From e33e19d0587146859d48a134ec9fd94e7b7ba5cd Mon Sep 17 00:00:00 2001
From: "FWoltermann@gmail.com"
 <FWoltermann@gmail.com@076cb2c4-205e-83fd-5cf3-1be9aa105544>
Date: Thu, 8 Dec 2011 14:53:40 +0000
Subject: Initial upload

---
 nGenEx/Shadow.cpp | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 nGenEx/Shadow.cpp

(limited to 'nGenEx/Shadow.cpp')

diff --git a/nGenEx/Shadow.cpp b/nGenEx/Shadow.cpp
new file mode 100644
index 0000000..3038062
--- /dev/null
+++ b/nGenEx/Shadow.cpp
@@ -0,0 +1,176 @@
+/*  Project nGenEx
+    Destroyer Studios LLC
+    Copyright © 1997-2004. All Rights Reserved.
+
+    SUBSYSTEM:    nGenEx.lib
+    FILE:         Shadow.cpp
+    AUTHOR:       John DiCamillo
+
+
+    OVERVIEW
+    ========
+    Dynamic Stencil Shadow Volumes
+*/
+
+#include "MemDebug.h"
+#include "Shadow.h"
+#include "Light.h"
+#include "Solid.h"
+#include "Scene.h"
+#include "Video.h"
+
+static bool visible_shadow_volumes = false;
+
+// +--------------------------------------------------------------------+
+
+Shadow::Shadow(Solid* s)
+   : verts(0), nverts(0), max_verts(0), edges(0), num_edges(0), enabled(true)
+{
+   solid = s;
+
+   if (solid && solid->GetModel()) {
+      Model*   model       = solid->GetModel();
+      int      npolys      = model->NumPolys();
+
+      max_verts = model->NumVerts() * 4;
+      verts     = new(__FILE__,__LINE__) Vec3[max_verts];
+      edges     = new(__FILE__,__LINE__) WORD[npolys * 6];
+   }
+}
+
+// +--------------------------------------------------------------------+
+
+Shadow::~Shadow()
+{
+   if (verts)  delete [] verts;
+   if (edges)  delete [] edges;
+}
+
+// +--------------------------------------------------------------------+
+
+void
+Shadow::Reset()
+{
+   num_edges   = 0;
+   nverts      = 0;
+}
+
+// +--------------------------------------------------------------------+
+
+void
+Shadow::Render(Video* video)
+{
+   if (enabled)
+      video->DrawShadow(solid, nverts, verts, visible_shadow_volumes);
+}
+
+// +--------------------------------------------------------------------+
+
+void
+Shadow::Update(Light* light)
+{
+   Reset();
+
+   if (!light || !solid || !solid->GetModel() || !edges) return;
+
+   Vec3     lpos        = light->Location();
+   bool     directional = light->Type() == Light::LIGHT_DIRECTIONAL;
+   Model*   model       = solid->GetModel();
+
+   ListIter<Surface> iter = model->GetSurfaces();
+   while (++iter) {
+      Surface* s = iter.value();
+
+      // transform light location into surface object space
+      Matrix xform(solid->Orientation()); // XXX should be: (s->GetOrientation());
+
+      Vec3 tmp = light->Location();
+
+      if (!directional)
+         tmp -= (solid->Location() + s->GetOffset());
+
+      lpos.x = tmp * Vec3(xform(0,0), xform(0,1), xform(0,2));
+      lpos.y = tmp * Vec3(xform(1,0), xform(1,1), xform(1,2));
+      lpos.z = tmp * Vec3(xform(2,0), xform(2,1), xform(2,2));
+
+      // compute the silohuette for the mesh with respect to the light:
+      
+      for (int i = 0; i < s->NumPolys(); i++) {
+         Poly* p = s->GetPolys() + i;
+
+         // skip polys with non-shadowing materials:
+         if (p->material && !p->material->shadow)
+            continue;
+
+         // if this poly faces the light:
+         if (p->plane.normal * lpos > 0) {
+            for (int n = 0; n < p->nverts; n++) {
+               if (n < p->nverts-1)
+                  AddEdge(p->vlocs[n], p->vlocs[n+1]);
+               else
+                  AddEdge(p->vlocs[n], p->vlocs[0]);
+            }
+         }
+      }
+
+      // extrude the silohuette away from the light source
+      // to create the shadow volume:
+
+      Vec3 extent = lpos * -1;
+      extent.Normalize();
+      extent *= 50.0e3f; //solid->Radius() * 2.1f;
+
+      for (i = 0; i < (int) num_edges; i++) {
+         if (nverts+6 <= max_verts) {
+            Vec3 v1 = s->GetVLoc()[edges[2*i+0]];
+            Vec3 v2 = s->GetVLoc()[edges[2*i+1]];
+            Vec3 v3 = v1 + extent;
+            Vec3 v4 = v2 + extent;
+
+            verts[nverts++] = v1;
+            verts[nverts++] = v2;
+            verts[nverts++] = v3;
+
+            verts[nverts++] = v2;
+            verts[nverts++] = v4;
+            verts[nverts++] = v3;
+         }
+      }
+   }
+}
+
+void
+Shadow::AddEdge(WORD v1, WORD v2)
+{
+   // Remove interior edges (which appear in the list twice)
+   for (DWORD i = 0; i < num_edges; i++) {
+      if ((edges[2*i+0] == v1 && edges[2*i+1] == v2) ||
+          (edges[2*i+0] == v2 && edges[2*i+1] == v1))
+      {
+         if (num_edges > 1) {
+            edges[2*i+0] = edges[2*(num_edges-1)+0];
+            edges[2*i+1] = edges[2*(num_edges-1)+1];
+         }
+
+         num_edges--;
+         return;
+      }
+   }
+
+   edges[2*num_edges+0] = v1;
+   edges[2*num_edges+1] = v2;
+
+   num_edges++;
+}
+
+bool
+Shadow::GetVisibleShadowVolumes()
+{
+   return visible_shadow_volumes;
+}
+
+void
+Shadow::SetVisibleShadowVolumes(bool vis)
+{
+   visible_shadow_volumes = vis;
+}
-- 
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