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[Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

 

[Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity, Trying To Fix The Calculation Of Position In 2D Space + 0 Gravity
vikkman

30 Oct, 2009 - 08:34 AM
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Joined: 29 Oct, 2009
Posts: 5
Hy, my name is viKKmaN.
After 5 days of continous reading the dark gdk tutorials + documentation i managed to get to this project:
- 2D Space Game
- Implemented 0 Gravity Myself
- Ship Moving Forward
- Ship Turning Left / Right

My problem is with calculating the velocity after spinning the ship.

EXAMPLE OF WHAT HAPPENS:
IPB Image
EXAMPLE OF WHAT I WISH TO ACHIEVE:
IPB Image

MY while(LoopGDK()) Contents:
CODE

float PosX = 0, PosY = 0, VelocityX = 0, VelocityY = 0, ShipAngle = 0, ShipAngleR = 0;
dbLoadImage("ship.bmp", 1);
dbSprite(2, PosX, PosY, 1);
while(LoopGDK())
    {
        if(dbEscapeKey())
            break;
        if(dbSpaceKey())
        {
            VelocityX = 0;
            VelocityY = 0;
        }
        if(dbUpKey())
        {
            ShipAngleR = ShipAngle;
            if(VelocityX > -2)
            {
                VelocityX -=  Speed/100;
            }
            if(VelocityY > -2)
            {
                VelocityY -=  Speed/100;
            }
        }
        if(dbRightKey())
        {
            ShipAngle += Turning/10;
            if(ShipAngle > 360 || ShipAngle < -360)
                ShipAngle = 0;
        }
        if(dbLeftKey())
        {
            ShipAngle -= Turning/10;
            if(ShipAngle > 360 || ShipAngle < -360)
                ShipAngle = 0;
        }
        PosX += cos((ShipAngleR+90)*(PI/180))*(VelocityX);
        PosY += sin((ShipAngleR+90)*(PI/180))*(VelocityY);
        dbSprite(2, PosX, PosY, 2);
        dbOffsetSprite(2, dbSpriteWidth(2)/2, dbSpriteHeight(2)/2);
        dbRotateSprite(2, ShipAngle);        
        dbSync();
    }


This post has been edited by vikkman: 30 Oct, 2009 - 08:57 AM

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Aeternalis

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

30 Oct, 2009 - 01:38 PM
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Is the "UP" key your thrust?

Hmm misread your code.. looking at it further.


Aet

This post has been edited by Aeternalis: 30 Oct, 2009 - 01:51 PM
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vikkman

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

30 Oct, 2009 - 02:19 PM
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Yes. The up key is my thrust, left/right for steering and as you can see the program simulates 0 gravity. My problem is with calculating the new thrust after changing the ships angle, the new ship angle difering from the direction the ship was originaly heading. As i sayd the thrust remains maximum (2) if i change the direction of the ship. I don't know how to calculate the new thrust based on the diference of angles, that is why i am asking for help.
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L0CKnL0aD7

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

30 Oct, 2009 - 04:30 PM
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I don't really understand your question, it works fine no? wink2.gif you can perfectly move your ship in an arc trajectory.
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jbeme

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

30 Oct, 2009 - 10:35 PM
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You would first need to track the current angle of the ship. Then figure out the sideways force being applied to make it turn. Then write an equation figuring out how the side force affects the forward momentum. If I understand your problem.
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vikkman

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

31 Oct, 2009 - 02:30 AM
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QUOTE(L0CKnL0aD7 @ 30 Oct, 2009 - 04:30 PM) *

I don't really understand your question, it works fine no? wink2.gif you can perfectly move your ship in an arc trajectory.

Yes, it moves perfectly in an arc trajectory when i press "UP" + "LEFT"/"RIGHT" keys at the same time.
But as you can see i added a variable ShipAngleR which i use for retrieving the new ship angle when i press "UP".
This means i can move my ship in the direction it's headed, than rotate it however i want using "LEFT"/"RIGHT" keys(without afecting the course of the ship), than press thrust to move in the new direction.

Leme give you a hint. I am trying to recreate the 0 gravity simulated in the game "star sonata" if any of you played it, and the controling there.

This post has been edited by vikkman: 31 Oct, 2009 - 02:31 AM
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L0CKnL0aD7

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

31 Oct, 2009 - 04:56 AM
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Ah, now I get your problem:P

What you should do:
Store the vector of your old velocity and combine it with your new velocity vector, but I cant relay find a good solution for this. crazy.gif I'll hopefully get one in time. tongue.gif
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vikkman

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

31 Oct, 2009 - 05:32 AM
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I'll sure stick my eyes to this thread untill you, me or anyone else finds a solution.
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TyVeryMuch

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

2 Nov, 2009 - 11:29 PM
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nvm my bad

This post has been edited by TyVeryMuch: 3 Nov, 2009 - 05:58 AM
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vikkman

RE: [Visual C++][Dark GDK] 2D Game / Controling Ship In 0 Gravity

3 Nov, 2009 - 05:31 AM
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Fixed it. But now i have a diferent problem. Setting the maximum speed for the ship. & keeping it on screen.
Here's the code:

CODE

while(LoopGDK())
    {
        if(dbEscapeKey())
            break;
        if(dbControlKey()) // This is for stopping the ship in emergency times
        {
            if(VelocityX < -0.5)
                VelocityX += Thrust/100;
            else
                if(VelocityX > 0.5)
                    VelocityX -= Thrust/100;
                else
                    VelocityX = 0;
            if(VelocityY > 0.5)
                VelocityY -= Thrust/100;
            else
                if(VelocityY < -0.5)
                    VelocityY += Thrust/100;
                else
                    VelocityY = 0;
        }
        if(dbUpKey())
        {
            ShipAngle = ShipAngleNew;
                VelocityX -= sin((ShipAngle+180)*(PI/180))*(Thrust/100);
                VelocityY += cos((ShipAngle+180)*(PI/180))*(Thrust/100);
        }
        if(dbRightKey())
        {
            ShipAngleNew += Turning/10;
            if(ShipAngleNew > 360)
                ShipAngleNew -= 360;
        }
        if(dbLeftKey())
        {
            ShipAngleNew -= Turning/10;
            if(ShipAngleNew < -360)
                ShipAngleNew += 360;
        }
        PosX += VelocityX;
        PosY += VelocityY;
        dbSprite(2, PosX, PosY, 2);
        dbRotateSprite(2, ShipAngleNew);
        dbSync();
    }


This post has been edited by vikkman: 3 Nov, 2009 - 05:32 AM
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