![]() This function can easily initialize the particles in a way that is completely unrelated to the particleDead(nParticle) function, the fire engine though, is more logically connected with it. The variable m_nParticles is set by the function init(nParticles) and needs not to be manually altered with. Because random number generation is used to give values to the variables in this, the default random number generator needs to be seeded: The resetParticles() function is called initially, and can be called more times to bring the particles to the position they were initially. The virtual functions resetParticles() and particleDead should be used to set the variables of the individual particles. Add any variables that your engine would use and use its constructor to initialize these variables as needed. Creating Your Own EngineĬreate a class to encapsulate the effect, inheriting from QdParticleEngine. The greater the number of particles the engine controls the slower the effect will go at its maximum speed. The init function can only be called once. ![]() When the engine is deconstructed it deletes these particles off the heap. The parameter is the number of particles to exist in the array. The particles are created in an array of particles on the heap with the function init(nParticles). Sets what value should be added to the life each time the particle is updated. When the life value is 0 the particle is "dead". The gravity factor can make gravitational forces stronger or weaker. SetGravityFactor(nParticle, fGravityFactor) When particle is initialized it should be set to 0. Sets age for computation of the effect of gravity. Sets initial position of the upper left corner. Sets initial position of the lower right corner. If the direction is set with positive Y values, and gravity is set with small negative Y values the particle will rise, slow down, and then fall. The force of gravity is similar to the direction, except as the age of the particle increases its effect does too. SetFadeColor(nParticle,fRed,fGreen,fBlue,fAlpha)Įach time the particle is updated the current color becomes its previous value plus the value of the color given.Įach time the particle is update its coordinates become their previous value plus the value of the value given. The color of the particle will be determined through this and the colors of the bitmap. Sets the color to change to prior to the particle is drawn. SetCurrentColor(nParticle,fRed,fGreen,fBlue,fAlpha) Table 1.1 QdParticleEngine's member functions. Below is a list of QdParticleEngine's member functions to manipulate the data stored in the particles. ![]() The variables that the particles have control their behavior, and after the particles are initialized, they should not be changed manually. The particle engine is used to manipulate the particles and their variables. The particle is encapsulated in QdParticle and is used by the QdParticleEngine. It uses glut to simplify the Windows programming aspect of the demonstration, and the actual particle engine does not rely on it in any way. You may wish to look at the fire demo of this particle engine. Once all the particles die, the effect will stop, or if as the engine is alerted that the particles are dead, it can reinitialize it and it can be displayed again. The particle engine controls the particles and makes them react according to the rules of the particle itself.Īs the particles fade away, the particle engine is alerted that the particle is dead. Each particle has its own location, size, velocity, color, life and image. Depending on the need for performance and realistic appearance, the number of particles can range from 50 to thousands. The effects are created by creating a definite number of particles. Particle effects can be used to simulate fire, fireworks, water fountains, snow, rain, explosions and many other things. The concept of particle effects is very simple. Any suggestions, ideas, or modifications of this code are welcome. The code offered here is far from perfect, but it is a merely a start to this endeavor. The included particle engine is intended to greatly simplify the creation of such effects. Despite the great power of the library, it can be a great hassle to create particle effects. OpenGL is a powerful graphical library, which can be used to render some amazing effects.
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