Home of the Open Source Delphi&C++Builder OpenGL tool. About. GLScene is an OpenGL based 3D library. It was initially written for Delphi, now it is running in C++ Builder, Kylix, Delphi and Lazarus. Introduction. This is a very basic introduction on how to combine GLScene ([]) and Newton Game Dynamics (NGD, []) when writing a.
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Tutorial – GLScene and Newton in Delphi (without oxNewton)
Note that there is a component oxNewton, http: I will not be using this component in this tutorial. I wrote this document mainly for myself as a kind of reference.
All I did was a bit of copy-pasting. I’m a complete newbie so don’t believe anything I say Start a new project. In the GLScene component add a cube, a plane floora lightsource and a camera.
Since I’m an engineer, I like a right handed coordinate system with the z-axis pointing upwards. Set the camera target to the cube. Place the camera and lightsource somewhere away from the cube else you won’t see it. Bodies have mass and inertia. For correct physical behaviour it is very important to set realistic moments of inertia. We now have to place the newton body at the correct position and orientation in our world.
These parameters are controlled by the newton body matrix. This is a 4×4 transformation matrix exact details? We can therefore simply say this:.
Such connections are usefull when needing to access GLScene objects from Newton’s callbacks for instance. Even if you don’t see an immediate need for, it’s a good rule of thumb to always set them, because you will need them in any application doing more than a basic demo. We have now created a Newton instance of our GLCube and placed it in the newton world.
To control the body, we need to be able to apply forces on it. This can be done using the ForceAndTorqueCallback function. To set a function for our newton body use. Similarly we need to update the position of the GLCube in the Glworld when the postion of our body in de newton world changes.
Moderation Process Reminder
The Newton-GLScene binding based on Tag and User Data previously described will be very usefull here, since you will be able to write UpdateGraphicObject callback in a generic way, retrieving the graphical object to be updated from the body passed to it. This way, the same callback can be used for any object sharing the same physical behaviour.
A word of explanation about collision releasing: Since the reference count is set to 1 when you glsdene the collision object, and then incremented each time you connect this collision to a body, it is required to decrement the count by releasing the collision object when you don’t need to manipulate it in the code any more. Doing this, the reference count will be equal to the number of bodies using it, and everybody will be happy: Newton freezes you bodies when they’re moving very slowly.
If, for whatever reason, you don’t want this then use. In this function we can apply forces and moment on the body. Forces are applied at the centre of hutorial body and in world coordinates so Blscene axis glscen upwards. Assuming the Centre of Gravity is located at the Centre of the body we can use:.
Forces are applied at the centre of the body. If you want to apply a force on a arbitrary point on the body gkscene need to rewrite it as a equivalent force and torque system acting at the CoB. This is also the way to apply gravity when CoB and CoG do not coincide. This is done as follows.
Tutorial – GLScene and Newton in Delphi (without oxNewton) – Newton Wiki
Damping is a force acting in a direction opposite to the velocity. It can be implemented as follows:. A reference to the glcube was stored in the newtonbodyuserdata before. We can now simple copy the transformation matrix from the newton body to the glscene object.
Easy once you know how to tutogial it Download an example project here: Retrieved from ” http: Views Page Discussion View source History. Personal tools Log in. Contribute Templates Work In Progress.