TheGameCreators - CodeBase - SetSpriteCategoryBits SetSpriteCollideBits PhysicsRayCastCategory

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Category: Math / Physics

Version: 1.0

Information

Uploaded: 4th Apr 2015 04:19

Modified: 22nd May 2020 18:20

Author: AFA

Summary

show use of "SetSpriteCategoryBits" and "SetSpriteCollideBits" and "PhysicsRayCastCategory"

Full Description

see inside source code, please

AGK Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

remstart

topics: 		show use of "SetSpriteCategoryBits" and "SetSpriteCollideBits" and "PhysicsRayCastCategory"

created on: 	2015_01_18 (edited on 2015_03_15) - AGK 2

by AFA

[]	 		<- 	falling blocks with five different colors will

1) pass the ray and then

2) collide with obstacle of the SAME color

|_|			<-	obstacle, red

|_|			<-	obstacle, green

------------- 	<- 	this ray filters two colors by category (PhysicsRayCastCategory)

|_|			<-	obstacle, blue

|_|			<-	obstacle, yellow

remend

// set window properties

SetWindowTitle( "Category Demo" )

Screen_X = 800

Screen_Y = 800

SetWindowSize( Screen_X, Screen_Y, 0 )

SetVirtualResolution( Screen_X, Screen_Y )

SetPrintSize  ( Screen_Y / 30 )

// set physics

SetPhysicsWallTop (0)	// open top				only the red block is affected by this, see SetSpriteCollideBits below

SetPhysicsWallBottom(1)	// close bottom			only the red block is affected by this, see SetSpriteCollideBits below

SetPhysicsWallLeft (1)	// close left wall		only the red block is affected by this, see SetSpriteCollideBits below

SetPhysicsWallRight (1)	// close right wall		only the red block is affected by this, see SetSpriteCollideBits below

SetPhysicsGravity ( 0, 25)	// set gravity

// set colors

MaxColor = 4					// 4 colors + white   (4 obstacles)

// create an image

Render()

GetImage(100, 0, 0, Screen_X/20, Screen_X/20)

Update(0)

swap()

//Create Sprites - "obstacles"

Dim Obstacle[MaxColor]

For s = 1 to MaxColor 	// s = 1: no white obstacle

Obstacle[s] = CreateSprite(100)

SetSpriteScale( Obstacle[s], Screen_X, Screen_X)

SetSpriteSize( Obstacle[s], Screen_X/10, Screen_X/10)

SetSpriteOffset( Obstacle[s], Screen_X/10/2, Screen_X/10/2 )

SetSpriteAngle ( Obstacle[s], 45 )

SetSpritePhysicsOn ( Obstacle[s], 1 )	// 1=static, 2=dynamic, 3=kinematic

SetSpriteShape ( Obstacle[s], 2 )		// 0=no shape, 1=circle, 2=box, 3=polygon

SetSpritePhysicsRestitution ( Obstacle[s], 0.5 )

//Create Sprites - "blocks"

Dim Block[MaxColor]

For s = 0 to MaxColor 	// all colors

Block[s] = CreateSprite(100)

SetSpriteScale( Block[s], Screen_X, Screen_X)

SetSpriteSize( Block[s], Screen_X/16, Screen_X/16)

SetSpriteOffset( Block[s], Screen_X/32, Screen_X/32 )

SetSpritePhysicsOn ( Block[s], 2 )			// 1=static, 2=dynamic, 3=kinematic

SetSpritePhysicsCanRotate ( Block[s], 1) 	// allow rotating

SetSpriteShape ( Block[s], 2 )				// 0=no shape, 1=circle, 2=box, 3=polygon

SetSpritePhysicsRestitution ( Block[s], 0.5 )

// delete image

If GetImageExists(100) then DeleteImage (100)

// set color of obstacles (no white)

SetSpriteColor ( Obstacle[1], 255, 000, 000, 255 )	// red

SetSpriteColor ( Obstacle[2], 000, 255, 000, 255 )	// green

SetSpriteColor ( Obstacle[3], 000, 000, 255, 255 )	// blue

SetSpriteColor ( Obstacle[4], 255, 255, 000, 255 )	// yellow

// set color of blocks

SetSpriteColor ( Block[0], 255, 255, 255, 255 )	// white

SetSpriteColor ( Block[1], 255, 000, 000, 255 )	// red

SetSpriteColor ( Block[2], 000, 255, 000, 255 )	// green

SetSpriteColor ( Block[3], 000, 000, 255, 255 )	// blue

SetSpriteColor ( Block[4], 255, 255, 000, 255 )	// yellow

// set pile of obstacles with different colors

For i = 1 to MaxColor

SetSpritePositionByOffset( Obstacle[i], Screen_X/2, Screen_Y/(MaxColor+1) * i)

// hide blocks

For i = 0 to MaxColor

SetSpritePositionByOffset( Block[i], -100, 0)

// set category bits for the the obstacles - aim: same colors get same category

For ColorNumber = 1 to MaxColor

Select ColorNumber

// Extract from AGK-help

// "By default all sprites belong to category 1 (0x0001 the 'rightmost bit') and collide with all categories (0xffff)."

//			This 'rightmost bit' is the one in the first row below:   > 1 <

Case 1 : SetSpriteCategoryBits ( Obstacle[ColorNumber], %0000000000000001) : EndCase	// red 	 - one bit at the last digit	 -> obstacle gets category 1

Case 2 : SetSpriteCategoryBits ( Obstacle[ColorNumber], %0000000000000010) : EndCase	// green - one bit at the 2nd last digit -> obstacle gets category 2

Case 3 : SetSpriteCategoryBits ( Obstacle[ColorNumber], %0000000000000100) : EndCase	// blue  - one bit at the 3rd last digit -> obstacle gets category 3

Case 4 : SetSpriteCategoryBits ( Obstacle[ColorNumber], %0000000000001000) : EndCase	// yell  - one bit at the 4rd last digit -> obstacle gets category 4

EndSelect

// set collide bits for the blocks - aim: same colors get same colloide bit as category (see above)

For ColorNumber = 0 to MaxColor	// (including white)

Select ColorNumber

Case 0 : SetSpriteCollideBits ( Block[ColorNumber], %0000000000000000) : EndCase	// white block = no collision with any obstacle

Case 1 : SetSpriteCollideBits ( Block[ColorNumber], %0000000000000001) : EndCase	// red 	 - one bit at the last digit	 -> block collides with sprites of category 1

Case 2 : SetSpriteCollideBits ( Block[ColorNumber], %0000000000000010) : EndCase	// green - one bit at the 2nd last digit -> block collides with sprites of category 2

Case 3 : SetSpriteCollideBits ( Block[ColorNumber], %0000000000000100) : EndCase	// blue  - one bit at the 3rd last digit -> block collides with sprites of category 3

Case 4 : SetSpriteCollideBits ( Block[ColorNumber], %0000000000001000) : EndCase	// yell  - one bit at the 4th last digit -> block collides with sprites of category 4

EndSelect

// This setup is for the RayCast, it has nothing to do with collision between 'block' and 'obstacle'.

// Category bits for the blocks are set to define colors getting filtered by the ray.

For ColorNumber = 0 to MaxColor	// (including white)

Select ColorNumber

Case 0 : SetSpriteCategoryBits  ( Block[ColorNumber], %0000000000000000) : EndCase	// white block = no category

Case 1 : SetSpriteCategoryBits  ( Block[ColorNumber], %1000000000000001) : EndCase	// red 	  	   = category 1 and 16

Case 2 : SetSpriteCategoryBits  ( Block[ColorNumber], %0100000000000010) : EndCase	// green 	   = category 2 and 15

Case 3 : SetSpriteCategoryBits  ( Block[ColorNumber], %0000000000000100) : EndCase	// blue    	   = category 3

Case 4 : SetSpriteCategoryBits  ( Block[ColorNumber], %0000000000001000) : EndCase	// yellow 	   = category 4

EndSelect

remstart

conversion hex - binary - deci:

hex 	- 	bit mask 		    - deci

0x0001	- 	%0000000000000001 	- 1

0x0002	-	%0000000000000010 	- 2

0x0004	-	%0000000000000100 	- 4

0x0008	-	%0000000000001000 	- 8

0x0010	-	%0000000000010000 	- 16

0x0100	-	%0000000000100000 	- 32

..		-	..					- ..

.		-	.					- .

example as hex:

Case 1 : SetSpriteCategoryBits ( Obstacle[ColorNumber], 0x0001) : EndCase

------------------------------------------------------------------------------------------------------------------------

advanced hint:

Seemingly these four commands are affected by category, too.

As 'SetPhysicsWallTop' is set to 1 (= close), the red block will not appear,

it keeps laying on the top of the top-wall - outside the screen.

SetPhysicsWallTop    (0/1)	// open/close top

SetPhysicsWallBottom (0/1)	// open/close bottom

SetPhysicsWallLeft   (0/1)	// open/close left wall

SetPhysicsWallRight  (0/1)	// open/close right wall

remend

SetClearColor(255, 255, 215)

ClearScreen()

// set timer

TimeReleaseNewBlock = GetSeconds()

Color = 0

Repeat

// release a new block

If  GetSeconds() >= TimeReleaseNewBlock + 4

If Color < MaxColor then Inc Color Else Color = 0

diff = round ( screen_X / 30 )

SetSpritePositionByOffset ( Block[Color], Screen_X/2-diff/2+random(0,diff), -Screen_Y/20)

TimeReleaseNewBlock = GetSeconds()

EndIf

// casts a ray to filter sprites with category 15 and 16

If PhysicsRayCastCategory ( %1100000000000000, 0, Screen_Y/2, Screen_X, Screen_Y/2) = 1

// this way of declaration is really not ideal, enough for this demo - but in real better use an array with user-defined-types...

CodeBase - SetSpriteCategoryBits SetSpriteCollideBits PhysicsRayCastCategory

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Author Name:	AFA
CodeBase Entries:	2