Moved Stars45 to StarsEx

1 files changed, 174 insertions, 0 deletions

diff --git a/StarsEx/Shadow.cpp b/StarsEx/Shadow.cpp
new file mode 100644
index 0000000..f64c033
--- /dev/null
+++ b/StarsEx/Shadow.cpp
@@ -0,0 +1,174 @@
+/*  Starshatter: The Open Source Project
+    Copyright (c) 2021-2022, Starshatter: The Open Source Project Contributors
+    Copyright (c) 2011-2012, Starshatter OpenSource Distribution Contributors
+    Copyright (c) 1997-2006, Destroyer Studios LLC.
+
+    AUTHOR:       John DiCamillo
+
+
+    OVERVIEW
+    ========
+    Dynamic Stencil Shadow Volumes
+*/
+
+#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 Vec3[max_verts];
+        edges     = new 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 (int 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;
+}