void GetEyeOutputViewport( Hmd_Eye eEye, GraphicsAPIConvention eAPIType, uint32_t *pnX, uint32_t *pnY, uint32_t *pnWidth, uint32_t *pnHeight )
Returns the viewport in pixels in display space that the game should render into for the specified eye. 返回特定眼睛的观察口对应显示空间的像素数据
eEye- Eye_Left or Eye_Right. 决定返回哪只眼睛的观察口。Determines which eye the function should return the viewport for.eAPIType- 匹配对应转换API返回相应修改值。Modifies the return values to match the conventions of the specified API. One of:API_DirectX- `API_OpenGL
pnX- X position of the eye’s viewport within the windowpnY- Y position of the eye’s viewport within the windowpnWidth- width of the eye’s viewport within the windowpnHeight- height of the eye’s viewport within the window
