Video

An intro before the title screen, a cutscene between levels, a looping background behind the menu: sometimes the thing to show is a video. I play MP4 and WebM files, sound and all.

Crash-tan’s Tip: The games in this book have a short video in their folder, clip.mp4: three seconds of me under the stars, with no sound. Put a video of your own in your game’s folder to hear one play.

Loading and playing

LOADVIDEO loads a video from the game’s folder and gives it a name, the way LOADIMG does for an image. PLAYVIDEO plays it on a layer, and your program carries on while it plays. !! loop starts it again each time it ends, and !! mute plays it without its sound.

SCREEN 320, 240
LOADVIDEO "clip.mp4", "menu"
PLAYVIDEO "menu", 1 !! loop mute

That’s a background for a menu: round and round, quietly, while the menu is drawn and the keys are read.

A cutscene

WAITVIDEO waits until a video has finished, so the program stops there and starts again when the video’s over. That’s a cutscene: play it, wait, then the next level.

When a video ends, its last picture stays, so the end of a cutscene doesn’t flash to an empty screen. This one plays on layer 0, the layer PRINT writes on, so “Level 1” goes on top of that last picture. On a higher layer, the picture would cover it.

SCREEN 320, 240
LOADVIDEO "clip.mp4", "intro"
PLAYVIDEO "intro", 0
WAITVIDEO "intro"
PRINT "Level 1"

The controls

PAUSEVIDEO pauses a video and RESUMEVIDEO carries on from where it was. SEEKVIDEO jumps to a time, in seconds, so SEEKVIDEO "intro", 0 goes back to the start. STOPVIDEO stops it for good, and a WAITVIDEO that was waiting for it stops waiting.

Players like to skip a cutscene they’ve seen. While the program waits on WAITVIDEO, a thread of its own watches the keys: Space skips, P pauses and R starts again.

SCREEN 320, 240
LOADVIDEO "clip.mp4", "intro"

FUNCTION controls()
    paused = FALSE
    DO
        IF COOLDOWN(1)
            IF keydown("Space") THEN STOPVIDEO "intro"
            IF keydown("R") THEN SEEKVIDEO "intro", 0
        END IF
        IF COOLDOWN(15) AND keydown("P")
            IF paused THEN RESUMEVIDEO "intro" ELSE PAUSEVIDEO "intro"
            paused = NOT paused
        END IF
    LOOP
END FUNCTION

PLAYVIDEO "intro", 0
CALL THREAD controls, "controls"
WAITVIDEO "intro"
STOP THREAD "controls"
PRINT "Level 1"

The COOLDOWN(15) on P means holding it down doesn’t flick between paused and playing sixty times a second.

When the video isn’t there

A game can check for its video before playing it, and go straight on without one. There’s no intro.mp4 in the book’s games, so this one skips to the level.

SCREEN 320, 240
IF fileexists("intro.mp4")
    LOADVIDEO "intro.mp4", "intro"
    PLAYVIDEO "intro", 0
    WAITVIDEO "intro"
END IF
PRINT "Level 1"

Level 1

Videos aren’t layers

Every platform plays video its own way, to use the hardware that’s made for it: in the browser it’s the browser’s own video player. So a video doesn’t always take on what you’ve done to its layer. Don’t count on a layer’s shader, transparency or clipping to change how a video looks.