/* * ** 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 "hw_clipper.h" #include "basics.h" #include "build.h" #include "printf.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 != nullptr) { temp = node; node = node->next; Free(temp); } node = silhouette; while (node != nullptr) { temp = node; node = node->next; Free(temp); } cliphead = nullptr; silhouette = nullptr; starttime++; } //----------------------------------------------------------------------------- // // SetSilhouette // //----------------------------------------------------------------------------- void Clipper::SetSilhouette() { ClipNode *node = cliphead; ClipNode *last = nullptr; while (node != nullptr) { ClipNode *snode = NewRange(node->start, node->end); if (silhouette == nullptr) silhouette = snode; snode->prev = last; if (last != nullptr) last->next = snode; last = snode; node = node->next; } } //----------------------------------------------------------------------------- // // IsRangeVisible // //----------------------------------------------------------------------------- bool Clipper::IsRangeVisible(binangle startAngle, binangle endAngle) { ClipNode *ci; ci = cliphead; if (endAngle.asbam()==0 && ci && ci->start==0) return false; while (ci != nullptr && ci->start < endAngle.asbam()) { if (startAngle.asbam() >= ci->start && endAngle.asbam() <= ci->end) { return false; } ci = ci->next; } return true; } //----------------------------------------------------------------------------- // // AddClipRange // //----------------------------------------------------------------------------- void Clipper::AddClipRange(binangle start_, binangle end_) { auto start = start_.asbam(), end = end_.asbam(); ClipNode *node, *temp, *prevNode; 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 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 != nullptr && 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 = nullptr; temp = NewRange(start, end); while (node != nullptr && node->start < end) { prevNode = node; node = node->next; } temp->next = node; if (node == nullptr) { 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(binangle start_, binangle end_) { auto start = start_.asbam(), end = end_.asbam(); ClipNode *node; if (silhouette) { node = silhouette; while (node != nullptr && node->end <= start) { node = node->next; } if (node != nullptr && node->start <= start) { if (node->end >= end) return; start = node->end; node = node->next; } while (node != nullptr && 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 != 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->end=start; temp->next=node->next; temp->prev=node; node->next=temp; if (temp->next) temp->next->prev=temp; break; } node = node->next; } } } //----------------------------------------------------------------------------- // // ! 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. // //----------------------------------------------------------------------------- binangle Clipper::PointToAngle(const vec2_t& pos) { vec2_t vec = pos - viewpoint; #if 0 if (vec.x == 0 && vec.y == 0) { return 0; } else { double result = vec.y / double(abs(vec.x) + fabs(vec.y)); if (vec.x < 0) { result = 2. - result; } return bamang(xs_Fix<30>::ToFix(result)); } #else return q16ang(gethiq16angle(vec.x, vec.y)); #endif } void Clipper::DumpClipper() { for (auto node = cliphead; node; node = node->next) { Printf("Range from %f to %f\n", bamang(node->start).asdeg(), bamang(node->end).asdeg()); } }