source: trunk/src/opengl/gl2paintengineex/qglgradientcache.cpp@ 651

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#include <private/qdrawhelper_p.h>
#include <private/qgl_p.h>

#include "qglgradientcache_p.h"

QT_BEGIN_NAMESPACE

static void QGL2GradientCache_free(void *ptr)
{
    delete reinterpret_cast<QGL2GradientCache *>(ptr);
}

Q_GLOBAL_STATIC_WITH_ARGS(QGLContextResource, qt_gradient_caches, (QGL2GradientCache_free))

QGL2GradientCache *QGL2GradientCache::cacheForContext(const QGLContext *context)
{
    QGL2GradientCache *p = reinterpret_cast<QGL2GradientCache *>(qt_gradient_caches()->value(context));
    if (!p) {
        QGLShareContextScope scope(context);
        p = new QGL2GradientCache;
        qt_gradient_caches()->insert(context, p);
    }
    return p;
}

void QGL2GradientCache::cleanCache() {
    QGLGradientColorTableHash::const_iterator it = cache.constBegin();
    for (; it != cache.constEnd(); ++it) {
        const CacheInfo &cache_info = it.value();
        glDeleteTextures(1, &cache_info.texId);
    }
    cache.clear();
}

GLuint QGL2GradientCache::getBuffer(const QGradient &gradient, qreal opacity)
{
    quint64 hash_val = 0;

    QGradientStops stops = gradient.stops();
    for (int i = 0; i < stops.size() && i <= 2; i++)
        hash_val += stops[i].second.rgba();

    QGLGradientColorTableHash::const_iterator it = cache.constFind(hash_val);

    if (it == cache.constEnd())
        return addCacheElement(hash_val, gradient, opacity);
    else {
        do {
            const CacheInfo &cache_info = it.value();
            if (cache_info.stops == stops && cache_info.opacity == opacity && cache_info.interpolationMode == gradient.interpolationMode()) {
                return cache_info.texId;
            }
            ++it;
        } while (it != cache.constEnd() && it.key() == hash_val);
        // an exact match for these stops and opacity was not found, create new cache
        return addCacheElement(hash_val, gradient, opacity);
    }