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climb: add rock collision

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This commit is contained in:
Vince Weaver 2024-09-18 22:25:58 -04:00
parent e88c70c92a
commit 54e1768aff
1 changed files with 173 additions and 0 deletions
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173
games/peasant_mini/cliff/climb.s
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@ -316,9 +316,27 @@ move_bird_done:
ldx #0
stx CURRENT_ROCK
move_rock_loop:
ldx CURRENT_ROCK
lda PEASANT_FALLING
bne no_rock_collision
; collision detect
jsr rock_collide
bcc no_rock_collision
; collision happened!
lda #1
sta PEASANT_FALLING
no_rock_collision:
lda rock_state,X
beq move_rock_normal
cmp #3
@ -833,3 +851,158 @@ bird_no_collide:
clc
rts
;===========================
; check for rock collisions
;===========================
; which rock in X
rock_collide:
; 0 = bit, 1 = little
lda rock_type,X
bne little_rock_collide
;===========================
; big rock collide
big_rock_collide:
; big rock is 3x22
; little rock is 2x14
; peasant is 3x30
; doing a sort of Minkowski Sum collision detection here
; with the rectangular regions
; might be faster to set it up so you can subtract, but that leads
; to issues when we go negative and bcc/bcs are unsigned compares
; if (rock_x+1<PEASANT_X-1) no_collide
; equivalent, if (rock_x+2<PEASANT_X)
; equivalent, if (PEASANT_X-1 >= rock_x+1)
lda rock_x,X
sta TEMP_CENTER
inc TEMP_CENTER ; rock_x+1
sec
lda PEASANT_X
sbc #1 ; A is PEASANT_X-1
cmp TEMP_CENTER ; compare with rock_x+1
bcs rock_no_collide ; bge
; if (rock_x+1>=PEASANT_X+3) no collide
; equivalent, if (rock_x-2>=PEASANT_X)
; equivalent, if (PEASANT_X+3<rock_x+1)
; carry clear here
adc #4 ; A is now PEASANT_X+3
cmp TEMP_CENTER
bcc rock_no_collide ; blt
; bird = 16
; rock = 22
; if (rock_y+11<PEASANT_Y-11) no_collide
; equivalent, if (rock_y+22<PEASANT_Y)
; equivalent, if (PEASANT_Y-11>=rock_y+11)
lda rock_y,X
clc
adc #11
sta TEMP_CENTER
lda PEASANT_Y
sec
sbc #11 ; A is now PEASANT_Y-11
cmp TEMP_CENTER
bcs rock_no_collide ; blt
; if (rock_Y+11>=PEASANT_Y+41) no collide
; equivalent, if (rock_y-30>=PEASANT_Y)
; equivalent, if (PEASANT_Y+41<rock_y+11)
; carry clear here
adc #41 ; A is now bird_y+30
cmp TEMP_CENTER
bcc rock_no_collide ; blt
rock_yes_collide:
sec
rts
rock_no_collide:
clc
rts
;=================================
; little rock collision
; Arkansas here we come
little_rock_collide:
; little rock is 2x14
; peasant is 3x30
; doing a sort of Minkowski Sum collision detection here
; with the rectangular regions
; if (PEASANT_X >= rock_x+2) no collide
; rr
; ppp
lda rock_x,X
sta TEMP_CENTER
inc TEMP_CENTER ; rock_x+1
inc TEMP_CENTER ; rock_x+2
sec
lda PEASANT_X ; A is PEASANT_X
cmp TEMP_CENTER ; compare with rock_x+1
bcs rock_no_collide ; bge
; if (PEASANT_X+3<rock_x)
; if (PEASANT_X+5<rock_x+2)
; rrzz
; pppzz
; carry clear here
adc #5 ; A is now PEASANT_X+5
cmp TEMP_CENTER ; rock_x+2
bcc rock_no_collide ; blt
; bird = 16
; big rock = 22
; little rock = 14
; if (rock_y+7<PEASANT_Y-7) no_collide
; equivalent, if (rock_y+14<PEASANT_Y)
; equivalent, if (PEASANT_Y-7>=rock_y+7)
lda rock_y,X
clc
adc #7
sta TEMP_CENTER
lda PEASANT_Y
sec
sbc #7 ; A is now PEASANT_Y-7
cmp TEMP_CENTER
bcs rock_no_collide ; blt
; if (rock_Y+7>=PEASANT_Y+37) no collide
; equivalent, if (rock_y-30>=PEASANT_Y)
; equivalent, if (PEASANT_Y+37<rock_y+7)
; carry clear here
adc #27 ; A is now bird_y+30
cmp TEMP_CENTER
bcc rock_no_collide ; blt
bcs rock_yes_collide ; bra