OBJ Support For MD3 Tags For Attachment Tutorial

[Baker7]

Tutorial for OBJ supporting MD3 Tags For Attachment

Step 1: Open model_brush.c
Step 2: Copy the following code and press CTRL-V in appropriate place in Mod_OBJ_Load(model_t *mod, void *buffer, void *bufferend)
Step 3: Declare the int idx I didn't mention
Step 4:

		// Baker: modification "tagname"
		else if (String_Match(argv[0], "tagname")) {
		// tagname propellor_topz -50.2 0.0 26.8
		// tagname propellor_rear 102.8 0.7 20.6
			loadmodel->num_tagframes = 1; // loadmodel->numframes; // Just 1 right?
			idx = loadmodel->num_tags ++;
			loadmodel->data_tags = 
				(aliastag_t *)Mem_Realloc(loadmodel->mempool, loadmodel->data_tags, 
					loadmodel->num_tagframes * loadmodel->num_tags * sizeof(aliastag_t));

			c_strlcpy (loadmodel->data_tags[idx].name, argv[1]);

			loadmodel->data_tags[idx].matrixgl[9] = atof(argv[2]);
			loadmodel->data_tags[idx].matrixgl[10] = atof(argv[3]);
			loadmodel->data_tags[idx].matrixgl[11] = atof(argv[4]);

			// Baker: Throw an identity matrix in there for now, is this right?
			loadmodel->data_tags[idx].matrixgl[0] = 1;
			loadmodel->data_tags[idx].matrixgl[1] = 0;
			loadmodel->data_tags[idx].matrixgl[2] = 0;

			loadmodel->data_tags[idx].matrixgl[3] = 0;
			loadmodel->data_tags[idx].matrixgl[4] = 1;
			loadmodel->data_tags[idx].matrixgl[5] = 0;

			loadmodel->data_tags[idx].matrixgl[6] = 0;
			loadmodel->data_tags[idx].matrixgl[7] = 0;
			loadmodel->data_tags[idx].matrixgl[8] = 1;

OBJS: The main one is helicopter_less_2.obj which uses "tagname propellor_rear 102.8 0.7 20.6" to indicate attachment point.

helicopter.zip

In QuakeC you have do something like:

	entity xt = spawn();	
	setattachment (xt, self, "propellor_topz");
	xt.model = "models/vehicles/helicopter_propellor.obj";

Eventually I'll do a little QuakeC demo with the model.

[hemebond]

@Baker7 Does one add the tagname lines manually to the .obj file or is it already supported by the editor/exporter?

[Baker7]

@Baker7 Does one add the tagname lines manually to the .obj file or is it already supported by the editor/exporter?

Manually. OBJ files are text files.

Note: To self, release something with that helicopter in it so a working example is out in the real world.

Might add -- I have .mdl with attachments also ... you pick a specific triangle of the model and can make it an attachment point ... when the .mdl is loaded, the attachment data is generated for indicated triangles.

[Baker7]

Hemebond ...

Here is a test case for you ...

Download Link: https://www.moddb.com/mods/zircon-engine/downloads/the-helicopter-map

Helicopter lives in models/vehicles/helicopter.obj

QC ... qc/extras/misc_mdl_entity.c

[hemebond]

Might add -- I have .mdl with attachments also ... you pick a specific triangle of the model and can make it an attachment point ... when the .mdl is loaded, the attachment data is generated for indicated triangles.

Is this a separate change from what you shared in the first comment?

[Baker7]

.mdl md3tags is a separate change and was quite a huge amount of work (has to pre-compute triangle rotation at model load time for every morphframe). .mdl md3tags was implemented in Zircon Beta #59 and Zircon Beta #58 didn't have it, so using WinMerge or your favorite open source diff application to compare the 2 folders shows the changes pretty clearly.

#58 is https://www.moddb.com/mods/zircon-engine/downloads/zircon-beta-release-58-win64-binary-source
#59 is https://www.moddb.com/mods/zircon-engine/downloads/zircon-beta-release-59-win64-linux-binaries-source

But the payoff is making Shambler into your own personal Mr. Potatohead ...