Vectrex Development with VPy: The Python-Based Alternative to Assembly

def loop():
    x = J1_X()  # Read joystick X position
    y = J1_Y()  # Read joystick Y position
 
    DRAW_CIRCLE(x, y, 30, 80)  # Draw circle at joystick position

LOOP:       LDB     Joy_x       ; Load joystick X into B
            CLRA                ; Clear A (16-bit value)
            LDD     Joy_y       ; Load Y into D
 
            PSHS    B,CC        ; Save registers
            LDX     #$C800      ; Point to vector RAM
            STX     Temp1       ; Store pointer
 
            ; ... 50+ more lines of address calculations ...
 
            JSR     Draw_Line   ; Call BIOS routine
            PULS    B,CC        ; Restore registers
 
            BRA     LOOP        ; Repeat

score: u16 = 0           # 16-bit unsigned (0-65535)
level: i8 = 1            # 8-bit signed (-128 to 127)
position_x: i16 = 100    # 16-bit signed (-32768 to 32767)
enemies = []             # Auto-type (defaults to i16 arrays)

DRAW_LINE(0, 0, 50, 50, 80)      # Draw line from (0,0) to (50,50) with brightness 80
DRAW_CIRCLE(x, y, 30, 80)        # Draw circle at (x,y) with radius 30, brightness 80
DRAW_RECT(x, y, width, height, brightness)  # Rectangle at (x,y) with dimensions
DRAW_POLYGON(3, 80, 0, 0, 50, 0, 25, 50)   # Polygon: 3 points, brightness 80, then x1,y1,x2,y2,x3,y3

def loop():
    # Read joystick analog values
    x = J1_X()  # Joystick 1 X (-128 to 127)
    y = J1_Y()  # Joystick 1 Y (-128 to 127)
 
    # Check button states (0 = not pressed, 1 = pressed)
    if J1_BUTTON_1() == 1:
        shoot()
 
    if J1_BUTTON_2() == 1:
        jump()
 
    # Alternative: use UPDATE_BUTTONS() to refresh state
    UPDATE_BUTTONS()

# Set display brightness (must be called in setup or before drawing)
SET_INTENSITY(80)
 
# Play background music (call once at startup or when needed)
PLAY_MUSIC("pang_theme")
 
# Stop current music playback
STOP_MUSIC()
 
# Update audio system each frame (auto-injected by compiler)
AUDIO_UPDATE()

STATE_MENU = 0
STATE_GAME = 1
STATE_GAMEOVER = 2
 
current_state = STATE_MENU
 
def loop():
    if current_state == STATE_MENU:
        draw_menu()
    elif current_state == STATE_GAME:
        update_game()
        draw_game()

# main.vpy
 
def setup():
    SET_INTENSITY(80)
 
def loop():
    x = J1_X()
    y = J1_Y()
 
    DRAW_CIRCLE(x, y, 30, 80)

# VECTREX PONG - Full Game Example (CORRECTED)
# Control: Use joystick to move paddle up/down
# Goal: Destroy all bricks and don't let the ball get past!
 
META TITLE = "PONG"
META MUSIC = music1
 
# CONSTANTS
SCREEN_WIDTH: i16 = 115
SCREEN_HEIGHT: i16 = 115
PADDLE_WIDTH: i16 = 5
PADDLE_HEIGHT: i16 = 30
BALL_RADIUS: i8 = 3
BRICK_WIDTH: i16 = 15
BRICK_HEIGHT: i8 = 8
BRICK_COLS: u8 = 4
BRICK_ROWS: u8 = 3
TOTAL_BRICKS: u8 = 12
HALF_PADDLE: i16 = 15
 
# Paddle X positions (fixed)
PLAYER_PADDLE_X: i16 = -110
AI_PADDLE_X: i16 = 110
 
# VARIABLES
score: u16 = 0
lives: u8 = 3
level_complete: u8 = 0
game_state: u8 = 0  # 0=TITLE, 1=PLAY, 2=GAMEOVER
 
ball_x: i16 = 0
ball_y: i16 = 0
ball_vx: i8 = 2
ball_vy: i8 = 1
 
player_y: i16 = 0
ai_y: i16 = 0
 
brick_active = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]  # Brick states
 
def clamp(value, min_val, max_val):
    if value < min_val:
        return min_val
    if value > max_val:
        return max_val
    return value
 
def get_brick_row(index):
    if index < 4:
        return 0
    elif index < 8:
        return 1
    else:
        return 2
 
def check_brick_collision():
    for i in range(TOTAL_BRICKS):
        if brick_active[i] == 0:
            continue
 
        col = i % BRICK_COLS
        row = get_brick_row(i)
 
        brick_x = -80 + col * BRICK_WIDTH
        brick_y = 50 - row * BRICK_HEIGHT
 
        # AABB collision
        if ball_x > brick_x and ball_x < brick_x + BRICK_WIDTH:
            if ball_y > brick_y and ball_y < brick_y + BRICK_HEIGHT:
                brick_active[i] = 0
                ball_vy = -ball_vy
                return 1
 
    return 0
 
def check_paddle_collision():
    # Check player paddle (left side at Y position)
    if ball_x < PLAYER_PADDLE_X + PADDLE_WIDTH:
        if ball_y > player_y - HALF_PADDLE and ball_y < player_y + HALF_PADDLE:
            ball_vx = -ball_vx
            return 1
 
    # Check AI paddle (right side at Y position)
    if ball_x > AI_PADDLE_X - PADDLE_WIDTH:
        if ball_y > ai_y - HALF_PADDLE and ball_y < ai_y + HALF_PADDLE:
            ball_vx = -ball_vx
            return 1
 
    return 0
 
def draw_title():
    PRINT_TEXT(-40, 50, "VECTREX")
    PRINT_TEXT(-25, 35, "PONG")
    PRINT_TEXT(-50, 0, "Press Button")
    PRINT_TEXT(-50, -15, "to Start")
 
def draw_game():
    # Draw bricks
    for i in range(TOTAL_BRICKS):
        if brick_active[i] == 1:
            col = i % BRICK_COLS
            row = get_brick_row(i)
            brick_x = -80 + col * BRICK_WIDTH
            brick_y = 50 - row * BRICK_HEIGHT
            DRAW_RECT(brick_x, brick_y, BRICK_WIDTH, BRICK_HEIGHT, 80)
 
    # Draw player paddle (left side, vertical)
    DRAW_RECT(PLAYER_PADDLE_X, player_y, PADDLE_WIDTH, PADDLE_HEIGHT, 80)
 
    # Draw AI paddle (right side, vertical)
    DRAW_RECT(AI_PADDLE_X, ai_y, PADDLE_WIDTH, PADDLE_HEIGHT, 80)
 
    # Draw ball
    DRAW_CIRCLE(ball_x, ball_y, BALL_RADIUS, 80)
 
    # Draw score and lives at top
    SET_INTENSITY(60)
    PRINT_TEXT(-110, 105, "SCORE")
    PRINT_NUMBER(-110, 95, score)
    PRINT_TEXT(85, 105, "LIVES")
    PRINT_NUMBER(95, 95, lives)
 
def draw_gameover():
    SET_INTENSITY(80)
    PRINT_TEXT(-30, 50, "GAME OVER")
    PRINT_TEXT(-30, 20, "SCORE:")
    PRINT_NUMBER(10, 20, score)
    PRINT_TEXT(-50, -20, "Press to Restart")
 
def main():
    SET_INTENSITY(80)
    game_state = 0
    ball_x = 0
    ball_y = 0
    player_y = 0
    ai_y = 0
 
def loop():
    UPDATE_BUTTONS()
 
    if game_state == 0:  # TITLE
        draw_title()
        if J1_BUTTON_1() == 1:
            game_state = 1
            score = 0
            lives = 3
            ball_x = 0
            ball_y = 0
            ball_vx = 2
            ball_vy = 1
            player_y = 0
            ai_y = 0
 
    elif game_state == 1:  # PLAY
        # Update player paddle (controlled by joystick)
        player_y = J1_Y()
        player_y = clamp(player_y, -85, 85)
 
        # AI follows ball (simple AI on Y axis)
        if ai_y < ball_y - 10:
            ai_y = ai_y + 2
        elif ai_y > ball_y + 10:
            ai_y = ai_y - 2
        ai_y = clamp(ai_y, -85, 85)
 
        # Update ball position
        ball_x = ball_x + ball_vx
        ball_y = ball_y + ball_vy
 
        # Wall collisions (top and bottom)
        if ball_y > SCREEN_HEIGHT:
            ball_vy = -ball_vy
            ball_y = SCREEN_HEIGHT - 1
        if ball_y < -SCREEN_HEIGHT:
            ball_vy = -ball_vy
            ball_y = -SCREEN_HEIGHT + 1
 
        # Check collisions with bricks and paddles
        check_brick_collision()
        check_paddle_collision()
 
        # Ball out of bounds on left or right (lost)
        if ball_x < -SCREEN_WIDTH:
            lives = lives - 1
            if lives == 0:
                game_state = 2
            else:
                ball_x = 0
                ball_y = 0
                ball_vx = 2
                ball_vy = 1
        elif ball_x > SCREEN_WIDTH:
            lives = lives - 1
            if lives == 0:
                game_state = 2
            else:
                ball_x = 0
                ball_y = 0
                ball_vx = -2
                ball_vy = 1
 
        # Win condition (all bricks destroyed)
        if level_complete == 0:
            bricks_left = 0
            for i in range(TOTAL_BRICKS):
                if brick_active[i] == 1:
                    bricks_left = bricks_left + 1
            if bricks_left == 0:
                score = score + 100
                level_complete = 1
 
        draw_game()
 
    elif game_state == 2:  # GAMEOVER
        draw_gameover()
        if J1_BUTTON_1() == 1:
            game_state = 0
            # Reset bricks
            for i in range(TOTAL_BRICKS):
                brick_active[i] = 1
            level_complete = 0

DRAW_LINE(x1, y1, x2, y2, brightness)        # Draw line
DRAW_CIRCLE(x, y, radius, brightness)        # Draw circle
DRAW_POLYGON(num_points, brightness, x1, y1, x2, y2, ...)  # Draw polygon
DRAW_VECTOR(x, y, brightness)                # Draw vector
DRAW_RECT(x, y, width, height, brightness)   # Draw rectangle
DRAW_FILLED_RECT(x, y, width, height, brightness)  # Filled rectangle
DRAW_ARC(x, y, radius, start_angle, end_angle, brightness)  # Draw arc
DRAW_ELLIPSE(x, y, width, height, brightness)  # Draw ellipse
MOVE(x, y)                                    # Move pen position

J1_X()                           # Return joystick X (-128 to 127, signed)
J1_Y()                           # Return joystick Y (-128 to 127, signed)
J1_BUTTON_1()                    # Return button 1 state (0 or 1)
J1_BUTTON_2()                    # Return button 2 state (0 or 1)
J1_BUTTON_3()                    # Return button 3 state (0 or 1)
J1_BUTTON_4()                    # Return button 4 state (0 or 1)
UPDATE_BUTTONS()                 # Update all button states

PLAY_MUSIC(track_name)           # Start background music by name
STOP_MUSIC()                     # Stop music playback
PLAY_SFX(sound_name)             # Play sound effect
AUDIO_UPDATE()                   # Update audio subsystem (auto-injected)
MUSIC_UPDATE()                   # Update music playback (auto-injected)

SET_INTENSITY(brightness)        # Set default brightness (0-127)
WAIT_RECAL()                     # Wait for screen recalibration (auto-injected)

abs(value)                       # Absolute value
min(a, b)                        # Minimum of two values
max(a, b)                        # Maximum of two values
clamp(value, min_val, max_val)  # Clamp value to range
 
# Trigonometry (uses 128-entry lookup tables)
sin(angle)                       # Sine
cos(angle)                       # Cosine
tan(angle)                       # Tangent
sqrt(value)                      # Square root
pow(base, exponent)              # Power
atan2(y, x)                      # Arc tangent of y/x
rand()                           # Random number (0-32767)
rand_range(min, max)             # Random in range

PRINT_TEXT(x, y, text)           # Draw text at position
PRINT_NUMBER(x, y, number)       # Draw number at position
DEBUG_PRINT(message)             # Print to debug console
DEBUG_PRINT_LABELED(label, value)  # Print with label
DEBUG_PRINT_STR(string)          # Print string to console

wait(frames)                     # Wait N frames
beep()                           # Play beep sound
fade_in(duration)                # Fade in display
fade_out(duration)               # Fade out display
peek(address)                    # Read byte from ROM (constant address only)
poke(address, value)             # Write byte to RAM (constant address only)
asm(assembly_code)               # Inline assembly (advanced)