qgl.cpp

奇趣公司比较新的qt/emd版本

/****************************************************************************
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of the QtOpenGL module of the Qt Toolkit.
**
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** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
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** In addition, as a special exception, Trolltech gives you certain
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** Exception version 1.0, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
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** In addition, as a special exception, Trolltech, as the sole copyright
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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****************************************************************************/

#include "qapplication.h"
#include "qplatformdefs.h"
#include "qgl.h"
#include <qdebug.h>
#include "qpixmap.h"
#include "qimage.h"
#include "qgl_p.h"
#include <private/qpaintengine_opengl_p.h>
#include "qcolormap.h"
#include "qcache.h"
#include "qfile.h"
#include "qlibrary.h"

#if defined(Q_WS_X11) || defined(Q_WS_MAC) || defined(Q_WS_QWS)
QGLExtensionFuncs QGLContextPrivate::qt_extensionFuncs;
#endif

QThreadStorage<QGLThreadContext *> qgl_context_storage;

Q_GLOBAL_STATIC(QGLFormat, qgl_default_format)

class QGLDefaultOverlayFormat: public QGLFormat
{
public:
    inline QGLDefaultOverlayFormat()
    {
        setOption(QGL::FormatOption(0xffff << 16)); // turn off all options
        setOption(QGL::DirectRendering);
        setPlane(1);
    }
};
Q_GLOBAL_STATIC(QGLDefaultOverlayFormat, defaultOverlayFormatInstance)

QGLExtensions::Extensions QGLExtensions::glExtensions = 0;
bool QGLExtensions::nvidiaFboNeedsFinish = false;

#ifndef APIENTRY
# define APIENTRY
#endif
typedef void (APIENTRY *pfn_glCompressedTexImage2DARB) (GLenum, GLint, GLenum, GLsizei,
                                                        GLsizei, GLint, GLsizei, const GLvoid *);
static pfn_glCompressedTexImage2DARB qt_glCompressedTexImage2DARB = 0;

#if defined(Q_WS_X11)
#include "private/qt_x11_p.h"
#define INT32 dummy_INT32
#define INT8 dummy_INT8
#include <GL/glx.h>
#undef INT32
#undef INT8
#include "qx11info_x11.h"
#elif defined(Q_WS_MAC)
# include <private/qt_mac_p.h>
#endif

#include <stdlib.h> // malloc

#ifndef APIENTRY
#define APIENTRY
#endif

/*!
    \namespace QGL

    \brief The QGL namespace specifies miscellaneous identifiers used
    in the Qt OpenGL module.

    \ingroup multimedia
*/

/*!
    \enum QGL::FormatOption

    This enum specifies the format options.

    \value DoubleBuffer
    \value DepthBuffer
    \value Rgba
    \value AlphaChannel
    \value AccumBuffer
    \value StencilBuffer
    \value StereoBuffers
    \value DirectRendering
    \value HasOverlay
    \value SampleBuffers
    \value SingleBuffer
    \value NoDepthBuffer
    \value ColorIndex
    \value NoAlphaChannel
    \value NoAccumBuffer
    \value NoStencilBuffer
    \value NoStereoBuffers
    \value IndirectRendering
    \value NoOverlay
    \value NoSampleBuffers

    \sa {Sample Buffers Example}
*/

/*****************************************************************************
  QGLFormat implementation
 *****************************************************************************/


/*!
    \class QGLFormat
    \brief The QGLFormat class specifies the display format of an OpenGL
    rendering context.

    \ingroup multimedia

    A display format has several characteristics:
    \list
    \i \link setDoubleBuffer() Double or single buffering.\endlink
    \i \link setDepth() Depth buffer.\endlink
    \i \link setRgba() RGBA or color index mode.\endlink
    \i \link setAlpha() Alpha channel.\endlink
    \i \link setAccum() Accumulation buffer.\endlink
    \i \link setStencil() Stencil buffer.\endlink
    \i \link setStereo() Stereo buffers.\endlink
    \i \link setDirectRendering() Direct rendering.\endlink
    \i \link setOverlay() Presence of an overlay.\endlink
    \i \link setPlane() The plane of an overlay format.\endlink
    \i \link setSampleBuffers() Multisample buffers.\endlink
    \endlist

    You can also specify preferred bit depths for the depth buffer,
    alpha buffer, accumulation buffer and the stencil buffer with the
    functions: setDepthBufferSize(), setAlphaBufferSize(),
    setAccumBufferSize() and setStencilBufferSize().

    Note that even if you specify that you prefer a 32 bit depth
    buffer (e.g. with setDepthBufferSize(32)), the format that is
    chosen may not have a 32 bit depth buffer, even if there is a
    format available with a 32 bit depth buffer. The main reason for
    this is how the system dependant picking algorithms work on the
    different platforms, and some format options may have higher
    precedence than others.

    You create and tell a QGLFormat object what rendering options you
    want from an OpenGL rendering context.

    OpenGL drivers or accelerated hardware may or may not support
    advanced features such as alpha channel or stereographic viewing.
    If you request some features that the driver/hardware does not
    provide when you create a QGLWidget, you will get a rendering
    context with the nearest subset of features.

    There are different ways to define the display characteristics of
    a rendering context. One is to create a QGLFormat and make it the
    default for the entire application:
    \code
    QGLFormat fmt;
    fmt.setAlpha(true);
    fmt.setStereo(true);
    QGLFormat::setDefaultFormat(fmt);
    \endcode

    Or you can specify the desired format when creating an object of
    your QGLWidget subclass:
    \code
    QGLFormat fmt;
    fmt.setDoubleBuffer(false);                 // single buffer
    fmt.setDirectRendering(false);              // software rendering
    MyGLWidget* myWidget = new MyGLWidget(fmt, ...);
    \endcode

    After the widget has been created, you can find out which of the
    requested features the system was able to provide:
    \code
    QGLFormat fmt;
    fmt.setOverlay(true);
    fmt.setStereo(true);
    MyGLWidget* myWidget = new MyGLWidget(fmt, ...);
    if (!myWidget->format().stereo()) {
        // ok, goggles off
        if (!myWidget->format().hasOverlay()) {
            qFatal("Cool hardware required");
        }
    }
    \endcode

    \legalese
        OpenGL is a trademark of Silicon Graphics, Inc. in the
        United States and other countries.
    \endlegalese

    \sa QGLContext, QGLWidget
*/

static inline void transform_point(GLdouble out[4], const GLdouble m[16], const GLdouble in[4])
{
#define M(row,col)  m[col*4+row]
    out[0] =
        M(0, 0) * in[0] + M(0, 1) * in[1] + M(0, 2) * in[2] + M(0, 3) * in[3];
    out[1] =
        M(1, 0) * in[0] + M(1, 1) * in[1] + M(1, 2) * in[2] + M(1, 3) * in[3];
    out[2] =
        M(2, 0) * in[0] + M(2, 1) * in[1] + M(2, 2) * in[2] + M(2, 3) * in[3];
    out[3] =
        M(3, 0) * in[0] + M(3, 1) * in[1] + M(3, 2) * in[2] + M(3, 3) * in[3];
#undef M
}

static inline GLint qgluProject(GLdouble objx, GLdouble objy, GLdouble objz,
           const GLdouble model[16], const GLdouble proj[16],
           const GLint viewport[4],
           GLdouble * winx, GLdouble * winy, GLdouble * winz)
{
   GLdouble in[4], out[4];

   in[0] = objx;
   in[1] = objy;
   in[2] = objz;
   in[3] = 1.0;
   transform_point(out, model, in);
   transform_point(in, proj, out);

   if (in[3] == 0.0)
      return GL_FALSE;

   in[0] /= in[3];
   in[1] /= in[3];
   in[2] /= in[3];

   *winx = viewport[0] + (1 + in[0]) * viewport[2] / 2;
   *winy = viewport[1] + (1 + in[1]) * viewport[3] / 2;

   *winz = (1 + in[2]) / 2;
   return GL_TRUE;
}

/*!
    Constructs a QGLFormat object with the factory default settings:
    \list
    \i \link setDoubleBuffer() Double buffer:\endlink Enabled.
    \i \link setDepth() Depth buffer:\endlink Enabled.
    \i \link setRgba() RGBA:\endlink Enabled (i.e., color index disabled).
    \i \link setAlpha() Alpha channel:\endlink Disabled.
    \i \link setAccum() Accumulator buffer:\endlink Disabled.
    \i \link setStencil() Stencil buffer:\endlink Disabled.
    \i \link setStereo() Stereo:\endlink Disabled.
    \i \link setDirectRendering() Direct rendering:\endlink Enabled.
    \i \link setOverlay() Overlay:\endlink Disabled.
    \i \link setPlane() Plane:\endlink 0 (i.e., normal plane).
    \i \link setSampleBuffers() Multisample buffers:\endlink Disabled.
    \endlist
*/

QGLFormat::QGLFormat()
{
    d = new QGLFormatPrivate;
}


/*!
    Creates a QGLFormat object that is a copy of the current \link
    defaultFormat() application default format\endlink.

    If \a options is not 0, this copy is modified by these format
    options. The \a options parameter should be \c FormatOption values
    OR'ed together.

    This constructor makes it easy to specify a certain desired format
    in classes derived from QGLWidget, for example:
    \code
    // The rendering in MyGLWidget depends on using
    // stencil buffer and alpha channel
    MyGLWidget::MyGLWidget(QWidget* parent)
        : QGLWidget(QGLFormat(QGL::StencilBuffer | QGL::AlphaChannel), parent)
    {
        if (!format().stencil())
            qWarning("Could not get stencil buffer; results will be suboptimal");
        if (!format().alpha())
            qWarning("Could not get alpha channel; results will be suboptimal");
        ...
    }
    \endcode

    Note that there are \c FormatOption values to turn format settings
    both on and off, e.g. \c DepthBuffer and \c NoDepthBuffer,
    \c DirectRendering and \c IndirectRendering, etc.

    The \a plane parameter defaults to 0 and is the plane which this
    format should be associated with. Not all OpenGL implementations
    supports overlay/underlay rendering planes.

    \sa defaultFormat(), setOption()
*/

QGLFormat::QGLFormat(QGL::FormatOptions options, int plane)
{
    d = new QGLFormatPrivate;
    QGL::FormatOptions newOpts = options;
    d->opts = defaultFormat().d->opts;
    d->opts |= (newOpts & 0xffff);
    d->opts &= ~(newOpts >> 16);
    d->pln = plane;
}

/*!
    Constructs a copy of \a other.
*/

QGLFormat::QGLFormat(const QGLFormat &other)
{
    d = new QGLFormatPrivate;
    *d = *other.d;
}

/*!
    Assigns \a other to this object.
*/

QGLFormat &QGLFormat::operator=(const QGLFormat &other)
{
    *d = *other.d;
    return *this;
}

/*!
    Destroys the QGLFormat.
*/
QGLFormat::~QGLFormat()
{
    delete d;
}

/*!
    \fn bool QGLFormat::doubleBuffer() const

    Returns true if double buffering is enabled; otherwise returns
    false. Double buffering is enabled by default.

    \sa setDoubleBuffer()
*/

/*!
    If \a enable is true sets double buffering; otherwise sets single
    buffering.

    Double buffering is enabled by default.

    Double buffering is a technique where graphics are rendered on an
    off-screen buffer and not directly to the screen. When the drawing
    has been completed, the program calls a swapBuffers() function to
    exchange the screen contents with the buffer. The result is
    flicker-free drawing and often better performance.

    \sa doubleBuffer(), QGLContext::swapBuffers(),
    QGLWidget::swapBuffers()
*/

void QGLFormat::setDoubleBuffer(bool enable)
{
    setOption(enable ? QGL::DoubleBuffer : QGL::SingleBuffer);
}


/*!
    \fn bool QGLFormat::depth() const

    Returns true if the depth buffer is enabled; otherwise returns
    false. The depth buffer is enabled by default.

    \sa setDepth(), setDepthBufferSize()
*/

/*!
    If \a enable is true enables the depth buffer; otherwise disables
    the depth buffer.

    The depth buffer is enabled by default.

    The purpose of a depth buffer (or Z-buffering) is to remove hidden
    surfaces. Pixels are assigned Z values based on the distance to
    the viewer. A pixel with a high Z value is closer to the viewer
    than a pixel with a low Z value. This information is used to
    decide whether to draw a pixel or not.

    \sa depth(), setDepthBufferSize()
*/

void QGLFormat::setDepth(bool enable)
{
    setOption(enable ? QGL::DepthBuffer : QGL::NoDepthBuffer);
}


/*!
    \fn bool QGLFormat::rgba() const

    Returns true if RGBA color mode is set. Returns false if color
    index mode is set. The default color mode is RGBA.

    \sa setRgba()
*/

/*!
    If \a enable is true sets RGBA mode. If \a enable is false sets
    color index mode.

    The default color mode is RGBA.

    RGBA is the preferred mode for most OpenGL applications. In RGBA
    color mode you specify colors as red + green + blue + alpha
    quadruplets.

    In color index mode you specify an index into a color lookup
    table.

    \sa rgba()
*/

void QGLFormat::setRgba(bool enable)
{
    setOption(enable ? QGL::Rgba : QGL::ColorIndex);
}


/*!
    \fn bool QGLFormat::alpha() const

    Returns true if the alpha buffer in the framebuffer is enabled;
    otherwise returns false. The alpha buffer is disabled by default.