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First timer Particle
August 30, 2002 04:07 PM
Hey guys Iam tring to whip up my first particle engine, I wanna use the advanced particle engine theory but I don''t understand where do begin or how to load the particles can you please anylize this for me?
You miss 100% of the shots you do not take. - Wayne Gretzky
122
August 30, 2002 04:12 PM
Well, what is the advanced particle engine theory?
Apart from that, there are LOTS of pages on the web detailing particle engines. Check http://freespace.virgin.net/hugo.elias/ - for example
Apart from that, there are LOTS of pages on the web detailing particle engines. Check http://freespace.virgin.net/hugo.elias/ - for example
August 30, 2002 04:14 PM
As with all software you should start simple. eg. give each particle a position, velocity, lifetime, texture, ect... Then when you get things working add more complex attributes. As far as "loading" particles. I suppose you could load attributes from a file you create with an editor you created. That is what i do!
154
August 30, 2002 05:46 PM
We did projectile motion in maths and i just used the equation there to move my particle, and specified the initial velocity etc.. and whatever else was in the equation, then the particle will move naturally during it''s lifetime according to the parameters you specified. I''ll just cut and paste the code if you can be bothered to look through:
the globals which affect all particles:
Particle class:
constructor destructor:
initialize particle:
update particle position:
draw particle (in OpenGL)
So everytime i need to create an explosion for example I just use particle.init() in a loop and specify a random initial velocity, then when drawing the scene call particle.update() to update the position and particle.render() to draw it. It''s fun playing with the parameters too
I was just told that it''s better to use floats to store positions and convert them to ints before rendering them so you don''t loose accuracy in calculations though.. I wrote the particle class yesterday without having seen any other examples or tutorials so it may not be the best or optimal way to do it, but i''d appreciate if someone could give some suggestions as it seems to only manage about 100 000 point particles and another galaxy collider program i saw could do 150 000 on my PC.
the globals which affect all particles:
//affects all particlesfloat gx = 0.0f; //gravity x float gy = -9.8f; //gravity yfloat gz = 0.0f; //gravity zfloat timescale = 0.06f; //time speed Particle class:
typedef struct{ float r; float g; float b;} COLOR;class Particle{public: Particle(void); ~Particle(void); void init(int initialX, int initialY, int initialZ, //initialize particle float initialVx, float initialVy, float initialVz, float mass, COLOR particleRGB); void draw(void); //draw particle void update(bool lifeCheck); //update particle position int getSize(void) { return size; } //get particle size void setSize(int Size) { size = Size; } //set particle size void drawPoints(bool pnt) { points = pnt; } //particle rendering mode float getLifetime(void) { return lifetime; } //get particle lifetime void setLifetime(float duration) { lifetime = duration; } //set particle lifetime float getMass(void) { return m; } //get particle mass void setMass(float mass) { m = mass; } //set particle mass int getx(void) { return x; } //get x position int gety(void) { return y; } //get y position int getz(void) { return z; } //get z positionprivate: int ix, iy, iz; //initial position int x, y, z; //current position float ivx, ivy, ivz; //initial velocity float vx, vy, vz; //current velocity COLOR color; //particle colour float t; //lifetime float m; //mass int size; //particle size bool points; //draw points or quads float lifetime; //particle life duration}; constructor destructor:
//----------------------------------------------------------------//constructors and destructor//----------------------------------------------------------------Particle::Particle(void){ ix = iy = iz = 0; //initial xyz x = y = z = 0; //current xyz ivx = ivx = ivz = 0.0f; //initial velocity xyz vx = vy = vz = 0.0f; //current velocity xyz color.r = color.b = color.g = 0; //shade colour t = 0.0f; //time m = 0.0f; //mass size = 5; //size points = false; //render mode lifetime = 15.0f; //particle life time}Particle::~Particle(void){} initialize particle:
//-------------------------------------------------------------------//initialize particle //-------------------------------------------------------------------void Particle::init(int initialX, int initialY, int initialZ, float initialVx, float initialVy, float initialVz, float mass, COLOR particleRGB){ ix = initialX; iy = initialY; iz = initialZ; ivx = initialVx; ivy = initialVy; ivz = initialVz; m = mass; color.r = particleRGB.r; color.g = particleRGB.g; color.b = particleRGB.b; t = 0.0f; update(false);} update particle position:
//-----------------------------------------------------------------//update particle position using equations of projectile motion //-----------------------------------------------------------------void Particle::update(bool lifeCheck){ t += timescale; //increment particle lifetime //update velocity vx = (gx * t) + ivx; vy = (gy * t) + ivy; vz = (gz * t) + ivz; //update position x = (int)((0.5 * gx * SQRD(t)) + (ivx * t) + ix); y = (int)((0.5 * gy * SQRD(t)) + (ivy * t) + iy); z = (int)((0.5 * gz * SQRD(t)) + (ivz * t) + iz); //check if particle "died" if ((t > lifetime) && (lifeCheck)) { //restart particle init(ix, iy, iz, ivx, ivy, ivz, m, color); }} draw particle (in OpenGL)
//-----------------------------------------------------------------//render particle//-----------------------------------------------------------------void Particle::draw(void){ int xvertex, yvertex, zvertex = 0; glColor3f(color.r, color.g, color.b); //render points or quads for particles if (points) { glBegin(GL_POINTS); glVertex3i(x, y, z); glEnd(); } else { glBegin(GL_QUADS); //bottom left xvertex = x; yvertex = y; zvertex = z; glTexCoord2f(0.0f, 0.0f); glVertex3i(xvertex, yvertex, zvertex); //top left xvertex = x; yvertex = y + size; zvertex = z; glTexCoord2f(0.0f, 1.0f); glVertex3i(xvertex, yvertex, zvertex); //top right xvertex = x + size; yvertex = y + size; zvertex = z; glTexCoord2f(1.0f, 1.0f); glVertex3i(xvertex, yvertex, zvertex); //bottom right xvertex = x + size; yvertex = y; zvertex = z; glTexCoord2f(1.0f, 0.0f); glVertex3i( xvertex, yvertex, zvertex); glEnd(); }} So everytime i need to create an explosion for example I just use particle.init() in a loop and specify a random initial velocity, then when drawing the scene call particle.update() to update the position and particle.render() to draw it. It''s fun playing with the parameters too
I was just told that it''s better to use floats to store positions and convert them to ints before rendering them so you don''t loose accuracy in calculations though.. I wrote the particle class yesterday without having seen any other examples or tutorials so it may not be the best or optimal way to do it, but i''d appreciate if someone could give some suggestions as it seems to only manage about 100 000 point particles and another galaxy collider program i saw could do 150 000 on my PC.
151
August 31, 2002 12:59 AM
You will need...
color
motion vars
alive/dead var
time-to-live var.
You can then work from there....
I guess you could do motion that way. *shrug*
I`d simply use the newtonian? method.
Psedocoded a bit...
cVector position
cVector velocity
cVector accel
velocity += accel
position += velocity
You proably will want a drag vector or two to decrease your accel or whatever in given directions.
thats how i am implementing motion...
hope this helps some.
Bugle4d
color
motion vars
alive/dead var
time-to-live var.
You can then work from there....
I guess you could do motion that way. *shrug*
I`d simply use the newtonian? method.
Psedocoded a bit...
cVector position
cVector velocity
cVector accel
velocity += accel
position += velocity
You proably will want a drag vector or two to decrease your accel or whatever in given directions.
thats how i am implementing motion...
hope this helps some.
Bugle4d
~V'lionBugle4d
August 31, 2002 07:46 AM
Wow, thanks so much Kyo and everyone else, you guys are really great.
I have learned alot from you guys.
I have learned alot from you guys.
You miss 100% of the shots you do not take. - Wayne Gretzky
122
August 31, 2002 10:10 PM
quote:
Original post by Vlion
You will need...
color
motion vars
alive/dead var
time-to-live var.
You can then work from there....
And boy, can you work from there. The particle effects in our current game use a gazillion different fields...
quote:
You proably will want a drag vector or two to decrease your accel or whatever in given directions.
We''ve found that drag+acceleration is not worth the effort. Particles reach terminal velocity rather quickly for realistic drag/accel combinations.
So just having velocity or is enough if the ''perfect'' simulation would include accel and drag. Saves quite a bit of CPU time, cutting out on a vector multiply and a vector add per particle.
Have fun, and make sure you buy Mortal Kombat when it comes out
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