Update procedures

[shapes.git] / source / zsorterto2D.cc

/* This file is part of Shapes.
 *
 * Shapes is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * Shapes is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Shapes.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2008, 2010 Henrik Tidefelt
 */

#include <cmath>

#include "shapestypes.h"
#include "shapesexceptions.h"
#include "astexpr.h"
#include "consts.h"
#include "angleselect.h"
#include "astvar.h"
#include "astclass.h"
#include "statetypes.h"
#include "lighttypes.h"
#include "shadingtypes.h"
#include "globals.h"
#include "zbufinternals.h"
#include "constructorrepresentation.h"
#include "warn.h"

#include <ctype.h>
#include <list>
#include <algorithm>

using namespace Shapes;

namespace Shapes
{
        namespace Computation
        {

                struct SplitJob
                {
                        // This is not the most natural place to define CompoundObject, but since we need it...
                        typedef std::list< Computation::ZBufTriangle > CompoundObject;

                        CompoundObject::iterator splitted_;
                        std::vector< CompoundObject * >::iterator splittingObject_;
                        CompoundObject::iterator splitting_;

                        SplitJob( const CompoundObject::iterator & splitted, const std::vector< CompoundObject * >::iterator & splittingObject, const CompoundObject::iterator & splitting )
                                : splitted_( splitted ), splittingObject_( splittingObject ), splitting_( splitting )
                        { }
                };
        }
}


RefCountPtr< const Lang::Drawable2D >
Lang::ZSorter::typed_to2D( const Kernel::PassedDyn & dyn, const Lang::Transform3D & tf, const RefCountPtr< const Lang::Drawable3D > & self ) const
{
        Concrete::Length eyez = dyn->getEyeZ( );

        std::list< RefCountPtr< const Lang::LightSource > > commonLights;
        std::list< RefCountPtr< const Lang::LightSource > > allShadowLights;

        {
                typedef typeof *lightPile_ PileType;
                for( PileType::const_iterator src = lightPile_->begin( ); src != lightPile_->end( ); ++src )
                        {
                                if( (*src)->shadows( ) )
                                        {
                                                allShadowLights.push_back( (*src)->typed_transformed( tf ) );
                                        }
                                else
                                        {
                                                commonLights.push_back( (*src)->typed_transformed( tf ) );
                                        }
                        }
        }

        if( ! allShadowLights.empty( ) )
                {
                        throw Exceptions::MiscellaneousRequirement( "Shadow lights cannot be used in a z-sorter." );
                }

        // There is one queue per original object.      This structure will be where all the
        // triangles resides at the beginning of the treatment of each shadow light or the
        // view occlusion computation.
        //
        // We begin by initializing these queues.
        typedef Computation::SplitJob::CompoundObject CompoundObject;   // It is a bit unnatural to define the type somewhere but here...

        const size_t pileSize = pile_->size( );
        size_t triangleCount = 0;

        // Now the main storage for triangles is set up
        typedef PtrOwner_back_Access< std::vector< CompoundObject * > > CompoundMemType;
        CompoundMemType compoundMem;
        compoundMem.reserve( pileSize );

        // Then we fill it with triangles that don't intersect.
        // Note that it is a responsibility of push_zBufTriangles to not push any tiny triangles.
        {
                Computation::SplicingLine spliceLine;
                std::list< Computation::SplitJob > job;
                typedef typeof *pile_ PileType;
                for( PileType::const_iterator src = pile_->begin( ); src != pile_->end( ); ++src )
                        {
                                std::list< Computation::ZBufTriangle > * tmpList = new std::list< Computation::ZBufTriangle >;
                                // Since there cannot be shadow lights in a z sorter, it is OK not to include the backsides of single sided facets.
                                (*src)->push_zBufTriangles( tf, eyez, tmpList, true ); // true means allow dropping back sides of single sided objects
                                for( CompoundObject::iterator i = tmpList->begin( ); i != tmpList->end( ); ++i )
                                        {
                                                typedef std::vector< CompoundObject * >::iterator ObjectIterator;
                                                for( ObjectIterator o = compoundMem.begin( ); o != compoundMem.end( ); ++o )
                                                        {
                                                                for( CompoundObject::iterator j = (*o)->begin( ); j != (*o)->end( ); ++j )
                                                                        {
                                                                                if( j->intersection( *i, & spliceLine ) &&
                                                                                                j->overlapsAlong( *i, spliceLine, Computation::theTrixelizeOverlapTol ) )
                                                                                        {
                                                                                                job.push_back( Computation::SplitJob( i, o, j ) );
                                                                                                goto splitFound1;
                                                                                        }
                                                                        }
                                                        }
                                        splitFound1:
                                                continue; // this is just a no-op to make this a valid jump destination
                                        }
                                while( ! job.empty( ) )
                                        {
                                                Computation::SplitJob & currentJob = job.front( );
                                                if( ! currentJob.splitted_->intersection( *currentJob.splitting_, & spliceLine ) )
                                                        {
                                                                throw Exceptions::InternalError( "These triangles were known to intsersect, and now they're parallel!" );
                                                        }

                                                // New triangles are added to the end of tmpList, and the iterator to the first new triangle is returned.
                                                CompoundObject::iterator i = currentJob.splitted_->spliceAlong( spliceLine, tmpList );

                                                // Now the procedure from above is repeated, but not comparing against triangles that have already been checked.
                                                for( ; i != tmpList->end( ); ++i )
                                                        {
                                                                CompoundObject::iterator j = currentJob.splitting_;
                                                                ++j;
                                                                typedef std::vector< CompoundObject * >::iterator ObjectIterator;
                                                                for( ObjectIterator o = currentJob.splittingObject_; o != compoundMem.end( ); ++o )
                                                                        {
                                                                                // For the splitting object object (the first in this loop), the first triangle to compare against
                                                                                // was set above.       For the other object, all triangles shall be compared against (that is, j starts from
                                                                                // the beginning).
                                                                                if( o != currentJob.splittingObject_ )
                                                                                        {
                                                                                                j = (*o)->begin( );
                                                                                        }
                                                                                for( ; j != (*o)->end( ); ++j )
                                                                                        {
                                                                                                if( j->intersection( *i, & spliceLine ) &&
                                                                                                                j->overlapsAlong( *i, spliceLine, Computation::theTrixelizeOverlapTol ) )
                                                                                                        {
                                                                                                                job.push_back( Computation::SplitJob( i, o, j ) );
                                                                                                                goto splitFound2;
                                                                                                        }
                                                                                        }
                                                                        }
                                                        splitFound2:
                                                                continue; // this is just a no-op to make this a valid jump destination
                                                        }

                                                tmpList->erase( currentJob.splitted_ );
                                                job.pop_front( );
                                        }
                                compoundMem.push_back( tmpList );
                                triangleCount += tmpList->size( );
                        }
        }


        // In order to be able to deal with the triangles efficiently from here on, I put them all in a long vector.
        // This has one drawback, though, being that we will lose track of the fact that triangles belonging to the same
        // facet does not have to be checked for depth order.   However, I count on them not being ordered thanks to the
        // tolerance used in the overlap test.
        std::vector< const Computation::ZBufTriangle * > triangleMem;
        triangleMem.reserve( triangleCount );
        for( std::vector< CompoundObject * >::iterator o = compoundMem.begin( ); o != compoundMem.end( ); ++o )
                {
                        for( CompoundObject::iterator j = (*o)->begin( ); j != (*o)->end( ); ++j )
                                {
                                        triangleMem.push_back( & *j );
                                }
                }
        if( triangleMem.size( ) != triangleCount )
                {
                        throw Exceptions::InternalError( "Some triangles are missing!" );
                }


        // I keep track of which objects an object has to be drawn after.       The objects that are not
        // waiting for other objects to be drawn are kept in a special list.
        // To do this efficiently, each object need to know how many objects it is waiting for to be
        // drawn.       It must also know what objects to update when it has been drawn.        An object is identified
        // by the pointer to its list, so the additional information must be kept in a separate structure.
        // As usual, objects are identified by their position in a memory vector.
        // At this state, "to draw" an object means to place it in drawOrder.

        std::list< const Computation::ZBufTriangle * > drawOrder;
        if( triangleCount > 0 ) // This avoids a bug that would otherwise occur due to computing triangleCount - 1
                {
                        std::vector< size_t > waitCounters;
                        waitCounters.resize( triangleCount, 0 );
                        std::vector< std::list< size_t > > waitingObjects;
                        waitingObjects.resize( triangleCount );

                        // We begin by setting up waitingObjects and waitCounters.
                        // This involves testing each object against all other objects.
                        for( size_t i0 = 0; i0 < triangleCount - 1; ++i0 )      // Ugly bug if triangleCount == 0
                                {
                                        const Computation::ZBufTriangle * t0 = triangleMem[ i0 ];
                                        for( size_t i1 = i0 + 1; i1 < triangleCount; ++i1 )
                                                {
                                                        const Computation::ZBufTriangle * t1 = triangleMem[ i1 ];
                                                        if( t0->overlaps( *t1 ) )
                                                                {
                                                                        Concrete::Coords2D commonPoint( 0, 0 );
                                                                        if( ! t0->overlaps( *t1, & commonPoint, Computation::theTrixelizeOverlapTol ) )
                                                                                {
                                                                                        // Too little overlap.
                                                                                        continue;
                                                                                }
                                                                        if( t0->isOnTopOfAt( *t1, commonPoint ) )
                                                                                {
                                                                                        waitingObjects[ i1 ].push_back( i0 );
                                                                                        ++waitCounters[ i0 ];
                                                                                }
                                                                        else
                                                                                {
                                                                                        waitingObjects[ i0 ].push_back( i1 );
                                                                                        ++waitCounters[ i1 ];
                                                                                }
                                                                }
                                                }
                                }

                        // Then the queue of objects to be "drawn" is initialized.
                        std::list< size_t > drawQueue;
                        std::map< const Computation::PaintedPolygon3D *, size_t > trianglesInPolygon;
                        {
                                std::vector< size_t >::iterator wi = waitCounters.begin( );
                                for( size_t i = 0; i < triangleCount; ++i, ++wi )
                                        {
                                                if( *wi == 0 )
                                                        {
                                                                drawQueue.push_back( i );
                                                                ++trianglesInPolygon[ triangleMem[ i ]->painter_ ];
                                                        }
                                        }
                        }

                        // Now, when the triangles are "drawn", that is, placed in drawOrder, they shall be placed so
                        // in such a way that triangles that belong to the same polygon appear in sequence as often as possible.
                        // While there is probably accurate ways to treat this problem, I resort to some simple heuristics here.
                        // The question is basically how to pick a polygon among those than contain a triangle that may be drawn.

                        size_t drawnCount = 0;
                        while( drawnCount < triangleCount )
                                {
                                        while( ! drawQueue.empty( ) )
                                                {
                                                        // First, use find the polygon whith the most triangles in drawQueue.
                                                        const Computation::PaintedPolygon3D * painter = 0;

                                                        // Note that triangles that belong to the same polygon will never overlap, and hence drawing triangles that belong
                                                        // to painter will not make other triangles that belong to painter ready to be drawn.   This algorithm depends on
                                                        // this!

                                                        size_t bestCount = 0;
                                                        {
                                                                typedef typeof trianglesInPolygon MapType;
                                                                MapType::iterator best_j;
                                                                for( MapType::iterator j = trianglesInPolygon.begin( ); j != trianglesInPolygon.end( ); ++j )
                                                                        {
                                                                                if( j->second > bestCount )
                                                                                        {
                                                                                                bestCount = j->second;
                                                                                                best_j = j;
                                                                                        }
                                                                        }
                                                                painter = best_j->first;
                                                                trianglesInPolygon.erase( best_j ); // If we need this again it will be re-created.
                                                        }

                                                        // Soon, bestCount triangles will have been drawn, but the value of bestCount will then be destroyed.
                                                        drawnCount += bestCount;

                                                        // There shall be bestCount triangles to draw, so by counting the number of triangles we find we may not
                                                        // have to search all of drawQueue.
                                                        for( std::list< size_t >::iterator ii = drawQueue.begin( ); bestCount > 0; )
                                                                {
                                                                        size_t i = *ii;
                                                                        if( triangleMem[ i ]->painter_ != painter )
                                                                                {
                                                                                        ++ii;
                                                                                        continue;
                                                                                }

                                                                        std::list< size_t >::iterator erase_i = ii;
                                                                        ++ii;
                                                                        drawQueue.erase( erase_i );
                                                                        --bestCount;

                                                                        drawOrder.push_back( triangleMem[ i ] );
                                                                        triangleMem[ i ] = 0;

                                                                        const std::list< size_t > & waitList = waitingObjects[ i ];
                                                                        for( std::list< size_t >::const_iterator j = waitList.begin( ); j != waitList.end( ); ++j )
                                                                                {
                                                                                        --waitCounters[ *j ];
                                                                                        if( waitCounters[ *j ] == 0 )
                                                                                                {
                                                                                                        drawQueue.push_back( *j );
                                                                                                        // Note that it is assumed that ( triangleMem[ *j ]->painter_ != painter ) !
//                                                                                                       if( triangleMem[ *j ]->painter_ == painter )
//                                                                                                               {
//                                                                                                                       throw Exceptions::InternalError( "Triangle waiting for another triangle in the same polygon!" );
//                                                                                                               }
                                                                                                        ++trianglesInPolygon[ triangleMem[ *j ]->painter_ ];
                                                                                                }
                                                                                }

                                                                }

                                                }
                                        if( drawnCount < triangleCount )
                                                {
                                                        // Resolve cyclic overlap the hard way...
                                                        WARN_OR_THROW( Exceptions::MiscellaneousRequirement( "Cyclic overlaps are not allowed in a z sorter; a small triangle had to be drawn too deep." ) )
                                                        Concrete::Area bestArea = HUGE_VAL;
                                                        size_t besti = 0;
                                                        // This search is a somewhat expensive since we must search the whole list.
                                                        typedef typeof triangleMem ListType;
                                                        ListType::iterator ti = triangleMem.begin( );
                                                        for( size_t i = 0; i < triangleCount; ++i, ++ti )
                                                                {
                                                                        if( *ti == 0 )
                                                                                {
                                                                                        continue;
                                                                                }
                                                                        Concrete::Area tmpArea = (*ti)->area( );
                                                                        if( tmpArea < bestArea )
                                                                                {
                                                                                        bestArea = tmpArea;
                                                                                        besti = i;
                                                                                }
                                                                }
                                                        drawQueue.push_back( besti );
                                                        ++trianglesInPolygon[ triangleMem[ besti ]->painter_ ];
                                                        waitCounters[ besti ] = 0;      // This will avoid that this is drawn again, since the counter will never _reach_ 0 now.
                                                }
                                }
                }


        // It is now time to take care of the lines.
        // The first thing we shall do is to remove what is occluded by triangles.
        // Note that triangles will be drawn before the lines, and that is the only way lines
        // can occlude triangles.
        // Then, we make sure that the lines are drawn in back-to-front order, clipping occluded lines
        // behind the line occluding them to avoid cyclic locking.

        std::list< const Computation::ZBufLine * > lineQueue;
        {
                typedef typeof *linePile_ PileType;
                for( PileType::const_iterator src = linePile_->begin( ); src != linePile_->end( ); ++src )
                        {
                                (*src)->push_zBufLine( tf, eyez, & lineQueue );
                        }
        }

        std::list< const Computation::ZBufLine * > disjointLines;
        while( ! lineQueue.empty( ) )
                {

                        std::list< const Computation::ZBufLine * > queue1;
                        std::list< const Computation::ZBufLine * > queue2;

                        std::list< const Computation::ZBufLine * > * currentQueue = & queue1;
                        std::list< const Computation::ZBufLine * > * otherQueue = & queue2;

                        currentQueue->push_back( lineQueue.front( ) );
                        lineQueue.pop_front( );

                        typedef typeof drawOrder ListType;
                        for( ListType::const_iterator i = drawOrder.begin( ); i != drawOrder.end( ); ++i )
                                {
                                        while( ! currentQueue->empty( ) )
                                                {
                                                        const Computation::ZBufLine * currentLine = currentQueue->front( );
                                                        currentQueue->pop_front( );
                                                        if( currentLine->overlaps( **i ) )
                                                                {
                                                                        currentLine->splice( **i, otherQueue );
                                                                        delete currentLine;
                                                                }
                                                        else
                                                                {
                                                                        otherQueue->push_back( currentLine );
                                                                }
                                                }

                                        {
                                                // swap the queues
                                                std::list< const Computation::ZBufLine * > * tmp = currentQueue;
                                                currentQueue = otherQueue;
                                                otherQueue = tmp;
                                        }
                                }

                        // When we reach here the line segments are in currentQueue.
                        // These segments are ready to be inserted in the line z buffer.

                        // The algorithm below is inefficient, because it will generally make the overlap comparison
                        // several times for any overlaping pair of line segments.
                        while( ! currentQueue->empty( ) )
                                {
                                        const Computation::ZBufLine * current = currentQueue->front( );
                                        currentQueue->pop_front( );

                                        bool foundOverlap = false;
                                        typedef typeof disjointLines ListType;
                                        for( ListType::iterator i = disjointLines.begin( ); i != disjointLines.end( );
                                                         ++i )
                                                {
                                                        if( current->overlaps( **i ) )
                                                                {
                                                                        const Computation::ZBufLine * line = *i;
                                                                        disjointLines.erase( i );
                                                                        // Note that splice is responsible for deleting that of *i and current which is not used.
                                                                        Computation::ZBufLine::splice( line, current,
                                                                                                                                                                                                 & disjointLines,
                                                                                                                                                                                                 currentQueue );
                                                                        foundOverlap = true;
                                                                        break;
                                                                }
                                                }
                                        if( ! foundOverlap )
                                                {
                                                        disjointLines.push_back( current );
                                                }
                                }
                }


        RefCountPtr< const Lang::Group2D > res = Lang::THE_NULL2D;

        const bool SHOW_TRIXELS = false;
        if( SHOW_TRIXELS )
                {
                        // This is a debug mode

                        typedef typeof drawOrder ListType;
                        for( ListType::const_iterator i = drawOrder.begin( ); i != drawOrder.end( ); ++i )
                                {
                                        res = RefCountPtr< const Lang::Group2D >( new Lang::GroupPair2D( (*i)->debugFrame( ),
                                                                                                                                                                                                                                                                                                         res,
                                                                                                                                                                                                                                                                                                         metaState_ ) );
                                }
                }
        else
                {
                        // This is the standard mode

                        // Remember that the grouping of triangles into polygons can probably be improved!

                        typedef typeof drawOrder ListType;
                        for( ListType::iterator i = drawOrder.begin( ); i != drawOrder.end( ); ) // Note that i shall not be incremented here.
                                {
                                        const Computation::PaintedPolygon3D * painter = (*i)->painter_;
                                        if( painter->getColor( ) == Lang::THE_OCCLUDING_WHITE )
                                                {
                                                        ++i;
                                                        continue;
                                                }

                                        std::list< Computation::ZBufTriangle > regions;
                                        // This is a hideous copy!
                                        regions.push_back( **i );

                                        // Now we'll simply join the triangle **i with the immediately following triangles sharing the same painter.
                                        // The job of joining triangles thus consists in placing them in a good order in drawOrder.

                                        ++i;
                                        for( ; i != drawOrder.end( ) && (*i)->painter_ == painter; ++i )
                                                {
                                                        // Another hideous copy!
                                                        regions.push_back( **i );
                                                }

                                        // If this would have been a z-buffer, we should add the common lights to the shadow lights here,
                                        // but in a z-sorter there are no shadow lights.
                                        RefCountPtr< const Lang::PaintedPolygon2D > tmp = painter->polygon_to2D( dyn, tf, commonLights );

                                        // The following statement will consume the objects in regions.
                                        res = RefCountPtr< const Lang::Group2D >( new Lang::GroupPair2D( tmp->clip( & regions, tmp ),
                                                                                                                                                                                                                                                                                                         res,
                                                                                                                                                                                                                                                                                                         metaState_ ) );
                                }
                }


        // Memory cleanup of the triangles should be taken care of by compoundMem.


        // Finally we draw the lines.
        while( ! disjointLines.empty( ) )
                {
                        const Computation::ZBufLine * current = disjointLines.front( );
                        disjointLines.pop_front( );
                        res = RefCountPtr< const Lang::Group2D >( new Lang::GroupPair2D( current->stroke2D( ),
                                                                                                                                                                                                                                                                                         res,
                                                                                                                                                                                                                                                                                         metaState_ ) );
                        delete current;
                }


        return res;
}