File indexing completed on 2024-04-21 03:49:34

 // SPDX-License-Identifier: LGPL-2.1-or-later
 //
 // SPDX-FileCopyrightText: 2007 Carlos Licea <carlos _licea@hotmail.com>
 // SPDX-FileCopyrightText: 2008 Inge Wallin <inge@lysator.liu.se>
 // SPDX-FileCopyrightText: 2011 Bernhard Beschow <bbeschow@cs.tu-berlin.de>
 //
 
 
 // local
 #include "GenericScanlineTextureMapper.h"
 
 // Qt
 #include <qmath.h>
 #include <QRunnable>
 
 // Marble
 #include "GeoPainter.h"
 #include "MarbleDirs.h"
 #include "MarbleDebug.h"
 #include "ScanlineTextureMapperContext.h"
 #include "StackedTileLoader.h"
 #include "TextureColorizer.h"
 #include "ViewParams.h"
 #include "ViewportParams.h"
 #include "MathHelper.h"
 #include "AbstractProjection.h"
 
 using namespace Marble;
 
 class GenericScanlineTextureMapper::RenderJob : public QRunnable
 {
 public:
     RenderJob( StackedTileLoader *tileLoader, int tileLevel, QImage *canvasImage, const ViewportParams *viewport, MapQuality mapQuality, int yTop, int yBottom );
 
     void run() override;
 
 private:
     StackedTileLoader *const m_tileLoader;
     const int m_tileLevel;
     QImage *const m_canvasImage;
     const ViewportParams *const m_viewport;
     const MapQuality m_mapQuality;
     const int m_yTop;
     const int m_yBottom;
 };
 
 GenericScanlineTextureMapper::RenderJob::RenderJob( StackedTileLoader *tileLoader, int tileLevel, QImage *canvasImage, const ViewportParams *viewport, MapQuality mapQuality, int yTop, int yBottom )
     : m_tileLoader( tileLoader ),
       m_tileLevel( tileLevel ),
       m_canvasImage( canvasImage ),
       m_viewport( viewport ),
       m_mapQuality( mapQuality ),
       m_yTop( yTop ),
       m_yBottom( yBottom )
 {
 }
 
 
 GenericScanlineTextureMapper::GenericScanlineTextureMapper( StackedTileLoader *tileLoader )
     : TextureMapperInterface()
     , m_tileLoader( tileLoader )
     , m_radius( 0 )
     , m_threadPool()
 {
 }
 
 void GenericScanlineTextureMapper::mapTexture( GeoPainter *painter,
                                                 const ViewportParams *viewport,
                                                 int tileZoomLevel,
                                                 const QRect &dirtyRect,
                                                 TextureColorizer *texColorizer )
 {
     if ( m_canvasImage.size() != viewport->size() || m_radius != viewport->radius() ) {
         const QImage::Format optimalFormat = ScanlineTextureMapperContext::optimalCanvasImageFormat( viewport );
 
         if ( m_canvasImage.size() != viewport->size() || m_canvasImage.format() != optimalFormat ) {
             m_canvasImage = QImage( viewport->size(), optimalFormat );
         }
 
         if ( !viewport->mapCoversViewport() ) {
             m_canvasImage.fill( 0 );
         }
 
         m_radius = viewport->radius();
         m_repaintNeeded = true;
     }
 
     if ( m_repaintNeeded ) {
         mapTexture( viewport, tileZoomLevel, painter->mapQuality() );
 
         if ( texColorizer ) {
             texColorizer->colorize( &m_canvasImage, viewport, painter->mapQuality() );
         }
 
         m_repaintNeeded = false;
     }
 
     const int radius = viewport->radius() * viewport->currentProjection()->clippingRadius();
 
     QRect rect( viewport->width() / 2 - radius, viewport->height() / 2 - radius,
                 2 * radius, 2 * radius);
     rect = rect.intersected( dirtyRect );
     painter->drawImage( rect, m_canvasImage, rect );
 }
 
 void GenericScanlineTextureMapper::mapTexture( const ViewportParams *viewport, int tileZoomLevel, MapQuality mapQuality )
 {
     // Reset backend
     m_tileLoader->resetTilehash();
 
     const int imageHeight = viewport->height();
     const qint64  radius      = viewport->radius() * viewport->currentProjection()->clippingRadius();
 
     // Calculate the actual y-range of the map on the screen
     const int skip = ( mapQuality == LowQuality ) ? 1
                                                   : 0;
     const int yTop = ( imageHeight / 2 - radius >= 0 ) ? imageHeight / 2 - radius
                                                        : 0;
     const int yBottom = ( yTop == 0 ) ? imageHeight - skip
                                       : yTop + radius + radius - skip;
 
     const int numThreads = m_threadPool.maxThreadCount();
     const int yStep = qCeil(qreal( yBottom - yTop ) / qreal(numThreads));
     for ( int i = 0; i < numThreads; ++i ) {
         const int yStart = yTop +  i      * yStep;
         const int yEnd   = qMin(yBottom, yTop + (i + 1) * yStep);
         QRunnable *const job = new RenderJob( m_tileLoader, tileZoomLevel, &m_canvasImage, viewport, mapQuality, yStart, yEnd );
         m_threadPool.start( job );
     }
 
     m_threadPool.waitForDone();
 
     m_tileLoader->cleanupTilehash();
 }
 
 void GenericScanlineTextureMapper::RenderJob::run()
 {
     const int imageWidth  = m_canvasImage->width();
     const int imageHeight  = m_canvasImage->height();
     const qint64  radius  = m_viewport->radius();
 
     const bool interlaced   = ( m_mapQuality == LowQuality );
     const bool highQuality  = ( m_mapQuality == HighQuality
                              || m_mapQuality == PrintQuality );
     const bool printQuality = ( m_mapQuality == PrintQuality );
 
     // Evaluate the degree of interpolation
     const int n = ScanlineTextureMapperContext::interpolationStep( m_viewport, m_mapQuality );
 
     // Calculate north pole position to decrease pole distortion later on
     qreal northPoleX, northPoleY;
     bool globeHidesNorthPole;
     GeoDataCoordinates northPole(0, m_viewport->currentProjection()->maxLat(), 0);
     m_viewport->screenCoordinates(northPole, northPoleX, northPoleY, globeHidesNorthPole );
 
     // initialize needed variables that are modified during texture mapping:
 
     ScanlineTextureMapperContext context( m_tileLoader, m_tileLevel );
 
     qreal clipRadius = radius * m_viewport->currentProjection()->clippingRadius();
 
 
     // Paint the map.
     for ( int y = m_yTop; y < m_yBottom; ++y ) {
 
         // rx is the radius component in x direction
         const int rx = (int)sqrt( (qreal)( clipRadius * clipRadius
                                       - ( ( y - imageHeight / 2 )
                                           * ( y - imageHeight / 2 ) ) ) );
 
         // Calculate the actual x-range of the map within the current scanline.
         //
         // If the circular border of the earth disk is still visible then xLeft
         // equals the scanline position of the most left pixel that gets covered
         // by the earth disk. In terms of math this equals the half image width minus
         // the radius component on the current scanline in x direction ("rx").
         //
         // If the zoom factor is high enough then the whole screen gets covered
         // by the earth and the border of the earth disk isn't visible anymore.
         // In that situation xLeft equals zero.
         // For xRight the situation is similar.
 
         const int xLeft  = ( imageWidth / 2 - rx > 0 ) ? imageWidth / 2 - rx
                                                        : 0;
         const int xRight = ( imageWidth / 2 - rx > 0 ) ? xLeft + rx + rx
                                                        : imageWidth;
 
         QRgb * scanLine = (QRgb*)( m_canvasImage->scanLine( y ) ) + xLeft;
 
         const int xIpLeft  = ( imageWidth / 2 - rx > 0 ) ? n * (int)( xLeft / n + 1 )
                                                          : 1;
         const int xIpRight = ( imageWidth / 2 - rx > 0 ) ? n * (int)( xRight / n - 1 )
                                                          : n * (int)( xRight / n - 1 ) + 1;
 
         // Decrease pole distortion due to linear approximation ( y-axis )
         bool crossingPoleArea = false;
         if ( !globeHidesNorthPole
              && northPoleY - ( n * 0.75 ) <= y
              && northPoleY + ( n * 0.75 ) >= y )
         {
             crossingPoleArea = true;
         }
 
         int ncount = 0;
 
 
         for ( int x = xLeft; x < xRight; ++x ) {
 
             // Prepare for interpolation
             const int leftInterval = xIpLeft + ncount * n;
 
             bool interpolate = false;
 
             if ( x >= xIpLeft && x <= xIpRight ) {
 
                 // Decrease pole distortion due to linear approximation ( x-axis )
                 if ( crossingPoleArea
                      && northPoleX >= leftInterval + n
                      && northPoleX < leftInterval + 2 * n
                      && x < leftInterval + 3 * n )
                 {
                     interpolate = false;
                 }
                 else {
                     x += n - 1;
                     interpolate = !printQuality;
                     ++ncount;
                 }
             }
             else
                 interpolate = false;
 
             qreal lon;
             qreal lat;
             m_viewport->geoCoordinates(x,y, lon, lat, GeoDataCoordinates::Radian);
 
             if ( interpolate ) {
                 if ( highQuality )
                     context.pixelValueApproxF( lon, lat, scanLine, n );
                 else
                     context.pixelValueApprox( lon, lat, scanLine, n );
 
                 scanLine += ( n - 1 );
             }
 
             if ( x < imageWidth ) {
                 if ( highQuality )
                     context.pixelValueF( lon, lat, scanLine );
                 else
                     context.pixelValue( lon, lat, scanLine );
             }
 
             ++scanLine;
         }
 
         // copy scanline to improve performance
         if ( interlaced && y + 1 < m_yBottom ) {
 
             const int pixelByteSize = m_canvasImage->bytesPerLine() / imageWidth;
 
             memcpy( m_canvasImage->scanLine( y + 1 ) + xLeft * pixelByteSize,
                     m_canvasImage->scanLine( y     ) + xLeft * pixelByteSize,
                     ( xRight - xLeft ) * pixelByteSize );
             ++y;
         }
     }
 }