Inverse rendering from multi-view photographs is an ill-posed problem because it must jointly disentangle geometry, reflectance, and illumination. Existing 3DGS pipelines either optimize all factors in a single stage, failing to model view-dependent occlusion, or split the task into multiple stages, forfeiting end-to-end optimality. We present a one-stage 3DGS inverse-rendering framework that recovers geometry, BRDFs, and view-dependent occlusion in real time. Each Gaussian stores 4th-order spherical-harmonic visibility coefficients learned from splat transparencies, eliminating ray tracing. A prototype-based material prior decouples lighting from reflectance, and deferred split-sum shading keeps the pipeline fully differentiable while enabling HDR relighting. Experiments on indoor and outdoor benchmarks demonstrate that our approach improves inverse-rendering objectives, while remaining competitive on novel-view synthesis compared to strong reconstruction baselines such as 3DGS.