<48/54>VDP1 User's Manual/7.6 Transformed sprite drawing command

★ HARDWARE Manual ★ VDP1 User's Manual ★ Chapter 7 Command

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VDP1 User's Manual/Chapter 7 Commands

■7.6 Transformed sprite drawing command

The transform sprite drawing command draws a character pattern to the frame buffer. When drawing, you can specify the character pattern to be flipped vertically, flipped horizontally, scaled, stretched, rotated, and twisted at specified coordinates.
When the end bit is 0B and the command selection bit is 0010B, it is a deformed sprite drawing command.
The contents of the command table are as follows:

bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 CMDCTRL +00 0 JP 0 0 0 0 0 0 Dir 0 0 1 0 CMDLINK +02 LINK specification/8H 0 0 CMDPMOD +04 M.O. 0 0 0 PC Cl Cm Me E.C. SP Color mode color calculation CMDCOLR +06 Color bank, color lookup table/8H (LSB fixed at 00) CMDSRCA +08 Character address/8H CMDSIZE +0A 0 0 Character size X/8 Character size Y/8 CMDXA +0C sign extension Vertex (A), X coordinate (XA) CMDYA +0E sign extension Vertex (A), Y coordinate (YA) CMDXB +10 sign extension Vertex (B), X coordinate (XB) CMDYB +12 sign extension Vertex (B), Y coordinate (YB) CMDXC +14 sign extension Vertex (C), X coordinate (XC) CMDYC +16 sign extension Vertex (C), Y coordinate (YC) CMDXD +18 sign extension Vertex (D), X coordinate (XD) CMDYD +1A sign extension Vertex (D), Y coordinate (YD) CMDGRDA +1C Gouraud shading table/8H 【note】 is ignored (don't care)

The transform sprite drawing command is defined as follows

Setting the end bit to 0B and the command selection bit to 0010B makes it a deformed sprite drawing command.

Specify the jump format. When the jump format is Assign or Call, divide the address of the next command table to be processed by 8H and set it to CMDLINK.

Set the character pattern read direction. By specifying the reading direction, you can reverse the image vertically or horizontally. If you specify inversion twice by specifying the read direction and specifying the apex (A), apex (B), apex (C), or apex (D), the inversion will cancel and return to the original state.

Set up high speed shrink. Specify whether to prioritize accuracy or speed.

Set pre-clipping. Specify whether to enable or disable it, considering the clipping area and the drawing position of the part.

Specify the user clipping enable bit and clipping mode. Specifies whether user clipping is outside or inside in clipping mode.

Set mesh enabled, end code disabled, transparent pixels disabled. Set MSB on for shade or window processing in VDP2.

Set the color mode that defines the character pattern. Specifies the color bank when the color mode is color bank mode. When in lookup table mode, divide the color lookup table address by 8H to define.

Specify color operation. Color calculation is valid in RGB mode. If you do not want to perform color calculations, specify Replace. When performing Gouraud shading processing, divide the Gouraud shading address table by 8H and specify. Gouraud shading processing is valid in RGB mode.

Divide the character pattern table address by 8H and define it in CMDSRCA. Define the width and height of the character size defined in the character pattern table in CMDSIZE. The horizontal size is defined as the value divided by 8.

Set the upper left coordinates of the drawing area to the vertex (A) (CMDXA, CMDYA), the upper right coordinates to the vertex (B) (CMDXB, CMDYB), the lower right coordinates to the vertex (C) (CMDXC, CMDYC), and the lower left coordinates to the vertex (C) (CMDXC, CMDYC). Define at vertex (D) (CMDXD, CMDYD). The positional relationship of the four vertices is arbitrary, so you can specify scaling, stretching, rotation, and twisting by specifying apex (A), apex (B), apex (C), and apex (D). . You can also flip vertically and horizontally.

Note: If you set two vertices to the same coordinates, the sprite will be drawn as a triangle. If you set 4 vertices to the same coordinates, the sprite will be drawn with 1 pixel.

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