This paper presents a passive depth map computation algorithm which runs entirely on programmable 3D graphics hardware at real-time speed. Previous implementations relied on the use of either mipmapping or correlation windows to increase the robustness of the calculated depth map. These methods, however, are inherently unable to compute the depths for fine 3D structures. To overcome this obstacle we introduce a pixel-based method which incorporates connectivity information between neighboring pixels, while maintaining the performance boost gained by implementing the algorithm on a highly parallelized architecture such as graphics hardware.