Making a bal bounce off walls - GameCreators Forum

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Nithead

15

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Joined: 9th Mar 2009

Location: Hampshire, England

Posted: 11th Mar 2009 19:53

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Firstly, i know ive already asked this but the tread seems to have gone dead.

Anyway part of the program i'm writing is supposed to make a ball bounce off when it collides with a wall. A formula I found seems to work perfectly for the two horizontal walls, but weirdly and unpredictably for the verticle walls.

#include "DarkGDK.h"

void DarkGDK ( void )
{
	
	dbSyncOn   ( );
	dbSyncRate ( 60 );

int Sid = 1;
	int Sx [100];
	int Sz [100];
	int Sg [100];
	int SBo;
	int SRo;
	int Sm;
	Sm = 2;
	int Sa [100];
	Sg[1] = 0;
	Sg[2] = 1;
	int Setup = 1;
	
	dbSetAmbientLight ( 0 );

dbRandomize ( 9 );

dbMakeObjectCube (201, 100);
	dbPositionObject (201, 0, 0, 0);
	dbScaleObject (201, 1000, 0.5, 1000);
	dbColorObject (201, dbRGB ( 0, 0, 0 ));
	
	dbMakeObjectCube (202, 100);
	dbPositionObject (202, 500, 0, 0);
	dbScaleObject (202, 40, 50, 1000);

dbMakeObjectCube (203, 100);
	dbPositionObject (203, -500, 0, 0);
	dbScaleObject (203, 40, 50, 1000);

dbMakeObjectCube (204, 100);
	dbPositionObject (204, 0, 0, 500 );
	dbScaleObject (204, 1040, 50, 40);

dbMakeObjectCube (205, 100);
	dbPositionObject (205, 0, 0, -500 );
	dbScaleObject (205, 1040, 50, 40);

while ( LoopGDK ( ) ) {
		
		dbPositionCamera ( 0, 1000, 0 );
		dbPointCamera ( 0, 0, 0 );

// Make initial spheres
		if (Setup == 1) {
			if (Sid <= 2) {
				
				SBo = 0;
				SRo = 0;
				
				Sx[Sid] = dbRND ( 500 );
				Sz[Sid] = dbRND ( 500 );
				Sa[Sid] = dbRND ( 360 );

dbMakeObjectSphere ( Sid, 50 );
				dbPositionObject ( Sid, Sx[Sid], 0, Sz[Sid] );
				dbYRotateObject ( Sid, Sa[Sid] );
				
				if (Sg[Sid] == 0){SRo = 1000;}
				if (Sg[Sid] == 1){SBo = 1000;}
				
				dbColorObject ( Sid, dbRGB ( SRo, 0, SBo ));
				
				Sid = Sid + 1;
				Sm = Sm + 1;

}}
		if (Sid > 2) {
			Setup = 0;
			Sm = 2;
			Sid = 1;
		}
		
		// Make initial spheres

//////////////////////////////////////////////////////////////////////////////////////

// Run the spheres

if ( Setup == 0 ) {
			if (Sid <= Sm) {

dbMoveObject ( Sid, 10 );
				
				if (dbObjectCollision ( Sid, 204 )) {
					Sa [Sid] = Sa [Sid] + (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 205 )) {
					Sa [Sid] = Sa [Sid] + (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 202 )) {
					Sa [Sid] = Sa [Sid] - (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 203 )) {
					Sa [Sid] = Sa [Sid] - (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}

Sid = Sid + 1;
			}}

if (Sid > Sm) {
			Sid = 1;
		}

dbSync();
	}

return;
}

+ Code Snippet

#include "DarkGDK.h"

void DarkGDK ( void )
{
	
	dbSyncOn   ( );
	dbSyncRate ( 60 );

	
	int Sid = 1;
	int Sx [100];
	int Sz [100];
	int Sg [100];
	int SBo;
	int SRo;
	int Sm;
	Sm = 2;
	int Sa [100];
	Sg[1] = 0;
	Sg[2] = 1;
	int Setup = 1;
	
	dbSetAmbientLight ( 0 );

	dbRandomize ( 9 );


	dbMakeObjectCube (201, 100);
	dbPositionObject (201, 0, 0, 0);
	dbScaleObject (201, 1000, 0.5, 1000);
	dbColorObject (201, dbRGB ( 0, 0, 0 ));
	
	dbMakeObjectCube (202, 100);
	dbPositionObject (202, 500, 0, 0);
	dbScaleObject (202, 40, 50, 1000);

	dbMakeObjectCube (203, 100);
	dbPositionObject (203, -500, 0, 0);
	dbScaleObject (203, 40, 50, 1000);

	dbMakeObjectCube (204, 100);
	dbPositionObject (204, 0, 0, 500 );
	dbScaleObject (204, 1040, 50, 40);

	dbMakeObjectCube (205, 100);
	dbPositionObject (205, 0, 0, -500 );
	dbScaleObject (205, 1040, 50, 40);


	while ( LoopGDK ( ) ) {
		
		dbPositionCamera ( 0, 1000, 0 );
		dbPointCamera ( 0, 0, 0 );

		// Make initial spheres
		if (Setup == 1) {
			if (Sid <= 2) {
				
				SBo = 0;
				SRo = 0;
				
				Sx[Sid] = dbRND ( 500 );
				Sz[Sid] = dbRND ( 500 );
				Sa[Sid] = dbRND ( 360 );

				dbMakeObjectSphere ( Sid, 50 );
				dbPositionObject ( Sid, Sx[Sid], 0, Sz[Sid] );
				dbYRotateObject ( Sid, Sa[Sid] );
				
				if (Sg[Sid] == 0){SRo = 1000;}
				if (Sg[Sid] == 1){SBo = 1000;}
				
				dbColorObject ( Sid, dbRGB ( SRo, 0, SBo ));
				
				Sid = Sid + 1;
				Sm = Sm + 1;

		}}
		if (Sid > 2) {
			Setup = 0;
			Sm = 2;
			Sid = 1;
		}
		
		// Make initial spheres

		//////////////////////////////////////////////////////////////////////////////////////

		// Run the spheres

		if ( Setup == 0 ) {
			if (Sid <= Sm) {


				dbMoveObject ( Sid, 10 );
				
				if (dbObjectCollision ( Sid, 204 )) {
					Sa [Sid] = Sa [Sid] + (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 205 )) {
					Sa [Sid] = Sa [Sid] + (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 202 )) {
					Sa [Sid] = Sa [Sid] - (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}
				if (dbObjectCollision ( Sid, 203 )) {
					Sa [Sid] = Sa [Sid] - (Sa [Sid] * 2);
					dbYRotateObject ( Sid, Sa[Sid] );
					dbMoveObject ( Sid, 10 );
				}	
				

				Sid = Sid + 1;
			}}

		if (Sid > Sm) {
			Sid = 1;
		}

	
	dbSync();
	}

	return;
}

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HowDo

21

Years of Service

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Joined: 28th Nov 2002

Location: United Kingdom

Posted: 11th Mar 2009 20:48 Edited at: 11th Mar 2009 20:49

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Form what I see in the code you are looking down on the objects so the wall are left -x right +x and (top of screen) back +z (bottom of screen) front -z.

does that help.

Dark Physics makes any hot drink go cold.

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Nithead

15

Years of Service

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Joined: 9th Mar 2009

Location: Hampshire, England

Posted: 11th Mar 2009 22:12

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how do i add that to my code?

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Nithead

15

Years of Service

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Joined: 9th Mar 2009

Location: Hampshire, England

Posted: 12th Mar 2009 00:26

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hang on i was aproaching it wrong, i needed to think of it in terms of velocity rather than angle:

#include "DarkGDK.h"

void DarkGDK ( void )
{
	
	dbSyncOn   ( );
	dbSyncRate ( 60 );

int Sid = 1;
	int Sx [100];
	int Sz [100];
	int Sg [100];
	int SBo;
	int SRo;
	int Sm;
	Sm = 2;
	int Smx [100];
	int Smz [100];
	Sg[1] = 0;
	Sg[2] = 1;
	int Setup = 1;
	
	dbSetAmbientLight ( 0 );

dbRandomize ( 2 );

dbMakeObjectCube (201, 100);
	dbPositionObject (201, 0, 0, 0);
	dbScaleObject (201, 1000, 0.5, 1000);
	dbColorObject (201, dbRGB ( 0, 0, 0 ));
	
	dbMakeObjectCube (202, 100);
	dbPositionObject (202, 500, 0, 0);
	dbScaleObject (202, 40, 50, 1000);

dbMakeObjectCube (203, 100);
	dbPositionObject (203, -500, 0, 0);
	dbScaleObject (203, 40, 50, 1000);

dbMakeObjectCube (204, 100);
	dbPositionObject (204, 0, 0, 500 );
	dbScaleObject (204, 1040, 50, 40);

dbMakeObjectCube (205, 100);
	dbPositionObject (205, 0, 0, -500 );
	dbScaleObject (205, 1040, 50, 40);

while ( LoopGDK ( ) ) {
		
		dbPositionCamera ( 0, 1000, 0 );
		dbPointCamera ( 0, 0, 0 );

// Make initial spheres
		if (Setup == 1) {
			if (Sid <= 2) {
				
				SBo = 0;
				SRo = 0;
				
				Sx[Sid] = dbRND ( 500 );
				Sz[Sid] = dbRND ( 500 );
				Smx[Sid] = dbRND ( 10 );
				Smz[Sid] = 10 - Smx[Sid];

dbMakeObjectSphere ( Sid, 50 );
				dbPositionObject ( Sid, Sx[Sid], 0, Sz[Sid] );
				
				if (Sg[Sid] == 0){SRo = 1000;}
				if (Sg[Sid] == 1){SBo = 1000;}
				
				dbColorObject ( Sid, dbRGB ( SRo, 0, SBo ));
				
				Sid = Sid + 1;
				Sm = Sm + 1;

}}
		if (Sid > 2) {
			Setup = 0;
			Sm = 2;
			Sid = 1;
		}
		
		// Make initial spheres

//////////////////////////////////////////////////////////////////////////////////////

// Run the spheres

if ( Setup == 0 ) {
			if (Sid <= Sm) {

if (dbObjectCollision ( Sid, 202 )) {
					Smx[Sid] = Smx[Sid] * -1;
					Smz[Sid] = Smz[Sid] * 1;
				}
				if (dbObjectCollision ( Sid, 203 )) {
					Smx[Sid] = Smx[Sid] * -1;
					Smz[Sid] = Smz[Sid] * 1;
				}	
				if (dbObjectCollision ( Sid, 204 )) {
					Smx[Sid] = Smx[Sid] * 1;
					Smz[Sid] = Smz[Sid] * -1;
				}
				if (dbObjectCollision ( Sid, 205 )) {
					Smx[Sid] = Smx[Sid] * 1;
					Smz[Sid] = Smz[Sid] * -1;
				}
				
				Sx[Sid] = dbObjectPositionX ( Sid );
				Sz[Sid] = dbObjectPositionZ ( Sid );

dbPositionObject ( Sid, ( Sx[Sid] + Smx[Sid] ), 0,( Sz[Sid] + Smz[Sid] ) );

Sid = Sid + 1;
			
		}}

if (Sid > Sm) {
			Sid = 1;
		}

// Run the spheres

dbSync();
	}

return;
}

+ Code Snippet

#include "DarkGDK.h"

void DarkGDK ( void )
{
	
	dbSyncOn   ( );
	dbSyncRate ( 60 );

	
	int Sid = 1;
	int Sx [100];
	int Sz [100];
	int Sg [100];
	int SBo;
	int SRo;
	int Sm;
	Sm = 2;
	int Smx [100];
	int Smz [100];
	Sg[1] = 0;
	Sg[2] = 1;
	int Setup = 1;
	
	dbSetAmbientLight ( 0 );

	dbRandomize ( 2 );


	dbMakeObjectCube (201, 100);
	dbPositionObject (201, 0, 0, 0);
	dbScaleObject (201, 1000, 0.5, 1000);
	dbColorObject (201, dbRGB ( 0, 0, 0 ));
	
	dbMakeObjectCube (202, 100);
	dbPositionObject (202, 500, 0, 0);
	dbScaleObject (202, 40, 50, 1000);

	dbMakeObjectCube (203, 100);
	dbPositionObject (203, -500, 0, 0);
	dbScaleObject (203, 40, 50, 1000);

	dbMakeObjectCube (204, 100);
	dbPositionObject (204, 0, 0, 500 );
	dbScaleObject (204, 1040, 50, 40);

	dbMakeObjectCube (205, 100);
	dbPositionObject (205, 0, 0, -500 );
	dbScaleObject (205, 1040, 50, 40);


	while ( LoopGDK ( ) ) {
		
		dbPositionCamera ( 0, 1000, 0 );
		dbPointCamera ( 0, 0, 0 );

		// Make initial spheres
		if (Setup == 1) {
			if (Sid <= 2) {
				
				SBo = 0;
				SRo = 0;
				
				Sx[Sid] = dbRND ( 500 );
				Sz[Sid] = dbRND ( 500 );
				Smx[Sid] = dbRND ( 10 );
				Smz[Sid] = 10 - Smx[Sid];

				dbMakeObjectSphere ( Sid, 50 );
				dbPositionObject ( Sid, Sx[Sid], 0, Sz[Sid] );
				
				if (Sg[Sid] == 0){SRo = 1000;}
				if (Sg[Sid] == 1){SBo = 1000;}
				
				dbColorObject ( Sid, dbRGB ( SRo, 0, SBo ));
				
				Sid = Sid + 1;
				Sm = Sm + 1;

		}}
		if (Sid > 2) {
			Setup = 0;
			Sm = 2;
			Sid = 1;
		}
		
		// Make initial spheres

		//////////////////////////////////////////////////////////////////////////////////////

		// Run the spheres

		if ( Setup == 0 ) {
			if (Sid <= Sm) {

				
				

				if (dbObjectCollision ( Sid, 202 )) {
					Smx[Sid] = Smx[Sid] * -1;
					Smz[Sid] = Smz[Sid] * 1;
				}
				if (dbObjectCollision ( Sid, 203 )) {
					Smx[Sid] = Smx[Sid] * -1;
					Smz[Sid] = Smz[Sid] * 1;
				}	
				if (dbObjectCollision ( Sid, 204 )) {
					Smx[Sid] = Smx[Sid] * 1;
					Smz[Sid] = Smz[Sid] * -1;
				}
				if (dbObjectCollision ( Sid, 205 )) {
					Smx[Sid] = Smx[Sid] * 1;
					Smz[Sid] = Smz[Sid] * -1;
				}
				
				Sx[Sid] = dbObjectPositionX ( Sid );
				Sz[Sid] = dbObjectPositionZ ( Sid );

				dbPositionObject ( Sid, ( Sx[Sid] + Smx[Sid] ), 0,( Sz[Sid] + Smz[Sid] ) );

				Sid = Sid + 1;
			
		}}

		if (Sid > Sm) {
			Sid = 1;
		}

		// Run the spheres

	
	dbSync();
	}

	return;
}

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Dark GDK / Making a bal bounce off walls