• codenstuff (23/23) Jul 13 2015 I've been using Dgame framework for simple simulations.
• =?UTF-8?B?Ik3DoXJjaW8=?= Martins" (11/34) Jul 13 2015 This is not really a game development forum but here you go:
• codenstuff (3/15) Jul 13 2015 This does not work as expected. It keeps rotating object as long
• =?UTF-8?B?Ik3DoXJjaW8=?= Martins" (3/21) Jul 14 2015 I'm sorry. You should use setRotation() instead, rotate() just

"codenstuff" <nikolapav1985 gmail.com> writes:

I've been using Dgame framework for simple simulations.

I need moving object to be aligned to their velocity vectors.

How is it possible to do that using Dgame?

I see that shape object has setRotation and setRotationCenter. 
Not sure how to use these to achieve the effect. I realize that 
default is rotation around origin. This causes objects to drift 
over time.

Sample code

struct GameObject {
Point **position;
// array of pointers to object points
Point *acceleration;
Point *velocity;
double max_speed;
double max_force;
}

shape = new Shape(Geometry.Quads,
Vertex(object.position[0].x, object.position[0].y),
Vertex(object.position[1].x, object.position[1].y),
Vertex(object.position[2].x, object.position[2].y),
Vertex(object.position[3].x, object.position[3].y))

// rotate shape to face velocity here
shape.move(object.velocity.x, object.velocity.y);

=?UTF-8?B?Ik3DoXJjaW8=?= Martins" <marcioapm gmail.com> writes:

On Monday, 13 July 2015 at 16:11:03 UTC, codenstuff wrote:
 I've been using Dgame framework for simple simulations.

 I need moving object to be aligned to their velocity vectors.

 How is it possible to do that using Dgame?

 I see that shape object has setRotation and setRotationCenter. 
 Not sure how to use these to achieve the effect. I realize that 
 default is rotation around origin. This causes objects to drift 
 over time.

 Sample code

 struct GameObject {
 Point **position;
 // array of pointers to object points
 Point *acceleration;
 Point *velocity;
 double max_speed;
 double max_force;
 }

 shape = new Shape(Geometry.Quads,
 Vertex(object.position[0].x, object.position[0].y),
 Vertex(object.position[1].x, object.position[1].y),
 Vertex(object.position[2].x, object.position[2].y),
 Vertex(object.position[3].x, object.position[3].y))

 // rotate shape to face velocity here
 shape.move(object.velocity.x, object.velocity.y);

This is not really a game development forum but here you go:
auto rads = atan2(object.velocity.y, object.velocity.x); // 
returns radians
auto degs = angle * (180.0f / PI); // convert to degrees
shape.rotate(degs);

I suggest you store velocity as a Vector2f to avoid later 
confusion.

It is really useful to learn basic linear algebra, and 
trigonometry as a game developer - you will be needing these 
tools on a daily basis.

"codenstuff" <nikolapav1985 gmail.com> writes:

On Monday, 13 July 2015 at 19:07:55 UTC, Márcio Martins wrote:
 On Monday, 13 July 2015 at 16:11:03 UTC, codenstuff wrote:
 [...]

 This is not really a game development forum but here you go:
 auto rads = atan2(object.velocity.y, object.velocity.x); // 
 returns radians
 auto degs = angle * (180.0f / PI); // convert to degrees
 shape.rotate(degs);

 I suggest you store velocity as a Vector2f to avoid later 
 confusion.

 It is really useful to learn basic linear algebra, and 
 trigonometry as a game developer - you will be needing these 
 tools on a daily basis.

This does not work as expected. It keeps rotating object as long 
as vector is at angle. Any idea how to improve on this?

=?UTF-8?B?Ik3DoXJjaW8=?= Martins" <marcioapm gmail.com> writes:

On Tuesday, 14 July 2015 at 00:31:56 UTC, codenstuff wrote:
 On Monday, 13 July 2015 at 19:07:55 UTC, Márcio Martins wrote:
 On Monday, 13 July 2015 at 16:11:03 UTC, codenstuff wrote:
 [...]

 This is not really a game development forum but here you go:
 auto rads = atan2(object.velocity.y, object.velocity.x); // 
 returns radians
 auto degs = angle * (180.0f / PI); // convert to degrees
 shape.rotate(degs);

 I suggest you store velocity as a Vector2f to avoid later 
 confusion.

 It is really useful to learn basic linear algebra, and 
 trigonometry as a game developer - you will be needing these 
 tools on a daily basis.

 This does not work as expected. It keeps rotating object as 
 long as vector is at angle. Any idea how to improve on this?

I'm sorry. You should use setRotation() instead, rotate() just 
adds to the rotation.