Gyruss: Routine at A3E1

A3E1: Explode

Used by the routine at died.
explode	A3E1	LD A,$2A
	A3E3	LD ($7003),A
	A3E6	CALL display_ship_background_patterns	Display ship background patterns
	A3E9	LD A,$7F	Not allocated
	A3EB	LD (sprite_data),A	1st sprite
	A3EE	LD ($700E),A	2nd sprite
	A3F1	LD A,(active_shots)	Active shots
	A3F4	OR A	If zero
	A3F5	JR Z,explode_2	Then skip ahead
Deallocate all shots
	A3F7	LD IX,sprite_data	Sprite data table
	A3FB	LD DE,$000C	Size of each sprite
	A3FE	LD B,$20	32 sprites
	A400	LD A,$02	Is it type $02 (shot)?
explode_0	A402	CP (IX+$00)	...
	A405	JR NZ,explode_1	No, then skip
	A407	LD (IX+$00),$7F	Set as not allocated
	A40B	LD (IX+$08),$F8	Set y
explode_1	A40F	ADD IX,DE	Next sprite
	A411	DJNZ explode_0	Loop 32 times
Set center of projection for explosion
explode_2	A413	LD HL,($700A)	Y and X of 1st sprite
	A416	LD BC,$0404	Add 4 to each
	A419	ADD HL,BC	...
	A41A	LD (tmp_center_of_projection),HL	Save it in tmp_center_of_projection, which will be copied to center_of_projection
	A41D	LD A,($7004)	Byte 2 of 1st sprite
	A420	LD (tmp_sprite_data),A	Save it temporary
Allocate 6 sprites for explosion
	A423	LD IY,LA4B8
	A427	LD B,$06	Allocate 6 sprites
explode_3	A429	RST $28	Allocate sprite
	A42A	LD (IX+$00),$0D	Sprite type is $0D (a dot)
	A42E	LD (IX+$01),$00	Polar y
	A432	LD (IX+$02),$00	Polar x
	A436	LD (IX+$0B),$09	Set color (pink)
	A43A	RST $30	Load sprite pattern
	A43B	LD A,(tmp_sprite_data)	Restore byte 2 of 1st sprite
	A43E	ADD A,(IY+$00)	Add data from table
	A441	AND $3F	Mod $40
	A443	LD (IX+$02),A	Set polar x on new sprite
	A446	LD (IX+$01),$2A	Set polar y
	A44A	INC IY	Next init data
	A44C	DJNZ explode_3	Loop for 6 sprites
Game loop for 3 seconds
	A44E	LD B,$14	20
explode_4	A450	PUSH BC	Outer loop
	A451	CALL move_dots	Move dots
	A454	CALL upload_sprite_data	Upload sprite data
	A457	LD B,$09	9
explode_5	A459	HALT	Inner loop
	A45A	PUSH BC
	A45B	CALL display_stars	Display stars
	A45E	CALL process_sprites	Process sprites
	A461	CALL display_center_enemies	Display center enemies
	A464	CALL create_or_display_mines
	A467	CALL next_frame_upl_sprites	Upload sprites
	A46A	POP BC
	A46B	DJNZ explode_5	Loop 9 times
	A46D	POP BC
	A46E	DJNZ explode_4	Loop 20 times
	A470	RET