Drawing the landscape: DrawOneFaceTile

       Name: DrawOneFaceTile                                         [Show more]
       Type: Subroutine
   Category: Drawing the landscape
    Summary: Draw a tile with one quadrilateral (four-sided) face
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * DrawFlatTile calls DrawOneFaceTile
             * DrawSlopingTile calls DrawOneFaceTile


 Arguments:

   X                    The reference shape to use when picking the tile's
                        colour from the tileShapeColour table


.DrawOneFaceTile

 LDA tileShapeColour,X  \ Set polygonColours to the entry for the reference
 STA polygonColours     \ shape from the tileShapeColour or tileShapeColour+16
                        \ table, so we draw the polygon in the correct colour

 LDA #%00000000         \ Clear bits 6 and 7 of polygonType so the following
 STA polygonType        \ call to DrawPolygon draws a quadrilateral tile face

 JMP DrawPolygon        \ Jump to DrawPolygon to draw the quadrilateral and
                        \ return from the subroutine using a tail call