Initial commit

Torque/SDK/engine/util/rectClipper.cpp

@@ -0,0 +1,150 @@
+//-----------------------------------------------------------------------------
+// Torque Shader Engine
+// Copyright (C) GarageGames.com, Inc.
+//-----------------------------------------------------------------------------
+
+#include "util/rectClipper.h"
+
+namespace {
+
+inline void
+swap(F32& in_one, F32& in_two)
+{
+   F32 temp = in_one;
+   in_one   = in_two;
+   in_two   = temp;
+}
+
+}
+
+bool
+RectClipper::clipLine(const Point2I& in_rStart,
+                      const Point2I& in_rEnd,
+                      Point2I&       out_rStart,
+                      Point2I&       out_rEnd) const
+{
+   // Check for trivial rejection
+   if ((in_rStart.x < m_clipRect.point.x && in_rEnd.x < m_clipRect.point.x) ||
+       (in_rStart.x >= m_clipRect.point.x + m_clipRect.extent.x &&
+         in_rEnd.x >= m_clipRect.point.x + m_clipRect.extent.x))
+      return false;
+   if ((in_rStart.y < m_clipRect.point.y && in_rEnd.y < m_clipRect.point.y) ||
+       (in_rStart.y >= m_clipRect.point.y + m_clipRect.extent.y &&
+         in_rEnd.y >= m_clipRect.point.y + m_clipRect.extent.y))
+      return false;
+
+   F32 x1 = F32(in_rStart.x);
+   F32 y1 = F32(in_rStart.y);
+   F32 x2 = F32(in_rEnd.x);
+   F32 y2 = F32(in_rEnd.y);
+
+   // I'm using essentially what's in the Phoenix libs, Liang-Biarsky based, but
+   //  converted to FP math for greater precision on the back end...
+   //
+   bool flipped = false;
+   if (x1 > x2) 
+   {
+      swap(x1, x2);
+      swap(y1, y2);
+      flipped = !flipped;
+   }
+
+   F32 dx = x2 - x1;
+   F32 dy = y2 - y1;
+
+   // Clip x coord
+   F32 t;
+   if (x1 < F32(m_clipRect.point.x)) 
+   {
+      t   = (F32(m_clipRect.point.x) - x1) / F32(dx);
+      x1  = F32(m_clipRect.point.x);
+      y1 += t * dy;
+      dx  = x2 - x1;
+      dy  = y2 - y1;
+   }
+   if (x2 >= F32(m_clipRect.point.x + m_clipRect.extent.x))
+   {
+      t   = (F32(m_clipRect.point.x + m_clipRect.extent.x - 1) - x1) / F32(dx);
+      x2  = F32(m_clipRect.point.x + m_clipRect.extent.x - 1);
+      y2  = y1 + (t * dy);
+      dx  = x2 - x1;
+      dy  = y2 - y1;
+   }
+
+   // Recheck trivial rejection condition...
+   if((y1 > F32(m_clipRect.point.y + m_clipRect.extent.y - 1) &&
+         y2 > F32(m_clipRect.point.y + m_clipRect.extent.y - 1)) ||
+         (y1 < F32(m_clipRect.point.y) && y2 < F32(m_clipRect.point.y)))
+      return false;
+
+   if (y1 > y2) 
+   {
+      swap(x1, x2);
+      swap(y1, y2);
+      flipped = !flipped;
+   }
+
+   if (y1 < F32(m_clipRect.point.y)) 
+   {
+      t   = (F32(m_clipRect.point.y) - y1) / F32(dy);
+      y1  = F32(m_clipRect.point.y);
+      x1 += t * dx;
+      dx  = x2 - x1;
+      dy  = y2 - y1;
+   }
+   if (y2 > F32(m_clipRect.point.y + m_clipRect.extent.y - 1))
+   {
+      t   = (F32(m_clipRect.point.y + m_clipRect.extent.y - 1) - y1) / F32(dy);
+      y2  = F32(m_clipRect.point.y + m_clipRect.extent.y - 1);
+      x2  = x1 + (t * dx);
+   }
+
+   if (flipped == true) 
+   {
+      out_rEnd.x   = S32(x1 + 0.5f);
+      out_rEnd.y   = S32(y1 + 0.5f);
+      out_rStart.x = S32(x2 + 0.5f);
+      out_rStart.y = S32(y2 + 0.5f);
+   } 
+   else 
+   {
+      out_rStart.x = S32(x1 + 0.5f);
+      out_rStart.y = S32(y1 + 0.5f);
+      out_rEnd.x   = S32(x2 + 0.5f);
+      out_rEnd.y   = S32(y2 + 0.5f);
+   }
+
+   return true;
+}
+
+
+bool
+RectClipper::clipRect(const RectI& in_rRect,
+                      RectI&       out_rRect) const
+{
+   AssertFatal(in_rRect.isValidRect(), "Inappropriate min/max coords for rectangle");
+
+   if (in_rRect.point.x + in_rRect.extent.x - 1 < m_clipRect.point.x ||
+       in_rRect.point.x > m_clipRect.point.x + m_clipRect.extent.x - 1)
+      return false;
+   if (in_rRect.point.y + in_rRect.extent.y - 1 < m_clipRect.point.y ||
+       in_rRect.point.y > m_clipRect.point.y + m_clipRect.extent.y - 1)
+      return false;
+
+   if (in_rRect.point.x < m_clipRect.point.x) out_rRect.point.x = m_clipRect.point.x;
+   else                                       out_rRect.point.x = in_rRect.point.x;
+
+   if (in_rRect.point.y < m_clipRect.point.y) out_rRect.point.y = m_clipRect.point.y;
+   else                                       out_rRect.point.y = in_rRect.point.y;
+
+   Point2I bottomR;
+   bottomR.x = getMin(in_rRect.point.x + in_rRect.extent.x - 1,
+                     m_clipRect.point.x + m_clipRect.extent.x - 1);
+   bottomR.y = getMin(in_rRect.point.y + in_rRect.extent.y - 1,
+                     m_clipRect.point.y + m_clipRect.extent.y - 1);
+
+   out_rRect.extent.x = bottomR.x - out_rRect.point.x + 1;
+   out_rRect.extent.x = bottomR.y - out_rRect.point.y + 1;
+
+   return true;
+}