Hello everyone,

I am new to game programming, i am looking to code a 2-d side scroller which could do such things :
As the game begins, the ball starts rolling from left to right, and speeds up as the time goes on.
In its path, it faces obstacles like Triangles and Squares and combination of the two at random distances.
The player needs to jump the ball over the obstacles, suppose he hits the triangle he loses a life and stops if he hits a square and needs to jump over it, roll on the top and go ahead.
I need to code this very urgently, and i am confused in the proper C++ and ALLEGRO coding for
1. JUMP
2. Random Triangles and Squares.

Waiting for your replies.

I need to submit this in 4 days!

By random Triangles and Squares, i mean. when a ball rolls from right to left, triangles and squares and their combinations such as triangle-triangle, triangle-square etc are encountered as obstacles, and the player needs to jump over these to move ahead.

Yes i know the SRAND dunction, but how tu use it for these figures, is still cryptic.

I'll search again for JUMP, was looking for a simpler logic so as to understand it quickly and apply easily.

So this is homework?

As I have recently been implementing some jump mechanics myself, I took the time to produce a short tutorial covering one technique on how to implement jumping. It's based on some code you could have found if you had done a search I hope it's of use to you!

I guess you meant the rand() function. If you can generate random numbers within a range, you should then be able to generate the coordinates for your triangles and squares, and also what order they should come in.

It's easier to help if you show some code, and explain in more detail what you're having problem with.

You really should do it with vectors. Your hack is hard to visualize. Also, it's not a good idea to multiply by a Boolean, because in theory a true Boolean only needs to be non zero, it does not have to be 1.

Try using velocities (i.e. vectors) as I've done in my tutorial and other people have suggested.

I'm not sure if you want to be able to control the jumping height or not.

If not, then it's simply this:

• when the player pressed up, set dy to a negative value.

• if player is not on ground, increase dy with a positive value (gravity)

• update y using dy: y += dy

If you want controlled jumping height, see my tutorial I posted.

The ball bounces, but if the jump key is pressed, it bounces in the mid air.

All Triangles are generated in a small place, i.e all 4 triangles show up overlapping or inside each other, no random distance!

Whoa, thanks a lot The bounce is working now! But i am getting the obstacles of the game(have been testing only on triangles for now) all wrong. Have attached an image.

Have modified, only x1 of the triangle and its way better now, but i get overlapping triangles!!

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void InitTriangle(Triangle shapeT[], int size)
{
  for(int i=0; i<size; i++)
  {
  shapeT[i].ID = TRIANGLE;
  shapeT[i].pos_x1 = 100 + rand() % 600;
  shapeT[i].pos_y1 = 400;
  shapeT[i].pos_x2 = shapeT[i].pos_x1+20;
  shapeT[i].pos_y2 = 360;
  shapeT[i].pos_x3 = shapeT[i].pos_x1+40;
  shapeT[i].pos_y3 = 400;
  }
}

[UPDATED]
I have been trying. I have now managed to make things scroll and triangles and squares coming, but i am really in confusion with 2 things :

1. Squares and Triangles OVERLAP each other(as seen in the image).

{"name":"605627","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/f\/efd5069bfe3772701fee009ee6d06eca.jpg","w":806,"h":194,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/f\/efd5069bfe3772701fee009ee6d06eca"}

2. How can i make the screen scroll? I mean, for ex mario: you keep on going and things keep coming!!

Problem: Triangles overlap
What we want to achieve: Make them not overlap
Solution: Is there a way to see if they overlap and then do something about it?

Neil Walker : Why impossible ? What i am trying to code, already exists as an smart phone app. The game in the picture isnt the exact model of it.

Arvidsson : As in, you want me to paste the code? I am confused with the statement

"Solution: Is there a way to see if they overlap and then do something about it?"

jmasterx : will try it, have been into the overlapping issue.

As i added, the Ball move functions, for left, right and jump, the JUMP Logic seems to be not working. Cant figure out why?

Here's the updated code :

I doubt he'd label it "urgent" if he was trying to develop an app, it's homework that he procrastinated on.

What Arvidsson meant is the same as I did: THINK. You can't expect other people to keep solving everything for you. Sooner or later, you're going to have to think for yourself. What he posted was a basic recipe to solving your problem.

I'll restate it in the form of three questions you should ask yourself:

1. What is the problem?

2. What are the conditions that cause the problem?

3. Now that you know what the problem is and how it occurs, how do you fix it?

Ok, I'll take your word. Sounds like something for a job interview. Good luck.