Thread: lots of questions about opengl

alright, i'm making my first opengl program, pong, and as i don't know a lot about opengl, so i've been coming up with my own solutions for problems such as moving the paddles, and it's probably hideously impractical.

first, i constructed the blocks and the pong square with glBegin (GL_POLYGON), but i defined their x vertices with a previously declared array. when i do a WM_KEYDOWN it activates a function that does a loop to add or subtract to the coordinate numbers. as you can imagine, it doesn't flow too well. i've got the buffer swapping working, so that's not a problem, it's just being really jerky.

what should i do to move the blocks besides what i'm doing, and what's a better way to initiate the movement than WM_KEYDOWN?
also, what's the naming convention for the keys with KEYDOWN? i only know VK_ESCAPE, but my guesses for the other ones don't work.

any descriptions on how to actually use that stuff? how does translate() work, and how do i implement GLUT?

yeah, all that stuff with the libraries is easy, but how do you actually implement it? does it have a seperate set of keyboard functions?

about translate, how exactly do i use that on one particular set of coordinates? do i need to set up a class and make each paddle a different object?

do i need to set up a class and make each paddle a different object?

That would be alright. Here is how I would write one: (I may miss a few variables; please correct me if I'm wrong)

Paddle
public:
Paddle()
~Paddle()
int set_pos(float x, float y)
int set_vel(float x, float y)
int state;
float x,y;
float x_vel, y_vel;
std::string image_filename;
image data;

Where image is a container-type object that would hold the main part of the data. Alternativley, you could store image_filename inside data.

--Joe

Hi,

There is a set of GLUT tutorials from this URL: http://www.lighthouse3d.com/opengl/glut/index.php?1

Best Reagrds,
Yeoh

Originally Posted by n3v

about translate, how exactly do i use that on one particular set of coordinates? do i need to set up a class and make each paddle a different object?

Joeprogrammer's class implementation is the easiest way to setup a pong class, and this is the simplest way to use translate (i will use quad)

Code:

glTranslatef(xMove, yMove, zMove);   //define the variables somewhere;
glBegin(GL_QUADS);
       glVertex3f(0, 0, 0);         
       glVertex3f(2, 0, 0);
       glVertex3f(2, 1, 0);
       glVertex3f(0, 1, 0);
glEnd();

//these vertices assume that you're using glPerspective

Now, if you're not using 3D, use "glTranslated(x, y)" and "glVertex2d(x, y)". All you have to do now is make the a link when the button is press and transfer it back to the paddle class.