From 2bb7a482966b4883060aaa3c31ecbd354033c36b Mon Sep 17 00:00:00 2001
From: Lee Salzman <lsalzman@gmail.com>
Date: Tue, 6 May 2008 20:10:55 +0000
Subject: [PATCH] support for alpha-tested models

git-svn-id: svn://svn.code.sf.net/p/actiongame/code/trunk/ac@1890 e016b1c5-ed68-44aa-a2f7-31cac88cffde
---
 source/src/md2.h           |  1 +
 source/src/md3.h           |  1 +
 source/src/model.h         |  4 ++--
 source/src/rendermodel.cpp |  8 ++++++++
 source/src/vertmodel.h     | 29 +++++++++++++++++++++++------
 5 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/source/src/md2.h b/source/src/md2.h
index 042342b9..9e164be3 100644
--- a/source/src/md2.h
+++ b/source/src/md2.h
@@ -104,6 +104,7 @@ struct md2 : vertmodel
 
             mesh &m = *new mesh;
             meshes.add(&m);
+            m.owner = this;
 
             int *glcommands = new int[header.numglcommands];
             fseek(file, header.offsetglcommands, SEEK_SET);
diff --git a/source/src/md3.h b/source/src/md3.h
index f57d56f0..e7735d7e 100644
--- a/source/src/md3.h
+++ b/source/src/md3.h
@@ -94,6 +94,7 @@ struct md3 : vertmodel
             loopi(header.nummeshes)
             {
                 mesh &m = *meshes.add(new mesh);
+                m.owner = this;
                 md3meshheader mheader;
                 fseek(f, mesh_offset, SEEK_SET);
                 fread(&mheader, sizeof(md3meshheader), 1, f);
diff --git a/source/src/model.h b/source/src/model.h
index f347d076..11d56212 100644
--- a/source/src/model.h
+++ b/source/src/model.h
@@ -38,11 +38,11 @@ struct dynent;
 struct model
 {
     bool cullface;
-    float translucency, scale;
+    float alphatest, translucency, scale;
     vec translate;
     int batch;
 
-    model() : cullface(true), translucency(0.25f), scale(1), translate(0, 0, 0), batch(-1) {}
+    model() : cullface(true), alphatest(0.9f), translucency(0.25f), scale(1), translate(0, 0, 0), batch(-1) {}
     virtual ~model() {}
 
     virtual bool load() = 0;
diff --git a/source/src/rendermodel.cpp b/source/src/rendermodel.cpp
index 1a6f77c0..71b9a281 100644
--- a/source/src/rendermodel.cpp
+++ b/source/src/rendermodel.cpp
@@ -28,6 +28,14 @@ void mdltranslucent(int translucency)
 
 COMMAND(mdltranslucent, ARG_1INT);
 
+void mdlalphatest(int alphatest)
+{
+    checkmdl;
+    loadingmodel->alphatest = alphatest/100.0f;
+}
+
+COMMAND(mdlalphatest, ARG_1INT);
+
 void mdlscale(int percent)
 {
     checkmdl;
diff --git a/source/src/vertmodel.h b/source/src/vertmodel.h
index 559046d7..4aaafcb3 100644
--- a/source/src/vertmodel.h
+++ b/source/src/vertmodel.h
@@ -39,9 +39,12 @@ struct vertmodel : model
     struct tcvert { float u, v; ushort index; };
     struct tri { ushort vert[3]; };
 
+    struct part;
+
     struct mesh
     {
         char *name;
+        part *owner;
         vec *verts;
         tcvert *tcverts;
         tri *tris;
@@ -58,7 +61,7 @@ struct vertmodel : model
         GLuint statlist;
         int statlen;
 
-        mesh() : name(0), verts(0), tcverts(0), tris(0), skin(notexture), tex(0), dynbuf(0), dynidx(0), statlist(0) 
+        mesh() : name(0), owner(0), verts(0), tcverts(0), tris(0), skin(notexture), tex(0), dynbuf(0), dynidx(0), statlist(0) 
         {
             dyncur.fr1 = dynprev.fr1 = -1;
         }
@@ -138,12 +141,22 @@ struct vertmodel : model
             {
                 GLuint id = tex < 0 ? -tex : skin->id;
                 if(tex > 0) id = lookuptexture(tex)->id;
-                if(id!=lasttex)
+                if(id != lasttex)
                 {
                     glBindTexture(GL_TEXTURE_2D, id);
                     lasttex = id;
                 }
                 if(enablealphablend) { glDisable(GL_BLEND); enablealphablend = false; }
+                if(skin->bpp == 32 && owner->model->alphatest > 0)
+                {
+                    if(!enablealphatest) { glEnable(GL_ALPHA_TEST); enablealphatest = true; }
+                    if(lastalphatest != owner->model->alphatest)
+                    {
+                        glAlphaFunc(GL_GREATER, owner->model->alphatest);
+                        lastalphatest = owner->model->alphatest;
+                    }
+                }
+                else if(enablealphatest) { glDisable(GL_ALPHA_TEST); enablealphatest = false; }
                 if(!enabledepthmask) { glDepthMask(GL_TRUE); enabledepthmask = true; }
             }
 
@@ -590,6 +603,7 @@ struct vertmodel : model
             }
 
             if(enabledepthmask) { glDepthMask(GL_FALSE); enabledepthmask = false; }
+            if(enablealphatest) { glDisable(GL_ALPHA_TEST); enablealphatest = false; }
             if(!enablealphablend) 
             { 
                 glEnable(GL_BLEND);
@@ -669,23 +683,26 @@ struct vertmodel : model
         return parts.length()==1 && parts[0]->shadows;
     }
 
-    static bool enablealphablend, enabledepthmask;
+    static bool enablealphablend, enablealphatest, enabledepthmask;
     static GLuint lasttex;
+    static float lastalphatest;
 
     void startrender()
     {
-        enablealphablend = false;
+        enablealphablend = enablealphatest = false;
         enabledepthmask = true;
         lasttex = 0;
+        lastalphatest = -1;
     }
 
     void endrender()
     {
         if(enablealphablend) glDisable(GL_BLEND);
+        if(enablealphatest) glDisable(GL_ALPHA_TEST);
         if(!enabledepthmask) glDepthMask(GL_TRUE);
     }
 };
 
-bool vertmodel::enablealphablend = false, vertmodel::enabledepthmask = true;
+bool vertmodel::enablealphablend = false, vertmodel::enablealphatest = false, vertmodel::enabledepthmask = true;
 GLuint vertmodel::lasttex = 0;
-
+float vertmodel::lastalphatest = -1;