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Hello,

I've been trying to work out this code with mixed results.

Basic premise is a space ship firing lasers in whatever direction its facing

spriteCounter = the laser thats about to be fired
3 = the sprite for the players ship

I use some code to point the players ship wherever the pointer is clicking at the moment and it works perfectly.

I thought I would use this code to find the angle to shoot the laser at but its not working.

I can either get it to do the following:
- shoot 1 direction
- shoot various directions but NOT exactly where the ship is pointing

What should be the relevant portion of code :

void createLaser( vector<Laser>&passedArray )
{

float angle_X = 0.0;
	float angle_Y = 0.0;

float sprite_hit_X = 0.0;
	float sprite_hit_Y = 0.0;

lasers_active++;								// keeps track of how many lasers max of 30
	if(lasers_active > 29) lasers_active = 0;		// making sure we recycle the lasers from 0 to 29
	if(spriteCounter > 1999) spriteCounter = 1000;	// keeps the spriteID of individual lasers between 1000 and 1999

// a vector style array that holds the lasers and is iterated through to remove them once they have lived long enough or hit something
	passedArray[lasers_active].setActive(true);
	passedArray[lasers_active].setLaserTimer( agk::Timer()+1.8);
	passedArray[lasers_active].setSpriteID(spriteCounter);

if (agk::GetSpriteExists(spriteCounter) == 1) agk::DeleteSprite(spriteCounter);	// clear the sprite if it happen to still exist

agk::CreateSprite(spriteCounter,4);					// 4 is the image number of the sprite used for lasers
	agk::SetSpriteDepth(spriteCounter,200);				
	agk::SetSpriteOffset(spriteCounter,8,8);			// the image for the laser sprite is 16x16 therefore we are setting the offset by 8x8 so it is in the center
	agk::SetSpritePositionByOffset(spriteCounter,agk::GetDeviceWidth()/2, agk::GetDeviceHeight()/2); // the player ship is always in the center of the screen therefore we center the origin in the center

pointer_loc_X = agk::GetPointerX();
    pointer_loc_Y = agk::GetPointerY();
	
	// METHOD 0  use the ATanFull to find the angle based on where the mouse clicks in relationship to the laser origin
	angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter));

// METHOD 1 to get angle ; get angle of the sprite its self
	//angle_XY = agk::GetSpriteAngle(spriteCounter);

// METHOD 2 to get angle; get the angle the spaceship is facing
	//angle_XY = agk::GetSpriteAngle(3);
	agk::SetSpriteAngle(spriteCounter, angle_XY );

// get the cos and sin of x and y
	spX = agk::Cos(angle_XY);
	spY = agk::Sin(angle_XY);

// get the location of the laser sprite and add it to the spX spY (cos and sin)
	sprite_hit_X = agk::GetSpriteXByOffset(spriteCounter)  + spX ;
	sprite_hit_Y = agk::GetSpriteYByOffset(spriteCounter)  + spY ;

agk::SetSpritePositionByOffset(spriteCounter,sprite_hit_X, sprite_hit_Y);		// update the position not sure why but this helped at one point

float FORCE = 1000;																// the force or velocity I am aplying
	velocityX = (sprite_hit_X - agk::GetSpriteXByOffset(spriteCounter)  * FORCE);	// multiply the sprite hit point by the velocity
	velocityY = (sprite_hit_Y - agk::GetSpriteYByOffset(spriteCounter)  * FORCE);

agk::SetSpritePhysicsOn (spriteCounter, 2);		// turn physics on

// METHOD 0  using impulse and 'byoffset'
	agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteXByOffset(spriteCounter), agk::GetSpriteYByOffset(spriteCounter), velocityX,velocityY );
	
	// METHOD 1  using impulse and by x/y position
	//agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	//agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteX(spriteCounter), agk::GetSpriteY(spriteCounter), velocityX,velocityY );

// METHOD 2   using physicsvelocity
	//agk::SetSpritePhysicsVelocity(spriteCounter,velocityX, velocityY);
	//agk::SetSpritePhysicsAngularVelocity(spriteCounter, 0.3);
	//agk::SetSpritePhysicsDamping(spriteCounter, 0.1);

spriteCounter++;		// increment spriteID

return;
}

void createLaser( vector<Laser>&passedArray )
{



	float angle_X = 0.0;
	float angle_Y = 0.0;

	float sprite_hit_X = 0.0;
	float sprite_hit_Y = 0.0;

	lasers_active++;								// keeps track of how many lasers max of 30
	if(lasers_active > 29) lasers_active = 0;		// making sure we recycle the lasers from 0 to 29
	if(spriteCounter > 1999) spriteCounter = 1000;	// keeps the spriteID of individual lasers between 1000 and 1999

	// a vector style array that holds the lasers and is iterated through to remove them once they have lived long enough or hit something
	passedArray[lasers_active].setActive(true);
	passedArray[lasers_active].setLaserTimer( agk::Timer()+1.8);
	passedArray[lasers_active].setSpriteID(spriteCounter);

	if (agk::GetSpriteExists(spriteCounter) == 1) agk::DeleteSprite(spriteCounter);	// clear the sprite if it happen to still exist

	agk::CreateSprite(spriteCounter,4);					// 4 is the image number of the sprite used for lasers
	agk::SetSpriteDepth(spriteCounter,200);				
	agk::SetSpriteOffset(spriteCounter,8,8);			// the image for the laser sprite is 16x16 therefore we are setting the offset by 8x8 so it is in the center
	agk::SetSpritePositionByOffset(spriteCounter,agk::GetDeviceWidth()/2, agk::GetDeviceHeight()/2); // the player ship is always in the center of the screen therefore we center the origin in the center

	pointer_loc_X = agk::GetPointerX();
    pointer_loc_Y = agk::GetPointerY();
	
	// METHOD 0  use the ATanFull to find the angle based on where the mouse clicks in relationship to the laser origin
	angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter));

	// METHOD 1 to get angle ; get angle of the sprite its self
	//angle_XY = agk::GetSpriteAngle(spriteCounter);

	// METHOD 2 to get angle; get the angle the spaceship is facing
	//angle_XY = agk::GetSpriteAngle(3);
	agk::SetSpriteAngle(spriteCounter, angle_XY );	


	// get the cos and sin of x and y
	spX = agk::Cos(angle_XY);
	spY = agk::Sin(angle_XY);

	// get the location of the laser sprite and add it to the spX spY (cos and sin)
	sprite_hit_X = agk::GetSpriteXByOffset(spriteCounter)  + spX ;
	sprite_hit_Y = agk::GetSpriteYByOffset(spriteCounter)  + spY ;

	agk::SetSpritePositionByOffset(spriteCounter,sprite_hit_X, sprite_hit_Y);		// update the position not sure why but this helped at one point

	float FORCE = 1000;																// the force or velocity I am aplying
	velocityX = (sprite_hit_X - agk::GetSpriteXByOffset(spriteCounter)  * FORCE);	// multiply the sprite hit point by the velocity
	velocityY = (sprite_hit_Y - agk::GetSpriteYByOffset(spriteCounter)  * FORCE);

	agk::SetSpritePhysicsOn (spriteCounter, 2);		// turn physics on

	// METHOD 0  using impulse and 'byoffset'
	agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteXByOffset(spriteCounter), agk::GetSpriteYByOffset(spriteCounter), velocityX,velocityY );
	
	// METHOD 1  using impulse and by x/y position
	//agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	//agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteX(spriteCounter), agk::GetSpriteY(spriteCounter), velocityX,velocityY );

	// METHOD 2   using physicsvelocity
	//agk::SetSpritePhysicsVelocity(spriteCounter,velocityX, velocityY);
	//agk::SetSpritePhysicsAngularVelocity(spriteCounter, 0.3);
	//agk::SetSpritePhysicsDamping(spriteCounter, 0.1);

	
	spriteCounter++;		// increment spriteID 

	return;
}

trig is not my strong point so I assume I'm making a math error but I could also just be conceptualizing it wrong also?

Any tips welcome! Thanks!

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Van B

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Location: Sunnyvale

Posted: 5th Jun 2013 10:56

I wonder if RADians are running amock somewhere, maybe the Atanfull command.

What I'd expect is to at least have a consistent direction - it might not be exact, like you might need to subtract the angle from 180 or something like that, but to have totally random results would lead me to check if one of those commands is expecting radians.

Radians would exaggerate the angle you see, so even though an angle difference might be just 5 degrees - if the command is expecting radians, it'll be more like 40 degrees.

That's the only reason I can think that you'd have such spurious results.

I got a fever, and the only prescription, is more memes.

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Markus

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Posted: 5th Jun 2013 11:38 Edited at: 5th Jun 2013 11:42

i think you forget declare float for this.
spX =
spY =

and all the variable names are not good.

this you can replace
velocityX = (sprite_hit_X - agk::GetSpriteXByOffset(spriteCounter) * FORCE); // multiply the sprite hit point by the velocity
velocityY = (sprite_hit_Y - agk::GetSpriteYByOffset(spriteCounter) * FORCE);

=

velocityX = spX * FORCE;
velocityY = spY * FORCE;

a better name for sp is direction or dirX dirY

the direction you can get without sin/cos (the delta/distance you already use for ATanFull)
dx#=x2#-x1#
dy#=y2#-y1#
length#=sqrt(dx#*dx# + dy#*dy#)
if length#<1.0 then length#=1.0
dirX#=dx#/length#
dirY#=dy#/length#

//split force in x y
forceX#=dirX# * force#
forceY#=dirY# * force#

#=float

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Hodgey

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Posted: 5th Jun 2013 13:17

The thing I've noticed about using Atanfull in conjuction with sin and cos is that the angle given by Atanfull seems start at a different point than sin and cos. I find that with Atanfull, the unit circle is goes clockwise with 0 degrees at 12 o'clock. I believe sin and cos also go clockwise but their 0 starts at 3 o'clock. So there's a difference of 90 degrees.

With this line:

angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter));

Try adding 90 to it:

angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter)) + 90.0f;

If that doesn't work, try subtracting 90.

If that doesn't work...listen to someone else.

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Markus

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Posted: 5th Jun 2013 13:24

@Hodgey
about different point :
you can also exchange sin/cos or the sign.
i can't remember me, i try each time i need this.

@erebusman
if you want shoot with ship angle, the sprite image/ship nose should look
up.

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erebusman

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Posted: 5th Jun 2013 17:00

Thanks for all the great suggestions , heading out to work but I will try these out this evening!

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erebusman

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Posted: 6th Jun 2013 06:31 Edited at: 6th Jun 2013 07:21

Okay back from work and I played with all of the suggestions

We have the winning code with some comments about some things that worked, didnt work and adjustments that were needed

Thank you to everyone for your contribution:

void createLaser( vector<Laser>&passedArray )
{

float sprite_hit_X = 0.0;
	float sprite_hit_Y = 0.0;

lasers_active++;								// keeps track of how many lasers max of 30
	if(lasers_active > 29) lasers_active = 0;		// making sure we recycle the lasers from 0 to 29
	if(spriteCounter > 1999) spriteCounter = 1000;	// keeps the spriteID of individual lasers between 1000 and 1999

// a vector style array that holds the lasers and is iterated through to remove them once they have lived long enough or hit something
	passedArray[lasers_active].setActive(true);
	passedArray[lasers_active].setLaserTimer( agk::Timer()+1.8);
	passedArray[lasers_active].setSpriteID(spriteCounter);

if (agk::GetSpriteExists(spriteCounter) == 1) agk::DeleteSprite(spriteCounter);	// clear the sprite if it happen to still exist

agk::CreateSprite(spriteCounter,4);					// 4 is the image number of the sprite used for lasers
	agk::SetSpriteDepth(spriteCounter,200);				
	agk::SetSpriteOffset(spriteCounter,8,8);			// the image for the laser sprite is 16x16 therefore we are setting the offset by 8x8 so it is in the center
	agk::SetSpritePositionByOffset(spriteCounter,agk::GetDeviceWidth()/2, agk::GetDeviceHeight()/2); // the player ship is always in the center of the screen therefore we center the origin in the center

pointer_loc_X = agk::GetPointerX();
    pointer_loc_Y = agk::GetPointerY();
	
	// METHOD 0  use the ATanFull to find the angle based on where the mouse clicks in relationship to the laser origin
	angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter) )- 90;  // subtracting 90 was neccesary for the correct angle

// METHOD 1 to get angle ; get angle of the sprite its self
	// does not work
	//angle_XY = agk::GetSpriteAngle(spriteCounter);

// METHOD 2 to get angle; get the angle the spaceship is facing
	// also works fine, but I prefer the 'one line' method above
	//angle_XY = agk::GetSpriteAngle(3);
	//agk::SetSpriteAngle(spriteCounter, angle_XY );

// get the cos and sin of x and y
	float spX = agk::Cos(angle_XY);
	float spY = agk::Sin(angle_XY);

// get the location of the laser sprite and add it to the spX spY (cos and sin)
	sprite_hit_X = agk::GetSpriteXByOffset(spriteCounter)  + spX ;
	sprite_hit_Y = agk::GetSpriteYByOffset(spriteCounter)  + spY ;

float FORCE = 1000;																// the force or velocity I am aplying
	velocityX = (spX  * FORCE);	// multiply the sprite hit point by the velocity
	velocityY = (spY * FORCE);

agk::SetSpritePhysicsOn (spriteCounter, 2);		// turn physics on

// METHOD 0  using impulse and 'byoffset'
	// this works but results in a 'slow' laser
	//agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	//agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteXByOffset(spriteCounter), agk::GetSpriteYByOffset(spriteCounter), velocityX,velocityY );
	
	// METHOD 2   using physicsvelocity
	agk::SetSpritePhysicsVelocity(spriteCounter,velocityX, velocityY);
	agk::SetSpritePhysicsAngularVelocity(spriteCounter, 0.3);
	agk::SetSpritePhysicsDamping(spriteCounter, 0.1);

spriteCounter++;		// increment spriteID

return;
}

void createLaser( vector<Laser>&passedArray )
{

	float sprite_hit_X = 0.0;
	float sprite_hit_Y = 0.0;

	lasers_active++;								// keeps track of how many lasers max of 30
	if(lasers_active > 29) lasers_active = 0;		// making sure we recycle the lasers from 0 to 29
	if(spriteCounter > 1999) spriteCounter = 1000;	// keeps the spriteID of individual lasers between 1000 and 1999

	// a vector style array that holds the lasers and is iterated through to remove them once they have lived long enough or hit something
	passedArray[lasers_active].setActive(true);
	passedArray[lasers_active].setLaserTimer( agk::Timer()+1.8);
	passedArray[lasers_active].setSpriteID(spriteCounter);

	if (agk::GetSpriteExists(spriteCounter) == 1) agk::DeleteSprite(spriteCounter);	// clear the sprite if it happen to still exist

	agk::CreateSprite(spriteCounter,4);					// 4 is the image number of the sprite used for lasers
	agk::SetSpriteDepth(spriteCounter,200);				
	agk::SetSpriteOffset(spriteCounter,8,8);			// the image for the laser sprite is 16x16 therefore we are setting the offset by 8x8 so it is in the center
	agk::SetSpritePositionByOffset(spriteCounter,agk::GetDeviceWidth()/2, agk::GetDeviceHeight()/2); // the player ship is always in the center of the screen therefore we center the origin in the center

	pointer_loc_X = agk::GetPointerX();
    pointer_loc_Y = agk::GetPointerY();
	
	// METHOD 0  use the ATanFull to find the angle based on where the mouse clicks in relationship to the laser origin
	angle_XY = agk::ATanFull(pointer_loc_X - agk::GetSpriteXByOffset(spriteCounter), pointer_loc_Y - agk::GetSpriteYByOffset(spriteCounter) )- 90;  // subtracting 90 was neccesary for the correct angle

	// METHOD 1 to get angle ; get angle of the sprite its self
	// does not work
	//angle_XY = agk::GetSpriteAngle(spriteCounter);

	// METHOD 2 to get angle; get the angle the spaceship is facing
	// also works fine, but I prefer the 'one line' method above
	//angle_XY = agk::GetSpriteAngle(3);
	//agk::SetSpriteAngle(spriteCounter, angle_XY );	


	// get the cos and sin of x and y
	float spX = agk::Cos(angle_XY);
	float spY = agk::Sin(angle_XY);

	// get the location of the laser sprite and add it to the spX spY (cos and sin)
	sprite_hit_X = agk::GetSpriteXByOffset(spriteCounter)  + spX ;
	sprite_hit_Y = agk::GetSpriteYByOffset(spriteCounter)  + spY ;

	float FORCE = 1000;																// the force or velocity I am aplying
	velocityX = (spX  * FORCE);	// multiply the sprite hit point by the velocity
	velocityY = (spY * FORCE);


	agk::SetSpritePhysicsOn (spriteCounter, 2);		// turn physics on

	// METHOD 0  using impulse and 'byoffset'
	// this works but results in a 'slow' laser
	//agk::SetSpritePhysicsIsBullet(spriteCounter, 1 );  // 1 sets this to bullet physics   - I have toggled off and on makes no difference
	//agk::SetSpritePhysicsImpulse(spriteCounter, agk::GetSpriteXByOffset(spriteCounter), agk::GetSpriteYByOffset(spriteCounter), velocityX,velocityY );
	
	// METHOD 2   using physicsvelocity
	agk::SetSpritePhysicsVelocity(spriteCounter,velocityX, velocityY);
	agk::SetSpritePhysicsAngularVelocity(spriteCounter, 0.3);
	agk::SetSpritePhysicsDamping(spriteCounter, 0.1);

	
	spriteCounter++;		// increment spriteID 

	return;
}

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Markus

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Posted: 6th Jun 2013 10:27 Edited at: 6th Jun 2013 13:13

??? why, it rotate the laser sprite
SetSpritePhysicsAngularVelocity

i made a example

//MR Laser Shot

sprShip=createsprite(0)
setspritepositionbyoffset(sprShip,50,50)

do

mx#=getpointerx()
    my#=getpointery()

if getpointerpressed()
     Laser(sprShip,mx#,my#)
    endif

sync()

loop
end

function Laser(spr,mx#,my#)

dx#=mx# - GetSpriteXByOffset(spr)
    dy#=my# - GetSpriteYByOffset(spr)

angle# = ATanFull(dx#,dy#)

dirx# =  sin(angle#)
	diry# = -cos(angle#)

startx#= GetSpriteXByOffset(spr) + dirx# * 1.0
	starty#= GetSpriteYByOffset(spr) + diry# * 1.0

FORCE# = 1000.0
	forcex# = dirx# * FORCE#
	forcey# = diry# * FORCE#

sprLaser=CreateSprite(0)
	setspritesize(sprLaser,1,10)
	setspritecolor(sprLaser,255,0,0,255)
    setspritepositionbyoffset(sprLaser,startx#, starty#)
    setspriteangle(sprLaser,angle#)
	SetSpriteDepth(sprLaser,200)
	SetSpritePhysicsOn(sprLaser, 2)
	SetSpritePhysicsIsBullet(sprLaser, 1 )
	SetSpritePhysicsDamping(sprLaser, 0.0)
	SetSpritePhysicsfriction(sprLaser, 0.0)
    SetSpritePhysicsCanRotate(sprLaser,0)
    SetSpritePhysicsIsSensor(sprLaser,1)
    SetSpritePhysicsRestitution(sprLaser, 0.0)
	//SetSpritePhysicsImpulse(sprLaser, startx#, starty#, forcex#,forcey# )
	SetSpritePhysicsVelocity(sprLaser,forcex#, forcey#)

//... Memory Laser Sprite

endfunction


//MR Laser Shot

sprShip=createsprite(0)
setspritepositionbyoffset(sprShip,50,50)

do

    mx#=getpointerx()
    my#=getpointery()

    if getpointerpressed()
     Laser(sprShip,mx#,my#)
    endif

    sync()

loop
end

function Laser(spr,mx#,my#)

    dx#=mx# - GetSpriteXByOffset(spr)
    dy#=my# - GetSpriteYByOffset(spr)

	angle# = ATanFull(dx#,dy#)

	dirx# =  sin(angle#)
	diry# = -cos(angle#)

	startx#= GetSpriteXByOffset(spr) + dirx# * 1.0
	starty#= GetSpriteYByOffset(spr) + diry# * 1.0

	FORCE# = 1000.0
	forcex# = dirx# * FORCE#
	forcey# = diry# * FORCE#

	sprLaser=CreateSprite(0)
	setspritesize(sprLaser,1,10)
	setspritecolor(sprLaser,255,0,0,255)
    setspritepositionbyoffset(sprLaser,startx#, starty#)
    setspriteangle(sprLaser,angle#)
	SetSpriteDepth(sprLaser,200)
	SetSpritePhysicsOn(sprLaser, 2)
	SetSpritePhysicsIsBullet(sprLaser, 1 )
	SetSpritePhysicsDamping(sprLaser, 0.0)
	SetSpritePhysicsfriction(sprLaser, 0.0)
    SetSpritePhysicsCanRotate(sprLaser,0)
    SetSpritePhysicsIsSensor(sprLaser,1)
    SetSpritePhysicsRestitution(sprLaser, 0.0)
	//SetSpritePhysicsImpulse(sprLaser, startx#, starty#, forcex#,forcey# )
	SetSpritePhysicsVelocity(sprLaser,forcex#, forcey#)

    //... Memory Laser Sprite

endfunction

next example

//MR Laser Shot

SetPhysicsCCD( 1 )
setphysicsgravity(0,0)

dim list[10]
global listindex
listindex=0

dim listtarget[100]
Targets()

sprShip=createsprite(0)
setspritepositionbyoffset(sprShip,50,50)

do

print(GetManagedSpriteCount())

mx#=getpointerx()
    my#=getpointery()

if e then e=e-1
    if getpointerstate()=1 and e=0
     Laser(sprShip,mx#,my#)
     e=3
    endif

Colli()

sync()

loop
end

function Targets()

for i=1 to 100
    x#=random(0,100)
    y#=random(0,100)
    spr=createsprite(0)
    setspritepositionbyoffset(spr,x#,y#)
    setspritesize(spr,1,1)
    //setspritegroup(spr,10)
    SetSpritePhysicsOn(spr, 1)
    SetSpritePhysicsIsSensor(spr,1)

listtarget[i]=spr
 next

endfunction

function Laser(spr,mx#,my#)

dx#=mx# - GetSpriteXByOffset(spr)
    dy#=my# - GetSpriteYByOffset(spr)

drawline(mx#,my#,GetSpriteXByOffset(spr),GetSpriteyByOffset(spr),255,255,0)

angle# = ATanfull(dx#,dy#)

l#=sqrt(dx#*dx# + dy#*dy#)
    if l#<1.0 then l#=1.0

//dirx# =  sin(angle#)
	//diry# = -cos(angle#)

dirx# = dx# / l#
	diry# = dy# / l#

startx#= GetSpriteXByOffset(spr) + (dirx# * 1.0)
	starty#= GetSpriteYByOffset(spr) + (diry# * 1.0)

FORCE# = 100.0
	forcex# = dirx# * FORCE#
	forcey# = diry# * FORCE#

index=GetLaserIndex()
    if index=>0
        //print(index)

sprLaser=CreateSprite(0)
        //setspritegroup(sprLaser,1)
        setspritecolor(sprLaser,255,0,0,255)
        setspritetransparency(sprLaser,0)
        setspritesize(sprLaser,1,10)
        setspriteoffset(sprLaser,0.5,5.0)
        setspritepositionbyoffset(sprLaser,startx#, starty#)
        setspriteangle(sprLaser,angle#)
        SetSpriteDepth(sprLaser,200)
        SetSpritePhysicsOn(sprLaser, 2)
        SetSpritePhysicsCOM( sprLaser, 0, 0 )
        SetSpritePhysicsIsBullet(sprLaser, 1 )
        SetSpritePhysicsDamping(sprLaser, 0.1)
        SetSpritePhysicsfriction(sprLaser, 0.1)
        SetSpritePhysicsCanRotate(sprLaser,0)
        //setspritephysicsmass(sprLaser,0.1)
        SetSpritePhysicsIsSensor(sprLaser,1)
        SetSpritePhysicsRestitution(sprLaser, 0.01)
        //SetSpritePhysicsImpulse(sprLaser, startx#, starty#, forcex#,forcey# )
        SetSpritePhysicsangularVelocity(sprLaser,0)
        SetSpritePhysicsVelocity(sprLaser,forcex#, forcey#)

list[index]=sprLaser

endif

endfunction

function GetLaserIndex()

ret=-1

for i=0 to 10
     if list[i]=0
        ret=i
        exit
     endif
    next

endfunction ret

function Colli()

for i=0 to 10
     spr=list[i] //Laser
     if getspriteexists(spr)
       c=GetSpriteFirstContact(spr)
       do
           if c=0 then exit
           sprHit=GetSpriteContactSpriteID2()
           //if getspritegroup(sprHit)=xy
           if sprHit<>0
            if DeleteTarget(sprHit)=1
            endif
           endif
           c=GetSpritenextContact()
       loop

//in Screen?
       if GetSpriteInBox( spr, 0, 0, 100, 100 ) =0
        DeleteLaser(i)
       endif

endif
    next

endfunction

function DeleteLaser(i)
           deletesprite(list[i])
           list[i]=0
endfunction

function DeleteTarget(spr)

ret=0

for i=1 to 100
     sprTarget=listtarget[i] //Target
     if sprTarget=spr
       deletesprite(sprTarget)
       listtarget[i]=0
       ret=1
       exit
     endif
    next

endfunction ret

//MR Laser Shot

SetPhysicsCCD( 1 )
setphysicsgravity(0,0)

dim list[10]
global listindex
listindex=0

dim listtarget[100]
Targets()

sprShip=createsprite(0)
setspritepositionbyoffset(sprShip,50,50)

do

    print(GetManagedSpriteCount())

    mx#=getpointerx()
    my#=getpointery()

    if e then e=e-1
    if getpointerstate()=1 and e=0
     Laser(sprShip,mx#,my#)
     e=3
    endif

    Colli()

    sync()

loop
end

function Targets()

 for i=1 to 100
    x#=random(0,100)
    y#=random(0,100)
    spr=createsprite(0)
    setspritepositionbyoffset(spr,x#,y#)
    setspritesize(spr,1,1)
    //setspritegroup(spr,10)
    SetSpritePhysicsOn(spr, 1)
    SetSpritePhysicsIsSensor(spr,1)

    listtarget[i]=spr
 next

endfunction

function Laser(spr,mx#,my#)

    dx#=mx# - GetSpriteXByOffset(spr)
    dy#=my# - GetSpriteYByOffset(spr)

    drawline(mx#,my#,GetSpriteXByOffset(spr),GetSpriteyByOffset(spr),255,255,0)

	angle# = ATanfull(dx#,dy#)

    l#=sqrt(dx#*dx# + dy#*dy#)
    if l#<1.0 then l#=1.0

	//dirx# =  sin(angle#)
	//diry# = -cos(angle#)

	dirx# = dx# / l#
	diry# = dy# / l#

	startx#= GetSpriteXByOffset(spr) + (dirx# * 1.0)
	starty#= GetSpriteYByOffset(spr) + (diry# * 1.0)

	FORCE# = 100.0
	forcex# = dirx# * FORCE#
	forcey# = diry# * FORCE#

    index=GetLaserIndex()
    if index=>0
        //print(index)

        sprLaser=CreateSprite(0)
        //setspritegroup(sprLaser,1)
        setspritecolor(sprLaser,255,0,0,255)
        setspritetransparency(sprLaser,0)
        setspritesize(sprLaser,1,10)
        setspriteoffset(sprLaser,0.5,5.0)
        setspritepositionbyoffset(sprLaser,startx#, starty#)
        setspriteangle(sprLaser,angle#)
        SetSpriteDepth(sprLaser,200)
        SetSpritePhysicsOn(sprLaser, 2)
        SetSpritePhysicsCOM( sprLaser, 0, 0 )
        SetSpritePhysicsIsBullet(sprLaser, 1 )
        SetSpritePhysicsDamping(sprLaser, 0.1)
        SetSpritePhysicsfriction(sprLaser, 0.1)
        SetSpritePhysicsCanRotate(sprLaser,0)
        //setspritephysicsmass(sprLaser,0.1)
        SetSpritePhysicsIsSensor(sprLaser,1)
        SetSpritePhysicsRestitution(sprLaser, 0.01)
        //SetSpritePhysicsImpulse(sprLaser, startx#, starty#, forcex#,forcey# )
        SetSpritePhysicsangularVelocity(sprLaser,0)
        SetSpritePhysicsVelocity(sprLaser,forcex#, forcey#)

        list[index]=sprLaser

    endif

endfunction

function GetLaserIndex()

    ret=-1

    for i=0 to 10
     if list[i]=0
        ret=i
        exit
     endif
    next

endfunction ret

function Colli()

    for i=0 to 10
     spr=list[i] //Laser
     if getspriteexists(spr)
       c=GetSpriteFirstContact(spr)
       do
           if c=0 then exit
           sprHit=GetSpriteContactSpriteID2()
           //if getspritegroup(sprHit)=xy
           if sprHit<>0
            if DeleteTarget(sprHit)=1
            endif
           endif
           c=GetSpritenextContact()
       loop

       //in Screen?
       if GetSpriteInBox( spr, 0, 0, 100, 100 ) =0
        DeleteLaser(i)
       endif

     endif
    next

endfunction

function DeleteLaser(i)
           deletesprite(list[i])
           list[i]=0
endfunction

function DeleteTarget(spr)

    ret=0

    for i=1 to 100
     sprTarget=listtarget[i] //Target
     if sprTarget=spr
       deletesprite(sprTarget)
       listtarget[i]=0
       ret=1
       exit
     endif
    next

endfunction ret

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erebusman

12

Years of Service

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Joined: 23rd Jul 2011

Location: Sacramento, CA

Posted: 7th Jun 2013 06:29

@Markus

The code samples you have seem to both do the same thing to me?

However I think I know what you mean.. does the laser sprite spin around in circles?

I noticed the same behavior so I made the sprite round and it looks sort of like a "photon torpedo" from Star Trek.

I would like to also have a straight 'laser beam' so I like the idea you are using too, I may have to try that out.

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Markus

Valued Member

20

Years of Service

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Joined: 10th Apr 2004

Location: Germany

Posted: 7th Jun 2013 09:08 Edited at: 7th Jun 2013 09:09

i try a longer sprite but the sprite angle did not hit the mouse pointer target!?

the same problem you wrote at top.

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Marl

12

Years of Service

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Joined: 19th Nov 2011

Location: Bradford, UK

Posted: 7th Jun 2013 09:58 Edited at: 7th Jun 2013 09:59

If you want to use a blank sprite to create a laser, I have found it better to create a horizontal line for the sprite not a vertical one and put the offset at the left.

laserSprite = createsprite(0)
setSpriteSize(laserSprite,targetDistance#,2)
setSpriteOffset(laserSprite,0,1)
setSpritePositionByOffset(laserSprite,gunPosX,gunPosY)
setSpriteAngle(laserSprite,targetAngle#)

That way the angle of zero degrees is in line with the maths of sin/cos. - i.e. pointing to the right.

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Chris Harries

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Joined: 13th Jun 2013

Location:

Posted: 13th Jun 2013 09:51