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https://github.com/ZDoom/Raze.git
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659 lines
18 KiB
C++
659 lines
18 KiB
C++
/*
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*
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** gl_clipper.cpp
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**
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** Handles visibility checks.
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** Loosely based on the JDoom clipper.
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**
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**---------------------------------------------------------------------------
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** Copyright 2003 Tim Stump
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** All rights reserved.
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**
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** Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions
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** are met:
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**
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** 1. Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** 2. Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in the
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** documentation and/or other materials provided with the distribution.
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** 3. The name of the author may not be used to endorse or promote products
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** derived from this software without specific prior written permission.
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**
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** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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**---------------------------------------------------------------------------
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**
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*/
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#include "hw_clipper.h"
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#include "basics.h"
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#include "build.h"
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#include "printf.h"
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//-----------------------------------------------------------------------------
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//
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//
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//
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//-----------------------------------------------------------------------------
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void Clipper::ValidateList()
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{
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#ifdef _DEBUG
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// Make sure we catch ordering issues right away in debug mode.
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auto check = cliphead;
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while (check)
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{
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assert(!check->next || check->end <= check->next->start);
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check = check->next;
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}
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#endif
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}
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//-----------------------------------------------------------------------------
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//
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// RemoveRange
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//
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//-----------------------------------------------------------------------------
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void Clipper::RemoveRange(ClipNode * range, bool free)
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{
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if (range == cliphead)
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{
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cliphead = cliphead->next;
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if (cliphead) cliphead->prev = nullptr;
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}
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else
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{
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if (range->prev) range->prev->next = range->next;
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if (range->next) range->next->prev = range->prev;
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}
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if (free) Free(range);
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ValidateList();
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}
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//-----------------------------------------------------------------------------
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//
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// InsertRange
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//
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//-----------------------------------------------------------------------------
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bool Clipper::InsertRange(ClipNode* prev, ClipNode* node)
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{
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if (node->start == node->end)
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{
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Free(node);
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return false;
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}
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assert(node->start <= node->end);
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assert(!prev || prev->end <= node->start);
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assert(!prev || !prev->next || prev->next->start >= node->end);
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if (node->topclip <= node->bottomclip)
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{
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if (prev)
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{
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if (prev->topclip <= prev->bottomclip && prev->end >= node->start)
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{
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prev->end = node->end;
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Free(node);
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if (prev->next && prev->end >= prev->next->start && prev->next->topclip <= prev->next->bottomclip)
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{
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prev->end = prev->next->end;
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RemoveRange(prev->next);
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return true;
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}
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ValidateList();
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return false;
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}
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else if (prev->next && node->end >= prev->next->start && prev->next->topclip <= prev->next->bottomclip)
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{
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prev->next->start = node->start;
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Free(node);
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ValidateList();
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return false;
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}
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}
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}
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if (prev)
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{
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node->next = prev->next;
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prev->next = node;
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}
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else
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{
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node->next = cliphead;
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cliphead = node;
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}
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node->prev = prev;
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if (node->next) node->next->prev = node;
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ValidateList();
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return false;
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}
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//-----------------------------------------------------------------------------
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//
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// SplitRange
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//
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//-----------------------------------------------------------------------------
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void Clipper::SplitRange(ClipNode* node, int start, int end, float topclip, float bottomclip)
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{
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assert(start < end);
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int clones = 0;
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if (end < node->end)
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{
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int nodeend = node->end;
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node->end = end;
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auto endnode = NewRange(end, nodeend, node->topclip, node->bottomclip);
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InsertRange(node, endnode);
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}
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if (start > node->start)
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{
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node->end = start;
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auto startnode = NewRange(start, end, topclip, bottomclip);
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InsertRange(node, startnode);
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}
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else
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{
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// remove and reinsert to do proper checks of the clipping window.
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auto prev = node->prev;
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RemoveRange(node, false);
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node->topclip = topclip;
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node->bottomclip = bottomclip;
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InsertRange(prev, node);
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}
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}
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//-----------------------------------------------------------------------------
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//
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// Clear
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//
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//-----------------------------------------------------------------------------
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void Clipper::Clear(binangle rangestart)
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{
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ClipNode *node = cliphead;
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ClipNode *temp;
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while (node != nullptr)
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{
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temp = node;
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node = node->next;
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Free(temp);
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}
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cliphead = nullptr;
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if (visibleStart.asbam() != 0 || visibleEnd.asbam() != 0)
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{
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int vstart = int(visibleStart.asbam() - rangestart.asbam());
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if (vstart > 1) AddClipRange(0, vstart);
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int vend = int(visibleEnd.asbam() - rangestart.asbam());
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if (vend > 0 && vend < INT_MAX) AddClipRange(vend, INT_MAX);
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}
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}
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//-----------------------------------------------------------------------------
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//
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// IsRangeVisible
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//
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//-----------------------------------------------------------------------------
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bool Clipper::IsRangeVisible(int startAngle, int endAngle)
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{
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ClipNode *ci;
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ci = cliphead;
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if (endAngle == 0 && ci && ci->start==0) return false;
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while (ci != nullptr && ci->start < endAngle)
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{
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if (startAngle >= ci->start && endAngle <= ci->end && ci->topclip <= ci->bottomclip)
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{
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return false;
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}
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ci = ci->next;
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}
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return true;
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}
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//-----------------------------------------------------------------------------
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//
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// AddClipRange
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//
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//-----------------------------------------------------------------------------
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void Clipper::AddClipRange(int start, int end)
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{
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if (cliphead)
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{
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auto node = cliphead;
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while (node != nullptr && node->start < end)
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{
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// check to see if range contains any old ranges.
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// These can be removed, regardless whether they are a window or fully closed.
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if (node->start >= start && node->end <= end)
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{
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auto temp = node;
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node = node->next;
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RemoveRange(temp);
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}
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// check if the new range lies fully within an existing range.
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else if (node->start <= start && node->end >= end)
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{
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// if the existing range is closed, we're done.
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// Other split up the old window to insert the new range in the middle.
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if (node->topclip > node->bottomclip)
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{
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SplitRange(node, start, end, 0, 0);
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return;
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}
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}
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else
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{
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node = node->next;
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}
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}
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// at this point we know that overlaps can only be at one side because all full overlaps have been resolved already.
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// so what follows can at most intersect two other nodes - one at the left and one at the right
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node = cliphead;
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while (node != nullptr && node->start <= end)
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{
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// node overlaps at the start.
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if (node->start < start && node->end >= start)
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{
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if (node->topclip <= node->bottomclip)
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{
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node->end = end;
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auto next = node->next;
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if (next && next->start <= end)
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{
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// check if the following range overlaps. We know already that it will go past the end of the newly added range
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// (otherwise the first loop above would have taken care of it) so we can skip any checks for the full inclusion case.
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if (next->topclip <= next->bottomclip)
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{
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// next range is closed, so merge the two.
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node->end = next->end;
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RemoveRange(next);
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}
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else
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{
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next->start = end;
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}
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}
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// we're done and do not need to add a new node.
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ValidateList();
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return;
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}
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else
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{
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// if the old node is a window, restrict its size to the left of the new range and continue checking
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node->end = start;
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ValidateList();
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}
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}
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// range overlaps at the end.
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else if (node->start >= start && node->start <= end)
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{
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// node is closed - we can just merge this and exit
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if (node->topclip <= node->bottomclip)
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{
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node->start = start;
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ValidateList();
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return;
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}
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// node is a window - so restrict its size and insert the new node in front of it,
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else
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{
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node->start = end;
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auto mynode = NewRange(start, end, 0, 0);
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InsertRange(node->prev, mynode);
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return;
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}
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}
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node = node->next;
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}
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//found no intersections - just add range
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node = cliphead;
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ClipNode* prevNode = nullptr;
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// advance to the place where this can be inserted.
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while (node != nullptr && node->start < end)
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{
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prevNode = node;
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node = node->next;
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}
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auto mynode = NewRange(start, end, 0, 0);
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InsertRange(prevNode, mynode);
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}
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else
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{
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cliphead = NewRange(start, end, 0, 0);
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}
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}
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//-----------------------------------------------------------------------------
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//
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// AddWindowRange
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//
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//-----------------------------------------------------------------------------
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void Clipper::AddWindowRange(int start, int end, float topclip, float bottomclip, float viewz)
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{
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auto mergeClip = [](ClipNode* node, float& topclip, float& bottomclip, float viewz)
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{
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// If the node is already closed, return a closed range.
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if (node->topclip <= node->bottomclip)
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{
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topclip = bottomclip = 0;
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return;
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}
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float mintopclip = min(node->topclip, topclip);
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float maxbotclip = max(node->bottomclip, bottomclip);
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if (mintopclip > max(viewz, maxbotclip)) topclip = FLT_MAX;
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else topclip = mintopclip;
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if (maxbotclip < min(viewz, mintopclip)) bottomclip = -FLT_MAX;
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else bottomclip = maxbotclip;
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};
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ClipNode* prevNode = nullptr;
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if (cliphead)
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{
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auto node = cliphead;
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while (node != nullptr && node->start < end)
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{
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// check to see if range contains any old ranges.
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//-----------------------------------------------------------------------------
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//
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// existing range is part of new one.
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//
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//-----------------------------------------------------------------------------
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if (node->start >= start && node->end <= end)
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{
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int nodestart = node->start, nodeend = node->end;
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if (node->topclip > node->bottomclip) // we only need to make adjustments to the old node if it is not closed.
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{
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float mtopclip = topclip, mbottomclip = bottomclip;
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mergeClip(node, mtopclip, mbottomclip, viewz);
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// if the new window is closed, we must remove the old range and insert a closed one, so that it gets merged with its neighbours.
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if (mtopclip <= mbottomclip)
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{
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auto prev = node->prev;
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RemoveRange(node);
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auto mynode = NewRange(nodestart, nodeend, 0, 0);
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InsertRange(prev, mynode);
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}
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else
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{
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// in all other cases we must adjust the node's top and bottom
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node->topclip = mtopclip;
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node->bottomclip = mbottomclip;
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}
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}
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// At this point it is just easier to recursively add the sub-ranges because we'd have to run the full program on both anyway,
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// We must ensure the the new ranges' length are > 0.
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if (start < nodestart) AddWindowRange(start, nodestart, topclip, bottomclip, viewz);
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if (end > nodeend) AddWindowRange(nodeend, end, topclip, bottomclip, viewz);
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return;
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}
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//-----------------------------------------------------------------------------
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//
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// check if the new range lies fully within an existing range.
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//
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//-----------------------------------------------------------------------------
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else if (node->start <= start && node->end >= end)
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{
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// Shortcut if existing range is closed. In this case there's nothing to do.
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if (node->topclip <= node->bottomclip)
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{
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return;
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}
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float mtopclip = topclip, mbottomclip = bottomclip;
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mergeClip(node, mtopclip, mbottomclip, viewz);
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// existing range is a more narrow window on both sides, we're done.
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if (mtopclip > mbottomclip && mtopclip >= node->topclip && mbottomclip <= node->bottomclip)
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{
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return;
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}
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else
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{
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// adapt the window for the intersection.
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SplitRange(node, start, end, mtopclip, mbottomclip);
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return;
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}
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}
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else
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{
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node = node->next;
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}
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}
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// at this point we know that overlaps can only be at one side because all full overlaps have been resolved already.
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// so what follows can at most intersect two other nodes - one at the left and one at the right
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node = cliphead;
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while (node != nullptr && node->start <= end)
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{
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auto next = node->next; // get this before making any edits.
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//-----------------------------------------------------------------------------
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//
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// node overlaps the start of the new range
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//
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//-----------------------------------------------------------------------------
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if (node->start < start && node->end > start)
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{
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// if the old range is closed, just shorten the new one and continue.
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if (node->topclip < node->bottomclip)
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{
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start = node->end;
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ValidateList();
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if (start >= end) return; // may have been crushed to a single point.
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}
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else
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{
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float mtopclip = topclip, mbottomclip = bottomclip;
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mergeClip(node, mtopclip, mbottomclip, viewz);
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// if the old range is more narrow than the new one, just shorten the new one and continue.
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if (mtopclip > mbottomclip && mtopclip >= node->topclip && mbottomclip <= node->bottomclip)
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{
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start = node->end;
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ValidateList();
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if (start >= end) return; // may have been crushed to a single point.
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}
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// the unaltered new range is more narrow than the old one - just shorten the old one and go on.
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else if (topclip <= bottomclip || (topclip < node->topclip && bottomclip > node->bottomclip))
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{
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node->end = start;
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ValidateList();
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assert(node->end > node->start); // ensured by initial condition.
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}
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// if the intersection needs to take properties of both old and new we need to make a split.
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else
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{
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int nodeend = node->end;
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SplitRange(node, start, nodeend, mtopclip, mbottomclip);
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start = nodeend;
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if (start >= end) return; // may have been crushed to a single point.
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if (mtopclip <= mbottomclip) next = cliphead; // list may have become out of sync.
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}
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}
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}
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//-----------------------------------------------------------------------------
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//
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// nosw overlaps at the end of the new range.
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//
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//-----------------------------------------------------------------------------
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else if (node->start >= start && node->start < end)
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{
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// if the old range is closed, just shorten the new one and continue.
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if (node->topclip < node->bottomclip)
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{
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end = node->start;
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ValidateList();
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if (start >= end) return; // may have been crushed to a single point.
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}
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else
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{
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float mtopclip = topclip, mbottomclip = bottomclip;
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mergeClip(node, mtopclip, mbottomclip, viewz);
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// if the old range is more narrow than the new one, just shorten the new one and continue.
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if (mtopclip > mbottomclip && mtopclip >= node->topclip && mbottomclip <= node->bottomclip)
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{
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end = node->start;
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ValidateList();
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if (start >= end) return; // may have been crushed to a single point.
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}
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// the unaltered new range is more narrow than the old one - just shorten the old one and go on.
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else if (topclip <= bottomclip || (topclip < node->topclip && bottomclip > node->bottomclip))
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{
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node->start = end;
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ValidateList();
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assert(node->end > node->start);
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}
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// if the intersection needs to take properties of both old and new we need to make a split.
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else
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{
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int nodestart = node->start;
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SplitRange(node, nodestart, end, mtopclip, mbottomclip);
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end = nodestart;
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if (start >= end) return; // may have been crushed to a single point.
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if (mtopclip <= mbottomclip) next = cliphead; // list may have become out of sync.
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}
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}
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}
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node = next;
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}
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// cliphead *can* be null here if a sole existing older range got removed because this one covers it entirely.
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if (cliphead)
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{
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// we get here if a new range needs to be inserted.
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node = cliphead;
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// advance to the place where this can be inserted.
|
|
while (node != nullptr && node->start < end)
|
|
{
|
|
prevNode = node;
|
|
node = node->next;
|
|
}
|
|
assert(!prevNode || prevNode->end <= start);
|
|
assert(!prevNode || !prevNode->next || prevNode->next->start >= end);
|
|
assert(prevNode || (cliphead && (!cliphead->next || cliphead->next->start >= end)));
|
|
}
|
|
}
|
|
|
|
if (topclip > viewz) topclip = FLT_MAX;
|
|
if (bottomclip < viewz) bottomclip = -FLT_MAX;
|
|
// only insert a new node if it restricts the window.
|
|
if (topclip != FLT_MAX || bottomclip != -FLT_MAX)
|
|
{
|
|
auto mynode = NewRange(start, end, topclip, bottomclip);
|
|
InsertRange(prevNode, mynode);
|
|
}
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
//
|
|
// RemoveClipRange
|
|
//
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void Clipper::RemoveClipRange(int start, int end)
|
|
{
|
|
ClipNode *node, *temp;
|
|
|
|
if (cliphead)
|
|
{
|
|
//check to see if range contains any old ranges
|
|
node = cliphead;
|
|
while (node != nullptr && 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 != nullptr)
|
|
{
|
|
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->topclip, node->bottomclip);
|
|
node->end = start;
|
|
InsertRange(node, temp);
|
|
break;
|
|
}
|
|
node = node->next;
|
|
}
|
|
}
|
|
ValidateList();
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
//
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void Clipper::DumpClipper()
|
|
{
|
|
for (auto node = cliphead; node; node = node->next)
|
|
{
|
|
Printf("Range from %2.3f to %2.3f (top = %2.3f, bottom = %2.3f)\n", bamang(node->start).asdeg(), bamang(node->end).asdeg(), node->topclip, node->bottomclip);
|
|
}
|
|
}
|