Mega Man 2 graphics (lsmmega/mm2)

On even frames _sprites writes Mega Man's object slots (0 to $0F), then the enemies' ($10 to $1F), then the energy meters; on odd frames it writes the meters first and the slots in reverse, $1F down to $10, then $0F down to 0, so objects that lose the 8-per-scanline race lose it only every other frame. mm2-av/sprite-order-flip

About: Mega Man 2 Sprite flicker

Value

{
 "even": "slots 0-$1F, then meters",
 "odd": "meters, then slots $1F-0",
 "period": 2
}

Codemm2: Mega Man 2 disassembly (lsmmega/mm2) · home/sprites.asm#L12-L38@time_stopper_flag_not_set: LDA z:znmi_frame AND #%00000001 BNE @invert … @loop_1: JSR _draw_megaman_with_animation … CMP #$10 BNE @loop_1 @loop_2: JSR _draw_enemies_with_animation …mm2: Mega Man 2 disassembly (lsmmega/mm2) · home/sprites.asm#L43-L62@invert: JSR _draw_bar … LDA #$1F STA z:zsprites_pointer @loop_3: JSR _draw_enemies_with_animation BCS @max_2 DEC z:zsprites_pointer … @loop_4: JSR _draw_megaman_with_animation …Checked by claude, 2026-10-21 — read _sprites at the pinned commit

The "loses only every other frame" reading follows from the PPU's in-order search (nes-hardware/sprites-per-scanline); the atlas has not measured flicker in play. When the time stopper is active a separate path (_time_stopper_flag_set) runs instead.

Cited by: Mega Man 2, Sprite flicker

Mega Man 2 draws its energy meters as sprites, not a split screen; each meter is a column of 7 sprites from Y $18 down to $48, each showing 0-4 units, at X $10 for the weapon, $18 for life, and $28 for a boss. mm2-av/sprite-meters

About: Mega Man 2 Status bar split

Value

{
 "spritesPerMeter": 7,
 "unitsPerSprite": 4,
 "topY": 24,
 "x": {
  "weapon": 16,
  "life": 24,
  "boss": 40
 }
}

Codemm2: Mega Man 2 disassembly (lsmmega/mm2) · home/sprites.asm#L473-L476vertical_bar_base_ycoord = $18 hp_bar_xcoord = $18 weapon_bar_xcoord = $10 boss_bar_xcoord = $28mm2: Mega Man 2 disassembly (lsmmega/mm2) · home/sprites.asm#L530-L545_draw_bar_tile: LDY #6 @loop: LDA @vertical_bar_ycoord_table, Y STA aoam_y, X SEC LDA z:z00 SBC #4mm2: Mega Man 2 disassembly (lsmmega/mm2) · home/sprites.asm#L572-L579@vertical_bar_ycoord_table: .BYTE vertical_bar_base_ycoord + 0 … .BYTE vertical_bar_base_ycoord + 48Checked by claude, 2026-10-21 — read _draw_bar and _draw_bar_tile at the pinned commit

The loop starts at the bottom sprite (index 6) and takes 4 units per sprite, so a meter fills from the bottom up. Three meters on one line use 3 of the 8 sprite slots.

Cited by: Mega Man 2, Status bar split

Once a frame _background_palette counts up to a stage's frame byte and then copies the next 16-byte background palette set into the working palette, wrapping after the stage's set count; Heat Man's stage has 3 sets and a frame byte of 6, so its palette 3 rotates $36, $26, $16 one step every 7 frames. mm2-av/palette-sets

About: Mega Man 2 Palette cycling

Value

{
 "heatman": {
  "sets": 3,
  "frameByte": 6,
  "framesPerStep": 7,
  "palette3": [
   [
    54,
    38,
    22
   ],
   [
    38,
    22,
    54
   ],
   [
    22,
    54,
    38
   ]
  ]
 }
}

Codemm2: Mega Man 2 disassembly (lsmmega/mm2) · home/background_palette.asm#L1-L32_background_palette: … LDA apalette_animation_frame BEQ @skip INC z:zpalette_animation_timer CMP z:zpalette_animation_timer BCS @skip LDA #$00 STA z:zpalette_animation_timer INC z:zcurrent_palette_no LDA z:zcurrent_palette_no CMP ano_of_palette …mm2: Mega Man 2 disassembly (lsmmega/mm2) · home/nmi_wait.asm#L1-L12_nmi_wait_0e: … JSR _background_palette LDA #$00 STA z:znmi_wait @loop: LDA z:znmi_wait BEQ @loopmm2: Mega Man 2 disassembly (lsmmega/mm2) · stages/heatman_wily1/heatman_wily1_palette_init.asm#L1-L34;heatman palette init ; number of background animation palette(s), frame(s) .BYTE 3, 6 … .BYTE black, pale_red, white_red, light_red … .BYTE black, white_red, light_red, pale_red … .BYTE black, light_red, pale_red, white_redmm2: Mega Man 2 disassembly (lsmmega/mm2) · constants/palettes.asm#L1-L55dark_gray … light_gray … light_red … white_gray = $20 … pale_gray = $30 … pale_redChecked by claude, 2026-10-21 — read _background_palette, its per-frame call, Heat Man's palette data, and the color enum at the pinned commit

The step comes when the counter exceeds the frame byte (BCS skips while byte ≥ counter), so a byte of 6 steps every 7 frames. The enum counts from $00, so light_red = $16, white_red = $26, pale_red = $36. Which tiles use palette 3 in Heat Man's stage (the lava falls, by appearance) was not read from the level data.

Cited by: Mega Man 2, Palette cycling