<51/54> VDP1 User's Manual / 7.9 Line drawing command

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

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VDP1 User's Manual / Chapter 7 Commands

■ 7.9 Line drawing command

The line drawing command draws a rectangle in the framebuffer. The inside of the rectangle is not filled.
This is a line drawing command when the end bit is 0B and the command selection bit is 0110B.
The contents of the command table are as follows:

bit 15 14 13 12 11 Ten 9 8 7 6 5 4 3 2 1 0 CMDCTRL +00 0 JP 0 0 0 0 0 0 0 0 0 1 1 0 CMDLINK +02 LINK designation / 8H 0 0 CMDPMOD +04 MO 0 0 0 Pc Cl Cm Me 1 1 0 0 0 Color calculation CMDCOLR +06 Non-texture color +08 + 0A 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) +14 +16 +18 + 1A CMDGRDA + 1C Gouraud shading table / 8H 【note】 Is ignored (don't care)

The line drawing command is defined as follows.

Setting the end bit to 0B and the command selection bit to 0110B results in a polyline drawing command.
Specify the jump format. When the jump format is assign or call, divide the address of the command table to be processed next by 8H and set it to CMDLINK.
Set pre-clipping. Consider the clipping area and the drawing position of the part, and specify whether it is enabled or disabled.
Specifies the user clipping enabled bit and the clipping mode. Specifies whether user clipping is outside or inside in clipping mode.
Set mesh enable. When the mesh is enabled, the entire line may not be drawn depending on the position and shape of the line.
Sets the MSB on for shading or windowing in VDP2.
Set the color mode to 000B. Set the color code to non-texture color (CMDCOLR).
Specifies the color operation. Color calculation is effective when the non-texture color is in RGB mode. If you do not want to perform color calculation, specify replacement. When performing Gouraud shading processing, specify the address of the Gouraud shading table by dividing it by 8H. Gouraud shading is effective when the non-texture color is in RGB mode. Only vertices (A) and vertices (B) of the Gouraud shading table are valid, and vertices (C) and vertices (D) are ignored.
Define the vertices (A) of the line to be drawn as CMDXA and CMDYA, and the vertices (B) as CMDXB and CMDYB.
Note: If you set two vertices to the same coordinates, the line will be drawn in 1 pixel.

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