Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Rendered
VP_TEXT_RENDER_OUTPUT_RENDER
Parameter: VideoPost
VP_TEXT_RENDER_OUTPUT_VIDEOPOST
Parameter: MultiPass
VP_TEXT_RENDER_OUTPUT_MULTIPASS
Parameter: Title
VP_TEXT_STRING
Parameter: U
VP_TEXT_U
Parameter: V
VP_TEXT_V
Parameter: Tab Size
VP_TEXT_TAB_SIZE
Parameter: Align
VP_TEXT_ALIGN
Parameter: Align
VP_TEXT_INFO_ALIGN
Parameter: Objects
VP_TEXT_INFO_OBJECTCOUNT
Parameter: Lights
VP_TEXT_INFO_LIGHTCOUNT
Parameter: Polygons
VP_TEXT_INFO_POLYGONCOUNT
Parameter: Vertices
VP_TEXT_INFO_VERTEXCOUNT
Parameter: Render Time
VP_TEXT_INFO_SCENETIME
Parameter: Color
VP_TEXT_PEN
Parameter: Opacity
VP_TEXT_PEN_OPACITY
Parameter: Color
VP_TEXT_PAPER
Parameter: Opacity
VP_TEXT_PAPER_OPACITY
Parameter: Border Offset
VP_TEXT_PAPER_BORDER
Parameter: Rounding
VP_TEXT_PAPER_ROUNDING
Parameter: Draw Border
VP_TEXT_PAPER_DRAW_BORDER
Parameter: Image
VP_TEXT_WATERMARK
Parameter: Opacity
VP_TEXT_WATERMARK_OPACITY
Parameter: Scale
VP_TEXT_WATERMARK_SCALE
Parameter: Vertical Alignment
VP_TEXT_WATERMARK_V_ALIGN
Parameter: Horizontal Alignment
VP_TEXT_WATERMARK_H_ALIGN