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shooting bullets

Started by phil67rpg Jun 16, 2013 at 8:09 PM 6 replies 3.6k views

Original Post

Jun 16, 2013 at 8:09 PM

I am working on a asteroids game. I am able to move the spaceship up and down and left and right. I just want it to shoot bullets using the space bar.

here is the code for the shooting bullets function.

void bullet()
{
glPointSize(2.0f);
glBegin(GL_POINTS);
glVertex3f(0.0f,up,0.0f);
glEnd();
up+=0.1f;
if(up >= 10.0f)
{
up=0.5f;
}
}

SimonForsman

Jun 16, 2013 at 10:39 PM

why do you have rendering code in your bullet function ?

you want to spawn a bullet with an initial position just in front of the ship and a velocity vector pointing in the direction the ship is facing, then you'll just update and render the bullet like any other gameobject.

phil67rpg

Jun 16, 2013 at 10:41 PM

Posted Today, 03:39 PM

why do you have rendering code in your bullet function

should I have the rendering code in my main rendering function?

SimonForsman

Jun 16, 2013 at 10:53 PM

Posted Today, 03:39 PM

why do you have rendering code in your bullet function

should I have the rendering code in my main rendering function?

if the main rendering function renders the ships and asteroids then yes, it should render your bullets as well.

phil67rpg

Jun 17, 2013 at 12:43 AM

if the main rendering function renders the ships and asteroids then yes, it should render your bullets as well.

hey I did the above and it worked, thanks

phil67rpg

Jun 17, 2013 at 1:35 AM

is there anyway to rotate an object without using the glRotatef function?

phil67rpg

Jun 17, 2013 at 2:31 AM

well I figured out how to rotate an object properly. I am actually getting this programming stuff using opengl and c++.

SimonForsman

Jun 18, 2013 at 6:59 AM

is there anyway to rotate an object without using the glRotatef function?

Yes, you can create a transformation matrix manually. (Rotatef is really just a shorthand function for creating and applying a rotation matrix to the current matrix (the one at the top of the stack). you can push and pop matrices to/from the stack using glpushmatrix/popmatrix and resetting the top matrix using glLoadIdentity(), or load your own matrix to the top of the stack using glLoadMatrix.

The only thing you should never do(unless you got a very low number of vertices in which case software transformation might be faster than creating the matrix, but then it most likely doesn't matter what you do anyway) is modify the vertex positions directly, each vertex is transformed using the transformation and projection matrices by the hardware (and it has to do that anyway)

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