Why is in Qt/Opengl glMapBuffer slower than glBufferData?
Unsolved
Mobile and Embedded
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I tried on Android for a huge terrain model (around 10Mill vertices/indices, 250MB)
m_vertexBuf.allocate(m_pVertices->size() * sizeof(QVector4D)); void* buffer_data = m_vertexBuf.map(QOpenGLBuffer::WriteOnly); memcpy(buffer_data, m_pVertices->constData(), m_pVertices->size() * sizeof(QVector4D)); m_vertexBuf.unmap(); m_vertexBuf.release();
instead of
m_vertexBuf.allocate(m_pVertices->constData(), m_pVertices->size() * sizeof(QVector4D));
but it's 0.4sec slower(!) during loading.