Particles
<Hi Ed, I checked out you particle animtions. Holy Moly! You are one awsome
programmer!>
Thanks! (But lets just say that you like the results of my programming<g>)
< By the way, are you a computer graphics Gun for Hire?>
Sure, but tell me more about what you need.
< Anyway, im interested in getting it. Is it an open particle system or more
like the 3ds studio canned type (spurt, Explode etc.)>
Open.
< Is there any interface, or is it scripting?>
Here are a few paragraphs from a draft of the documentation,
but it'll give you an idea of how you interface with the system.
(It's already obsolete. I've added a lot of features and am now
struggling with how interface with the user).
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Introduction
With APS you can experiment with moving objects that interact with each
other through a field.
You can, for example, use a gravity field. You will find that
many interesting example result from from fields that do not exit in nature.
You can use two kinds of objects: "particles" and "masses."
A "mass" generates a field and its motion is affected by the field produced
by other masses. "Particles" are also affected by fields, but they do not
themselves generate a field.
Particles are used to reduce the number of computations. Whenever possible
use them instead of masses. They should be used, for example, to simulate
dust under the effect of the earth's gravity. Or to simulate the particles
in the Saturn's rings.
You can use up to ?? masses and ????? particles. Since particles don't
contribute a field their presence has no effect on other objects. You can
rerun a problem with a new set of particles and overlay the result on top of
an existing animation.
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Specifying values
The program is shipped with values set for two masses and 100
particles orbiting the first mass.
To create an animation you modify the existing values
by editing the program itself (make a backup first!). You can use
the POCO editor from the main screen of Animator by selecting:
– Poco / Program / 1. Edit.
then
– Poco / Program / Save as
– Poco / Program / Run
The values you can modify are located near the beginning in several
clearly delimited areas.
The first of these area is shown below:
// User Supplied Values
//______________________________________________
//
//___________ Mass position and velocity _______
double Mass0_x_pos = 180;
double Mass0_y_pos = 100;
int Can_mass0_move = YES;
double Mass0_x_vel = 0;
double Mass0_y_vel = 0;
double Mass0_accel = 10;
int Mass0_color =YELLOW;
int Mass0_draw_size = 1;
double Mass1_x_pos = 190;
double Mass1_y_pos = 100;
int Can_mass1_move = NO;
double Mass1_x_vel = 0;
double Mass1_y_vel = 0;
double Mass1_accel = 10;
int Mass1_color =ORANGE;
int Mass1_draw_size = 2;