Routines
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48210: Apply Sprite Attributes (3-Wide)
Used by the routine at Draw_Sprites.
Applies colour attributes to a sprite's screen position. First writes the sprite's own colour attribute, then writes the background colour (2 RED ink) on top. The sprite occupies a 3x2 or 3x3 character cell area depending on alignment.
Input
HL Screen buffer address of the sprite
IX Pointer to the sprite state data
ApplySpriteAttributes3Wide 48210 LD C,88 Set the attribute base to 88 (i.e. the attribute buffer at 22528).
48212 LD D,0 D=0.
Check if the sprite's X position is on a character boundary. If not, set bit 0 of D to indicate an extra column is needed.
48214 LD A,(IX+0) Load A with the sprite X position from *IX+0.
48217 AND %00000111 Keep only bits 0-2 (sub-character X offset).
48219 JR Z,ApplySpriteAttributes3Wide_SpriteColour Jump to ApplySpriteAttributes3Wide_SpriteColour if X-aligned.
48221 SET 0,D Set bit 0 of D (not X-aligned, need extra column).
First pass: write the sprite's own colour attribute to the attribute file. Skip if the attribute is 255 (transparent).
ApplySpriteAttributes3Wide_SpriteColour 48223 LD E,(IX+2) Load E with the sprite colour attribute from *IX+2.
48226 LD A,E Jump to ApplySpriteAttributes3Wide_Background if the attribute byte is transparent (255).
48227 CP 255
48229 JR Z,ApplySpriteAttributes3Wide_Background
48231 PUSH HL Stash the screen buffer address on the stack.
48232 CALL WriteAttributeBlock3Wide Call WriteAttributeBlock3Wide to write the sprite attribute.
48235 POP HL Restore the screen buffer address from the stack.
Second pass: write the background attribute (2 RED ink) over the sprite area using the room attribute base (248 maps to RoomAttributeBuffer).
ApplySpriteAttributes3Wide_Background 48236 LD C,248 C=248.
48238 LD E,2 E=RED.
48240 CALL WriteAttributeBlock3Wide Call WriteAttributeBlock3Wide to write the background attribute.
48243 RET Return.
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