[DBP] Check for Point in Sector - GameCreators Forum

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Scraggle

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Joined: 10th Jul 2003

Location: Yorkshire

Posted: 7th Jul 2009 13:24 Edited at: 7th Jul 2009 13:28

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A sector can be imagined as a slice from a circular cake.
This code will check to see if a point falls within a sector.
The sector can be any size and facing any direction.

set display mode 640, 480, 32, 1

type type_sector
	x 					as float
	y 					as float
	radius 			as float
	angle 			as float
	size 				as float
endtype

global sector 		as type_sector
global vDistance 	as integer = 1

sector.x          = 320
sector.y          = 240
sector.radius     = 240
sector.angle      = 0
sector.size       = 45 `Make this half of the angle of the sector (to save future calculations) 
null              = make vector2( vDistance )

make memblock from bitmap 1, 0
create_target_image()

sync on

do
	paste image 1, 0, 0, 1
	
	not$ = " not"
	if in_sector( mousex(), mousey() ) then not$ = ""

center text 320, 0, "Mouse is" + not$ + " in sector"
	center text 320, 450, "Use arrow keys to rotate and scale the sector"
	center text 320, 465, "Use ctrl/shift to change sector size"
	
	if user_input() then create_target_image()
	
	sync
loop

function in_sector( x as integer, y as integer )
	
	`check for distance
	if get_distance( x, y, sector.x, sector.y ) < sector.radius
		angle# = wrapvalue( atanfull( sector.x - x, sector.y - y ) )
		
		`check angle
		if abs( angle# - sector.angle ) < sector.size
			in = 1
		endif 
		
		`Check for angle wrap around (0 becomes 360 etc.)
		if sector.angle < sector.size
			if abs( angle# - sector.angle ) > 360 - sector.size
				in = 1
			endif
		endif
		if sector.angle > 360 - sector.size
			if abs( angle# - sector.angle ) > 360 - sector.size
				in = 1
			endif
		endif
	endif
	
endfunction in

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

set vector2 vDistance, x1-x2, y1-y2
   result# = length vector2( vDistance )
      
endfunction result#

function create_target_image()
	
	for y = 0 to 479 
		for x = 0 to 639
			write memblock byte 1, (y * 640 * 4) + (x * 4) + 14, in_sector( x, y ) * 255
			write memblock byte 1, (y * 640 * 4) + (x * 4) + 15, 255
		next x
	next y
	make image from memblock 1, 1
	
endfunction

function user_input()
	
	if leftkey()    then sector.angle = wrapvalue( sector.angle + 5 ) : redraw = 1
	if rightkey()   then sector.angle = wrapvalue( sector.angle - 5 ) : redraw = 1
	if upkey()      then inc sector.radius, 5                         : redraw = 1
	if downkey()    then dec sector.radius, 5                         : redraw = 1
	if controlkey() then dec sector.size, 5                           : redraw = 1
	if shiftkey()   then inc sector.size, 5                           : redraw = 1

endfunction redraw

+ Code Snippet

set display mode 640, 480, 32, 1

type type_sector
	x 					as float
	y 					as float
	radius 			as float
	angle 			as float
	size 				as float
endtype

global sector 		as type_sector
global vDistance 	as integer = 1

sector.x          = 320
sector.y          = 240
sector.radius     = 240
sector.angle      = 0
sector.size       = 45 `Make this half of the angle of the sector (to save future calculations) 
null              = make vector2( vDistance ) 

make memblock from bitmap 1, 0
create_target_image()

sync on

do
	paste image 1, 0, 0, 1
	
	not$ = " not"
	if in_sector( mousex(), mousey() ) then not$ = ""

	center text 320, 0, "Mouse is" + not$ + " in sector"
	center text 320, 450, "Use arrow keys to rotate and scale the sector"
	center text 320, 465, "Use ctrl/shift to change sector size"
	
	if user_input() then create_target_image()
	
	sync
loop

function in_sector( x as integer, y as integer )
	
	`check for distance
	if get_distance( x, y, sector.x, sector.y ) < sector.radius
		angle# = wrapvalue( atanfull( sector.x - x, sector.y - y ) )
		
		`check angle
		if abs( angle# - sector.angle ) < sector.size
			in = 1
		endif 
		
		`Check for angle wrap around (0 becomes 360 etc.)
		if sector.angle < sector.size
			if abs( angle# - sector.angle ) > 360 - sector.size
				in = 1
			endif
		endif
		if sector.angle > 360 - sector.size
			if abs( angle# - sector.angle ) > 360 - sector.size
				in = 1
			endif
		endif
	endif
	
endfunction in

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

   set vector2 vDistance, x1-x2, y1-y2
   result# = length vector2( vDistance )
      
endfunction result#

function create_target_image()
	
	for y = 0 to 479 
		for x = 0 to 639
			write memblock byte 1, (y * 640 * 4) + (x * 4) + 14, in_sector( x, y ) * 255
			write memblock byte 1, (y * 640 * 4) + (x * 4) + 15, 255
		next x
	next y
	make image from memblock 1, 1
	
endfunction

function user_input()
	
	if leftkey()    then sector.angle = wrapvalue( sector.angle + 5 ) : redraw = 1
	if rightkey()   then sector.angle = wrapvalue( sector.angle - 5 ) : redraw = 1
	if upkey()      then inc sector.radius, 5                         : redraw = 1
	if downkey()    then dec sector.radius, 5                         : redraw = 1
	if controlkey() then dec sector.size, 5                           : redraw = 1
	if shiftkey()   then inc sector.size, 5                           : redraw = 1

endfunction redraw

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HowDo

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Joined: 28th Nov 2002

Location: United Kingdom

Posted: 7th Jul 2009 15:02

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This would work well with the pie chart code.

Dark Physics makes any hot drink go cold.

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feiting shadow

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Joined: 12th Sep 2006

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Posted: 7th Jul 2009 19:38 Edited at: 7th Jul 2009 19:39

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oh my god...

any chance this could be modified to display images and create a GUI system that's like HowDo's pie-chart idea?

I'm unfamiliar with images and memblocks, but this might be worth getting that on my list of reading material.

I could just make images shaped like this but hard-coded for angles is probably easier, with images loading in arcs.

Edit: Similar to my button system (below somewhere), with mouseover and mouseclick being displayed differently.

Signed
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RiiDii

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Location: Inatincan

Posted: 10th Jul 2009 18:59

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Nice work Scraggle. This a very clean way to have an AI "see" within a forward-viewing area.

Open MMORPG: It's your game!

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Dark Dragon

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Location: In the ring, Kickin\' *donkeybutt*.

Posted: 11th Jul 2009 05:55

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Quote: "This a very clean way to have an AI "see" within a forward-viewing area."

Perfect for a 'stealth' game's Gaurds.....

Your signature has been erased by a mod because it was too big.CHANGE IT OR DIE!!!!!

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RiiDii

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Joined: 20th Jan 2005

Location: Inatincan

Posted: 14th Jul 2009 00:30 Edited at: 14th Jul 2009 00:40

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Scraggle, you have inspired me. Here is a 3D version of your sector code (you might hardly recognize it).

Basics - same as yours, just added in a Vertical arc sector along with the Horizontal arc sector. Because there is a lot of 3D information, objects were used to pass data to the function instead of individual data items (coordinates, angles, arcs, and so on). It currently only works on a horizontal plain in a 3D environment; as opposed to allowing full 3D rotation.

The snippet is below in the code box. I've also upload a sample showing how the sector works using a Peripheral Vision demo. Objects within the sector's arc and radius become fully visible, while objects outside of the sector are dimmed.

Sector Code Snippet

function in_sector( SourceObj as DWord, TargetObj as DWord, SectArcH as Float, SectArcV as Float, SectRad as Float)

`Declarations
   SectX       as Float
   SectY       as Float
   SectZ       as Float
   SectAng     as Float

TargX       as Float
   TargY       as Float
   TargZ       as Float

Distance    as Float

inFlag      as Boolean = 0

`Defensive Code

If SourceObj<1                      Then ExitFunction inFlag
   If Not Object Exist(SourceObj)      Then ExitFunction inFlag

If TargetObj<1                      Then ExitFunction inFlag
   If Not Object Exist(TargetObj)      Then ExitFunction inFlag

`Set variables
   SectX       = Object Position X(SourceObj)
   SectY       = Object Position Y(SourceObj)
   SectZ       = Object Position Z(SourceObj)
   SectAng     = WrapValue(Object Angle Y(SourceObj))

TargX       = Object Position X(TargetObj)
   TargY       = Object Position Y(TargetObj)
   TargZ       = Object Position Z(TargetObj)

SectArcH     =SectArcH*.5
   SectArcV     =SectArcV*.5

`check for distance
   Distance    =get_distance( TargX, TargZ, SectX, SectZ )
   `Object is outside of sector radius
   if Distance > SectRad               Then ExitFunction inFlag

`Get the Y-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargX-SectX , TargZ-SectZ ) )

`check angle
   if abs( angle# - SectAng ) < SectArcH
      inFlag         = 1
   endif
   `Check for angle wrap around (0 becomes 360 etc.)
   if SectAng < SectArcH or SectAng > (360 - SectArcH)
      if abs( angle# - SectAng ) > 360 - SectArcH
         inFlag      = 1
      endif
   endif

if inFlag   = 0                     Then ExitFunction inFlag

inFlag      = 0

`Get the vertical-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargY-SectY , Distance ) )
   if angle# < SectArcV or angle# > (360-sectArcV)
      inFlag         = 1
   endif

endfunction inFlag

Function Initialize_Distance_Functions()
   Dim initDistance(0)
   If initDistance(0) Then ExitFunction
   initDistance(0)=1
   Global Distance3D = 1
   NoValue=Make Vector3(Distance3D)
   Global Distance2D = 2
   NoValue=Make Vector2(Distance2D)
Endfunction

function get_target_distance(object1,obj2x#,obj2y#,obj2z#)

Initialize_Distance_Functions()

If object1<1 Then Exitfunction 0.0
   If Object Exist(object1)=0 Then ExitFunction 0.0

ObjX#=Object Position X(Object1)
   ObjY#=Object Position Y(Object1)
   ObjZ#=Object Position Z(Object1)

Set Vector3 Distance3D,obj2x#-ObjX#,obj2y#-ObjY#,obj2z#-ObjZ#

distance# =  Length Vector3(Distance3D)

endfunction distance#

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

Initialize_Distance_Functions()

set vector2 Distance2D, x1-x2, y1-y2
   result# = length vector2( Distance2D )

endfunction result#

+ Code Snippet

function in_sector( SourceObj as DWord, TargetObj as DWord, SectArcH as Float, SectArcV as Float, SectRad as Float)

   `Declarations
   SectX       as Float
   SectY       as Float
   SectZ       as Float
   SectAng     as Float

   TargX       as Float
   TargY       as Float
   TargZ       as Float

   Distance    as Float

   inFlag      as Boolean = 0

   `Defensive Code

   If SourceObj<1                      Then ExitFunction inFlag
   If Not Object Exist(SourceObj)      Then ExitFunction inFlag

   If TargetObj<1                      Then ExitFunction inFlag
   If Not Object Exist(TargetObj)      Then ExitFunction inFlag

   `Set variables
   SectX       = Object Position X(SourceObj)
   SectY       = Object Position Y(SourceObj)
   SectZ       = Object Position Z(SourceObj)
   SectAng     = WrapValue(Object Angle Y(SourceObj))

   TargX       = Object Position X(TargetObj)
   TargY       = Object Position Y(TargetObj)
   TargZ       = Object Position Z(TargetObj)

   SectArcH     =SectArcH*.5
   SectArcV     =SectArcV*.5

   `check for distance
   Distance    =get_distance( TargX, TargZ, SectX, SectZ )
   `Object is outside of sector radius
   if Distance > SectRad               Then ExitFunction inFlag


   `Get the Y-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargX-SectX , TargZ-SectZ ) )

   `check angle
   if abs( angle# - SectAng ) < SectArcH
      inFlag         = 1
   endif
   `Check for angle wrap around (0 becomes 360 etc.)
   if SectAng < SectArcH or SectAng > (360 - SectArcH)
      if abs( angle# - SectAng ) > 360 - SectArcH
         inFlag      = 1
      endif
   endif

   if inFlag   = 0                     Then ExitFunction inFlag

   inFlag      = 0

   `Get the vertical-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargY-SectY , Distance ) )
   if angle# < SectArcV or angle# > (360-sectArcV)
      inFlag         = 1
   endif

endfunction inFlag


Function Initialize_Distance_Functions()
   Dim initDistance(0)
   If initDistance(0) Then ExitFunction
   initDistance(0)=1
   Global Distance3D = 1
   NoValue=Make Vector3(Distance3D)
   Global Distance2D = 2
   NoValue=Make Vector2(Distance2D)
Endfunction


function get_target_distance(object1,obj2x#,obj2y#,obj2z#)

   Initialize_Distance_Functions()

   If object1<1 Then Exitfunction 0.0
   If Object Exist(object1)=0 Then ExitFunction 0.0

   ObjX#=Object Position X(Object1)
   ObjY#=Object Position Y(Object1)
   ObjZ#=Object Position Z(Object1)

   Set Vector3 Distance3D,obj2x#-ObjX#,obj2y#-ObjY#,obj2z#-ObjZ#

   distance# =  Length Vector3(Distance3D)

endfunction distance#

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

   Initialize_Distance_Functions()

   set vector2 Distance2D, x1-x2, y1-y2
   result# = length vector2( Distance2D )

endfunction result#

This image shows the values that need to be passed to the function (and also what the sector looks like).

For the demo, use the WASD keys to move the camera around. Press the Space key to "lock" the camera's position current position (as far as the Peripheral Vision code is concerned) and move around to see what the arc looks like from the side.

Open MMORPG: It's your game!

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kaedroho

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Joined: 21st Aug 2007

Location: Oxford,UK

Posted: 14th Jul 2009 22:01 Edited at: 14th Jul 2009 22:05

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RiiDii, I helped you out a little with rotation and 3D sectors.

You will need to make 1 vector and 4 matrices for it to work.

Untested but it should work.

function in_sector( SourceObj as DWord, TargetObj as DWord, SectArcH as Float, SectArcV as Float, SectRad as Float,FreeVector as dword,FreeMatrix1 as dword,FreeMatrix2 as dword,FreeMatrix3 as dword,FreeMatrix4 as dword)

`Declarations
   SectX       as Float
   SectY       as Float
   SectZ       as Float
   SectAng     as Float

TargX       as Float
   TargY       as Float
   TargZ       as Float

Distance    as Float

inFlag      as Boolean = 0

`Defensive Code

If SourceObj<1                      Then ExitFunction inFlag
   If Not Object Exist(SourceObj)      Then ExitFunction inFlag

If TargetObj<1                      Then ExitFunction inFlag
   If Not Object Exist(TargetObj)      Then ExitFunction inFlag

`Set variables
   SectX       = Object Position X(SourceObj)
   SectY       = Object Position Y(SourceObj)
   SectZ       = Object Position Z(SourceObj)
   SectAngX    = Object Angle X(SourceObj)
   SectAngY    = Object Angle Y(SourceObj)
   SectAngZ    = Object Angle Z(SourceObj)

SectAng     = 0
   
   TargX       = Object Position X(TargetObj)
   TargY       = Object Position X(TargetObj)
   TargZ       = Object Position X(TargetObj)
   
   SectArcH     =SectArcH*.5
   SectArcV     =SectArcV*.5

`Set vector
   set vector4 FreeVector,SectX,SectY,SectZ
   
   `Set Matrices
   rotate x matrix4 FreeMatrix1,-SectAngX/57.2958
   rotate y matrix4 FreeMatrix2,-SectAngY/57.2958
   rotate z matrix4 FreeMatrix3,-SectAngZ/57.2958
   translate matrix4 FreeMatrix4,TargX-SectX,TargY-SectY,TargZ-SectZ
   
   multiply matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix2
   multiply matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix3
   add matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix4
   
   transform vector4 FreeVector,FreeVector,FreeMatrix1
   
   TargX=X Vector4(FreeVector)
   TargY=Y Vector4(FreeVector)
   TargZ=Z Vector4(FreeVector)
   
   SectX       = 0
   SectY       = 0
   SectZ       = 0

`check for distance
   Distance    =get_distance( TargX, TargZ, SectX, SectZ )
   `Object is outside of sector radius
   if Distance > SectRad               Then ExitFunction inFlag

`Get the Y-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargX-SectX , TargZ-SectZ ) )

`check angle
   if abs( angle# - SectAng ) < SectArcH
      inFlag         = 1
   endif
   `Check for angle wrap around (0 becomes 360 etc.)
   if SectAng < SectArcH or SectAng > (360 - SectArcH)
      if abs( angle# - SectAng ) > 360 - SectArcH
         inFlag      = 1
      endif
   endif

if inFlag   = 0                     Then ExitFunction inFlag

inFlag      = 0

`Get the vertical-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargY-SectY , Distance ) )
   if angle# < SectArcV or angle# > (360-sectArcV)
      inFlag         = 1
   endif

endfunction inFlag

Function Initialize_Distance_Functions()
   Dim initDistance(0)
   If initDistance(0) Then ExitFunction
   initDistance(0)=1
   Global Distance3D = 1
   NoValue=Make Vector3(Distance3D)
   Global Distance2D = 2
   NoValue=Make Vector2(Distance2D)
Endfunction

function get_target_distance(object1,obj2x#,obj2y#,obj2z#)

Initialize_Distance_Functions()

If object1<1 Then Exitfunction 0.0
   If Object Exist(object1)=0 Then ExitFunction 0.0

ObjX#=Object Position X(Object1)
   ObjY#=Object Position Y(Object1)
   ObjZ#=Object Position Z(Object1)

Set Vector3 Distance3D,obj2x#-ObjX#,obj2y#-ObjY#,obj2z#-ObjZ#

distance# =  Length Vector3(Distance3D)

endfunction distance#

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

Initialize_Distance_Functions()

set vector2 Distance2D, x1-x2, y1-y2
   result# = length vector2( Distance2D )

endfunction result#

+ Code Snippet

function in_sector( SourceObj as DWord, TargetObj as DWord, SectArcH as Float, SectArcV as Float, SectRad as Float,FreeVector as dword,FreeMatrix1 as dword,FreeMatrix2 as dword,FreeMatrix3 as dword,FreeMatrix4 as dword)

   `Declarations
   SectX       as Float
   SectY       as Float
   SectZ       as Float
   SectAng     as Float

   TargX       as Float
   TargY       as Float
   TargZ       as Float

   Distance    as Float

   inFlag      as Boolean = 0

   `Defensive Code

   If SourceObj<1                      Then ExitFunction inFlag
   If Not Object Exist(SourceObj)      Then ExitFunction inFlag

   If TargetObj<1                      Then ExitFunction inFlag
   If Not Object Exist(TargetObj)      Then ExitFunction inFlag

   `Set variables
   SectX       = Object Position X(SourceObj)
   SectY       = Object Position Y(SourceObj)
   SectZ       = Object Position Z(SourceObj)
   SectAngX    = Object Angle X(SourceObj)
   SectAngY    = Object Angle Y(SourceObj)
   SectAngZ    = Object Angle Z(SourceObj)
   

   
   SectAng     = 0
   
   TargX       = Object Position X(TargetObj)
   TargY       = Object Position X(TargetObj)
   TargZ       = Object Position X(TargetObj)
   
   SectArcH     =SectArcH*.5
   SectArcV     =SectArcV*.5


   `Set vector
   set vector4 FreeVector,SectX,SectY,SectZ
   
   `Set Matrices
   rotate x matrix4 FreeMatrix1,-SectAngX/57.2958
   rotate y matrix4 FreeMatrix2,-SectAngY/57.2958
   rotate z matrix4 FreeMatrix3,-SectAngZ/57.2958
   translate matrix4 FreeMatrix4,TargX-SectX,TargY-SectY,TargZ-SectZ
   
   multiply matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix2
   multiply matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix3
   add matrix4 FreeMatrix1,FreeMatrix1,FreeMatrix4
   
   transform vector4 FreeVector,FreeVector,FreeMatrix1
   
   TargX=X Vector4(FreeVector)
   TargY=Y Vector4(FreeVector)
   TargZ=Z Vector4(FreeVector)
   
   SectX       = 0
   SectY       = 0
   SectZ       = 0

   `check for distance
   Distance    =get_distance( TargX, TargZ, SectX, SectZ )
   `Object is outside of sector radius
   if Distance > SectRad               Then ExitFunction inFlag


   `Get the Y-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargX-SectX , TargZ-SectZ ) )

   `check angle
   if abs( angle# - SectAng ) < SectArcH
      inFlag         = 1
   endif
   `Check for angle wrap around (0 becomes 360 etc.)
   if SectAng < SectArcH or SectAng > (360 - SectArcH)
      if abs( angle# - SectAng ) > 360 - SectArcH
         inFlag      = 1
      endif
   endif

   if inFlag   = 0                     Then ExitFunction inFlag

   inFlag      = 0

   `Get the vertical-angle of the Target Object relative to the Source Object
   angle# = wrapvalue( atanfull( TargY-SectY , Distance ) )
   if angle# < SectArcV or angle# > (360-sectArcV)
      inFlag         = 1
   endif

endfunction inFlag


Function Initialize_Distance_Functions()
   Dim initDistance(0)
   If initDistance(0) Then ExitFunction
   initDistance(0)=1
   Global Distance3D = 1
   NoValue=Make Vector3(Distance3D)
   Global Distance2D = 2
   NoValue=Make Vector2(Distance2D)
Endfunction


function get_target_distance(object1,obj2x#,obj2y#,obj2z#)

   Initialize_Distance_Functions()

   If object1<1 Then Exitfunction 0.0
   If Object Exist(object1)=0 Then ExitFunction 0.0

   ObjX#=Object Position X(Object1)
   ObjY#=Object Position Y(Object1)
   ObjZ#=Object Position Z(Object1)

   Set Vector3 Distance3D,obj2x#-ObjX#,obj2y#-ObjY#,obj2z#-ObjZ#

   distance# =  Length Vector3(Distance3D)

endfunction distance#

function get_distance( x1 as float, y1 as float, x2 as float, y2 as float )

   Initialize_Distance_Functions()

   set vector2 Distance2D, x1-x2, y1-y2
   result# = length vector2( Distance2D )

endfunction result#

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Code Snippets / [DBP] Check for Point in Sector

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