motiontrail: Clean up and optimization of C++ implementation

direct/src/motiontrail/cMotionTrail.cxx

@@ -15,7 +15,16 @@
 #include "cMotionTrail.h"
 #include "renderState.h"
 #include "colorAttrib.h"
+#include "cmath.h"
 
+static PN_stdfloat one_minus_x(PN_stdfloat x) {
+  x = 1.0 - x;
+  if (x < 0.0) {
+    x = 0.0;
+  }
+
+  return x;
+}
 
 TypeHandle CMotionTrail::_type_handle;
 
@@ -173,21 +182,20 @@ check_for_update (PN_stdfloat current_time) {
   return state;
 }
 
-PN_stdfloat one_minus_x (PN_stdfloat x) {
+/**
-  x = 1.0 - x;
+ *
-  if (x < 0.0) {
+ */
-    x = 0.0;
+void CMotionTrail::
-  }
+begin_geometry() {
-
+  begin_geometry(0);
-  return x;
 }
 
 /**
  *
  */
 void CMotionTrail::
-begin_geometry ( ) {
+begin_geometry(int num_quads) {
-
+  const int num_vertices = num_quads * 4;
   const GeomVertexFormat *format;
 
   _vertex_index = 0;
@@ -205,14 +213,56 @@ begin_geometry ( ) {
   _color_writer.clear();
   _texture_writer.clear();
 
+  Thread *current_thread = Thread::get_current_thread();
+
   _vertex_data = new GeomVertexData("vertices", format, Geom::UH_static);
-  _vertex_writer = GeomVertexWriter (_vertex_data, "vertex");
+  _vertex_data->unclean_set_num_rows(num_vertices);
-  _color_writer = GeomVertexWriter (_vertex_data, "color");
+  _vertex_writer = GeomVertexWriter(_vertex_data, "vertex", current_thread);
+  _color_writer = GeomVertexWriter(_vertex_data, "color", current_thread);
   if (_use_texture) {
-    _texture_writer = GeomVertexWriter (_vertex_data, "texcoord");
+    _texture_writer = GeomVertexWriter(_vertex_data, "texcoord", current_thread);
   }
 
+  // We know how many triangles we'll be adding, so add them up front.
   _triangles = new GeomTriangles(Geom::UH_static);
+  if (num_quads * 6 <= 65535) {
+    _triangles->set_index_type(GeomEnums::NT_uint16);
+  } else {
+    _triangles->set_index_type(GeomEnums::NT_uint32);
+  }
+
+  {
+    PT(GeomVertexArrayDataHandle) idx_handle = _triangles->modify_vertices_handle(current_thread);
+    idx_handle->unclean_set_num_rows(num_quads * 6);
+    if (num_quads * 6 <= 65535) {
+      // 16-bit index case.
+      uint16_t *idx_ptr = (uint16_t *)idx_handle->get_write_pointer();
+
+      for (int i = 0; i < num_vertices; i += 4) {
+        *(idx_ptr++) = i + 0;
+        *(idx_ptr++) = i + 1;
+        *(idx_ptr++) = i + 2;
+        *(idx_ptr++) = i + 1;
+        *(idx_ptr++) = i + 3;
+        *(idx_ptr++) = i + 2;
+      }
+    } else {
+      // 32-bit index case.
+      uint32_t *idx_ptr = (uint32_t *)idx_handle->get_write_pointer();
+
+      for (int i = 0; i < num_vertices; i += 4) {
+        *(idx_ptr++) = i + 0;
+        *(idx_ptr++) = i + 1;
+        *(idx_ptr++) = i + 2;
+        *(idx_ptr++) = i + 1;
+        *(idx_ptr++) = i + 3;
+        *(idx_ptr++) = i + 2;
+      }
+    }
+  }
+
+  // We can compute this value much faster than GeomPrimitive can.
+  _triangles->set_minmax(0, num_vertices - 1, nullptr, nullptr);
 }
 
 /**
@@ -220,38 +270,22 @@ begin_geometry ( ) {
  */
 void CMotionTrail::
 add_geometry_quad(LVector3 &v0, LVector3 &v1, LVector3 &v2, LVector3 &v3, LVector4 &c0, LVector4 &c1, LVector4 &c2, LVector4 &c3, LVector2 &t0, LVector2 &t1, LVector2 &t2, LVector2 &t3) {
+  _vertex_writer.set_data3(v0);
+  _vertex_writer.set_data3(v1);
+  _vertex_writer.set_data3(v2);
+  _vertex_writer.set_data3(v3);
 
-  _vertex_writer.add_data3 (v0);
+  _color_writer.set_data4(c0);
-  _vertex_writer.add_data3 (v1);
+  _color_writer.set_data4(c1);
-  _vertex_writer.add_data3 (v2);
+  _color_writer.set_data4(c2);
-  _vertex_writer.add_data3 (v3);
+  _color_writer.set_data4(c3);
-
-  _color_writer.add_data4 (c0);
-  _color_writer.add_data4 (c1);
-  _color_writer.add_data4 (c2);
-  _color_writer.add_data4 (c3);
 
   if (_use_texture) {
-    _texture_writer.add_data2 (t0);
+    _texture_writer.set_data2(t0);
-    _texture_writer.add_data2 (t1);
+    _texture_writer.set_data2(t1);
-    _texture_writer.add_data2 (t2);
+    _texture_writer.set_data2(t2);
-    _texture_writer.add_data2 (t3);
+    _texture_writer.set_data2(t3);
   }
-
-  int vertex_index;
-  vertex_index = _vertex_index;
-
-  _triangles -> add_vertex (vertex_index + 0);
-  _triangles -> add_vertex (vertex_index + 1);
-  _triangles -> add_vertex (vertex_index + 2);
-  _triangles -> close_primitive ( );
-
-  _triangles -> add_vertex (vertex_index + 1);
-  _triangles -> add_vertex (vertex_index + 3);
-  _triangles -> add_vertex (vertex_index + 2);
-  _triangles -> close_primitive ( );
-
-  _vertex_index += 4;
 }
 
 /**
@@ -259,52 +293,39 @@ add_geometry_quad (LVector3 &v0, LVector3 &v1, LVector3 &v2, LVector3 &v3, LVect
  */
 void CMotionTrail::
 add_geometry_quad(LVector4 &v0, LVector4 &v1, LVector4 &v2, LVector4 &v3, LVector4 &c0, LVector4 &c1, LVector4 &c2, LVector4 &c3, LVector2 &t0, LVector2 &t1, LVector2 &t2, LVector2 &t3) {
+  _vertex_writer.set_data3(v0[0], v0[1], v0[2]);
+  _vertex_writer.set_data3(v1[0], v1[1], v1[2]);
+  _vertex_writer.set_data3(v2[0], v2[1], v2[2]);
+  _vertex_writer.set_data3(v3[0], v3[1], v3[2]);
 
-  _vertex_writer.add_data3 (v0 [0], v0 [1], v0 [2]);
+  _color_writer.set_data4(c0);
-  _vertex_writer.add_data3 (v1 [0], v1 [1], v1 [2]);
+  _color_writer.set_data4(c1);
-  _vertex_writer.add_data3 (v2 [0], v2 [1], v2 [2]);
+  _color_writer.set_data4(c2);
-  _vertex_writer.add_data3 (v3 [0], v3 [1], v3 [2]);
+  _color_writer.set_data4(c3);
-
-  _color_writer.add_data4 (c0);
-  _color_writer.add_data4 (c1);
-  _color_writer.add_data4 (c2);
-  _color_writer.add_data4 (c3);
 
   if (_use_texture) {
-    _texture_writer.add_data2 (t0);
+    _texture_writer.set_data2(t0);
-    _texture_writer.add_data2 (t1);
+    _texture_writer.set_data2(t1);
-    _texture_writer.add_data2 (t2);
+    _texture_writer.set_data2(t2);
-    _texture_writer.add_data2 (t3);
+    _texture_writer.set_data2(t3);
   }
-
-  int vertex_index;
-  vertex_index = _vertex_index;
-
-  _triangles -> add_vertex (vertex_index + 0);
-  _triangles -> add_vertex (vertex_index + 1);
-  _triangles -> add_vertex (vertex_index + 2);
-  _triangles -> close_primitive ( );
-
-  _triangles -> add_vertex (vertex_index + 1);
-  _triangles -> add_vertex (vertex_index + 3);
-  _triangles -> add_vertex (vertex_index + 2);
-  _triangles -> close_primitive ( );
-
-  _vertex_index += 4;
 }
 
 /**
  *
  */
-void CMotionTrail::end_geometry ( ) {
+void CMotionTrail::
+end_geometry() {
   static CPT(RenderState) state;
   if (state == nullptr) {
     state = RenderState::make(ColorAttrib::make_vertex());
   }
 
-  PT(Geom) geometry;
+  _vertex_writer.clear();
+  _color_writer.clear();
+  _texture_writer.clear();
 
-  geometry = new Geom (_vertex_data);
+  PT(Geom) geometry = new Geom(_vertex_data);
   geometry->add_primitive(_triangles);
 
   if (_geom_node) {
@@ -318,32 +339,20 @@ void CMotionTrail::end_geometry ( ) {
  */
 void CMotionTrail::
 update_motion_trail(PN_stdfloat current_time, LMatrix4 *transform) {
+  int debug = false;
 
-  int debug;
+  if (!_frame_list.empty()) {
-  int total_frames;
+    if (_frame_list.front()._transform == UnalignedLMatrix4(*transform)) {
-
-  debug = false;
-
-  total_frames = _frame_list.size ( );
-  if (total_frames >= 1) {
-    FrameList::iterator frame_iterator;
-    CMotionTrailFrame motion_trail_frame;
-
-    frame_iterator = _frame_list.begin ( );
-    motion_trail_frame = *frame_iterator;
-    if (motion_trail_frame._transform == UnalignedLMatrix4(*transform)) {
       // duplicate transform
       return;
     }
   }
 
-  int total_vertices;
   PN_stdfloat color_scale;
   LMatrix4 start_transform;
   LMatrix4 end_transform;
   LMatrix4 inverse_matrix;
 
-  total_vertices = _vertex_list.size ( );
   color_scale = _color_scale;
   if (_fade) {
     PN_stdfloat elapsed_time;
@@ -364,15 +373,10 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
   _last_update_time = current_time;
 
   // remove expired frames
-  PN_stdfloat minimum_time;
+  PN_stdfloat minimum_time = current_time - _time_window;
-
-  minimum_time = current_time - _time_window;
-
-  CMotionTrailFrame motion_trail_frame;
 
   while (!_frame_list.empty()) {
-    motion_trail_frame = _frame_list.back();
+    if (_frame_list.back()._time >= minimum_time) {
-    if (motion_trail_frame._time >= minimum_time) {
       break;
     }
 
@@ -382,22 +386,20 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
   // add new frame to beginning of list
   {
     CMotionTrailFrame motion_trail_frame;
-
     motion_trail_frame._time = current_time;
     motion_trail_frame._transform = *transform;
-
+    _frame_list.push_front(std::move(motion_trail_frame));
-    _frame_list.push_front(motion_trail_frame);
   }
 
   // convert frames and vertices to geometry
-  total_frames = _frame_list.size ( );
+  int total_frames = (int)_frame_list.size();
+  int total_vertices = (int)_vertex_list.size();
 
   if (debug) {
     printf("update_motion_trail, total_frames = %d, total_vertices = %d, nurbs = %d, _calculate_relative_matrix = %d \n", total_frames, total_vertices, _use_nurbs, _calculate_relative_matrix);
   }
 
-  if ((total_frames >= 2) && (total_vertices >= 2)) {
+  if (total_frames >= 2 && total_vertices >= 2) {
-    int total_segments;
     PN_stdfloat minimum_time;
     PN_stdfloat delta_time;
     CMotionTrailFrame last_motion_trail_frame;
@@ -406,16 +408,14 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
 
     // convert vertex list to vertex array
     int index = 0;
-    _vertex_array = new CMotionTrailVertex [total_vertices];
+    CMotionTrailVertex *vertex_array = new CMotionTrailVertex[total_vertices];
     for (vertex_iterator = _vertex_list.begin(); vertex_iterator != _vertex_list.end(); vertex_iterator++) {
-      _vertex_array [index] = *vertex_iterator;
+      vertex_array[index] = *vertex_iterator;
-      index++;
+      ++index;
     }
 
-    // begin geometry
+    const int total_segments = total_frames - 1;
-    this -> begin_geometry ( );
+    const int total_vertex_segments = total_vertices - 1;
-
-    total_segments = total_frames - 1;
 
     last_motion_trail_frame = _frame_list.back();
     minimum_time = last_motion_trail_frame._time;
@@ -426,11 +426,8 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       inverse_matrix.invert_in_place();
     }
 
-    if (_use_nurbs && (total_frames >= 5)) {
+    if (_use_nurbs && total_frames >= 5) {
-
       // nurbs version
-      int total_vertex_segments;
-      PN_stdfloat total_distance;
       LVector3 vector;
       LVector4 v;
       LVector4 v0;
@@ -438,8 +435,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       LVector4 v2;
       LVector4 v3;
 
-      total_vertex_segments = total_vertices - 1;
+      PN_stdfloat total_distance = 0.0f;
-      total_distance = 0.0f;
 
       // reset NurbsCurveEvaluators for each vertex (the starting point for
       // the trail)
@@ -447,8 +443,8 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
         CMotionTrailVertex *motion_trail_vertex;
         PT(NurbsCurveEvaluator) nurbs_curve_evaluator;
 
-        for (index = 0; index < total_vertices; index++) {
+        for (int index = 0; index < total_vertices; ++index) {
-          motion_trail_vertex = &_vertex_array [index];
+          motion_trail_vertex = &vertex_array[index];
           nurbs_curve_evaluator = motion_trail_vertex->_nurbs_curve_evaluator;
           nurbs_curve_evaluator->set_order(4);
           nurbs_curve_evaluator->reset(total_segments);
@@ -456,17 +452,12 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       }
 
       // add vertices to each NurbsCurveEvaluator
-      int segment_index;
       CMotionTrailFrame motion_trail_frame_start;
       CMotionTrailFrame motion_trail_frame_end;
 
-      segment_index = 0;
-
       FrameList::iterator frame_iterator;
       frame_iterator = _frame_list.begin();
-      while (segment_index < total_segments) {
+      for (int segment_index = 0; segment_index < total_segments; ++segment_index) {
-        int vertex_segement_index;
-
         motion_trail_frame_start = *frame_iterator;
         frame_iterator++;
         motion_trail_frame_end = *frame_iterator;
@@ -484,7 +475,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
         CMotionTrailVertex *motion_trail_vertex_end;
         PT(NurbsCurveEvaluator) nurbs_curve_evaluator;
 
-        motion_trail_vertex_start = &_vertex_array [0];
+        motion_trail_vertex_start = &vertex_array[0];
 
         v0 = start_transform.xform(motion_trail_vertex_start->_vertex);
         v2 = end_transform.xform(motion_trail_vertex_start->_vertex);
@@ -492,10 +483,11 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
         nurbs_curve_evaluator = motion_trail_vertex_start->_nurbs_curve_evaluator;
         nurbs_curve_evaluator->set_vertex(segment_index, v0);
 
-        vertex_segement_index = 0;
+        for (int vertex_segment_index = 0;
-        while (vertex_segement_index < total_vertex_segments) {
+             vertex_segment_index < total_vertex_segments;
-          motion_trail_vertex_start = &_vertex_array [vertex_segement_index];
+             ++vertex_segment_index) {
-          motion_trail_vertex_end = &_vertex_array [vertex_segement_index + 1];
+          motion_trail_vertex_start = &vertex_array[vertex_segment_index];
+          motion_trail_vertex_end = &vertex_array[vertex_segment_index + 1];
 
           v1 = start_transform.xform(motion_trail_vertex_end->_vertex);
           v3 = end_transform.xform(motion_trail_vertex_end->_vertex);
@@ -503,7 +495,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           nurbs_curve_evaluator = motion_trail_vertex_end->_nurbs_curve_evaluator;
 
           nurbs_curve_evaluator->set_vertex(segment_index, v1);
-          if (vertex_segement_index == (total_vertex_segments - 1)) {
+          if (vertex_segment_index == (total_vertex_segments - 1)) {
             PN_stdfloat distance;
 
             v = v1 - v3;
@@ -511,24 +503,20 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
             distance = vector.length();
             total_distance += distance;
           }
-
-          vertex_segement_index += 1;
         }
-
-        segment_index += 1;
       }
 
       // evaluate NurbsCurveEvaluator for each vertex
       PT(NurbsCurveResult) *nurbs_curve_result_array;
 
       nurbs_curve_result_array = new PT(NurbsCurveResult)[total_vertices];
-      for (index = 0; index < total_vertices; index++) {
+      for (int index = 0; index < total_vertices; ++index) {
 
         CMotionTrailVertex *motion_trail_vertex;
         PT(NurbsCurveEvaluator) nurbs_curve_evaluator;
         PT(NurbsCurveResult) nurbs_curve_result;
 
-        motion_trail_vertex = &_vertex_array [index];
+        motion_trail_vertex = &vertex_array[index];
 
         nurbs_curve_evaluator = motion_trail_vertex->_nurbs_curve_evaluator;
         nurbs_curve_result = nurbs_curve_evaluator->evaluate();
@@ -546,37 +534,25 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       }
 
       // create quads from NurbsCurveResult
-      PN_stdfloat total_curve_segments;
+      PN_stdfloat total_curve_segments = total_distance / _resolution_distance;
-
-      total_curve_segments = (total_distance / _resolution_distance);
       if (total_curve_segments < total_segments) {
         total_curve_segments = total_segments;
       }
 
+      const int total_curve_segments_int = (int)cceil(total_curve_segments);
+      begin_geometry(total_curve_segments_int * total_vertex_segments);
+
       {
-        LVector3 v0;
+        LVector3 v0, v1, v2, v3;
-        LVector3 v1;
+        LVector4 c0, c1, c2, c3;
-        LVector3 v2;
+        LVector2 t0, t1, t2, t3;
-        LVector3 v3;
-
-        LVector4 c0;
-        LVector4 c1;
-        LVector4 c2;
-        LVector4 c3;
-
-        LVector2 t0;
-        LVector2 t1;
-        LVector2 t2;
-        LVector2 t3;
 
         LVector4 vertex_start_color;
         LVector4 vertex_end_color;
 
-        PN_stdfloat curve_segment_index;
+        for (int curve_segment_index = 0;
-
+             curve_segment_index < total_curve_segments_int;
-        curve_segment_index = 0.0;
+             ++curve_segment_index) {
-        while (curve_segment_index < total_curve_segments) {
-
           PN_stdfloat st;
           PN_stdfloat et;
           PN_stdfloat start_t;
@@ -584,17 +560,13 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           PN_stdfloat color_start_t;
           PN_stdfloat color_end_t;
 
-          int vertex_segement_index;
-
           CMotionTrailVertex *motion_trail_vertex_start;
           CMotionTrailVertex *motion_trail_vertex_end;
           PT(NurbsCurveResult) start_nurbs_curve_result;
           PT(NurbsCurveResult) end_nurbs_curve_result;
 
-          vertex_segement_index = 0;
-
           st = curve_segment_index / total_curve_segments;
-          et = (curve_segment_index + 1.0) / total_curve_segments;
+          et = (curve_segment_index + 1) / total_curve_segments;
 
           start_t = st;
           end_t = et;
@@ -604,7 +576,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
             end_t *= end_t;
           }
 
-          motion_trail_vertex_start = &_vertex_array [0];
+          motion_trail_vertex_start = &vertex_array[0];
 
           vertex_start_color = motion_trail_vertex_start->_end_color + (motion_trail_vertex_start->_start_color - motion_trail_vertex_start ->_end_color);
 
@@ -617,18 +589,20 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           t0.set(one_minus_x(st), motion_trail_vertex_start->_v);
           t2.set(one_minus_x(et), motion_trail_vertex_start->_v);
 
-          while (vertex_segement_index < total_vertex_segments) {
+          for (int vertex_segment_index = 0;
+               vertex_segment_index < total_vertex_segments;
+               ++vertex_segment_index) {
 
             PN_stdfloat start_nurbs_start_t;
             PN_stdfloat start_nurbs_end_t;
             PN_stdfloat end_nurbs_start_t;
             PN_stdfloat end_nurbs_end_t;
 
-            motion_trail_vertex_start = &_vertex_array [vertex_segement_index];
+            motion_trail_vertex_start = &vertex_array[vertex_segment_index];
-            motion_trail_vertex_end = &_vertex_array [vertex_segement_index + 1];
+            motion_trail_vertex_end = &vertex_array[vertex_segment_index + 1];
 
-            start_nurbs_curve_result = nurbs_curve_result_array [vertex_segement_index];
+            start_nurbs_curve_result = nurbs_curve_result_array[vertex_segment_index];
-            end_nurbs_curve_result = nurbs_curve_result_array [vertex_segement_index + 1];
+            end_nurbs_curve_result = nurbs_curve_result_array[vertex_segment_index + 1];
 
             start_nurbs_start_t = start_nurbs_curve_result->get_start_t();
             start_nurbs_end_t = start_nurbs_curve_result->get_end_t();
@@ -657,7 +631,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
             t1.set(one_minus_x(st), motion_trail_vertex_end->_v);
             t3.set(one_minus_x(et), motion_trail_vertex_end->_v);
 
-            this -> add_geometry_quad (v0, v1, v2, v3, c0, c1, c2, c3, t0, t1, t2, t3);
+            add_geometry_quad(v0, v1, v2, v3, c0, c1, c2, c3, t0, t1, t2, t3);
 
             // reuse calculations
             c0 = c1;
@@ -665,26 +639,21 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
 
             t0 = t1;
             t2 = t3;
-
-            vertex_segement_index += 1;
           }
-
-          curve_segment_index += 1.0;
         }
       }
 
-      for (index = 0; index < total_vertices; index++) {
+      for (int index = 0; index < total_vertices; ++index) {
         nurbs_curve_result_array[index] = nullptr;
       }
 
       delete[] nurbs_curve_result_array;
     }
     else {
-
       // non-nurbs version
-      int segment_index;
+      const int total_vertex_segments = total_vertices - 1;
-      int vertex_segment_index;
+
-      int total_vertex_segments;
+      begin_geometry(total_segments * total_vertex_segments);
 
       PN_stdfloat st;
       PN_stdfloat et;
@@ -693,20 +662,9 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       PN_stdfloat color_start_t;
       PN_stdfloat color_end_t;
 
-      LVector4 v0;
+      LVector4 v0, v1, v2, v3;
-      LVector4 v1;
+      LVector4 c0, c1, c2, c3;
-      LVector4 v2;
+      LVector2 t0, t1, t2, t3;
-      LVector4 v3;
-
-      LVector4 c0;
-      LVector4 c1;
-      LVector4 c2;
-      LVector4 c3;
-
-      LVector2 t0;
-      LVector2 t1;
-      LVector2 t2;
-      LVector2 t3;
 
       LVector4 vertex_start_color;
       LVector4 vertex_end_color;
@@ -714,11 +672,8 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
       CMotionTrailFrame motion_trail_frame_start;
       CMotionTrailFrame motion_trail_frame_end;
 
-      segment_index = 0;
+      FrameList::iterator frame_iterator = _frame_list.begin();
-      FrameList::iterator frame_iterator;
+      for (int segment_index = 0; segment_index < total_segments; ++segment_index) {
-      frame_iterator = _frame_list.begin ( );
-      while (segment_index < total_segments) {
-
         CMotionTrailVertex *motion_trail_vertex_start;
         CMotionTrailVertex *motion_trail_vertex_end;
 
@@ -737,9 +692,6 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           end_t *= end_t;
         }
 
-        vertex_segment_index = 0;
-        total_vertex_segments = total_vertices - 1;
-
         if (_calculate_relative_matrix) {
           start_transform.multiply(motion_trail_frame_start._transform, inverse_matrix);
           end_transform.multiply(motion_trail_frame_end._transform, inverse_matrix);
@@ -749,7 +701,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           end_transform = motion_trail_frame_end._transform;
         }
 
-        motion_trail_vertex_start = &_vertex_array [0];
+        motion_trail_vertex_start = &vertex_array[0];
 
         v0 = start_transform.xform(motion_trail_vertex_start->_vertex);
         v2 = end_transform.xform(motion_trail_vertex_start->_vertex);
@@ -763,10 +715,11 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
         t0.set(st, motion_trail_vertex_start->_v);
         t2.set(et, motion_trail_vertex_start->_v);
 
-        while (vertex_segment_index < total_vertex_segments) {
+        for (int vertex_segment_index = 0;
-
+             vertex_segment_index < total_vertex_segments;
-          motion_trail_vertex_start = &_vertex_array [vertex_segment_index];
+             ++vertex_segment_index) {
-          motion_trail_vertex_end = &_vertex_array [vertex_segment_index + 1];
+          motion_trail_vertex_start = &vertex_array[vertex_segment_index];
+          motion_trail_vertex_end = &vertex_array[vertex_segment_index + 1];
 
           v1 = start_transform.xform(motion_trail_vertex_end->_vertex);
           v3 = end_transform.xform(motion_trail_vertex_end->_vertex);
@@ -781,7 +734,7 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
           t1.set(st, motion_trail_vertex_end->_v);
           t3.set(et, motion_trail_vertex_end->_v);
 
-          this -> add_geometry_quad (v0, v1, v2, v3, c0, c1, c2, c3, t0, t1, t2, t3);
+          add_geometry_quad(v0, v1, v2, v3, c0, c1, c2, c3, t0, t1, t2, t3);
 
           // reuse calculations
           v0 = v1;
@@ -792,18 +745,12 @@ update_motion_trail (PN_stdfloat current_time, LMatrix4 *transform) {
 
           t0 = t1;
           t2 = t3;
-
-          vertex_segment_index += 1;
         }
-
-        segment_index += 1;
       }
     }
 
-    // end geometry
+    end_geometry();
-    this -> end_geometry ( );
 
-    delete[] _vertex_array;
+    delete[] vertex_array;
-    _vertex_array = nullptr;
   }
 }

direct/src/motiontrail/cMotionTrail.h

@@ -90,6 +90,7 @@ PUBLISHED:
 public:
 
   void begin_geometry();
+  void begin_geometry(int num_quads);
   void add_geometry_quad(LVector3 &v0, LVector3 &v1, LVector3 &v2, LVector3 &v3, LVector4 &c0, LVector4 &c1, LVector4 &c2, LVector4 &c3, LVector2 &t0, LVector2 &t1, LVector2 &t2, LVector2 &t3);
   void add_geometry_quad(LVector4 &v0, LVector4 &v1, LVector4 &v2, LVector4 &v3, LVector4 &c0, LVector4 &c1, LVector4 &c2, LVector4 &c3, LVector2 &t0, LVector2 &t1, LVector2 &t2, LVector2 &t3);
   void end_geometry();