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