PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a heavyweight, dark-wash denim. Unlike the user's current elastic t-shirt, this material has high structural rigidity and shear resistance. It should not cling to the muscles but rather bridge gaps between body contours. The reflection mapping must show a matte finish with low specular highlights, restricted mainly to the rigid folds at the elbows and placket. - **Key Features:** The simulation must preserve the "layered look" (the open denim shirt revealing the white crew-neck t-shirt underneath). Critical details include the structure of the spread collar, the left breast pocket with distinct stitching, the button placket texturing, and the cuff thickness. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** The user has a muscular, stocky build (broad shoulders and chest). The denim shirt must drape with a "relaxed fit" logic, adding volume to the silhouette rather than hugging the skin. The fabric must deform realistically at the elbows—creating sharp, stiff creases at the crook of the arm holding the phone, and bunching slightly at the wrists due to the long sleeves meeting the hands. - **Occlusion Handling:** **CRITICAL:** The smartphone and the user's right hand (holding the phone) are dominant foreground elements covering the sternum/chest area. The virtual garment must be rendered strictly *behind* the hand and device. The watch on the right wrist and the bracelet on the left wrist create collision points; the denim cuffs should either cover these or rest naturally just above them depending on sleeve length calculation. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user environment features mixed indoor lighting, likely a window source to the viewer's left (suggested by the blue curtain and highlights) and warmer ambient reflection from the wooden door. The studio-lit source garment must be darkened to match the lower exposure of the selfie. Shadows must be cast from the left-to-right across the folds of the denim, and a subtle "mirror grain" or ISO noise must be applied to the cloth to match the photo quality. - **Color Calibration:** The source denim is a cool, deep blue. This must be desaturated slightly and warmed to harmonize with the brown wooden tones of the door behind the user, preventing the shirt from looking like a high-contrast "sticker." PHASE 4: IDENTITY PROTECTION - **Facial Lock:** Absolute freeze on the user's hair, forehead, eyes, beard, and the visible skin of the neck above the collar line. The phone covering the lower face must remain pixel-perfect. - **Body Integrity:** Strictly forbid any mesh contraction or slimming algorithms. The user's muscular shoulder width and chest volume must be maintained; the denim shirt must sit *on top* of his current volume, making the overall silhouette slightly bulkier, not smaller.