qt-everywhere-src-5.14.1/qtdeclarative/src/quick/scenegraph/qsgopengldistancefieldglyphcache_p.h

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#ifndef QSGOPENGLDISTANCEFIELDGLYPHCACHE_H
#define QSGOPENGLDISTANCEFIELDGLYPHCACHE_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "qsgadaptationlayer_p.h"
#include <QtGui/qopenglfunctions.h>
#include <qopenglshaderprogram.h>
#include <qopenglbuffer.h>
#include <qopenglvertexarrayobject.h>
#include <QtGui/private/qopenglengineshadersource_p.h>
#include <private/qsgareaallocator_p.h>

QT_BEGIN_NAMESPACE

class QOpenGLSharedResourceGuard;
#if !defined(QT_OPENGL_ES_2)
class QOpenGLFunctions_3_2_Core;
#endif

class Q_QUICK_PRIVATE_EXPORT QSGOpenGLDistanceFieldGlyphCache : public QSGDistanceFieldGlyphCache
{
public:
    QSGOpenGLDistanceFieldGlyphCache(QOpenGLContext *c, const QRawFont &font);
    virtual ~QSGOpenGLDistanceFieldGlyphCache();

    void requestGlyphs(const QSet<glyph_t> &glyphs) override;
    void storeGlyphs(const QList<QDistanceField> &glyphs) override;
    void referenceGlyphs(const QSet<glyph_t> &glyphs) override;
    void releaseGlyphs(const QSet<glyph_t> &glyphs) override;

    bool useTextureResizeWorkaround() const;
    bool useTextureUploadWorkaround() const;
    bool createFullSizeTextures() const;

    void setMaxTextureCount(int max) { m_maxTextureCount = max; }
    int maxTextureCount() const { return m_maxTextureCount; }

    bool eightBitFormatIsAlphaSwizzled() const override { return !m_coreProfile; }

private:
    bool loadPregeneratedCache(const QRawFont &font);
    inline bool isCoreProfile() const { return m_coreProfile; }

    struct TextureInfo {
        GLuint texture;
        QSize size;
        QRect allocatedArea;
        QDistanceField image;
        int padding = -1;

        TextureInfo(const QRect &preallocRect = QRect(0, 0, 1, 1)) : texture(0), allocatedArea(preallocRect) { }
    };

    void createTexture(TextureInfo * texInfo, int width, int height, const void *pixels);
    void createTexture(TextureInfo * texInfo, int width, int height);
    void resizeTexture(TextureInfo * texInfo, int width, int height);

    TextureInfo *textureInfo(int index)
    {
        Q_ASSERT(m_maxTextureWidth > 0 && m_maxTextureHeight > 0);
        for (int i = m_textures.count(); i <= index; ++i) {
            if (createFullSizeTextures())
                m_textures.append(QRect(0, 0, m_maxTextureWidth, m_maxTextureWidth));
            else
                m_textures.append(TextureInfo());
        }

        return &m_textures[index];
    }

    void createBlitProgram()
    {
        m_blitProgram = new QOpenGLShaderProgram;
        {
            const QString source = QLatin1String(qopenglslMainWithTexCoordsVertexShader)
                                 + QLatin1String(qopenglslUntransformedPositionVertexShader);

            m_blitProgram->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, source);
        }
        {
            const QString source = QLatin1String(qopenglslMainFragmentShader)
                                 + QLatin1String(qopenglslImageSrcFragmentShader);

            m_blitProgram->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, source);
        }
        m_blitProgram->bindAttributeLocation("vertexCoordsArray", QT_VERTEX_COORDS_ATTR);
        m_blitProgram->bindAttributeLocation("textureCoordArray", QT_TEXTURE_COORDS_ATTR);
        m_blitProgram->link();
    }

    int m_maxTextureWidth;
    int m_maxTextureHeight;
    int m_maxTextureCount;
    bool m_coreProfile;

    QList<TextureInfo> m_textures;
    QHash<glyph_t, TextureInfo *> m_glyphsTexture;
    QSet<glyph_t> m_unusedGlyphs;

    QSGAreaAllocator *m_areaAllocator;

    QOpenGLShaderProgram *m_blitProgram;
    QOpenGLBuffer m_blitBuffer;
    QOpenGLVertexArrayObject m_vao;

    QOpenGLSharedResourceGuard *m_fboGuard;
    QOpenGLFunctions *m_funcs;
#if !defined(QT_OPENGL_ES_2)
    QOpenGLFunctions_3_2_Core *m_coreFuncs;
#endif
};

QT_END_NAMESPACE

#endif // QSGOPENGLDISTANCEFIELDGLYPHCACHE_H