b3dProjectedY

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

This function retrieves Y result. Projection sequence: (1) Call b3dCameraProject(camera, worldX, worldY, worldZ) to transform 3D position, (2) Call b3dProjectedY(camera) to get screen Y (and b3dProjectedX/Z for X and depth). Screen Y range: typically 0 to viewportHeight (or g_3D_resolutionHeight if fullscreen), negative values or values > viewportHeight indicate off-screen top/bottom. Y-axis convention: screen Y increases downward (0=top edge, height=bottom edge), matches DirectX screen space. Use cases: (1) Name tags (draw text at projected X/Y), (2) HUD anchors (anchor UI to 3D positions), (3) Health bars (show bar above entity head), (4) Waypoint markers (show direction indicator), (5) Off-screen indicators (detect when objects leave viewport vertically). Common pattern: b3dCameraProject(cam, entX, entY, entZ), x=b3dProjectedX(cam), y=b3dProjectedY(cam), BBR_DrawImage(img, x, y). Typical usage: retrieve projected coordinates every frame after projection, use for 2D drawing over 3D scene. Off-screen detection: if y < 0, object is above top edge, if y > viewportHeight, object is below bottom edge, combine with X check for full off-screen detection. Viewport offset: screen Y includes viewport offset (camera->viewportY), 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), b3dProjectedX/Z retrieve X coordinate and depth, b3dCameraViewport sets viewport region.