qzdoom/src/gl/scene/gl_clipper.cpp

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/*
*
** gl_clipper.cpp
**
** Handles visibility checks.
** Loosely based on the JDoom clipper.
**
**---------------------------------------------------------------------------
** Copyright 2003 Tim Stump
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
#include "gl/scene/gl_clipper.h"
#include "g_levellocals.h"
unsigned Clipper::starttime;
Clipper::Clipper()
{
starttime++;
}
//-----------------------------------------------------------------------------
//
// RemoveRange
//
//-----------------------------------------------------------------------------
void Clipper::RemoveRange(ClipNode * range)
{
if (range == cliphead)
{
cliphead = cliphead->next;
}
else
{
if (range->prev) range->prev->next = range->next;
if (range->next) range->next->prev = range->prev;
}
Free(range);
}
//-----------------------------------------------------------------------------
//
// Clear
//
//-----------------------------------------------------------------------------
void Clipper::Clear()
{
ClipNode *node = cliphead;
ClipNode *temp;
blocked = false;
while (node != NULL)
{
temp = node;
node = node->next;
Free(temp);
}
node = silhouette;
while (node != NULL)
{
temp = node;
node = node->next;
Free(temp);
}
cliphead = NULL;
silhouette = NULL;
starttime++;
}
//-----------------------------------------------------------------------------
//
// SetSilhouette
//
//-----------------------------------------------------------------------------
void Clipper::SetSilhouette()
{
ClipNode *node = cliphead;
ClipNode *last = NULL;
while (node != NULL)
{
ClipNode *snode = NewRange(node->start, node->end);
if (silhouette == NULL) silhouette = snode;
snode->prev = last;
if (last != NULL) last->next = snode;
last = snode;
node = node->next;
}
}
//-----------------------------------------------------------------------------
//
// IsRangeVisible
//
//-----------------------------------------------------------------------------
bool Clipper::IsRangeVisible(angle_t startAngle, angle_t endAngle)
{
ClipNode *ci;
ci = cliphead;
if (endAngle==0 && ci && ci->start==0) return false;
while (ci != NULL && ci->start < endAngle)
{
if (startAngle >= ci->start && endAngle <= ci->end)
{
return false;
}
ci = ci->next;
}
return true;
}
//-----------------------------------------------------------------------------
//
// AddClipRange
//
//-----------------------------------------------------------------------------
void Clipper::AddClipRange(angle_t start, angle_t end)
{
ClipNode *node, *temp, *prevNode;
if (cliphead)
{
//check to see if range contains any old ranges
node = cliphead;
while (node != NULL && node->start < end)
{
if (node->start >= start && node->end <= end)
{
temp = node;
node = node->next;
RemoveRange(temp);
}
else if (node->start<=start && node->end>=end)
{
return;
}
else
{
node = node->next;
}
}
//check to see if range overlaps a range (or possibly 2)
node = cliphead;
while (node != NULL && node->start <= end)
{
if (node->end >= start)
{
// we found the first overlapping node
if (node->start > start)
{
// the new range overlaps with this node's start point
node->start = start;
}
if (node->end < end)
{
node->end = end;
}
ClipNode *node2 = node->next;
while (node2 && node2->start <= node->end)
{
if (node2->end > node->end) node->end = node2->end;
ClipNode *delnode = node2;
node2 = node2->next;
RemoveRange(delnode);
}
return;
}
node = node->next;
}
//just add range
node = cliphead;
prevNode = NULL;
temp = NewRange(start, end);
while (node != NULL && node->start < end)
{
prevNode = node;
node = node->next;
}
temp->next = node;
if (node == NULL)
{
temp->prev = prevNode;
if (prevNode) prevNode->next = temp;
if (!cliphead) cliphead = temp;
}
else
{
if (node == cliphead)
{
cliphead->prev = temp;
cliphead = temp;
}
else
{
temp->prev = prevNode;
prevNode->next = temp;
node->prev = temp;
}
}
}
else
{
temp = NewRange(start, end);
cliphead = temp;
return;
}
}
//-----------------------------------------------------------------------------
//
// RemoveClipRange
//
//-----------------------------------------------------------------------------
void Clipper::RemoveClipRange(angle_t start, angle_t end)
{
ClipNode *node;
if (silhouette)
{
node = silhouette;
while (node != NULL && node->end <= start)
{
node = node->next;
}
if (node != NULL && node->start <= start)
{
if (node->end >= end) return;
start = node->end;
node = node->next;
}
while (node != NULL && node->start < end)
{
DoRemoveClipRange(start, node->start);
start = node->end;
node = node->next;
}
if (start >= end) return;
}
DoRemoveClipRange(start, end);
}
//-----------------------------------------------------------------------------
//
// RemoveClipRange worker function
//
//-----------------------------------------------------------------------------
void Clipper::DoRemoveClipRange(angle_t start, angle_t end)
{
ClipNode *node, *temp;
if (cliphead)
{
//check to see if range contains any old ranges
node = cliphead;
while (node != NULL && node->start < end)
{
if (node->start >= start && node->end <= end)
{
temp = node;
node = node->next;
RemoveRange(temp);
}
else
{
node = node->next;
}
}
//check to see if range overlaps a range (or possibly 2)
node = cliphead;
while (node != NULL)
{
if (node->start >= start && node->start <= end)
{
node->start = end;
break;
}
else if (node->end >= start && node->end <= end)
{
node->end=start;
}
else if (node->start < start && node->end > end)
{
temp = NewRange(end, node->end);
node->end=start;
temp->next=node->next;
temp->prev=node;
node->next=temp;
if (temp->next) temp->next->prev=temp;
break;
}
node = node->next;
}
}
}
//-----------------------------------------------------------------------------
//
//
//
//-----------------------------------------------------------------------------
angle_t Clipper::AngleToPseudo(angle_t ang)
{
double vecx = cos(ang * M_PI / ANGLE_180);
double vecy = sin(ang * M_PI / ANGLE_180);
double result = vecy / (fabs(vecx) + fabs(vecy));
if (vecx < 0)
{
result = 2.f - result;
}
return xs_Fix<30>::ToFix(result);
}
//-----------------------------------------------------------------------------
//
// ! Returns the pseudoangle between the line p1 to (infinity, p1.y) and the
// line from p1 to p2. The pseudoangle has the property that the ordering of
// points by true angle around p1 and ordering of points by pseudoangle are the
// same.
//
// For clipping exact angles are not needed. Only the ordering matters.
// This is about as fast as the fixed point R_PointToAngle2 but without
// the precision issues associated with that function.
//
//-----------------------------------------------------------------------------
angle_t R_PointToPseudoAngle(double x, double y)
{
double vecx = x - r_viewpoint.Pos.X;
double vecy = y - r_viewpoint.Pos.Y;
if (vecx == 0 && vecy == 0)
{
return 0;
}
else
{
double result = vecy / (fabs(vecx) + fabs(vecy));
if (vecx < 0)
{
result = 2. - result;
}
return xs_Fix<30>::ToFix(result);
}
}
//-----------------------------------------------------------------------------
//
// R_CheckBBox
// Checks BSP node/subtree bounding box.
// Returns true
// if some part of the bbox might be visible.
//
//-----------------------------------------------------------------------------
static const uint8_t checkcoord[12][4] = // killough -- static const
{
{3,0,2,1},
{3,0,2,0},
{3,1,2,0},
{0},
{2,0,2,1},
{0,0,0,0},
{3,1,3,0},
{0},
{2,0,3,1},
{2,1,3,1},
{2,1,3,0}
};
bool Clipper::CheckBox(const float *bspcoord)
{
angle_t angle1, angle2;
int boxpos;
const uint8_t* check;
// Find the corners of the box
// that define the edges from current viewpoint.
boxpos = (r_viewpoint.Pos.X <= bspcoord[BOXLEFT] ? 0 : r_viewpoint.Pos.X < bspcoord[BOXRIGHT ] ? 1 : 2) +
(r_viewpoint.Pos.Y >= bspcoord[BOXTOP ] ? 0 : r_viewpoint.Pos.Y > bspcoord[BOXBOTTOM] ? 4 : 8);
if (boxpos == 5) return true;
check = checkcoord[boxpos];
2016-04-02 21:17:16 +00:00
angle1 = R_PointToPseudoAngle (bspcoord[check[0]], bspcoord[check[1]]);
angle2 = R_PointToPseudoAngle (bspcoord[check[2]], bspcoord[check[3]]);
return SafeCheckRange(angle2, angle1);
}