models: add mdx / Kingpin models support

Without meshes support.

Based on documentation from https://kingpin.info/?p=mdx
Author: tical@kingpin.com

src/client/refresh/files/models.c

@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 1997-2001 Id Software, Inc.
  * Copyright (c) 2005-2015 David HENRY
+ * Copyright (c) 2011 Sajt (https://icculus.org/qshed/qwalk/)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -1674,11 +1675,11 @@ Mod_LoadModel_MD2(const char *mod_name, const void *buffer, int modfilelen,
 	int ofs_meshes, ofs_skins, ofs_st, ofs_tris, ofs_glcmds, ofs_frames, ofs_end;
 	vec3_t translate = {0, 0, 0};
 	const dtriangle_t *pintri;
+	dmdxmesh_t *mesh_nodes;
 	const dstvert_t *pinst;
 	const int *pincmd;
 	dmdl_t pinmodel;
 	dmdx_t *pheader;
-	dmdxmesh_t *mesh_nodes;
 	void *extradata;
 	int i, framesize;
 
@@ -2230,13 +2231,6 @@ Mod_LoadModel_DKM(const char *mod_name, const void *buffer, int modfilelen,
 	for (i=0 ; i<sizeof(dkm_header_t)/sizeof(int) ; i++)
 		((int *)&header)[i] = LittleLong(((int *)buffer)[i]);
 
-	if (header.ident != DKMHEADER)
-	{
-		R_Printf(PRINT_ALL, "%s: %s has wrong ident (%i should be %i)",
-				__func__, mod_name, header.ident, DKMHEADER);
-		return NULL;
-	}
-
 	if (header.version != DKM1_VERSION && header.version != DKM2_VERSION)
 	{
 		R_Printf(PRINT_ALL, "%s: %s has wrong version number (%i should be %i)",
@@ -2332,6 +2326,103 @@ Mod_LoadModel_DKM(const char *mod_name, const void *buffer, int modfilelen,
 	return extradata;
 }
 
+static void *
+Mod_LoadModel_MDX(const char *mod_name, const void *buffer, int modfilelen,
+	struct image_s ***skins, int *numskins, modtype_t *type)
+{
+	dmdx_t dmdxheader, *pheader = NULL;
+	vec3_t translate = {0, 0, 0};
+	mdx_header_t header = {0};
+	dmdxmesh_t *mesh_nodes;
+	void *extradata = NULL;
+	int i;
+
+	if (sizeof(mdx_header_t) > modfilelen)
+	{
+		R_Printf(PRINT_ALL, "%s: model %s file size(%d) too small",
+				__func__, mod_name, modfilelen);
+	}
+
+	/* byte swap the header fields and sanity check */
+	for (i=0 ; i<sizeof(mdx_header_t)/sizeof(int) ; i++)
+		((int *)&header)[i] = LittleLong(((int *)buffer)[i]);
+
+	if (header.version != MDX_VERSION)
+	{
+		R_Printf(PRINT_ALL, "%s: %s has wrong version number (%i should be %i)",
+				__func__, mod_name, header.version, MDX_VERSION);
+		return NULL;
+	}
+
+	if (header.ofs_end < 0 || header.ofs_end > modfilelen)
+	{
+		R_Printf(PRINT_ALL, "%s: model %s file size(%d) too small, should be %d",
+				__func__, mod_name, modfilelen, header.ofs_end);
+		return NULL;
+	}
+
+	/* copy back all values */
+	memset(&dmdxheader, 0, sizeof(dmdxheader));
+	dmdxheader.skinwidth = header.skinwidth;
+	dmdxheader.skinheight = header.skinwidth;
+	/* has same frame structure */
+	if (header.framesize < (
+		sizeof(daliasframe_t) + (header.num_xyz - 1) * sizeof(dtrivertx_t)))
+	{
+		R_Printf(PRINT_ALL, "%s: model %s has incorrect framesize",
+				__func__, mod_name);
+		return NULL;
+	}
+
+	dmdxheader.framesize = sizeof(daliasxframe_t) - sizeof(dxtrivertx_t);
+	dmdxheader.framesize += header.num_xyz * sizeof(dxtrivertx_t);
+
+	dmdxheader.num_meshes = 1;
+	dmdxheader.num_skins = header.num_skins;
+	dmdxheader.num_xyz = header.num_xyz;
+	dmdxheader.num_st = header.num_xyz;
+	dmdxheader.num_tris = header.num_tris;
+	dmdxheader.num_frames = header.num_frames;
+	/* (count vert + 3 vert * (2 float + 1 int)) + final zero; */
+	dmdxheader.num_glcmds = (10 * dmdxheader.num_tris) + 1 * dmdxheader.num_meshes;
+
+	/* just skip header */
+	dmdxheader.ofs_meshes = sizeof(dmdxheader);
+	dmdxheader.ofs_skins = dmdxheader.ofs_meshes + dmdxheader.num_meshes * sizeof(dmdxmesh_t);
+	dmdxheader.ofs_st = dmdxheader.ofs_skins + dmdxheader.num_skins * MAX_SKINNAME;
+	dmdxheader.ofs_tris = dmdxheader.ofs_st + dmdxheader.num_st * sizeof(dstvert_t);
+	dmdxheader.ofs_frames = dmdxheader.ofs_tris + dmdxheader.num_tris * sizeof(dtriangle_t);
+	dmdxheader.ofs_glcmds = dmdxheader.ofs_frames + dmdxheader.num_frames * dmdxheader.framesize;
+	dmdxheader.ofs_end = dmdxheader.ofs_glcmds + dmdxheader.num_glcmds * sizeof(int);
+
+	*numskins = dmdxheader.num_skins;
+	extradata = Hunk_Begin(dmdxheader.ofs_end + Q_max(*numskins, MAX_MD2SKINS) * sizeof(struct image_s *));
+	pheader = Hunk_Alloc(dmdxheader.ofs_end);
+	*skins = Hunk_Alloc((*numskins) * sizeof(struct image_s *));
+
+	memcpy(pheader, &dmdxheader, sizeof(dmdxheader));
+
+	/* create single mesh */
+	mesh_nodes = (dmdxmesh_t *)((char *)pheader + pheader->ofs_meshes);
+	mesh_nodes[0].ofs_tris = 0;
+	mesh_nodes[0].num_tris = pheader->num_tris;
+
+	memcpy((byte*)pheader + pheader->ofs_skins, (byte *)buffer + header.ofs_skins,
+		pheader->num_skins * MAX_SKINNAME);
+	Mod_LoadSTvertList(pheader,
+		(dstvert_t *)((byte *)buffer + header.ofs_st));
+	Mod_LoadFrames_MD2(pheader, (byte *)buffer + header.ofs_frames,
+		header.framesize, translate);
+	Mod_LoadMD2TriangleList(pheader,
+		(dtriangle_t *)((byte *)buffer + header.ofs_tris));
+	Mod_LoadCmdGenerate(pheader);
+	Mod_LoadFixImages(mod_name, pheader, false);
+
+	*type = mod_alias;
+
+	return extradata;
+}
+
 /*
 =================
 Mod_LoadSprite_SP2
@@ -2527,6 +2618,11 @@ Mod_LoadModel(const char *mod_name, const void *buffer, int modfilelen,
 
 	switch (LittleLong(*(unsigned *)buffer))
 	{
+		case MDXHEADER:
+			extradata = Mod_LoadModel_MDX(mod_name, buffer, modfilelen,
+				skins, numskins, type);
+			break;
+
 		case DKMHEADER:
 			extradata = Mod_LoadModel_DKM(mod_name, buffer, modfilelen,
 				skins, numskins, type);

src/common/header/files.h

@@ -230,17 +230,17 @@ typedef struct
 
 typedef struct fmheader_s
 {
-	int			skinwidth;
-	int			skinheight;
-	int			framesize;		// byte size of each frame
+	int skinwidth;
+	int skinheight;
+	int framesize;		// byte size of each frame
 
-	int			num_skins;
-	int			num_xyz;
-	int			num_st;			// greater than num_xyz for seams
-	int			num_tris;
-	int			num_glcmds;		// dwords in strip/fan command list
-	int			num_frames;
-	int			num_mesh_nodes;
+	int num_skins;
+	int num_xyz;
+	int num_st;			// greater than num_xyz for seams
+	int num_tris;
+	int num_glcmds;		// dwords in strip/fan command list
+	int num_frames;
+	int num_mesh_nodes;
 } fmheader_t;
 
 /* Daikatana dkm format */
@@ -270,7 +270,7 @@ typedef struct dkm_header_s
 	int num_tris;
 	int num_glcmds;        /* dwords in strip/fan command list */
 	int num_frames;
-	int num_surf;          /* no idea */
+	int num_surf;          /* num meshes */
 
 	int ofs_skins;         /* each skin is a MAX_SKINNAME string */
 	int ofs_st;            /* byte offset from start for stverts */
@@ -278,10 +278,45 @@ typedef struct dkm_header_s
 	int ofs_frames;        /* offset for first frame */
 	int ofs_glcmds;
 	/* has 52 * num_surf and additional 24 * x structures */
-	int ofs_surf;          /* no idea */
+	int ofs_surf;          /* meshes */
 	int ofs_end;           /* end of file */
 } dkm_header_t;
 
+/* Kingpin mdx format */
+#define MDXHEADER			 (('X' << 24) + ('P' << 16) + ('D' << 8) + 'I')
+#define MDX_VERSION		4
+
+typedef struct mdx_header_s
+{
+	int ident;            /* magic number: "DKMD" */
+	int version;          /* version: 1 or 2 */
+
+	int skinwidth;
+	int skinheight;
+
+	int framesize;        /* byte size of each frame */
+
+	int num_skins;
+	int num_xyz;
+	int num_tris;
+	int num_glcmds;        /* dwords in strip/fan command list */
+	int num_frames;
+	int num_sfxdef;
+	int num_sfxent;
+	int num_subobj;
+
+	int ofs_skins;         /* each skin is a MAX_SKINNAME string */
+	int ofs_tris;          /* offset for dtriangles */
+	int ofs_frames;        /* offset for first frame */
+	int ofs_glcmds;
+	int ofs_st;
+	int ofs_sfxdef;
+	int ofs_sfxent;
+	int ofs_bbox;
+	int ofs_dummyend;
+	int ofs_end;
+} mdx_header_t;
+
 /* .MD3 mesh/anim files */
 #define ID3HEADER (('3' << 24) + ('P' << 16) + ('D' << 8) + 'I')
 #define ID3_VERSION 15