qpaintengine_opengl.cpp

奇趣公司比较新的qt/emd版本

    QSize sz(d->drawable.size());
    glViewport(0, 0, sz.width(), sz.height()); // XXX (Embedded): We need a solution for GLWidgets that draw in a part or a bigger surface...
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
#ifdef Q_WS_QWS
    glOrthof(0, sz.width(), sz.height(), 0, -999999, 999999);
#else
    glOrtho(0, sz.width(), sz.height(), 0, -999999, 999999);
#endif
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glEnable(GL_BLEND);
    d->composition_mode = QPainter::CompositionMode_SourceOver;

#ifndef Q_WS_QWS
    bool shared_ctx = qgl_share_reg()->checkSharing(d->drawable.context(), d->shader_ctx);

    if (!shared_ctx) {
        if (d->shader_ctx) {
            d->shader_ctx->makeCurrent();
            glBindTexture(GL_TEXTURE_1D, 0);
            glDeleteTextures(1, &d->grad_palette);

            if (has_frag_program && d->use_fragment_programs) {
                glDeleteTextures(1, &d->drawable_texture);
                d->deleteFragmentPrograms();
            }

            d->drawable.context()->makeCurrent();
        }
        d->shader_ctx = d->drawable.context();
        glGenTextures(1, &d->grad_palette);

        qt_mask_texture_cache()->clearCache();

        if (has_frag_program) {
            d->use_fragment_programs = d->createFragmentPrograms();

            if (!d->use_fragment_programs) {
                d->deleteFragmentPrograms();
                qWarning() << "QOpenGLPaintEngine: Failed to create fragment programs.";
            }
        }

        gccaps &= ~(RadialGradientFill | ConicalGradientFill | LinearGradientFill | PatternBrush | BlendModes);

        if (d->use_fragment_programs)
            gccaps |= (RadialGradientFill | ConicalGradientFill | LinearGradientFill | PatternBrush | BlendModes);
        else if (QGLExtensions::glExtensions & QGLExtensions::MirroredRepeat)
            gccaps |= LinearGradientFill;
    }

    if (d->use_fragment_programs && (!shared_ctx || sz.width() > d->drawable_texture_size.width()
                                                 || sz.height() > d->drawable_texture_size.height()))
    {
        // delete old texture if size has increased, otherwise it was deleted earlier
        if (shared_ctx)
            glDeleteTextures(1, &d->drawable_texture);

        glGenTextures(1, &d->drawable_texture);
        glBindTexture(GL_TEXTURE_2D, d->drawable_texture);
        QSize adjusted_size(qt_next_power_of_two(sz.width()),
                            qt_next_power_of_two(sz.height()));

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,
                     adjusted_size.width(),
                     adjusted_size.height(), 0,
                     GL_RGBA, GL_UNSIGNED_BYTE, NULL);

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        d->drawable_texture_size = adjusted_size;
    }
#endif

    setDirty(QPaintEngine::DirtyPen);
    setDirty(QPaintEngine::DirtyBrush);
    setDirty(QPaintEngine::DirtyCompositionMode);

#ifdef Q_WS_QWS
    // XXX: needed only if painting on a widget?
    updateClipRegion(QRegion(), Qt::NoClip);
#endif

    return true;
}

bool QOpenGLPaintEngine::end()
{
    Q_D(QOpenGLPaintEngine);
    d->flushDrawQueue();
    d->offscreen.end();
    glMatrixMode(GL_TEXTURE);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();
#ifndef Q_WS_QWS
    glMatrixMode(GL_PROJECTION);
    glLoadMatrixd(&d->projection_matrix[0][0]);
    glPopAttrib();
    glPopClientAttrib();
#endif

#ifndef Q_WS_QWS
    d->drawable.swapBuffers();
#endif
    d->drawable.doneCurrent();
    qt_mask_texture_cache()->maintainCache();

    return true;
}

void QOpenGLPaintEngine::updateState(const QPaintEngineState &state)
{
    Q_D(QOpenGLPaintEngine);
    QPaintEngine::DirtyFlags flags = state.state();

    bool update_fast_pen = false;

    if (flags & DirtyOpacity) {
        update_fast_pen = true;
        d->opacity = state.opacity();
        if (d->opacity > 1.0f)
            d->opacity = 1.0f;
        if (d->opacity < 0.f)
            d->opacity = 0.f;
        // force update
        flags |= DirtyPen;
        flags |= DirtyBrush;
    }

    if (flags & DirtyTransform) {
        update_fast_pen = true;
        updateMatrix(state.transform());
        // brush setup depends on transform state
        if (state.brush().style() != Qt::NoBrush)
            flags |= DirtyBrush;
    }

    if (flags & DirtyPen) {
        update_fast_pen = true;
        updatePen(state.pen());
    }

    if (flags & (DirtyBrush | DirtyBrushOrigin)) {
        updateBrush(state.brush(), state.brushOrigin());
    }

    if (flags & DirtyFont) {
        updateFont(state.font());
    }

    if (state.state() & DirtyClipEnabled) {
        if (state.isClipEnabled())
            updateClipRegion(painter()->clipRegion(), Qt::ReplaceClip);
        else
            updateClipRegion(QRegion(), Qt::NoClip);
    }

    if (flags & DirtyClipPath) {
        updateClipRegion(QRegion(state.clipPath().toFillPolygon().toPolygon(),
                                 state.clipPath().fillRule()),
                         state.clipOperation());
    }

    if (flags & DirtyClipRegion) {
        updateClipRegion(state.clipRegion(), state.clipOperation());
    }

    if (flags & DirtyHints) {
        updateRenderHints(state.renderHints());
    }

    if (flags & DirtyCompositionMode) {
        updateCompositionMode(state.compositionMode());
    }

    if (update_fast_pen) {
        Q_D(QOpenGLPaintEngine);
        qreal pen_width = d->cpen.widthF();
        d->has_fast_pen =
            ((pen_width == 0 || (pen_width <= 1 && d->txop <= QTransform::TxTranslate))
             || d->cpen.isCosmetic())
            && d->cpen.style() == Qt::SolidLine
            && d->cpen.isSolid();
    }
}


void QOpenGLPaintEnginePrivate::setInvMatrixData(const QTransform &inv_matrix)
{
    inv_matrix_data[0][0] = inv_matrix.m11();
    inv_matrix_data[1][0] = inv_matrix.m21();
    inv_matrix_data[2][0] = inv_matrix.m31();

    inv_matrix_data[0][1] = inv_matrix.m12();
    inv_matrix_data[1][1] = inv_matrix.m22();
    inv_matrix_data[2][1] = inv_matrix.m32();

    inv_matrix_data[0][2] = inv_matrix.m13();
    inv_matrix_data[1][2] = inv_matrix.m23();
    inv_matrix_data[2][2] = inv_matrix.m33();
}


void QOpenGLPaintEnginePrivate::updateGradient(const QBrush &brush, const QRectF &bounds)
{
#ifdef Q_WS_QWS
    Q_UNUSED(brush);
    Q_UNUSED(bounds);
#else
    bool has_mirrored_repeat = QGLExtensions::glExtensions & QGLExtensions::MirroredRepeat;
    Qt::BrushStyle style = brush.style();

    if (has_mirrored_repeat && style == Qt::LinearGradientPattern) {
        const QLinearGradient *g = static_cast<const QLinearGradient *>(brush.gradient());
        QTransform m = brush.transform();
        QPointF realStart = g->start();
        QPointF realFinal = g->finalStop();
        if (g->coordinateMode() == QGradient::ObjectBoundingMode) {
            qreal sx = bounds.x() + realStart.x() * bounds.width();
            qreal sy = bounds.y() + realStart.y() * bounds.height();
            qreal fx = bounds.x() + realFinal.x() * bounds.width();
            qreal fy = bounds.y() + realFinal.y() * bounds.height();
            realStart = QPointF(sx, sy);
            realFinal = QPointF(fx, fy);
        }
        QPointF start = m.map(realStart);
        QPointF stop;

        if (qFuzzyCompare(m.m11(), m.m22()) && m.m12() == 0.0 && m.m21() == 0.0) {
            // It is a simple uniform scale and/or translation
            stop = m.map(realFinal);
        } else {
            // It is not enough to just transform the endpoints.
            // We have to make sure the _pattern_ is transformed correctly.

            qreal odx = realFinal.x() - realStart.x();
            qreal ody = realFinal.y() - realStart.y();

            // nx, ny and dx, dy are normal and gradient direction after transform:
            qreal nx = m.m11()*ody - m.m21()*odx;
            qreal ny = m.m12()*ody - m.m22()*odx;

            qreal dx = m.m11()*odx + m.m21()*ody;
            qreal dy = m.m12()*odx + m.m22()*ody;

            qreal lx = 1.0/(dx - dy*nx/ny);
            qreal ly = 1.0/(dy - dx*ny/nx);
            qreal l = 1.0/sqrt(lx*lx+ly*ly);

            stop = start + QPointF(-ny, nx) * l/sqrt(nx*nx+ny*ny);
        }

        float tr[4], f;
        tr[0] = stop.x() - start.x();
        tr[1] = stop.y() - start.y();
        f = 1.0 / (tr[0]*tr[0] + tr[1]*tr[1]);
        tr[0] *= f;
        tr[1] *= f;
        tr[2] = 0;
        tr[3] = -(start.x()*tr[0] + start.y()*tr[1]);
        setGLBrush(Qt::white);
        qt_glColor4ubv(brush_color);
        glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
        glTexGenfv(GL_S, GL_OBJECT_PLANE, tr);
    }

    if (use_fragment_programs) {
        if (style == Qt::RadialGradientPattern) {
            const QRadialGradient *g = static_cast<const QRadialGradient *>(brush.gradient());
            QPointF realCenter = g->center();
            QPointF realFocal  = g->focalPoint();
            qreal   realRadius = g->radius();
            if (g->coordinateMode() == QGradient::ObjectBoundingMode) {
                qreal x = bounds.x() + realCenter.x() * bounds.width();
                qreal y = bounds.y() + realCenter.y() * bounds.height();
                realCenter = QPointF(x, y);

                x = bounds.x() + realFocal.x() * bounds.width();
                y = bounds.y() + realFocal.y() * bounds.height();
                realFocal = QPointF(x, y);

                realRadius = qMin(bounds.x() + bounds.width() * realRadius,
                                  bounds.y() + bounds.height() * realRadius);
            }
            QTransform translate(1, 0, 0, 1, -realFocal.x(), -realFocal.y());
            QTransform gl_to_qt(1, 0, 0, -1, 0, pdev->height());
            QTransform inv_matrix = gl_to_qt * matrix.inverted() * brush.transform().inverted() * translate;

            setInvMatrixData(inv_matrix);

            fmp_data[0] = realCenter.x() - realFocal.x();
            fmp_data[1] = realCenter.y() - realFocal.y();

            fmp2_m_radius2_data[0] = -fmp_data[0] * fmp_data[0] - fmp_data[1] * fmp_data[1] + realRadius * realRadius;
        } else if (style == Qt::ConicalGradientPattern) {
            const QConicalGradient *g = static_cast<const QConicalGradient *>(brush.gradient());
            QPointF realCenter = g->center();
            if (g->coordinateMode() == QGradient::ObjectBoundingMode) {
                qreal x = bounds.x() + bounds.width() * realCenter.x();
                qreal y = bounds.y() + bounds.height() * realCenter.y();
                realCenter = QPointF(x, y);
            }
            QTransform translate(1, 0, 0, 1, -realCenter.x(), -realCenter.y());
            QTransform gl_to_qt(1, 0, 0, -1, 0, pdev->height());
            QTransform inv_matrix = gl_to_qt * matrix.inverted() * brush.transform().inverted() * translate;

            setInvMatrixData(inv_matrix);

            angle_data[0] = -(g->angle() * 2 * Q_PI) / 360.0;
        } else if (style == Qt::LinearGradientPattern) {
            const QLinearGradient *g = static_cast<const QLinearGradient *>(brush.gradient());

            QPointF realStart = g->start();
            QPointF realFinal = g->finalStop();
            if (g->coordinateMode() == QGradient::ObjectBoundingMode) {
                qreal sx = bounds.x() + realStart.x() * bounds.width();
                qreal sy = bounds.y() + realStart.y() * bounds.height();
                qreal fx = bounds.x() + realFinal.x() * bounds.width();
                qreal fy = bounds.y() + realFinal.y() * bounds.height();
                realStart = QPointF(sx, sy);
                realFinal = QPointF(fx, fy);
            }

            QTransform translate(1, 0, 0, 1, -realStart.x(), -realStart.y());
            QTransform gl_to_qt(1, 0, 0, -1, 0, pdev->height());

            QTransform inv_matrix = gl_to_qt * matrix.inverted() * brush.transform().inverted() * translate;

            setInvMatrixData(inv_matrix);

            QPointF l = realFinal - realStart;

            linear_data[0] = l.x();
            linear_data[1] = l.y();

            linear_data[2] = 1.0f / (l.x() * l.x() + l.y() * l.y());
        } else if (style != Qt::SolidPattern) {
            QTransform translate(1, 0, 0, 1, brush_origin.x(), brush_origin.y());
            QTransform gl_to_qt(1, 0, 0, -1, 0, pdev->height());

            QTransform inv_matrix = gl_to_qt * matrix.inverted() * brush.transform().inverted() * translate;

            setInvMatrixData(inv_matrix);
        }
    }

    if (style >= Qt::LinearGradientPattern && style <= Qt::ConicalGradientPattern) {
        createGradientPaletteTexture(*brush.gradient());
    }
#endif
}


class QOpenGLTessellator : public QTessellator
{
public:
    QOpenGLTessellator() {}
    ~QOpenGLTessellator() { }
    QGLTrapezoid toGLTrapezoid(const Trapezoid &trap);
};

QGLTrapezoid QOpenGLTessellator::toGLTrapezoid(const Trapezoid &trap)
{
    QGLTrapezoid t;

    t.top = Q27Dot5ToDouble(trap.top);
    t.bottom = Q27Dot5ToDouble(trap.bottom);

    Q27Dot5 y = trap.topLeft->y - trap.bottomLeft->y;

    qreal topLeftY = Q27Dot5ToDouble(trap.topLeft->y);

    qreal tx = Q27Dot5ToDouble(trap.topLeft->x);
    qreal m = (-tx + Q27Dot5ToDouble(trap.bottomLeft->x)) / Q27Dot5ToDouble(y);
    t.topLeftX = tx + m * (topLeftY - t.top);
    t.bottomLeftX = tx + m * (topLeftY - t.bottom);

    y = trap.topRight->y - trap.bottomRight->y;

    qreal topRightY = Q27Dot5ToDouble(trap.topRight->y);

    tx = Q27Dot5ToDouble(trap.topRight->x);
    m = (-tx + Q27Dot5ToDouble(trap.bottomRight->x)) / Q27Dot5ToDouble(y);

    t.topRightX = tx + m * (topRightY - Q27Dot5ToDouble(trap.top));
    t.bottomRightX = tx + m * (topRightY - Q27Dot5ToDouble(trap.bottom));

    return t;
}

class QOpenGLImmediateModeTessellator : public QOpenGLTessellator
{
public:
    void addTrap(const Trapezoid &trap);
    void tessellate(const QPointF *points, int nPoints, bool winding) {
        trapezoids.reserve(trapezoids.size() + nPoints);
        setWinding(winding);
        QTessellator::tessellate(points, nPoints);
    }

    QVector<QGLTrapezoid> trapezoids;
};

void QOpenGLImmediateModeTessellator::addTrap(const Trapezoid &trap)
{
    trapezoids.append(toGLTrapezoid(trap));
}

#ifndef Q_WS_QWS
static void drawTrapezoid(const QGLTrapezoid &trap, const qreal offscreenHeight, QGLContext *ctx)
{
    qreal minX = qMin(trap.topLeftX, trap.bottomLeftX);
    qreal maxX = qMax(trap.topRightX, trap.bottomRightX);

    if (qFuzzyCompare(trap.top, trap.bottom) || qFuzzyCompare(minX, maxX) ||
        qFuzzyCompare(trap.topLeftX, trap.topRightX) && qFuzzyCompare(trap.bottomLeftX, trap.bottomRightX))