force on a body

[Rick]

How does the force Vec3 work for the force methods? I'm trying to visualize how this would work. Let's say we have a human standing and we wanted to make that human fly upwards and back would the Vec3 be below it's midsection? But wouldn't it need an angle also? Like at it's midsection and pointing slight up so the human would fly back and up?

 

Imagine the human is the character controller. I want to make the controller fly up and "back".

[Niosop]

Yup, then you'd apply a Vec3 like (0, 1, 1) which would be a 45 degree angle if you are using it's local coord system...or it might be -1 for the Z component...Scale the Y and Z to adjust force, so it might be (0, 50, 50) or something.

 

AddBodyForce applies the force to the whole body, so you don't need to worry about applying it to his midsection.

[Rick]

AddBodyForce applies the force to the whole body, so you don't need to worry about applying it to his midsection.

 

Ah, ok thanks!

[Rick]

OK, so it seems we can't apply forces on the controller. So I'm working on a work around. This works, BUT the body box rotates in the air which messes its orientation up so multiple force applying doesn't always produce the same result. It would be ideal if it didn't spin. Any ideas?

 

 

//	====================================================================
//	This file was generated by Leadwerks C++/LEO/BlitzMax Project Wizard
//	Written by Rimfrost Software
//	http://www.rimfrost.com 
//	====================================================================

#include "engine.h"

int main( int argn, char* argv[] )
{
Initialize() ;
RegisterAbstractPath("C:/Leadwerks Engine SDK");
SetAppTitle( "Test02" ) ;
Graphics( 800, 600 ) ;
AFilter() ;
TFilter() ;

TWorld	world;
TBuffer gbuffer;
TCamera camera;
TMesh	mesh;
TLight	light;
TMesh	ground;
TMaterial material;

world = CreateWorld() ;
if (!world) {
	MessageBoxA(0,"Error","Failed to create world.",0);
	return Terminate();
}

gbuffer=CreateBuffer(GraphicsWidth(),GraphicsHeight(),BUFFER_COLOR|BUFFER_DEPTH|BUFFER_NORMAL);

camera=CreateCamera();
PositionEntity(camera,Vec3(0, 5, -9));
RotateEntity(camera, Vec3(45, 0, 0));

material=LoadMaterial("abstract::cobblestones.mat");

//mesh=CreateCube();
//TBody meshBody = CreateBodyBox();
//EntityParent(mesh, meshBody);
//PositionEntity(meshBody, Vec3(2, 1, 0));
//PaintEntity(mesh,material);
//EntityType(meshBody, 2);
//SetBodyMass(meshBody, 1);

TController controller = CreateController();
EntityType(controller, 3);
SetBodyMass(controller, 1);

//CreateJointFixed(meshBody, controller);

ground=CreateCube();
ScaleEntity(ground,Vec3(10,1,10));
TBody groundBody = CreateBodyBox(10, 1, 10);
EntityParent(ground, groundBody);
PositionEntity(groundBody,Vec3(0,-2,0));
EntityType(groundBody, 1);
PaintEntity(ground,material);

Collisions(1, 2, 1);
Collisions(1, 3, 1);

light=CreateDirectionalLight();
RotateEntity(light,Vec3(45,45,45));

DebugPhysics(1);

TBody meshBody = CreateBodyBox();
RotateEntity(meshBody, Vec3(0, 45, 0));
EntityType(meshBody, 2);
SetBodyMass(meshBody, 1);

// Game loop
while( !KeyHit() && !AppTerminate() )
{
	if( !AppSuspended() ) // We are not in focus!
	{
		// Rotate cube
		if(KeyHit(KEY_SPACE))
		{
			PositionEntity(meshBody, EntityPosition(controller, 1), 1);

			AddBodyForce(meshBody, Vec3(0, 250, 250), 0);
		}

		// This is how we tell if we should be following the body box
		TVec3 vel = GetBodyVelocity(meshBody);
		if(vel.X != 0 || vel.Y != 0 || vel.Z != 0)
		{
			TVec3 pos = EntityPosition(meshBody, 1);
			pos.Y -= .5;
			PositionEntity(controller, pos, 1);
		}
		else
		{
			UpdateController(controller);
		}

		/*if(meshBody != 0)
		{
			TVec3 vel = GetBodyVelocity(meshBody);

			DrawText(10, 10, "Body Velocity %d, %d, %d", vel.X, vel.Y, vel.Z);*/
			/*if(ControllerAirborne(meshBody))
			{
				TVec3 pos = EntityPosition(meshBody, 1);
				pos.Y -= .5;
				PositionEntity(controller, pos, 1);
			}*/
		//}

		// Would only need to do this for the ability. Could stop once the body box is at rest
		//TVec3 pos = EntityPosition(meshBody, 1);
		//pos.Y -= .5;
		//PositionEntity(controller, pos, 1);
		//else
		//	UpdateController(controller);

		// Update timing and world
		UpdateAppTime();
		UpdateWorld(AppSpeed()) ;

		// Render
		SetBuffer(gbuffer);
		RenderWorld();
		SetBuffer(BackBuffer());
		RenderLights(gbuffer);

		vel = GetBodyVelocity(meshBody);
		DrawText(10, 10, "Body Velocity %d, %d, %d", vel.X, vel.Y, vel.Z);

		if(ControllerAirborne(controller) && (vel.X != 0 || vel.Y != 0 || vel.Z != 0))
		{
			DrawText(10, 50, "I am in the air"); 
		}

		// Send to screen
		Flip(0) ;
	}
}

// Done
return Terminate() ;
}

[Niosop]

Reset its rotation every frame?

[Rick]

Can't do it every frame since that would stop physics, but I was able to do it before applying the force and that works. I just have a feeling this is going to be buggy.

[Niosop]

Yeah. I ran into the same problem, I need to adjust position of the characters exactly each frame but still have them both affect other objects and be affected by other objects. I wasn't able to get a good balance in LE, so I just switched over to using Unity for a bit. Once I get everything worked out there and have a prototype I'll come back and work on porting it to LE.