QGLFramebufferObjectPool Class Reference

The QGLFramebufferObject class provides a pool of framebuffer objects for offscreen rendering purposes. More...

#include <qpixmapdata_gl_p.h>

Public Functions
QGLFramebufferObject *	acquire (const QSize &size, const QGLFramebufferObjectFormat &format, bool strictSize=false)
void	release (QGLFramebufferObject *fbo)

Properties
QList< QGLFramebufferObject * >	m_fbos

Detailed Description

The QGLFramebufferObject class provides a pool of framebuffer objects for offscreen rendering purposes.

Since

4.6

When requesting an FBO of a given size and format, an FBO of the same format and a size at least as big as the requested size will be returned.

Warning

This function is not part of the public interface.

Definition at line 79 of file qpixmapdata_gl_p.h.

Functions

acquire()

QGLFramebufferObject * QGLFramebufferObjectPool::acquire	(	const QSize &	size,
		const QGLFramebufferObjectFormat &	format,
		bool	strictSize = false
	)

Definition at line 99 of file qpixmapdata_gl.cpp.

Referenced by QGLWindowSurface::flush(), and QGLPixmapData::paintEngine().

{
    QGLFramebufferObject *chosen = 0;
    QGLFramebufferObject *candidate = 0;
    for (int i = 0; !chosen && i < m_fbos.size(); ++i) {
        QGLFramebufferObject *fbo = m_fbos.at(i);

        if (strictSize) {
            if (fbo->size() == requestSize && fbo->format() == requestFormat) {
                chosen = fbo;
                break;
            } else {
                continue;
            }
        }

        if (fbo->format() == requestFormat) {
            // choose the fbo with a matching format and the closest size
            if (!candidate || areaDiff(requestSize, candidate) > areaDiff(requestSize, fbo))
                candidate = fbo;
        }

        if (candidate) {
            m_fbos.removeOne(candidate);

            const QSize fboSize = candidate->size();
            QSize sz = fboSize;

            if (sz.width() < requestSize.width())
                sz.setWidth(qMax(requestSize.width(), qRound(sz.width() * 1.5)));
            if (sz.height() < requestSize.height())
                sz.setHeight(qMax(requestSize.height(), qRound(sz.height() * 1.5)));

            // wasting too much space?
            if (sz.width() * sz.height() > requestSize.width() * requestSize.height() * 4)
                sz = requestSize;

            if (sz != fboSize) {
                delete candidate;
                candidate = new QGLFramebufferObject(maybeRoundToNextPowerOfTwo(sz), requestFormat);
            }

            chosen = candidate;
        }
    }

    if (!chosen) {
        if (strictSize)
            chosen = new QGLFramebufferObject(requestSize, requestFormat);
        else
            chosen = new QGLFramebufferObject(maybeRoundToNextPowerOfTwo(requestSize), requestFormat);
    }

    if (!chosen->isValid()) {
        delete chosen;
        chosen = 0;
    }

    return chosen;
}

release()

void QGLFramebufferObjectPool::release

(

QGLFramebufferObject *

fbo

)

Definition at line 160 of file qpixmapdata_gl.cpp.

Referenced by QGLPixmapGLPaintDevice::endPaint(), and QGLWindowSurface::flush().

{
    if (fbo)
        m_fbos << fbo;
}

Properties

m_fbos

QList<QGLFramebufferObject *> QGLFramebufferObjectPool::m_fbos

private

Definition at line 86 of file qpixmapdata_gl_p.h.

Referenced by acquire(), and release().

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The documentation for this class was generated from the following files:

• /src/opengl/qpixmapdata_gl_p.h
• /src/opengl/qpixmapdata_gl.cpp