Function renderOcclusionQueryGoldfeather

OpenCSG/src/renderGoldfeather.cpp:488–564

    }

    static bool renderOcclusionQueryGoldfeather(const std::vector<Primitive*>& primitives)
    {
        scissor = new ScissorMemo;

        unsigned int layer = 0;

        scissor->setIntersected(primitives);
        scissor->setCurrent(primitives);

        OpenGL::OcclusionQuery* occlusionTest = 0;

        bool retVal = true;

        while (true) {
            if (channelMgr->request() == NoChannel) {
                channelMgr->free();
                channelMgr->request();
            }

            scissor->store(channelMgr->current());
            scissor->enableScissor();

            if (!occlusionTest) {
                occlusionTest = OpenGL::getOcclusionQuery(false);
                if (!occlusionTest) {
                    retVal = false;
                    break;
                }
            }

            channelMgr->renderToChannel(true);

            glStencilMask(OpenGL::stencilMask);
            glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

            glDepthFunc(GL_ALWAYS);
            glDepthMask(GL_TRUE);
            glColor4ub(255, 255, 255, 255);

            occlusionTest->beginQuery();
            OpenGL::renderLayer(layer, primitives);
            occlusionTest->endQuery();
            // the fragment count query could occur here, but benches show that
            // the algorithm is faster if the query is delayed.
            glClear(GL_STENCIL_BUFFER_BIT);

            parityTestAndDiscard(primitives, primitives, true, OpenGL::stencilMax);

            unsigned int anyFragmentRendered = occlusionTest->getQueryResult();
            if (!anyFragmentRendered) {
                retVal = true;
                break;
            }

            channelMgr->store(channelMgr->current(), primitives, layer);

            scissor->disableScissor();