objects/oUFO/step.gml

From spelunky.gmk, Spelunky Classic 1.1's source, © 2008, 2009 Derek Yu and Mossmouth, LLC, shown whole under the Spelunky User License v1.1b. Extracted by spelunky.ai's tools, an unofficial fan project, one file per script or event; the // ==== lines are the extractor's, naming each action of the event. Some scripts are others' work that Derek Yu credits in the source's readme.txt: Martin Piecyk's platform engine, ChevyRay's view scaling scripts and tsg1zzn's Super Sound System.

oUFO's step event, 131 lines of GML.

if ((x > view_xview[0]-20 and x < view_xview[0] + view_wview[0]+4 and        y > view_yview[0]-20 and y < view_yview[0] + view_hview[0]+4)){moveTo(xVel, yVel);if (hp < 1){    instance_create(x, y, oUFOCrash);    if (countsAsKill)    {        if (isRealLevel()) global.enemyKills[16] += 1;        global.ufos += 1;        global.kills += 1;    }    instance_destroy();}dir = 0;dist = point_distance(x, y, oCharacter.x, oCharacter.y);if (dist < 160 and not alerted){    alerted = true;    playSound(global.sndAlien);}if (status == DESTROY){    yVel = 0;    if (shiftToggle == 0) // right    {        xVel = 1;        shift += 1;        if (shift >= 64)        {            shiftToggle = 1;        }    }    else    {        xVel = -1;        shift -= 1;        if (shift <= -64)        {            shiftToggle = 0;        }    }        if (isCollisionLeft(1))    {        x += 1;        shiftToggle = 0;        shift = -64;    }        if (isCollisionRight(1))    {        x -= 1;        shiftToggle = 1;        shift = 64;    }        if (abs(oCharacter.x - (x+8)) < 8)    {        status = BLAST;        playSound(global.sndLaserCharge);    }        if (oPlayer1.y < y or y < oPlayer1.y-96) status = SEARCH;}else if (status = BLAST){    xVel = 0;    yVel = 0;    sprite_index = sUFOBlast;    if (image_index == 16)    {        instance_create(x+8, y+16, oLaser);        playSound(global.sndLaser);    }}else if (instance_exists(oCharacter) and not oCharacter.swimming and not oCharacter.dead){    if (y > oCharacter.y - 48)    {        if (yVel == 2) status = DESTROY;        yVel = -2;        //if (isCollisionTop(1)) y += 2;    }    else    {        if (yVel == -2) status = DESTROY;        yVel = 2;        //if (isCollisionBottom(1)) y -= 2;    }    if (shiftToggle == 0) // right    {        xVel = 1;        shift += 1;        if (shift >= 32)        {            shiftToggle = 1;            if (oCharacter.x > x) shift = 0;        }    }    else    {        xVel = -1;        shift -= 1;        if (shift <= -32)        {            shiftToggle = 0;            if (oCharacter.x < x) shift = 0;        }    }        if (isCollisionLeft(1))    {        x += 1;        shiftToggle = 0;        shift = -32;    }        if (isCollisionRight(1))    {        x -= 1;        shiftToggle = 1;        shift = 32;    }}}