Ah, so that was you who wrote the C wrapper? I saw that a while ago and considered using it, but after looking at and exploring how Chimpmunk2D works, I decided it was smaller, pretty darn good. That and Chipmunk2D is already C, so very little work was needed from me to convert it to work with Pascal.
Again, the physics part will be in my second release. The first part is just getting the vector graphics and a minimal GUI toolkit in OpenGL working. That plus an overview and reference website similar to my https://docs.getlazurs.org website.
If anyone cares to know more, here is a brief description of how my object oriented wrapper around Chipmunk2D physics is organized.
ISpace is the base object to work with physics. If you use the TPhyiscsScene class it's created and managed for you automatically. ISpace provides properties for controlling gravity, bodies, and joints. There is one ISpace object per physics simulation.
IBody objects are added to ISpace using ISpace.NewBody, ISpace.NewDynamic, and ISpace.NewStatic methods which create kinematic, dynamic, and static bodies respectively. Kinematic bodies react to collisions with each other and are affected by forces such as gravity. Dynamic bodies can be moved manually by the programmer, but are otherwise unaffected by forces and collisions. Static bodies cannot move but kinematic bodies may bounce off them.
IShape objects are added to bodies using IBody.NewCircle, IBody.NewRect, IBody.NewSegment, and IBody.NewPolygon method. A body by itself has no shape. Its shape is defined by the shapes you add to it. Shapes within the same body do not collide with each other or move with respect to the other shapes within the body. Each shape within a body can have different friction, density, and elasticity (or bounciness). The mass and center of gravity of a body is calculated by its constituent shapes.
IJoint includes a list of several joint types (I will not list them all here), and they can be used to connect two bodies together. Some joint types are motors, other are springs, and some are hinges or pivots. Collisions between bodies connected by a joint can be set to be ignored for those two bodies.
IArbitors allow you to either detect and handle collisions between body types you define. You can ignore them if you simply want the physics system to handle collisions for you.
Masks can be applied to body types, allowing you to say which bodies can collide with which other bodies. For example, if you were writing a game you could setup enemy bullets bodies to pass through enemy bodies using a simple mask. The enemy bullet bodies could then be setup to collide with the player body and wall bodies.
There is a lot more to the physics system, but my object orient design, plus some documentation and examples ought to get most people running in short order.
I have been mostly working on the graphics portion for the past week and haven't been working with the physics system in that time. Last time I was working on it I was trying to figure how how to make a decent rope. I am not at all satisfied with my initial work, and maybe someone can help me get rope physics working better, but below is the result of my first attempt.
Rope test : https://streamable.com/lli866
I'll put all the information above and the source code online in a git repository soon with a FOSS license. If anyone wants to help, let me know. Join me in the discord channel listed in my initial message, or see me on liberachat irc in the #fpc channel.
