2-7 Drawing Cycle Mode


N64 has four kinds of drawing cycle modes as below. The gDPSetCycleType function is used for setting the drawing cycle mode.


#Fill mode (FILL)
In FILL mode, the RDP writes pixels into the frame buffer using the color specified in the fill color register. At maximum speed (usually only attained with rectangles), two 32-bit pixels or four 16-bit pixels are written per cycle. In FILL mode, you cannot use polygon drawing functions such as gSP1Triangle.


#Copy mode (COPY)
In COPY mode, the RDP transfers the accepted textured pixels in TMEM to the frame buffer. At maximum speed (usually only attained with rectangles), two 32-bit pixels or four 16-bit pixels are copied per cycle. In COPY mode, you cannot use polygon drawing functions such as the gSP1Triangle function. However, you can use texturing functions such as the gSPTextureRectangle function.


#One-cycle mode (1CYCLE)
In 1CYCLE mode, the RDP fills a maximum of one pixel per clock cycle. In this mode, the RDP can fill a fairly high-quality pixel. Using 1CYCLE mode, you can generate pixels that are perspective corrected, bilinear filtered, modulate/decal textured, transparent, and z-buffered at a maximum bandwidth of one pixel per cycle. This mode uses each process unit in the RDP pipeline (RS, TX, TF, CC, BL, and MI) once.


#Two-cycle mode (2CYCLE)
In 2CYCLE mode, the RDP pipeline's process units are reconfigured for additional functionality at a slower maximum speed of one pixel per two clocks. Each process unit in the RDP pipeline is used twice except for the RS (the rasterizer).