Model Renderer|Fixed: Dynamically enlarge vertex buffers to accommoda…

…te model vertices

Previously Doomsday used fixed-size vertex buffers (and normals,
etc...) while rendering models. However, as there now appears to be
DMD files in the wild which use many more vertices than those which
may be created using the original md2tool; we must now dynamically
resize the vertex render buffers. Failure to do so results in the
engine writing past the end of the static buffers and trashing
memory.

Vertex buffers are now dynamically resized according to the maximum
number of vertices needed to render the densest model among those
presently loaded.

There however remains a fixed limit of 16192 vertices, primarily to
prevent model authors from going completey OTT. If a model contains
more than this number, a warning will be logged and the model will
simply not be rendered.

doomsday/engine/portable/include/rend_model.h

@@ -1,34 +1,32 @@
-/**\file
- *\section License
- * License: GPL
- * Online License Link: http://www.gnu.org/licenses/gpl.html
- *
- *\author Copyright © 2003-2012 Jaakko Keränen <jaakko.keranen@iki.fi>
- *\author Copyright © 2007-2012 Daniel Swanson <danij@dengine.net>
+/**
+ * @file rend_model.h
+ * 3D Model Renderer (v2.1). @ingroup gl
  *
- * 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
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * @authors Copyright &copy; 2003-2012 Jaakko Keränen <jaakko.keranen@iki.fi>
+ * @authors Copyright &copy; 2007-2012 Daniel Swanson <danij@dengine.net>
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor,
- * Boston, MA  02110-1301  USA
+ * <small>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 the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA</small>
  */
 
-/**
- * rend_model.h: 3D Models
- */
+#ifndef LIBDENG_RENDER_MODEL_H
+#define LIBDENG_RENDER_MODEL_H
 
-#ifndef __DOOMSDAY_RENDER_MODEL_H__
-#define __DOOMSDAY_RENDER_MODEL_H__
+/// Absolute maximum number of vertices per submodel supported by this module.
+#define RENDER_MAX_MODEL_VERTS  16192
 
+/// @todo Split this large inflexible structure into logical subcomponent pieces.
 typedef struct rendmodelparams_s {
 // Animation, frame interpolation.
     struct modeldef_s *mf, *nextMF;
@@ -41,7 +39,7 @@ typedef struct rendmodelparams_s {
     float           center[3], gzt; // The real center point and global top z for silhouette clipping.
     float           srvo[3]; // Short-range visual offset.
     float           distance; // Distance from viewer.
-    float           yaw, extraYawAngle, yawAngleOffset; // \todo we don't need three sets of angles, update users of this struct instead.
+    float           yaw, extraYawAngle, yawAngleOffset; ///< @todo We do not need three sets of angles...
     float           pitch, extraPitchAngle, pitchAngleOffset;
 
     float           extraScale;
@@ -57,7 +55,7 @@ typedef struct rendmodelparams_s {
     float           ambientColor[4];
     uint            vLightListIdx;
 
-    // Shinemaping:
+    // Shiney texture mapping:
     float           shineYawOffset;
     float           shinePitchOffset;
     boolean         shineTranslateWithViewerPos;
@@ -70,11 +68,43 @@ extern int mirrorHudModels;
 extern int modelShinyMultitex;
 extern float rendModelLOD;
 
+/**
+ * Registers the console commands and variables used by this module.
+ */
 void Rend_ModelRegister(void);
 
-/// Initialize this module.
+/**
+ * Initialize this module.
+ */
 void Rend_ModelInit(void);
 
-void Rend_RenderModel(const rendmodelparams_t *params);
+/**
+ * Shuts down this module.
+ */
+void Rend_ModelShutdown(void);
+
+/**
+ * Expand the render buffer to accommodate rendering models containing at most
+ * this number of vertices.
+ *
+ * @note It is not actually necessary to call this. The vertex buffer will be
+ *       enlarged automatically at render time to accommodate a given model so
+ *       long as it contains less than RENDER_MAX_MODEL_VERTS. If not the model
+ *       will simply not be rendered at all.
+ *
+ * @note Buffer reallocation is deferred until necessary, so repeatedly calling
+ *       this routine during initialization is OK.
+ *
+ * @param numVertices  New maximum number of vertices we'll be required to handle.
+ *
+ * @return  @c true= successfully expanded. May fail if @a numVertices is larger
+ *          than RENDER_MAX_MODEL_VERTS.
+ */
+boolean Rend_ModelExpandVertexBuffers(uint numVertices);
+
+/**
+ * Render a submodel according to paramaters.
+ */
+void Rend_RenderModel(const rendmodelparams_t* params);
 
-#endif
+#endif /// LIBDENG_RENDER_MODEL_H

doomsday/engine/portable/src/gl_main.c

@@ -549,6 +549,7 @@ void GL_Shutdown(void)
     }
     GL_ShutdownDeferredTask();
     FR_Shutdown();
+    Rend_ModelShutdown();
     Rend_SkyShutdown();
     Rend_Reset();
     GL_ShutdownRefresh();

doomsday/engine/portable/src/r_model.c

@@ -523,6 +523,13 @@ static int R_LoadModel(const Uri* uri)
         registerModelSkin(mdl, i);
     }
 
+    // Enlarge the vertex buffers to enable drawing of this model.
+    if(!Rend_ModelExpandVertexBuffers(mdl->info.numVertices))
+    {
+        Con_Message("Warning: Model \"%s\" contains more than %u vertices (%u), it will not be rendered.\n",
+                    Str_Text(&foundPath), (uint)RENDER_MAX_MODEL_VERTS, (uint)mdl->info.numVertices);
+    }
+
     Str_Free(&foundPath);
     return index;
 }