Blender exporter for colliders

[SpiderPig]

@Josh I'm writing a blender exporter for my own model format and I want it to also export a mesh as a collider but I don't know the formatting of the .collider file.  Is this something you could share?

[Josh]

Sure. It's a JSON string followed by byte 0, and then any binary data follows that. All offsets are relative to the start of the binary data, not its absolute position in the file.

	bool Collider::Save(const WString& path, const SaveFlags flags)
	{
		auto binstream = CreateBufferStream();
		auto stream = WriteFile(path);
		if (stream == NULL) return false;
		nlohmann::json j3 = nlohmann::json::object();
		if (shapeid == COLLIDER_COMPOUND)
		{
			j3["collider"]["parts"] = nlohmann::json::array();
			for (int n = 0; n < this->subshapes.size(); ++n)
			{
				nlohmann::json subshape;
				switch (subshapes[n]->shapeid)
				{
				case COLLIDER_BOX:
					subshape["shape"] = "BOX";
					break;
				case COLLIDER_CYLINDER:
					subshape["shape"] = "CYLINDER";
					break;
				case COLLIDER_SPHERE:
					subshape["shape"] = "SPHERE";
					break;
				case COLLIDER_CONE:
					subshape["shape"] = "CONE";
					break;
				case COLLIDER_MESH:
					subshape["shape"] = "MESH";
					j3["collider"]["optimized"] = subshapes[n]->optimizemesh;
					break;
				case COLLIDER_CONVEXHULL:
					subshape["shape"] = "CONVEXHULL";
					j3["collider"]["tolerance"] = subshapes[n]->tolerance;
					break;
				}
				if (subshapes[n]->shapeid == COLLIDER_CONVEXHULL)
				{
					subshape["vertices"] = subshapes[n]->finalvertices.size();
					subshape["data"] = binstream->GetSize();
					for (const auto v : subshapes[n]->finalvertices)
					{
						binstream->WriteFloat(v.x);
						binstream->WriteFloat(v.y);
						binstream->WriteFloat(v.z);
					}
				}
				else if (subshapes[n]->shapeid == COLLIDER_MESH)
				{
					subshape["faces"] = subshapes[n]->meshfaces.size();
					subshape["data"] = binstream->GetSize();
					for (const auto& face : subshapes[n]->meshfaces)
					{
						binstream->WriteInt(face.size());
						for (const auto& pos : face)
						{
							binstream->WriteFloat(pos.x);
							binstream->WriteFloat(pos.y);
							binstream->WriteFloat(pos.z);
						}
					}
				}
				else
				{
					subshape["size"] = { subshapes[n]->size.x, subshapes[n]->size.y, subshapes[n]->size.z };
					subshape["offset"] = { subshapes[n]->position.x, subshapes[n]->position.y, subshapes[n]->position.z };
					subshape["rotation"] = { subshapes[n]->rotation.x, subshapes[n]->rotation.y, subshapes[n]->rotation.z };
				}
				j3["collider"]["parts"].push_back(subshape);
			}
		}
		else
		{
			j3["collider"]["parts"] = nlohmann::json::array();
			j3["collider"]["parts"].push_back({});
			switch (shapeid)
			{
			case COLLIDER_BOX:
				j3["collider"]["parts"][0]["shape"] = "BOX";
				break;
			case COLLIDER_CYLINDER:
				j3["collider"]["parts"][0]["shape"] = "CYLINDER";
				break;
			case COLLIDER_CHAMFERCYLINDER:
				j3["collider"]["parts"][0]["shape"] = "CHAMFERCYLINDER";
				break;
			case COLLIDER_CAPSULE:
				j3["collider"]["parts"][0]["shape"] = "CAPSULE";
				break;
			case COLLIDER_SPHERE:
				j3["collider"]["parts"][0]["shape"] = "SPHERE";
				break;
			case COLLIDER_CONE:
				j3["collider"]["parts"][0]["shape"] = "CONE";
				break;
			case COLLIDER_MESH:
				j3["collider"]["optimized"] = optimizemesh;
				j3["collider"]["parts"][0]["shape"] = "MESH";
				break;
			case COLLIDER_CONVEXHULL:
				j3["collider"]["tolerance"] = tolerance;
				j3["collider"]["parts"][0]["shape"] = "CONVEXHULL";
				break;
			}
			if (shapeid == COLLIDER_MESH)
			{
				j3["collider"]["parts"][0]["faces"] = meshfaces.size();
				j3["collider"]["parts"][0]["data"] = binstream->GetSize();
				for (const auto& face : meshfaces)
				{
					binstream->WriteInt(face.size());
					for (const auto& pos : face)
					{
						binstream->WriteFloat(pos.x);
						binstream->WriteFloat(pos.y);
						binstream->WriteFloat(pos.z);
					}
				}
			}
			else if (shapeid == COLLIDER_CONVEXHULL)
			{
				j3["collider"]["parts"][0]["vertices"] = finalvertices.size();
				j3["collider"]["parts"][0]["data"] = binstream->GetSize();
				for (const auto v : finalvertices)
				{
					binstream->WriteFloat(v.x);
					binstream->WriteFloat(v.y);
					binstream->WriteFloat(v.z);
				}
			}
			else
			{
				j3["collider"]["parts"][0]["size"] = { size.x, size.y, size.z };
				j3["collider"]["parts"][0]["offset"] = { position.x, position.y, position.z };
				j3["collider"]["parts"][0]["rotation"] = { rotation.x, rotation.y, rotation.z };
			}
		}
		if (not properties.empty()) j3["extras"] = properties;
		stream->WriteString(j3.dump(1, '	'), false);
		if (binstream->GetSize())
		{
			stream->WriteByte(0);
			stream->Write(binstream->data->Data(), binstream->GetSize());
		}
		stream->Close();
		return true;
	}

 

[SpiderPig]

Thankyou.  This will speed up development for me by exporting straight from blender.  🙂

[reepblue]

1 hour ago, SpiderPig said:

Thankyou.  This will speed up development for me by exporting straight from blender.  🙂

If you can start with a simple .collider export extension for blender, I'm sure people would appreciate it!

[SpiderPig]

That's a good idea.  I'll do that.

[SpiderPig]

for (const auto& face : meshfaces)
{
	binstream->WriteInt(face.size());
	for (const auto& pos : face)
	{
		binstream->WriteFloat(pos.x);
		binstream->WriteFloat(pos.y);
		binstream->WriteFloat(pos.z);
	}
}

Is 'face : meshfaces' each polygon?

What is face.size()?  How many vertices per face?

[Josh]

face.size is the number of vertices in that face. Each face can have any number of vertices, so it can combine quads, triangles, or anything else with three or more vertices. Most of the time this will just be triangles.