Add support for points in wireframe meshes

This allows rendering of a vertex directly, rather than just as an
edge endpoint.  They're currently drawn as small '+' signs.  A
round dot would be better, but the code is passing a list of line
segments around, so this is simpler.

CommonUtil/RawData.cs

@@ -19,7 +19,8 @@ using System.Diagnostics;
 namespace CommonUtil {
     public class RawData {
         /// <summary>
-        /// Extracts an integer from the data stream.
+        /// Extracts an integer from the data stream.  Integers less than 4 bytes wide
+        /// are not sign-extended.
         /// </summary>
         /// <param name="data">Raw data stream.</param>
         /// <param name="offset">Start offset.</param>

PluginCommon/Interfaces.cs

@@ -327,20 +327,24 @@ namespace PluginCommon {
     /// <summary>
     /// Holds raw vertex/edge/normal data collected from a 2D or 3D wireframe mesh.  We use
     /// a left-handed coordinate system (+Z goes into the screen).  If the project being
-    /// disassembled uses different definitions for the axes, it's probably best to convert.
+    /// disassembled uses different definitions for the axes, it's probably best to convert
-    /// 2D data should use X/Y with Z=0.
+    /// them in the visualizer.  2D data should use X/Y with Z=0.
     ///
-    /// All objects will have vertices and edges.  Face normals are optional.
+    /// All objects will have vertices.  Most will have edges, some will have points.  Face
+    /// normals are optional.
     /// </summary>
     /// <remarks>
     /// The face-normal stuff is designed specifically for Elite.  Besides being one of the
     /// very few 6502-based games to use backface culling, it extended the concept to allow
     /// convex shapes to have protrusions.
     ///
+    /// Points are included primarily for the benefit of AVG games like Battlezone.
+    ///
     /// We favor multiple arrays over compound objects for this interface to avoid making
     /// such objects part of the plugin interface.
     ///
-    /// TODO(maybe): specify colors for edges.  Not widely used?
+    /// TODO(maybe): specify colors for points and edges.  Not widely used?  Could be handy for
+    /// color AVG games like Tempest.
     /// </remarks>
     public interface IVisualizationWireframe {
         // Each function returns the specified data.  Do not modify the returned arrays.
@@ -349,6 +353,7 @@ namespace PluginCommon {
         float[] GetVerticesY();
         float[] GetVerticesZ();
 
+        int[] GetPoints();
         IntPair[] GetEdges();
 
         float[] GetNormalsX();

PluginCommon/Util.cs

@@ -28,7 +28,8 @@ namespace PluginCommon {
     /// </summary>
     public static class Util {
         /// <summary>
-        /// Extracts an integer from the data stream.
+        /// Extracts an integer from the data stream.  Integers shorter than 4 bytes are
+        /// not sign-extended.
         /// </summary>
         /// <param name="data">Raw data stream.</param>
         /// <param name="offset">Start offset.</param>

PluginCommon/VisWireframe.cs

@@ -39,6 +39,7 @@ namespace PluginCommon {
         private List<float> mVerticesY = new List<float>();
         private List<float> mVerticesZ = new List<float>();
 
+        private List<int> mPoints = new List<int>();
         private List<IntPair> mEdges = new List<IntPair>();
 
         private List<float> mNormalsX = new List<float>();
@@ -72,6 +73,16 @@ namespace PluginCommon {
             return mVerticesX.Count - 1;
         }
 
+        /// <summary>
+        /// Adds a point to the list.
+        /// </summary>
+        /// <param name="index">Vertex index.</param>
+        /// <returns>Point index.  Indices start at zero and count up.</returns>
+        public int AddPoint(int index) {
+            mPoints.Add(index);
+            return mPoints.Count - 1;
+        }
+
         /// <summary>
         /// Adds an edge to the list.  The referenced vertices do not need to be defined
         /// before calling.
@@ -172,6 +183,14 @@ namespace PluginCommon {
                 return false;
             }
 
+            // check points
+            foreach (int vi in mPoints) {
+                if (vi < 0 || vi >= vertexCount) {
+                    msg = "invalid point (index=" + vi + "; count=" + vertexCount + ")";
+                    return false;
+                }
+            }
+
             // check edges
             foreach (IntPair ip in mEdges) {
                 if (ip.Val0 < 0 || ip.Val0 >= vertexCount ||
@@ -248,6 +267,10 @@ namespace PluginCommon {
             return mVerticesZ.ToArray();
         }
 
+        public int[] GetPoints() {
+            return mPoints.ToArray();
+        }
+
         public IntPair[] GetEdges() {
             return mEdges.ToArray();
         }

SourceGen/WireframeObject.cs

@@ -87,6 +87,7 @@ namespace SourceGen {
         }
 
         private List<Vertex> mVertices = new List<Vertex>();
+        private List<Vertex> mPoints = new List<Vertex>();
         private List<Edge> mEdges = new List<Edge>();
         private List<Face> mFaces = new List<Face>();
         private double mBigMag = -1.0;
@@ -105,7 +106,8 @@ namespace SourceGen {
 
             //
             // Start by extracting data from the visualization object.  Everything stored
-            // there is loaded into this object.
+            // there is loaded into this object.  The VisWireframe validator will have
+            // ensured that all the indices are in range.
             //
 
             float[] normalsX = visWire.GetNormalsX();
@@ -141,6 +143,11 @@ namespace SourceGen {
                     HasIndex(excludedVertices, i)));
             }
 
+            int[] points = visWire.GetPoints();
+            for (int i = 0; i < points.Length; i++) {
+                wireObj.mPoints.Add(wireObj.mVertices[i]);
+            }
+
             IntPair[] edges = visWire.GetEdges();
             int[] excludedEdges = visWire.GetExcludedEdges();
             for (int i = 0; i < edges.Length; i++) {
@@ -229,7 +236,8 @@ namespace SourceGen {
         /// <param name="doPersp">Perspective or othographic projection?</param>
         /// <param name="doBfc">Perform backface culling?</param>
         /// <returns>List a of line segments, which could be empty if backface culling
-        ///   was especially successful.</returns>
+        ///   was especially successful.  All segment coordinates are in the range
+        ///   [-1,1].</returns>
         public List<LineSeg> Generate(int eulerX, int eulerY, int eulerZ,
                 bool doPersp, bool doBfc) {
             List<LineSeg> segs = new List<LineSeg>(mEdges.Count);
@@ -293,6 +301,29 @@ namespace SourceGen {
                 }
             }
 
+            foreach (Vertex point in mPoints) {
+                // There are no "point faces" at the moment, so no BFC is applied.
+                Vector3 trv = rotMat.Multiply(point.Vec);
+                double xc, yc;
+                if (doPersp) {
+                    double zc = trv.Z * scale;
+                    xc = (trv.X * scale * zadj) / (zadj + zc);
+                    yc = (trv.Y * scale * zadj) / (zadj + zc);
+                } else {
+                    xc = trv.X * scale;
+                    yc = trv.Y * scale;
+                }
+
+                // Zero-length line segments don't do anything.  Try a '+'.
+                const double dist = 1 / 64.0;
+                double x0 = Math.Max(-1.0, xc - dist);
+                double x1 = Math.Min(xc + dist, 1.0);
+                segs.Add(new LineSeg(x0, yc, x1, yc));
+                double y0 = Math.Max(-1.0, yc - dist);
+                double y1 = Math.Min(yc + dist, 1.0);
+                segs.Add(new LineSeg(xc, y0, xc, y1));
+            }
+
             foreach (Edge edge in mEdges) {
                 if (doBfc) {
                     // To be visible, vertices and edges must either not specify any