Did you know that the Operator originally was part of another extension? It was. And now it’s time to share that extension .
I tried to figure out how to resolve collisions of the 3d character with level geometry and this is what I got.
Kinematic Walker
This is a tweakable kinematic character controller suitable for 3D games. When you wouldn’t like to use a dynamic body and prefer to have more control over the movement.
Although not all the collision cases are handled perfect at the moment, you can avoid problems by providing valid and smooth collision geometry of your level. The geometry in the demo is not smooth exclusively for stress testing purposes.
Ready to use with Operator or you own camera controller.
To be honest, this solution is still far from perfect at the moment, but enough to create a game. The main rule to avoid problems is to keep the level geometry simple and smooth. The main bad points are hidden internal geometry and complex acute corners.
To resolve collisions with obtuse corners, the standard solution described here is used.
To resolve collisions with acute angles, that solution is not perfect because it generates a huge number of conflicting collision messages that don’t fit in a single frame and cause the character to start shaking until he gets out of this collisions trap. Unfortunately, I haven’t found a way to calculate all of these collisions at once in Defold.
So what I did. If a character faces with an acute angle, he simply moves along it using the cross product of these two collision forces. If he faced in the same frame with an acute angle again - he just stops moving. As the result, the blunt angles push the capsule out, and the acute angles move it along or stop it at all.
About performance
I didn’t any optimization, so if you faced with lags, please let me know where the bottleneck is. I’ve never used a profiling utilities with Defold before, but I will try.
About creating the level geometry
To use this extension to its full potential, you additionally need a tool to quickly create a nice collision level geometry. I didn’t make this geometry in Defold itself. There is a solution and I will publish it as soon as possible
Yes, this would come in handy for the poor player
One thing I noticed: sometimes the camera does not keep its distance from the player but goes through it, maybe this would be worth changing.
I really love the smooth camera movement and the way the collisions are handled. Great job! I shall try and understand the magic you did in your scripts.
Many thanks for sharing this extension!
Thanks, I really hope this helps someone make the game. I tried to make the interface as flexible and modular as possible.
I agree that adding the respawn feature would be a nice improvement for the demo.
About getting the camera inside the character, it’s really not handled in any way right now. I think this is a good point to improve the operator extension.
The walker script needs to know about the collision mask of the level geometry in order to do raycasting.
We faced a problem when integrating this extension into @Alexander_Bulatov’s project. The player collision object has multiple collision groups in the mask, but the extension didn’t support more than one collision group, because the mask was set in go.property as a hash.
I released 1.1 with the new collision_mask message for cases where the collision object mask is different from default.
But it would be more convenient to do it automatically. I looked for how to get the collision mask from the collision object in runtime, but didn’t find anything. Is there any way to get the array of collision groups from the mask in the runtime?
Ah, I see. And the collision mask is set by the user from within Defold? Or from TrenchBroom? I’m not sure how the data is stored and how hard it would be to add a physics.get_mask_names() or something like that.
It’s not about TrenchBroom, but a more common case. The case step by step in the Defold Editor:
@Alexander_Bulatov placed few collision objects on the level with different collision groups “ground” and “platform”.
Added the capsule collision object to the player and set “ground, platform” to its mask.
Added walker.script to the player and set the url of the capsule to its go.property collision_standing.
In runtime, walker.scriptwants to use the mask of the capsule to detect a ground or ceiling with raycasting.
This is currently implemented with the collision_mask message which the user have to post by himself. But would be great to read it from the capsule collision object automatically during initialization of walker.script without additional message passing.
A capsule used to resolve all the collisions with obstacles. Ray casting is used only to check the ground, ceiling and stairs to prevent unnecessary collision resolving and to better understand the current state for jumping, sliding, falling, etc.
For example, if the player walks on the ground there is no need to fall inside the ground and resolve collision with getting the body up every frame. Another example, it’s more easy to understand can the player stand up when crouching or not by this way.
Could you tell me please if I need to somehow update the project to the new realities with the fixed_update() method?
@Pkeodfound that the kinematic walker capsule shakes against the walls on modern computers with Windows. But everything is fine on Macbook Air 2012 (!) and Macbook M1 2021.
The project has a kinematic body, manual collision resolution in on_message() and position updating in update(). The current code doesn’t contain the fixed_update() function at all.
Somebody please make a basic tutorial on 3D and how to unite all three of the basic components, the Kinematic Walker, Illumination and Operator TOGETHER in one project.
I mean, these are the basic building blocks, they all belong in one setup.
I’m migrating my game project from Godot, and while 2D dev in Defold is well covered, the 3D aspect is quite daunting and shrouded in mystery. Heck, I can’t even find proper camera control in editor perspective view, like, is there a free look mode? How can I rotate camera? There seems to be zero info on that in the docs. Only 2D (although the description says that Defold is essentially a 3D engine, yeah, that’s good to know but…)
I haven’t felt so helpless in quite a while, feeling like I’m ready to hire a commercial dev to help me out with this.
This is the game prototype I’ve made in Godot, and I need to rebuild it in Defold.
Looks like all three components I need are there. How do I bring them together in one project?
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