Java LWJGL How to calculate direction when firing a gun.

[SirPaul]

Hello Guys,

 

So i am totally lost with my "project".  I am developing a lot in Unity but i wanted to go a classic way and create a game from screatch using lwjgl. I figured out many things (procedural generation, chunks, loading mesh e.t.c) but my problem is : How it is with those Math.cos , Math.sin , when calculating an angle to fire at.  I can fire in front of me. which  is good, but i cannot fire 'Up' or 'Down'  so basicallly direction of Particle is not altered by Camera's YAW or Pitch.

Render method in my Main Class.private void render() {    // Clear the screen and depth buffer    GL11.glLoadIdentity();           camera.lookThrough();   GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);    //ch0.render();             GL11.glPushMatrix();    x = -camera.getPosition().x;    y = -camera.getPosition().y;    z = -camera.getPosition().z;         GL11.glTranslatef(-camera.getPosition().x ,camera.getPosition().y  ,-camera.getPosition().z );     GL11.glRotatef(yaw, 0.0f, 1.0f, 0.0f);      GL11.glRotatef(pitch, 1.0f, 0.0f, 0.0f);      if (Mouse.isButtonDown(0)){      yaw = -camera.getYaw();      pitch =-camera.getPitch();    //Spawn a box          Box b = new Box(x ,y  ,z,0.1f);               spawnedBoxes.add(b);         }      GL11.glPopMatrix();      for(int i = 0 ; i < spawnedBoxes.size();i++){                            // push box forward..       spawnedBoxes.get(i).centerZ-=4f;   --------------------- I think Here is the problem, i should Alter value of spawnedBoxes.get(i).centerX and centerY with the camera.getYaw or camera.getPitch  but i cant get the math right.                                                                    ---------------------           spawnedBoxes.get(i).render();        }                      //}          }

Camera CLASS : 

import org.lwjgl.opengl.GL11;import org.lwjgl.util.vector.Vector3f;import static org.lwjgl.opengl.GL11.*;public class FPSCameraController {  //3d vector to store the camera's position in    private Vector3f    position    = null;    /**  * @return the position  */ public Vector3f getPosition() {  return position; } //the rotation around the Y axis of the camera    private float       yaw         = 0.0f;    public float getYaw() {  return yaw; } public float getPitch() {  return pitch; } //the rotation around the X axis of the camera    private float       pitch       = 0.0f;  //Constructor that takes the starting x, y, z location of the camera    public FPSCameraController(float x, float y, float z)    {        //instantiate position Vector3f to the x y z params.        position = new Vector3f(x, y, z);    }  //increment the camera's current yaw rotation    public void yaw(float amount)    {        //increment the yaw by the amount param        yaw += amount;    }  //increment the camera's current yaw rotation    public void pitch(float amount)    {        //increment the pitch by the amount param        pitch += amount;    }  //moves the camera forward relative to its current rotation (yaw)    public void walkForward(float distance)    {        position.x -= distance * (float)Math.sin(Math.toRadians(yaw));        position.z += distance * (float)Math.cos(Math.toRadians(yaw));    }        public void flyUp(float distance)    {        position.y -= distance * 2;      //  position.z += distance * (float)Math.cos(Math.toRadians(yaw));    }    public void flyDown(float distance)    {        position.y += distance * 2;      //  position.z += distance * (float)Math.cos(Math.toRadians(yaw));    }         //moves the camera backward relative to its current rotation (yaw)    public void walkBackwards(float distance)    {        position.x += distance * (float)Math.sin(Math.toRadians(yaw));        position.z -= distance * (float)Math.cos(Math.toRadians(yaw));    }         //strafes the camera left relitive to its current rotation (yaw)    public void strafeLeft(float distance)    {        position.x -= distance * (float)Math.sin(Math.toRadians(yaw-90));        position.z += distance * (float)Math.cos(Math.toRadians(yaw-90));    }         //strafes the camera right relitive to its current rotation (yaw)    public void strafeRight(float distance)    {        position.x -= distance * (float)Math.sin(Math.toRadians(yaw+90));        position.z += distance * (float)Math.cos(Math.toRadians(yaw+90));    }    //translates and rotate the matrix so that it looks through the camera    //this dose basic what gluLookAt() does    public void lookThrough()    {        //roatate the pitch around the X axis        GL11.glRotatef(pitch, 1.0f, 0.0f, 0.0f);        //roatate the yaw around the Y axis        GL11.glRotatef(yaw, 0.0f, 1.0f, 0.0f);        //translate to the position vector's location        GL11.glTranslatef(position.x, position.y, position.z);    } }

Box.java import org.lwjgl.opengl.GL11;public class Box { private boolean isActive = false; float centerX, centerY, centerZ, size, yTop; public float getyTop() {  return yTop; } public void setyTop(float yTop) {  this.yTop = yTop; } public float getCenterZ() {  return centerZ; } public void setCenterZ(float centerZ) {  this.centerZ = centerZ; } public float getCenterY() {  return centerY; } public void setCenterY(float centerY) {  this.centerY = centerY; } public float getCenterX() {  return centerX; } public void setCenterX(float centerX) {  this.centerX = centerX; } public float getSize() {  return size; } public void setSize(float size) {  this.size = size; } float red, green, blue; public Box(float a, float b, float c, float d) {  centerX = -a;  centerY = b;  centerZ = -c;  yTop = -(centerY + d/2);  size = d;  red = 128;  green = 128;  blue = 1; } public Box(float a, float b, float c, float d, float r, float g, float bl) {  this(a, b, c, d);  red = r;  green = g;  blue = bl; } public void render() {  // Top//  TextureManager.textureWall.bind();  GL11.glBegin(GL11.GL_QUADS);  //GL11.glPolygonMode( GL11.GL_FRONT_AND_BACK, GL11.GL_FILL );  //GL11.glTranslatef(-centerX, centerY, -centerZ);    GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ - size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ - size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ + size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ + size);  // Bottom  GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ + size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ + size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ - size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ - size);  // One side  GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ + size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ + size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ + size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ + size);  // Moar sides  GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ - size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ - size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ - size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ - size);  // Last side  GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ + size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX - size, centerY + size, -centerZ - size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ - size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX - size, centerY - size, -centerZ + size);  // Real last side  GL11.glTexCoord2f(0, 0);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ - size);  GL11.glTexCoord2f(1, 0);  GL11.glVertex3f(-centerX + size, centerY + size, -centerZ + size);  GL11.glTexCoord2f(1, 1);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ + size);  GL11.glTexCoord2f(0, 1);  GL11.glVertex3f(-centerX + size, centerY - size, -centerZ - size);  GL11.glEnd(); } public boolean isActive() {  return isActive; } public void setActive(boolean isActive) {  this.isActive = isActive; }}

Would someone be so kind to explain me how to do such math ?

 

Here is a video somewhat describing the issue :

 

 

Thank you all for all suggestions .

[Nineshadow]

Oh,I remember bumping into that too.

Lemme check to see if I still have the project inside my Eclipse workspace...

Ah,no I don't.

 

Here :

spawnedBoxes.get(i).centerZ-=4f;

 

When you do that,you push the box whatever it the direction of the Z axis ( X , Y and Z come together in the camera).

You need to calculate where the box actually goes.

[SirPaul]

Oh,I remember bumping into that too.

Lemme check to see if I still have the project inside my Eclipse workspace...

Ah,no I don't.

But thanks for the effort   

[Nineshadow]

But thanks for the effort   

I updated my initial post.

 

You need to move the box in all 3 directions.

Does 

 

spawnedBoxes.get(i).centerX-=4f;

spawnedBoxes.get(i).centerY-=4f;

spawnedBoxes.get(i).centerZ-=4f;

 

Work?

[SirPaul]

I updated my initial post.

 

You need to move the box in all 3 directions.

Does 

 

spawnedBoxes.get(i).centerX-=4f;

spawnedBoxes.get(i).centerY-=4f;

spawnedBoxes.get(i).centerZ-=4f;

 

Work?

Well , how do you mean it, because the code does work.  but cube is sent somewhere diagonaly across the screen (to the 4,4,4 point );

It seems like simple mathematics (and it most certainly is) but i just cannot figure it out.

[Nineshadow]

Well , how do you mean it, because the code does work.  but cube is sent somewhere diagonaly across the screen (to the 4,4,4 point );

It seems like simple mathematics (and it most certainly is) but i just cannot figure it out.

Oh,right.Didn't think about that.

Let me think a little bit.

We need to calculate the distance it is offset in each axes.

[SirPaul]

Oh,right.Didn't think about that.

Let me think a little bit.

We need to calculate the distance it is offset in each axes.

If we will get this today you will totally return my confidence to continue coding i have spent too much time by this . 

[Nineshadow]

If we will get this today you will totally return my confidence to continue coding i have spent too much time by this . 

Well, we already managed to walk diagonally.

(float)Math.sin(Math.toRadians(yaw))

Try using that or something.

[SirPaul]

Well, we already managed to walk diagonally.

(float)Math.sin(Math.toRadians(yaw))

Try using that or something.

 yea i tried exactly that, but it doesnt work as it should .  

[SirPaul]

Well, we already managed to walk diagonally.

(float)Math.sin(Math.toRadians(yaw))

Try using that or something.

 

Actually, that kind of works, but have a very weak range.   so it should be something along those lines, but dont really know how.. 

[SirPaul]

Actually, that kind of works, but have a very weak range.   so it should be something along those lines, but dont really know how.. 

 

Okey so this is the finest i could get .

 

  spawnedBoxes.get(i).centerX-=(float)Math.sin(Math.toRadians(yaw * 4));

  spawnedBoxes.get(i).centerY-=(float)Math.sin(Math.toRadians(-pitch  * 4  ));

This does something like this : 

 

Any suggestions ?

[Nineshadow]

 

Okey so this is the finest i could get .

 

  spawnedBoxes.get(i).centerX-=(float)Math.sin(Math.toRadians(yaw * 4));

  spawnedBoxes.get(i).centerY-=(float)Math.sin(Math.toRadians(-pitch  * 4  ));

This does something like this : 

 

Any suggestions ?

 

That still moves all boxes.You need to create different instances(objects) for each one of them.

[SirPaul]

That still moves all boxes.You need to create different instances(objects) for each one of them.

 

I know thats not the problem, i can solve that in a second, its just for testing.   

I need to actually fix the 'range' of how much to the left and right can box spawn.

[LukeTim]

I'd recommend looking into Matrix Maths rather than using Sine, Cosine, angles etc...

If I understood your problem correctly, I think you need to use a cross product?

This might help... http://www.wikihow.com/Find-Perpendicular-Vectors-in-3-Dimensions