opengl_gal.h

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
 * Copyright (C) 2020-2021 KiCad Developers, see AUTHORS.txt for contributors.
 * Copyright (C) 2013-2017 CERN
 * @author Maciej Suminski <maciej.suminski@cern.ch>
 *
 * Graphics Abstraction Layer (GAL) for OpenGL
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#ifndef OPENGLGAL_H_
#define OPENGLGAL_H_

// GAL imports
#include <gal/graphics_abstraction_layer.h>
#include <gal/gal_display_options.h>
#include <gal/opengl/shader.h>
#include <gal/opengl/vertex_manager.h>
#include <gal/opengl/vertex_item.h>
#include <gal/opengl/cached_container.h>
#include <gal/opengl/noncached_container.h>
#include <gal/opengl/opengl_compositor.h>
#include <gal/hidpi_gl_canvas.h>

#include <unordered_map>
#include <boost/smart_ptr/shared_array.hpp>
#include <memory>
#include <wx/event.h>

#ifndef CALLBACK
#define CALLBACK
#endif

struct bitmap_glyph;

namespace KIGFX
{
class SHADER;
class GL_BITMAP_CACHE;

class OPENGL_GAL : public GAL, public HIDPI_GL_CANVAS
{
public:
    OPENGL_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions, wxWindow* aParent,
                wxEvtHandler* aMouseListener = nullptr, wxEvtHandler* aPaintListener = nullptr,
                const wxString& aName = wxT( "GLCanvas" ) );

    ~OPENGL_GAL();

    static wxString CheckFeatures( GAL_DISPLAY_OPTIONS& aOptions );

    bool IsOpenGlEngine() override { return true; }

    bool IsInitialized() const override
    {
        // is*Initialized flags, but it is enough for OpenGL to show up
        return IsShownOnScreen() && !GetClientRect().IsEmpty();
    }

    bool IsVisible() const override
    {
        return IsShownOnScreen() && !GetClientRect().IsEmpty();
    }

    // ---------------
    // Drawing methods
    // ---------------

    void DrawLine( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint ) override;

    void DrawSegment( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint,
                              double aWidth ) override;

    void DrawCircle( const VECTOR2D& aCenterPoint, double aRadius ) override;

    void DrawArc( const VECTOR2D& aCenterPoint, double aRadius,
                          double aStartAngle, double aEndAngle ) override;

    void DrawArcSegment( const VECTOR2D& aCenterPoint, double aRadius,
                                 double aStartAngle, double aEndAngle, double aWidth ) override;

    void DrawRectangle( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint ) override;

    void DrawPolyline( const std::deque<VECTOR2D>& aPointList ) override;
    void DrawPolyline( const VECTOR2D aPointList[], int aListSize ) override;
    void DrawPolyline( const SHAPE_LINE_CHAIN& aLineChain ) override;

    void DrawPolygon( const std::deque<VECTOR2D>& aPointList ) override;
    void DrawPolygon( const VECTOR2D aPointList[], int aListSize ) override;
    void DrawPolygon( const SHAPE_POLY_SET& aPolySet ) override;
    void DrawPolygon( const SHAPE_LINE_CHAIN& aPolySet ) override;

    void DrawCurve( const VECTOR2D& startPoint, const VECTOR2D& controlPointA,
                            const VECTOR2D& controlPointB, const VECTOR2D& endPoint,
                            double aFilterValue = 0.0 ) override;

    void DrawBitmap( const BITMAP_BASE& aBitmap ) override;

    void BitmapText( const wxString& aText, const VECTOR2D& aPosition,
                             double aRotationAngle ) override;

    void DrawGrid() override;

    // --------------
    // Screen methods
    // --------------

    void ResizeScreen( int aWidth, int aHeight ) override;

    bool Show( bool aShow ) override;

    void Flush() override;

    void ClearScreen( ) override;

    // --------------
    // Transformation
    // --------------

    void Transform( const MATRIX3x3D& aTransformation ) override;

    void Rotate( double aAngle ) override;

    void Translate( const VECTOR2D& aTranslation ) override;

    void Scale( const VECTOR2D& aScale ) override;

    void Save() override;

    void Restore() override;

    // --------------------------------------------
    // Group methods
    // ---------------------------------------------

    int BeginGroup() override;

    void EndGroup() override;

    void DrawGroup( int aGroupNumber ) override;

    void ChangeGroupColor( int aGroupNumber, const COLOR4D& aNewColor ) override;

    void ChangeGroupDepth( int aGroupNumber, int aDepth ) override;

    void DeleteGroup( int aGroupNumber ) override;

    void ClearCache() override;

    // --------------------------------------------------------
    // Handling the world <-> screen transformation
    // --------------------------------------------------------

    void SetTarget( RENDER_TARGET aTarget ) override;

    RENDER_TARGET GetTarget() const override;

    void ClearTarget( RENDER_TARGET aTarget ) override;

    virtual bool HasTarget( RENDER_TARGET aTarget ) override;

    void SetNegativeDrawMode( bool aSetting ) override {}

    void ComputeWorldScreenMatrix() override;

    // -------
    // Cursor
    // -------

    bool SetNativeCursorStyle( KICURSOR aCursor ) override;

    void DrawCursor( const VECTOR2D& aCursorPosition ) override;

    void PostPaint( wxPaintEvent& aEvent );

    void SetMouseListener( wxEvtHandler* aMouseListener )
    {
        m_mouseListener = aMouseListener;
    }

    void SetPaintListener( wxEvtHandler* aPaintListener )
    {
        m_paintListener = aPaintListener;
    }

    void EnableDepthTest( bool aEnabled = false ) override;

    bool IsContextLocked() override
    {
        return m_isContextLocked;
    }

    typedef struct
    {
        VERTEX_MANAGER* vboManager;

        std::deque< boost::shared_array<GLdouble> >& intersectPoints;
    } TessParams;

private:
    typedef GAL super;

    static const int    CIRCLE_POINTS   = 64;   
    static const int    CURVE_POINTS    = 32;   

    static wxGLContext*     m_glMainContext;    
    wxGLContext*            m_glPrivContext;    
    static int              m_instanceCounter;  
    wxEvtHandler*           m_mouseListener;
    wxEvtHandler*           m_paintListener;

    static GLuint           g_fontTexture;      

    // Vertex buffer objects related fields
    typedef std::unordered_map< unsigned int, std::shared_ptr<VERTEX_ITEM> > GROUPS_MAP;

    GROUPS_MAP              m_groups;           
    unsigned int            m_groupCounter;     
    VERTEX_MANAGER*         m_currentManager;   
    VERTEX_MANAGER*         m_cachedManager;    
    VERTEX_MANAGER*         m_nonCachedManager; 
    VERTEX_MANAGER*         m_overlayManager;   

    // Framebuffer & compositing
    OPENGL_COMPOSITOR*      m_compositor;       
    unsigned int            m_mainBuffer;       
    unsigned int            m_overlayBuffer;    
    RENDER_TARGET           m_currentTarget;    

    // Shader
    SHADER*                 m_shader;           

    // Internal flags
    bool                    m_isFramebufferInitialized; 
    static bool             m_isBitmapFontLoaded;       
    bool                    m_isBitmapFontInitialized;  
    bool                    m_isInitialized;            
    bool                    m_isGrouping;               
    bool                    m_isContextLocked;          
    int                     m_lockClientCookie;
    GLint                   ufm_worldPixelSize;
    GLint                   ufm_screenPixelSize;
    GLint                   ufm_pixelSizeMultiplier;

    wxCursor                m_currentwxCursor;          

    std::unique_ptr<GL_BITMAP_CACHE>            m_bitmapCache;

    // Polygon tesselation
    GLUtesselator*                              m_tesselator;
    std::deque< boost::shared_array<GLdouble> > m_tessIntersects;

    void lockContext( int aClientCookie ) override;

    void unlockContext( int aClientCookie ) override;

    void beginUpdate() override;

    void endUpdate() override;

    void beginDrawing() override;

    void endDrawing() override;

    bool updatedGalDisplayOptions( const GAL_DISPLAY_OPTIONS& aOptions ) override;

    void drawLineQuad( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint );

    void drawSemiCircle( const VECTOR2D& aCenterPoint, double aRadius, double aAngle );

    void drawFilledSemiCircle( const VECTOR2D& aCenterPoint, double aRadius, double aAngle );

    void drawStrokedSemiCircle( const VECTOR2D& aCenterPoint, double aRadius, double aAngle );

    void drawPolyline( const std::function<VECTOR2D (int)>& aPointGetter, int aPointCount );

    void drawPolygon( GLdouble* aPoints, int aPointCount );

    void drawTriangulatedPolyset( const SHAPE_POLY_SET& aPoly );


    int drawBitmapChar( unsigned long aChar );

    void drawBitmapOverbar( double aLength, double aHeight );

    std::pair<VECTOR2D, float> computeBitmapTextSize( const UTF8& aText ) const;

    // Event handling
    void onPaint( wxPaintEvent& aEvent );

    void skipMouseEvent( wxMouseEvent& aEvent );

    void onSetNativeCursor( wxSetCursorEvent& aEvent );

    void blitCursor();

    unsigned int getNewGroupNumber();

    double calcAngleStep( double aRadius ) const
    {
        // Bigger arcs need smaller alpha increment to make them look smooth
        return std::min( 1e6 / aRadius, 2.0 * M_PI / CIRCLE_POINTS );
    }

    double getWorldPixelSize() const;

    VECTOR2D getScreenPixelSize() const;

    void init();
};
} // namespace KIGFX

#endif  // OPENGLGAL_H_