured out how to put the Euler-math into a Mathmatical Expression patch?

Thanks,

sorenknud

http://en.wikipedia.org/wiki/Euler's_rotation_theorem

Simple Track Ball With Inertia (Composition by dust)

Author: dust
License: MIT
Date: 2010.03.26
Compatibility: 10.5, 10.6
Categories:
Required plugins:
(none)

here is a simple trackball you can use with exposed orientation values. now like the title says this is just a simple dirty implementation of a trackball. there is a simple patch that is basically a few math expressions nothing more than some 2nd grade math as in addition multiplication and division maybe division is 3rd grade can't remember now. so the simple patch should run on leopard as its just a few equations.

there is also a snow leopard patch that acts more like the stock trackball with inertia and friction etc..... like i said again this is a simple trackball meaning i'm not using euler angles and quaternions or z rotation. we are not flying space ships here just rotating things so sometimes there is no need for pitch roll and yaw from xy coordinates.

if you want that level of complexity or another degree of freedom or maybe more of a stock trackball feeling with exposed orientations just add the inertia from the simple trackball with inertia example presented here to my quaternion trackball located in this repository as it is a direct implementation of Apples trackball.h