b3dProjectedX

Returns projected screen X coordinate (from last b3dCameraProject call). Takes camera (camera entity handle). Returns screen X coordinate in pixels (Double), or 0.0 if invalid camera or camera->camera==nullptr. Reads camera->projectedX value stored by b3dCameraProject. Screen coordinates in viewport pixel space (0,0)=top-left.

This function retrieves X result. Projection sequence: (1) Call b3dCameraProject(camera, worldX, worldY, worldZ) to transform 3D position, (2) Call b3dProjectedX(camera) to get screen X, b3dProjectedY(camera) to get screen Y, b3dProjectedZ(camera) to get depth. Screen X range: typically 0 to viewportWidth (or g_3D_resolutionWidth if fullscreen), negative values or values > viewportWidth indicate off-screen left/right. Use cases: (1) Name tags (draw text at projected X/Y), (2) HUD anchors (anchor UI to 3D positions), (3) Minimap (convert 3D to 2D map coordinates), (4) Debug visualization (show 3D coordinates as 2D overlay), (5) Off-screen indicators (detect when objects leave viewport). Common pattern: b3dCameraProject(cam, entX, entY, entZ), x=b3dProjectedX(cam), y=b3dProjectedY(cam), BBR_Text(x, y, "Enemy"). Typical usage: retrieve projected coordinates every frame after projection, use for 2D drawing over 3D scene. Off-screen detection: if x < 0 or x > viewportWidth, object is off-screen horizontally (left or right edge), combine with Y check for full off-screen detection. Viewport offset: screen X includes viewport offset (camera->viewportX), so coordinates relative to full screen (not viewport-local). Performance: O(1) lookup (simple struct field access, no computation). Validation: returns 0.0 if camera invalid or camera->camera==nullptr (must call b3dCameraProject first to allocate and populate Camera3D). Related: b3dCameraProject performs projection (stores projectedX/Y/Z), b3dProjectedY/Z retrieve Y coordinate and depth, b3dCameraViewport sets viewport region.