opengl particle engine best practice?

I'm developing a simple game and I am currently switching from canvas to openGL. So my openGL experience is very limited. I'm trying to create a simple particle engine at thee moment and it works fine BUT with my current implementation I have to run this line on every draw() call [ vertexBuffer.put(vertices); ] and that is really slow.. Is there any way to get around this ?

code looks like this:

public class ParticlesTest {

    private float[] vertices;
    private short[] indices;


    private FloatBuffer vertexBuffer;


    private ShortBuffer indexBuffer;
    private ByteBuffer vbb;

    private int MAX_PARTICLES = 100;

    private ArrayList<Particle> particles;
    public ParticlesTest() {

        particles = new ArrayList<Particle>();

        vertices = new float[MAX_PARTICLES*6*3];
        indices = new short[MAX_PARTICLES*2];


        short cnt = 0;
        for(int i = 0; i < 60; i++){
            createParticle();

            indices[cnt] =  cnt;
            cnt++;
            indices[cnt] =  cnt;
            cnt++;

        }

        vbb = ByteBuffer.allocateDirect(vertices.length * 4);
        vbb.order(ByteOrder.nativeOrder());
        vertexBuffer = vbb.asFloatBuffer();
        vertexBuffer.put(vertices);
        vertexBuffer.position(0);

        ByteBuffer ibb = ByteBuffer.allocateDirect(indices.length * 2);
        ibb.order(ByteOrder.nativeOrder());
        indexBuffer = ibb.asShortBuffer();
        indexBuffer.put(indices);
        indexBuffer.position(0);



    }

    private void createParticle() {
        Particle particle = new Particle();
        particle.setSpeedX((float)(Math.random() * 20 - 10));
        particle.setSpeedY((float)(Math.random() * 20 - 10));
        particle.setX(100);
        particle.setY(100);

        particles.add(particle);


    }
    private void update(){

        int len = particles.size();

        for(int i = 0; i < len; i++){
            Particle particle = particles.get(i);

            float oldX = particle.getX();
            float oldY = particle.getY();
            float speedX = particle.getSpeedX();
            float speedY = particle.getSpeedY();

            oldX += speedX;
            oldY += speedY;

            particle.setX(oldX);
            particle.setY(oldY);

        开发者_JS百科    if(oldX < 0 || oldX > 400 || oldY < 0 || oldY > 600){
                particles.remove(i);
                len--;
            }
        }

        if(len < MAX_PARTICLES){
            createParticle();
        }
    }


    private void translate(){


        int vcount = 0;
        short icount = 0;

        int clen = vertices.length;

        for(int c = 0; c < clen; c++){
            vertices[c] = 0f;
        }


        int len = particles.size();

        for(int i = 0; i < len; i++){
            Particle particle = particles.get(i);

            float oldX = particle.getX();
            float oldY = particle.getY();

            float speedX = particle.getSpeedX();
            float speedY = particle.getSpeedY();

            vertices[vcount] =oldX;
            vcount++;
            vertices[vcount] = oldY;
            vcount++;
            vertices[vcount] = 0f;
            vcount++;

            vertices[vcount] =oldX + speedX;
            vcount++;
            vertices[vcount] = oldY + speedY;
            vcount++;
            vertices[vcount] = 0f;
            vcount++;

            indices[icount] = icount;
            icount++;
            indices[icount] = icount;
            icount++;

        }
    }


    public void draw(GL10 gl,int w,int h) {

        update();
        translate();

        vertexBuffer.put(vertices);

        vertexBuffer.position(0);

        //GLFPS.VERTS = vertices.length;


        // rendering.
        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);      
//      gl.glDrawElements(GL10.GL_LINE_STRIP, indices.length, GL10.GL_UNSIGNED_SHORT, indexBuffer);
        gl.glDrawElements(GL10.GL_LINES, indices.length, GL10.GL_UNSIGNED_SHORT, indexBuffer);



        // Disable the vertices buffer.
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    }
}

as a recommendation, creating an ArrayList of such a large number of objects can create a lot of memory overhead. Also, have you considered using GL ES 2.0 as opposed to 1? This way you can create a particle Shader program using GLSL, this will allow you to free up memory and do the calculations on the GPU as opposed to the CPU. That, should vastly increase the performance.

Is there any way to get around this ?

Allocate all your objects up front and keep reusing them while your game is running.

See my other post here.

OK I found a really good way to do this now (I think) . Instead of using a vertexbuffer of floats I have a vertexbuffer of Shorts. Now I run 15k particles on a galaxy S with 23fps.