ReC98/th03/sprite16[bss].asm

public _sprite16_clip_left, _sprite16_clip_right
public _sprite16_put_h, _sprite16_put_w

_sprite16_clip_left 	dw ?
_sprite16_clip_right	dw ?
_sprite16_put_h	dw ?
_sprite16_put_w	db ?
	db ?
[Reverse-engineering] [th03] Playfield sprite clipping coordinates Part of P0060, funded by Touhou Patch Center. 2019-11-21 20:53:24 +00:00			`public _sprite16_clip_left, _sprite16_clip_right`
[Reverse-engineering] [th03] SPRITE16 calls Aha! TH03's in-game graphics run in line-doubled 640×200 simply because that's what this SPRITE16.COM version was written for, making use of the PC-98 EGC for optimized blitting. Doesn't seem all too optimized though, given that it chooses to effectively draw every sprite twice, just in case it might overlap with something that's already in VRAM. It first clears the previous VRAM content at the drawing position according to the sprite's alpha mask, then ORs in the actual sprite data. The EGC can do monochrome alpha- tested blitting just as well as the GRCG, but once the sprite data covers all bitplanes, ORing is apparently the best it can do by itself? More technical details on the raster operations in the next push! Completes P0056, funded by rosenrose and [Anonymous]. 2019-11-03 11:47:10 +00:00			`public _sprite16_put_h, _sprite16_put_w`

[Reverse-engineering] [th03] Playfield sprite clipping coordinates Part of P0060, funded by Touhou Patch Center. 2019-11-21 20:53:24 +00:00			`_sprite16_clip_left dw ?`
			`_sprite16_clip_right dw ?`
[Reverse-engineering] [th03] SPRITE16 calls Aha! TH03's in-game graphics run in line-doubled 640×200 simply because that's what this SPRITE16.COM version was written for, making use of the PC-98 EGC for optimized blitting. Doesn't seem all too optimized though, given that it chooses to effectively draw every sprite twice, just in case it might overlap with something that's already in VRAM. It first clears the previous VRAM content at the drawing position according to the sprite's alpha mask, then ORs in the actual sprite data. The EGC can do monochrome alpha- tested blitting just as well as the GRCG, but once the sprite data covers all bitplanes, ORing is apparently the best it can do by itself? More technical details on the raster operations in the next push! Completes P0056, funded by rosenrose and [Anonymous]. 2019-11-03 11:47:10 +00:00			`_sprite16_put_h dw ?`
			`_sprite16_put_w db ?`
			`db ?`