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vertical lvl physics documentation

This commit is contained in:
Michael Miceli 2023-09-05 23:09:41 -04:00
parent d841c660e0
commit 666fc83fc4
5 changed files with 29 additions and 24 deletions
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4
src/bank1.asm
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@ -4251,7 +4251,7 @@ draw_player_hud_sprites:
stx $04
rts
; table for hud sprites (#$10 bytes)
; table for hud sprites, references pattern table tiles (#$10 bytes)
; medals for number of lives or
; GAME
; OVER
@ -4272,7 +4272,7 @@ set_x_adv_OAMDMA_addr:
adv_OAMDMA_addr:
txa ; move current write offset to a
clc ; clear carry in preparation for addition
adc #$c4 ; add #$c4 to current write offset ()
adc #$c4 ; add #$c4 to current write offset
tax ; move new offset back to x
rts

2
src/bank3.asm
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@ -755,7 +755,7 @@ level_6_palette_data:
level_6_nametable_update_palette_data:
.byte $aa,$aa,$aa,$55,$55,$00,$00
; namespace animation tiles codes - level 7 (#$c * #$5 = #$3c bytes)
; nametable animation tiles codes - level 7 (#$c * #$5 = #$3c bytes)
; first byte is number of groups of length 2 to update of data being written
; e.g. byte 0 (#$83) means to draw three rows of two tiles each
; $0c $0d store the ppu write address

2
src/bank4.asm
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@ -436,7 +436,7 @@ game_end_routine_04:
bne game_end_routine_exit ; exit if not the 8th frame (scroll every 8 frames)
inc VERTICAL_SCROLL ; vertical scroll offset
lda VERTICAL_SCROLL
cmp #$f0 ; see if the view window needs to be set back to $2000 (scroll reached bottom of $2800 namespace)
cmp #$f0 ; see if the view window needs to be set back to $2000 (scroll reached bottom of $2800 nametable)
bne @continue ; branch if no need to reset base nametable write address and vertical scroll
lda #$20 ; initialize PPU write address to #$200 and set/reset VERTICAL_SCROLL
sta $44 ; write nametable address high byte for PPU address #$2000

38
src/bank7.asm
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@ -4679,8 +4679,8 @@ handle_jump:
clc ; clear carry in preparation for addition
adc VERTICAL_SCROLL ; add vertical scroll offset
and #$0f ; keep bits .... xxxx
cmp #$08 ; see if result ends in #$08
bcs @apply_gravity ; branch to check collision every #$08 pixels
cmp #$08 ; seeing if result is less than #$08
bcs @apply_gravity ; branch to check collision only when result is less than #$08
@check_collision:
jsr get_player_bg_collision_code ; get player background collision code
@ -4698,9 +4698,9 @@ handle_jump:
tay ; set y position for bg collision check
lda SPRITE_X_POS,x ; load x position for bg collision check
jsr get_bg_collision ; determine player background collision code at position (a,y)
bpl @apply_gravity ; branch if not empty collision code (floor, water, solid)
lda #$00 ; a = #$00
sta PLAYER_Y_FAST_VELOCITY,x
bpl @apply_gravity ; branch if not solid collision
lda #$00 ; solid collision above player, set Y velocity to #$00
sta PLAYER_Y_FAST_VELOCITY,x ; gravity will then pull the player down
sta PLAYER_Y_FRACT_VELOCITY,x
@apply_gravity:
@ -5899,10 +5899,11 @@ load_column_of_tiles_to_cpu_buffer:
; - looped through until all tiles for a single column have been written
; - ultimately is called 4 times for each super-tile because each time renders only 1 column of pattern table tiles for the super-tile
; * updates the in-memory background collision (BG_COLLISION_DATA) information (set_tile_collision)
; Y is the LEVEL_SCREEN_SUPERTILES offset (level_X_supertiles_screen_XX)
; $03 is the column offset of the super-tile to write to CPU_GRAPHICS_BUFFER block (currently drawing column)
; #$37 super-tiles per screen for horizontal levels
; #$40 super-tiles per screen for vertical levels
; input
; * y - is the LEVEL_SCREEN_SUPERTILES offset (level_X_supertiles_screen_XX)
; * $03 - is the column offset of the super-tile to write to CPU_GRAPHICS_BUFFER block (currently drawing column)
; CPU address #$df48
load_level_supertile_data:
lda #$00 ; initialize LEVEL_SUPERTILE_DATA_PTR read offset
@ -5983,7 +5984,7 @@ set_vert_lvl_super_tiles:
and #$03 ; keep bits .... ..xx
asl
asl
sta $02
sta $02 ; byte offset into the super-tile
lda PPU_WRITE_TILE_OFFSET
and #$1c ; keep bits ...x xx..
asl
@ -6000,13 +6001,14 @@ set_vert_lvl_super_tiles:
@set_supertile_tiles:
lda #$00 ; a = #$00
sta $08
lda LEVEL_SCREEN_SUPERTILES,y ; read byte specifying which super-tile to load (level_X_supertiles_screen_XX)
lda LEVEL_SCREEN_SUPERTILES,y ; read byte specifying which super-tile to load
; decompressed level_X_supertiles_screen_XX data
asl
asl
rol $08
asl
rol $08
asl
asl ; 4 total asl instructions since each super-tile is #$10 bytes
rol $08
adc LEVEL_SUPERTILE_DATA_PTR ; (bank 3 pointer)
sta $00
@ -6164,8 +6166,8 @@ write_row_attribute_to_cpu_memory:
; determine tile collision code (0-3) for the pattern table tile updates BG_COLLISION_DATA
; input
; * a - namespace tile code from the super-tile
; * y - level namespace tile offset (level_X_SUPERTILE_data offset)
; * a - nametable tile code from the super-tile
; * y - level nametable tile offset (level_X_SUPERTILE_data offset)
; tile code 0 is always set to collision code 0
set_tile_collision:
sty $14 ; store super-tile tile data read offset in $14 (LEVEL_SUPERTILE_DATA_PTR offset)
@ -6173,15 +6175,16 @@ set_tile_collision:
bne tile_collision_exit ; exit if $11 is set
tay ; move the pattern table tile code to Y
beq set_collision_code_0 ; tile index is #$00, set to collision code 0 (empty)
; tile index #$00 is always collision code #$0
cmp COLLISION_CODE_1_TILE_INDEX ; compare against collision code 1 tile index
bcs collision_code_0_check ; pattern table tile is not collision code 1, check to see if collision code 0
bcs collision_code_0_check ; branch if pattern table tile is not collision code 1, check to see if collision code 0
lda #$01 ; set collision code to 1 (floor)
bne collision_continue ; continue
; check if empty collision code
collision_code_0_check:
cmp COLLISION_CODE_0_TILE_INDEX
bcs collision_code_2_check ; tile index is greater than collision code 2 limit, check if collision code 03
bcs collision_code_2_check ; tile index is greater than collision code 0 limit, check if collision code 2
set_collision_code_0:
lda #$00 ; set collision code to 0 (empty)
@ -6208,7 +6211,7 @@ collision_continue:
asl
asl
asl
asl ; shift the tile code (2 bits) all the way to the left 2 bits
asl ; shift the collision code (2 bits) all the way to the left 2 bits
sta $15 ; store modified collision code for super-tile into $15
ldy $12 ; load BG_COLLISION_DATA write offset
lda BG_COLLISION_DATA,y ; load existing collision byte (each byte contains collision data for 2 super-tiles)
@ -6221,7 +6224,7 @@ set_collision_tile_col_2:
asl
asl
asl
asl ; shift the tile code (2 bits) all the way to the bits 5 and 4 (..xx ....)
asl ; shift the collision code (2 bits) all the way to the bits 5 and 4 (..xx ....)
sta $15 ; store shifted collision code for super-tile into $15
ldy $12 ; load BG_COLLISION_DATA write offset
lda BG_COLLISION_DATA,y ; load existing collision byte (each byte contains collision data for 2 super-tiles)
@ -6232,7 +6235,7 @@ set_collision_tile_col_3:
dey ; see if second column by subtracting stored write offset
bne set_collision_tile_col_4 ; if not the second column, branch to see if 4th
asl
asl ; shift the tile code (2 bits) to the bits 2 and 2 (.... xx..)
asl ; shift the collision code (2 bits) to the bits 2 and 2 (.... xx..)
sta $15 ; store collision code for super-tile into $15
ldy $12 ; load BG_COLLISION_DATA write offset
lda BG_COLLISION_DATA,y ; load existing collision byte (each byte contains collision data for 2 super-tiles)
@ -6537,6 +6540,7 @@ load_next_next_supertiles_screen_indexes:
adc #$02 ; add #$02 to load screen in the future
bne load_supertiles_screen_indexes ; decompress and load super-tile indexes into LEVEL_SCREEN_SUPERTILES
; load the super tile indexes for the upcoming screen into memory at LEVEL_SCREEN_SUPERTILES
load_next_supertiles_screen_indexes:
lda LEVEL_SCREEN_NUMBER ; load current screen number within the level
clc ; clear carry in preparation for addition

7
src/constants.asm
View File

@ -86,7 +86,8 @@ PPU_WRITE_ADDRESS_LOW_BYTE = $62 ; used to populate the PPU write address i
PPU_WRITE_ADDRESS_HIGH_BYTE = $63 ; used to populate the PPU write address in the CPU_GRAPHICS_BUFFER
LEVEL_SCREEN_NUMBER = $64 ; the screen number of the current level (how many screens into the level)
LEVEL_SCREEN_SCROLL_OFFSET = $65 ; the number of pixels into LEVEL_SCREEN_NUMBER the level has scrolled. Goes from $00-$ff for each screen (256 pixels)
; for horizontal levels, this is how many pixels scrolled to the right, for vertical levels, this is how many pixels up scrolled
; for horizontal levels, this is how many pixels scrolled to the right
; for vertical levels, this is how many pixels up scrolled, note this value is equal to #$f0 - VERTICAL_SCROLL
; for indoor levels, after defeating a wall, increases from #$00 to #03
ATTRIBUTE_TBL_WRITE_LOW_BYTE = $66 ; the low byte of the attribute table write address to write to (always #$c0, never read)
ATTRIBUTE_TBL_WRITE_HIGH_BYTE = $67 ; the high byte of the attribute table write address to write to
@ -220,8 +221,8 @@ CONTROLLER_STATE_DIFF = $f5 ; stores the difference between the contro
CTRL_KNOWN_GOOD = $f9 ; used in input-reading code to know the last known valid read of controller input (similar to CONTROLLER_STATE)
VERTICAL_SCROLL = $fc ; the number of pixels to vertically scroll down
; (y component of PPUSCROLL) (see level_vert_scroll_and_song for initial values)
; outdoor levels are always #$e0 (224 pixels or 28 tiles down), indoor/base are always #$e8 (232 or 29 tiles down)
; waterfall level starts at #$00 and decrements as players move up screen (wrapping)
; horizontal levels are always #$e0 (224 pixels or 28 tiles down), indoor/base are always #$e8 (232 or 29 tiles down)
; waterfall level (vertical level) starts at #$00 and decrements as players move up screen (wrapping)
HORIZONTAL_SCROLL = $fd ; the horizontal scroll component of the PPUSCROLL, [#$0 - #$ff]
PPUMASK_SETTINGS = $fe ; used to store value of PPUMASK before writing to PPU
PPUCTRL_SETTINGS = $ff ; used to set PPUCTRL value for next frame