VDP1 32-bit video display processor

The Sega Saturn is equipped with dual custom VDP chips for graphics processing. The VDP 1 chip is primarily responsible for sprite generation. Polygon generation is accomplished through manipulation of the sprite engine. Texture mapping and goruard shading is also handled by the VDP 1. The VDP1 relies on a dual frame buffer that handlesrotation and stores textures in special 512K cache.

Both the VDP1 and VDP2 32-bit background and scroll plane video display processor have direct access to the both SH2s, as well as direct memory access (DMA) to both the main and video RAM.

• Rendering engine for primitives: textured and untextured polygons, untextured polylines and lines
• "Sprites" are textured polygons with specific rendering modes:
• Normal sprite (one point), shrinked/scaled sprite (two points), quadrangle (four points)
• Other rendering modes:
• Overwrite (replace framebuffer contents)
• Shadow (underlying framebuffer pixels rewritten with 1/2 brightness, primitive not drawn)
• Half luminosity (primitive rendered with 1/2 brightness)
• Half transparency (primitive and underlying framebuffer pixels averaged together)
• Gouraud shading for RGB-format textures only
• Dual 256KB frame buffers
• Programmable frame buffer depth of 8 or 16 bits per pixel
• Automatic erase feature to clear framebuffer with single color
• 200,000 texture-mapped polygons per second
• 500,000 flat-shaded polygons per second
• 60 frames of animation per second