High Tide Sandcastle

Vasilis Bellos
/
High Tide Sandcastle
about 1 hour ago
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game.m
function g = game
% High Tide Sandcastle
% A one-button pixel physics game.
% Tap to drop sand and build a sandcastle to protect the flag from the
% rising tide. Survive the night until the tide ebbs to beat the game.
g = struct(init = @I,update = @(s,d,p)M(s,d,p,1),render = @(~,s)M(s,0,0,2));
end

function s = I(ax)
% Decode the compressed game data and instruction table
c = J(jsondecode(char(D('󆮟󳳏񇤺򻶅󴱇󝽟𔦪𶵝𙨭򱐿𙀏󂎑󹬞񡽩񼗼􍴉􋤽󓞵􍐾񷾰񏵀𡝿􉭌𙄨􊏌񥈓󋚻􅒁񨝀󎽧򓩒󻔶񙫦󭼱󣪈򓰜񄛇󞪇󴹵񯓄򽽼񭊱񆞬򌇖񈡶𲯉򓊇򭩾򁔕񾐄񰉊󮐵򙾐񫐊񄵜󚚗񇣨񮤉񛬡򒙔𪾶򰶊򭖠񣊊󯨹𫖅󢝗󈺄󻠊󽱁􂌞񹹈񢪩񐽠󕗩򛃹𝆹󤥪𼷕󼆜򱧏􌍟򁹛񝊈𗊮󩈈𛨣񁷆󚑤􏕱񘎌񳶽􇝵򂑊񽡻񱵜򲿑񐿏򩈑򠢓򩽨򼱋𲉋𦩙󟷆􄝇𰬗񡣾򩔵򌓕􈈁􉥃󰂰򨍳񱿱򩜷񒺇󩂘񚽠񔧌󅾄񓅿􋍲򜾞𞽯󉜨򥘤󴅭󡓟񕠑񢾢񥲜󉥪󳆆𖞒􅂄𛿖󾱁𹰶򬏜𷼯𦵾𿤣𚸊󩤠􅅄񴽏񳼕󋼉񘨖𕎴񩲐󋈃𫓦􋄾򛅷񧯼񸺳𪧽򹀒󍶄򬐱񕍽񺠴򔄊񬤊󳾠񏲰󃣚򏿔󐏯򱧲񏐄𭻺񩶃𮧲򸗱񮀕𓿭󨨅򩸿򯧹򕔟򉴄򛪽򊷵񨶩􁰅󓢑򑴇󒻭򼔠󋙣󽋬󡟬󻿃󟞽򰩀򬹣𒘒𸨢򪊅򥹣񳕒򹐬𔓯񧍢񠝜񒽭𭜭򭥱󬜯񜖏񶁼𲨲󥷗򟐣󳐅񣗐󻦸򔰞򍘪񫐄𢼜񚌈񦥷𕘏򸒊󒁼󼚚򑭣󩈐𬾋񡉹󭓰󘓦񽪭󄛍񎦱󞥹🕷􀐹􂛨񇾴򑛮􀄞󬍢󑭑񰡦񓞙򻝘򐫌󵑵𵗑󆒺󼛾𬓨􂐝򰫈𿻥򍣀􆛬򅽱󮭦󳮺𔅿񒦞񿾖𐞫󝾂򺬊񦶮􍀯􎣊󐂀𧠩񭱅񷑘𥼓􈾃򷳞󵾉𹚗򁓞򯊢𻩱򓛉𜟶񣟺󃣤􁄳򖺴𫝃򥎋󆛘󁋉󳴆𭥟񟪤󁀫򯎵󬫑𬼳񝽉򩻂𗏖𻯏򔧲񜬜󠨱𔇗𔱙񎊇𲯈򊕧􅉪􁕯󈏠󶕑򶣅񐤉󿮲񙗲򚯨𴰴򝁼񊋾󶶩񌯘𫦂􆭨𐽐􈢼󵈒󖪮𲺽𔄑𸂎񪢘񼒮􏕇󖬛🱖񑢺󣦽񋿆𦿉𡋃𠓜򞇨񑡟😯􆼕򢫘񴙲񣵠񫏯󍞼򦱱񗟱𿂎󆜱򾱟𿟂􊱸􃛐򝨚󵨙􃃞񞃃񨍨򽒣򋷅󶃑򵳹󧇦󇐣𓍺򝺒򃧢򉀐𽍴󗫳򄭄󧌵󛧦򂆈񴧉񾱫󈣃񑃱򅼒𪋸򃈏򣝃񖋯􋅶𒇳񺼹򫉱􀶤񖜉𾯷𸛭󄵚󟋴򷠽𫞬򁊳񁋋󒞶𞮁񽠸򄔦񀅄򎎕򗿺󦳓򅜘񰰀󛸃򹒖􎠮򂒥򞸳򢢐򲄅󧋉󘢐𱘴񿰃𖽇𘿔򏘿򠰁󩮋𡗦񎱋󾌣񍆐􌽪򶩟򯯴񒒜',3340,128))));
v = D('𨂉󽡥󍡢󖷮󮕰񙛯򆒾󆒈󥊚򱾔񮘲򋸋񋜋󩑡񜉥󲺞󈝏񮦊򻖲񒎋󉅼񖮉򡪥񾌏򭘝򎬸򸻰򘫻𩆌񏑕򆀧򮌀󃲣򷤱󸓹򧷥𷄱򥽆񊟰󗘐񒽀򿏞󝀣򼌫񔄥󷃰񳖢򻳱𛦷򃼋𹡤񧿞򰽎򬸯𘒚󕛈􅲞󪓢񉋏򳟋󃶶𢽙򢆛󾸧񢥱󻠩򳣍𱉫𔽚󃉎񿾋򌰯󋷈𽙜󸍹򾇅𯚫󖣯􌃴𴿋񄎜󂯄𬛣񂁨񇲬򦡋񞅺򏪙𵑢󽴆𔤭񧺿򦀵򾧽󒍙𺀵󖧖􃱞񒱸󙵀􄸺񩒘񴵀𤩡񎎟򯯃񝮈򱉍𽚴𮿧򂛭񀠫󻶃򷙨򅔐𮂾򵘬񬗋󪹍񳡻󏆳򟨤񡅃󡊓򬀈𘨎򮪈󙛢񃵔򿣲򖄬񅐄񂣾󇈀򫣨𼾚𮻏񑯾򇸱𓀼򙅜򛺈񩼣𤻜񻌩򣵢􊼞򃹿󘟈󋜔򐚌𑉦򒈴񈎴􄢯𲎭󝐝񟔱󇡦򦅎񖲏򕅝񕡉񅄞񣆽𧂕󑑽񎻋񭉿󦞯󂥳󵯤񼌍󟪾􏻜򒌾񤋖𦙶򴗱񞃭񊘿򠇁􊺤񹌵𙕖󴝣󀊁󽨣󲗺􉙴󬖻񔫲󌐄󅌧򱱓𹐸򅌋𝨁񯑤򀛐򭾢󍩛򯱺󱈼򪛷􊉢򮀐򇖂򁬤󴑣󈫫򉄘𭽔򢠤򃗈󮧓򣟺󵺴󠲽􍴈󴾑򶹾񝊷򜠷󀩢􊷴󸉔􇪯􊮢󘶉𕽗񵻪𹰯򠈶􍩈󳀴򬹺񁳲񾐗󗴘󾭞󥢩𼨈𺫗󶷦󭀢񳕙𵹻񭡱񱏘󠡢󱱰򺇡񁢌󟪠򓰹񻻅񘖈𒔆񦑼򸈺򸾠򟩾򖊘񥖶𓯔󴚢񺵼򟽝𶽖󈼸򫃹񙨺󞡵󂪦񥨷򾥡񧫝󕍱󛡄򴓌󮢏𘼣􄉺򕕭񕨪𦩗򡑓񱨷񌧯򾰎󭤲򩐚𒌢񹀒𬁌􊉑𠣁𺍻򥲖񭠞󋦙񿎉􂜞𙬒𚄗󎄤󤙧󵼹􌂮񽠵񕚂񊔖򅗼󗰥󝰨񬺲񄄲偾凂󑫐񢄕򀿩󼟴𷹼󏱴󊷓󀮭󌪽򬻂񡱩򮗰𐢅󫡎򐑣񖷬񳡋󓁝񂎥𫗚񻊱𬁕򡩖󌁂򳯖𻐩𡆩򁵎󙍤񦤛񪆁󓗃񏦮𺈚񴹛򍴥򮀹򜖤񫚶񰩋򫼕󼊤𽛼󓧅󃠤񚲂񅑂񤮚𳰉󽠺򌋯󞥘𠚂񨶄󥲬𕳤񺯳󒏜􌷬򧝩𽆶󋄥򾰹󤼟񌀿𝦌🟰򚙒󟔲򻶾򸴝󵝪񅮅󻘦񓴼󸭌𪃐򶆱񆢏󺮔󟷦𡫚򴩕󬕤򘓋𳓭򆎒񖩱󤾾񀫹񳨹񕁂󗡥󓕃򉷸򘍑򼔦򝔚󭤉􇭶𿢊𗿌󾽋󩿻󰲢򉸬󈮘􏁳􋙞󒹜򤢃񵛯􂓹񪶈󂙈𷅢񿳠򍕒󁣐򳦂񫻈𢯢񃣆󪋟򛾿򂡚򓤦󆠳󠧗򶊖񘾔񿇇񒸁򾂒𳩄򊥁󃁆򗆬񁽙򝢊񅖲򲈺򷃵񗟺򾧔󑾓𨣂󇯪򄲜󉺿𦗞򗴴𦞢𞒑򄊁󞥳󅪎󶨌򞨮򹓊񆚡𮺅􇉼𱥑񷽂󊒎򺆪򢐹𨴱󶦳񼆠𑤯𷇭򄂈񃕯򇳔𘳱󏷷򇦢򇤈򃥈𓰪򨵱𯗥𤑨򯪎󨑺򊅮񘓇𢘕󤟒󣩛򀍹𶹠񂊕򉙼򖇞񣿁񽹷񰙚󃝨𸷢񔙽󎉧񳾫󽸋񊼇󔥋񃢳𵙏񤷣󩚛򏷕񛩨񞈪􄅋𺤰񮭯􅺢񪴓􄯆򜮝򞡟🌳󤗊𭝶􍄲󹦟񉐇𯘞󄭦𢯦𒝣𳣌񸣒󶷸󁷣󨲟󹰢󑳯񵜊񲜮󝁺򡞭򂍸񞺪󕄎򑿈𩆞񫧯񸔔񉒯񫋖𕜫󊨗񊢭񸮦񜴄󝬩򄈌򒸨򩃢񖉵񝝅󱬅𧠷𧜙򔻱򢋖󺭄𹪰񦁛񋄷񷓍󳩚𪺍󑱚󋃚𢃢򘳂򤌔񐠼󢢛𳪘󺥒􈯬򿘎򿏳𪄵񡮩񦅏𛈼󯮥𨌶򼖰񇐳󑬞򕱖򌘘򄭷񼹬񓶋𷯣񍐘󜃊󜯲󀷱񣤫򽋺򬛃󒆉򂝕󖩛􉉼񋱽򜃾󨟙򟍁񁭲񤏯𙑞񽡾񾹕󾧇𩨋􍪅񙺸񪖎񍐿򣩺𑿳󴣿􉓤󍋞񃹭򈲳񗡥񴕺𜨪􂚘󚁪󬾸򇉳􃶦󆶟󶼻󕟫򐄣񹇰󗂋𣳺󟙊񺏼󺢫򴛂񿀄򲜋򞠁𤦰񁫙󫀇🾵󽴉􈂽񈱹󌂧򎙁𔧱𷭎𦄾𨛳򚶿󒯼񛭮򎞥𬃯񀳕󸽦񑵮󪈱𽙏򌸜񢵬𫎲󣐈󿻩򁚢󭈾򤽻񇵯𗱓󬨱򝔹𠙣򽇨򓫷򊘇򍪲򍪿򢄠񟜘󣊇򗴼򵹱񵒖𓡃󇫅񔞪񎚲𵀅𛣚񽗻𹌓𙤻󪱇𔀵󻦾񉬂򾘻𼾈򙭨󮟭񻸛􌭦󤹠򎖍򺰐򉿅񏲅󎮙򒅰񠺱𻕞򯿭󥷁󐳼𚰚򧂖󥓔񐬱󑯒𹩁󘘖򣆁򌸡򏚄󻖖󅵕𓌽󦦲󣵦򺜕񔎃񴙾𶜞񶥕򐔼🮅񕌡󗽵󵅤򀗶򪙤󙜾󰊺򺌵򴆂񱖫󭪀􊾷󖇕򰆶󄿻󂄔񌰮󎿵𰶽󼠶󍬠󊜖󮻿󢠒񸯺󢆋󍞑󈐑񗮖𞥠񦦢𝈻󂓅􃂹􌋒𝝔򌉦󗫓򵷖񅥠󅻇󄖔󶦈񘇅󚄝󡜬񒼴𓜫򜣃򲏍􌿯󿐂񀿿񧦾𠦲󷳻򖣺񻋾󘕧𑌭񹱻󨙆󜢮𛕽򰕾󩳀񸊄򠲵񼆤򵒋􅾺𗭘𜴫񉽃򅰀􆑑򛋑􅤗𯯥𴆝񅇹𢩆󸞠񍪓𼑗򆌥𶌜񈝔􂕊񀓊򾄈󵲋񺌅񫜰𞂈򚿮􏽄󐫙񺻓󪑺𠲟򨛃񢉹򅓶򨅗񽕂񊗅񊐿󸱒󝣠񕳇񽅀򞑕𵧺󗷅􂏺񓃳𡡦󇜰񛾌񮘱򆐦񤩖򄑾󪒫󼎓𜿻򫷺򔮮󇜯𹳏󰲊𶆥񑘫󏌿򔫙󠆖𫀟𬡽𑦊񣮘񑳖􊬌񂕸󘕃򕐲򣂻񂕹􋴳򪏏򞕵񘸕򃿉𘐩󺙫򖊤󗄥􊼬񄉣񘶭񈈯𰚟񚡯𚦭󢯉󶐢񗍻񼇻򴯲󷅆󣨲񒰮񃬌򳾌񁈒򪓂񅱝񈦛𙺰򒗾񼥏󢏹򕐶񎱐򜮔񑀥󮻏񿸇𧵥򎰲򒫝󞰲򑄥󫟵򇔜񳳬򙡶􏬿񾂣򣡨򻩹򁣶򁸧󽩜𜺲򊪧􍦨񄵇򽽼񽕀򉯕򂆃󍢘􊀠󴾾􄷗󜂴񃠰񔡪򃉷񳐝񫱇󋢢񌹭񰥑򅲉󽶄񦋋𷂜𣷴񤰹󾝿󄯵򱦉𺇥򠽠􀩉𖉤򣬴򐄛񒑜򗙂򡍋򫏗򎛴𣬓򼒖򕻓󌒨񇘈󞤗񋺑𶉹􈻘񅚎󓝣񝺾󑒄񟨱򛐔󌥘󂎋𒮆򝢣󫳛򵒏󐃥񡘱򏱎򈔚񶆬򆝵񧇭񿡁󆲆𡌌򲨾򿣗򉷀򆯻󱢝𳓞𶬒򴒭񾏺񠶃𽂴󮌿󒌇򳶹󭟃񋢦񷑗𴡩󐰳𣶻󸼻񈬛𔕗񊎢𦮭񟫙󚟅򎼆򋥰񔤳𣥦𼊟򂬇񢦛󳘿򯀲򹭉𾶒񱜧󿀀񰈉򠋅񖮁󣖇􀁌􂂕򘺃𮂑񐘥󐲈𰎦𗺏󪔂񜖍𖟙򶶿򓲸󇺫𔗌󌈅񛷬𖿐𨨍󜩸􌌌񻙹󥚕򣴯𒧠񬻧􋭁򵙎񱁬񽭿󄱞򂇥􇮏𠢗𼕶򙶯𦹽񨌮񛧂򇒍󬠴󲏚󧀵𻵍񺟶𩐪󼙥򣃭􂻿򦼺򎽌򯢒񛷶򆸾񸈋񪿨򥉥󗴅𬘭󛗔򨑫򛀁򙌊󕤱򺏴󈈿󾩺𰲋􄶦򎹟񅦎􌸉񴠋򳦵򔺖􉼷𼓁𱂂󃌅񽶗􌏑򾑗񜌱񫸰󄡺񀺥򈍃􆠝𧶇󆹴􂜕󰬦𙽃󴁏󞪺𻻋󝃉򽿆񀔁񚥹󻽟񔞳񣙂𶉛𥉴𭿇񰖬𷞹𕘶򾗱򓌷󌓢񣞒񞚁𪡓񙩑񣨪񾆧󒅷񊈥𺶆򒖭𨸁󆏈󐝚󞺺󧎅􉉹𘧲󶰙񆨈񭮁򓒂󊞾󚥷𛧸𙀉񹖘񋪘򀉽󒼸𙧷󾥉񊊜񵔻𸃏񛱈򓂩򢳧𿋱󀳚🳳򪩣񹅂􇌄񛩐񆛁򅈙󼯼򔶾񿍭񗟢񨯏󙻭򼮝󡻼󊙩󡌸􀹃񈛏󂙚󪑀󯌈󔏵󖼛𴨯𩿑󙇌􏦏󹖠􁜏󤪡񤛔󁃆򠟔󜌫󴣕򡭍󅒆󈳠񖑂񟚨󂩘𔻨􌍿𞰞񒄣񼾿񝿕򌗯򏈚񐃗󳺫񣷨𧛦򸴱󼺖񽻍󯐚󘑱񠩠󞨜򀮃󓠌񁟛󫶒򠤰𾲰򑚢񊯘󉭩򖉴񖼥򟔰򒚽񖨇񻭾񖲁򕏒󼗡󛨸󟽑򢓸􊌺󑶳򋠐񏺢򛴗򳔴򁋨򋈱񔂄񞭫󌠟񁙏򶴥򛖇򡅎򺆉񢚊򔏙񈆸򕨘𴆉􋀁𬣢󯾴󪦞򘵘󽪝󡧅򟄊𔍕򸠗򚂹󠥒񸩵򕲜󪥽񒉄󛤮𺼚􊳝񗈪󼺨򬨊𔀡򱽓􆜊񀻎𲬿𽑃񛼘򚯠𖳺𪶞𠛨򙽆񡍺𳺲򢪉􁤣󐔲𵆄񜌌򀤰񄉂󞋁󍒍򊘏󠀡𳝢󈼅򖑪󒖈󏕬𤈻򗬌󽑯󳠁𜌑󪨸􀒎􈙛𛄑񯙨𑡿𕹏󒇠򽓟𰳑񙿚򙥻🋐𸎓񴖴󀾸񿞈𻔓񻯔򒑅򍢺򛻟𥈗󌇰򚋵󭦈񠨈󷽯󵶽󜎞𢧰󩆛􊗖𿥄𕂇𥍎񰐇򋒳󗲈񈸹񱙕󶕱򢥧򀱈𞹒򞘆򃂛򽤋򞗧򽚴򤨡󔞍񶱻󛵓򣻑򕼺𳣊󉛫񒌿􉢐󣁆󧶩󾉹𐭻𥠨񴘠𵱽񕷉򜞢󝁰񠾏󁾚񵸞𛦾񥎅񳊳򱬘񇸀򡹾񏋖󿶵򋿯򲬺𵂒񒁻󸕑򤮉󯴵񃊅򖨏򆑿𚗢',37280,32);
v = v(1:2:end)+32*v(2:2:end);
v = reshape(v,1165,[])';
[~,j] = sort(v(1,:));
v(2:end,j) = v(2:end,:);
m = {{@plus,@minus,@eq,@mtimes,@gt,@min,@(x)x,@(p,c,j)p+j*~c,@abs,@lt,@(x)all(x(:)),@rand,@not,@max,@floor,@round,@colon,@mod,@(a,varargin)a(varargin{:}),@A,@any,@le,@backdrop,@uminus,@cumsum,@sum,@mrdivide,@sin,@mpower,@power,@exp,@ge,@and,@or,@numel,@cummin,@times,@cummax,@horzcat,@find,@ceil,@(a)a',@ne,@pack,@wash,@flow,@double,@uint8,@cat,@vertcat,@rdivide,@char,@setfield,@MG,@(a,varargin)a{varargin{:}},@reshape,@interp1,@F,@sqrt,@atan2,@ones,@conv2,@repmat,@permute,@zeros,@kron},v,c(1:end-1),120,[1 450 762 1041 1100 1125 1134],c{end},sum(v>0)-2};
% Initialize the game state
s = cell2struct([cell(1,60),{m}],m{6},2);
s = E(s,ax);
end

function s = E(s,ax)
% Create the display image and build the first beach
ax.YDir = 'reverse';
ax.Color = [.1 .08 .2];
s.g = image(ax,[2 798],[2 598],zeros(150,200,3,'uint8'),Interpolation='nearest',HitTest='off',PickableParts='none');
s = M(s,0,0,3);
end

function [s,v] = M(s,d,p,k)
% Execute the decoded instructions; registers store the game state
m = s.M;
r = [{0,s,d,p},cell(1,m{4}-4),m{3}];
h = 0;
v = 1:8;
q = struct2cell(s);
r(5:3+numel(q)) = q(1:end-1);
f = m{1};
V = m{2};
N = m{7};
i = m{5}(k);
while 1
    o = V(1,i);
    e = V(2,i);
    c = N(i);
    i = i+1;
    if o == 1
        h = h+1;
        v(h) = i;
        i = m{5}(e);
    elseif o == 2
        if ~h
            break
        end
        i = v(h);
        h = h-1;
    else
        if e < 2
            r{1} = i;
        end
        if c == 2
            r{e} = f{o-2}(r{V(3,i-1)},r{V(4,i-1)});
        elseif c == 1
            r{e} = f{o-2}(r{V(3,i-1)});
        elseif c == 3
            r{e} = f{o-2}(r{V(3,i-1)},r{V(4,i-1)},r{V(5,i-1)});
        else
            r{e} = f{o-2}(r{V(3:c+2,i-1)});
        end
        if e < 2
            i = r{1};
        end
    end
end
if k ~= 2
    s = cell2struct([r(5:3+numel(q)),{m}],m{6},2);
end
v = r{3};
end

function v = D(t,n,b)
% Decode the game data and instruction streams using adaptive range coding
t = [1024 1]*reshape(mod(t,1024),2,[]);
[a,v,r,k,z,f] = deal(zeros(b,131071),zeros(1,n+4),1,1,0,2^20);
for i = 5:n+4
    while r < 8e9
        [r,z,k] = deal(r*f,z*f+t(k),k+1);
    end
    h = mod([0 cumsum(v(i-(1:4)).*b.^(0:3))]*31+(0:4)*7777,131071)+1;
    c = a(:,h);
    u = cumprod(16./(16+sum(c)),'reverse');
    c = [0;cumsum(1+floor((c*(u'/16)+u(1)/b)*f))];
    u = floor(r/c(end));
    j = sum(c <= z/u);
    z = z-c(j)*u;
    r = (c(j+1)-c(j))*u;
    v(i) = j;
    a(j,h) = a(j,h)+1;
end
v = v(5:end)-1;
end

function a = J(a)
% Restore the cell contents and row orientation
if iscell(a)
    a = cellfun(@J,a,'uni',0);
end
if iscolumn(a)
    a = a';
end
end

function m = flow(m,k,W)
% Advance the loose materials by one step
dx = 150*(2*mod(k,2)-1);
i = find(m < 7 & m ~= 2 & ~W);
r = mod(i-1,150)+1;
for p = [0 1]+mod(k,2)
    % Swap the heavier cells with the lighter cells below them
    f = i(mod(r+p,2) == 0 & r < 150);
    f = f(m(f) > m(f+1) & m(f) < 7);
    t = m(f);
    m(f) = m(f+1);
    m(f+1) = t;
    f = i(mod(r+p,2) == 1 & r > 1);
    f = f(m(f) < 2 & m(f-1) == 2);
    m(f-1) = m(f);
    m(f) = 2;
end
i = i(i+dx > 0 & i+dx < 30000);
% Sand slides diagonally when it cannot fall
c = i(m(i) > 4 & m(i) < 7);
c = c(m(c+1) >= m(c) & m(c+1+dx) < 5);
t = m(c+1+dx);
m(c+1+dx) = m(c);
m(c) = t;
% Water spreads sideways, more often toward the sea
dx = 150-300*(mod(k,3) == 0);
i = i(i+dx > 0 & i+dx < 30000);
for p = 1:2
    c = i(m(i) < 5 & m(i) ~= 2);
    c = c(m(c+dx) == 2 & (m(c) < 2 | m(c+1) >= m(c)));
    m(c+dx) = m(c);
    m(c) = 2;
    i = c+dx;
    i = i(i+dx > 0 & i+dx < 30000);
end
% Sink the packed sand that stands on air or water, on every second step
if mod(k,2)
    d = m == 7 & m([2:150 150],:) < 5;
    c = cumsum(m ~= 7,1);
    f = find(m == 7 & cummin(c+1e6*~d,1,'reverse') == c);
    m(f) = 2;
    m(f+1) = 7;
end
end

function m = wash(m,dt,W)
% Flood the cells of the sea; erode the sand in contact with water
r = rand(150,200);
m(W) = 4;
% Drain the water that the sea has left behind
m(m == 4 & ~W & (W([2:150 150],:) | W(:,[2:200 200]) | W(:,[1 1:199]) | r < .25*dt)) = 2;
% Wash away the loose sand; loosen the packed sand
n = conv2((m == 4)+0,[0 1 0;1 0 1;0 1 0],'same');
m(m > 4 & m < 7 & r < 3*dt*n) = 2;
m(m == 7 & r < 1.6*dt*n) = 5;
% Crumble the bare faces of packed sand under more than 16 cells of load
n = cumsum(m > 4,1) > 16 & (m(:,[1 1:199]) < 5 | m(:,[2:200 200]) < 5);
m(m == 7 & n & r > 1-2*dt) = 5;
end

function B = backdrop(Ka,Kb,O,St,C,Mi,X,Y,A,E,R,t,T)
% Paint the sky, the far sea, the headland and the light on the sea
% Calculate the darkness of the night; select the evening or the morning sun; set the color of the moonlight
p = max(0,min(1,min(t/45,(120-t)/25)));
e = t < 60;
n = cat(3,.7,.8,1);
% Blend the sunset and night backdrops; move the swell over the far sea
B = Ka+p*Kb;
B = B.*(1+.07*(Y > 108).*sin(Y*2+X/9-2*T));
% Draw the sun and its glow; light the clouds near it
d = sqrt((X-40-106*e).^2+(Y-(96+.6*t)*e-(186-.9*t)*~e).^2);
B = B+O.*(127*(1-.8*p)*exp(-d/26).*cat(3,1,.7,.35));
B = B+O.*max(0,min(1,11.5-d)).*(255*cat(3,1,.9-.4*p,.62-.4*p)-B);
g = 90*(1-p)*exp(-d/40);
% Move the full moon along its arc; draw its glow
x = X-30-7*t/6;
u = sin(pi*t/120);
y = Y-112+82*u;
d = sqrt(x.^2+y.^2);
B = B+O.*(36*exp(-d/12).*n);
% Draw the path of the sun or the moon on the sea
G = e*(1-p)*R+(Y > 108 & (mod(Y,2) == 0 | sin(X*91+Y*57+floor(3*T)) > .6)).*exp(-(x./(3+(Y-108)/3)).^2).*(110*p*u).*n;
% Light the clouds near the moon; draw the moon
g = g.*cat(3,1,.6,.2)+50*p*exp(-d/30).*n;
B = B+O.*max(0,min(1,6.5-d)).*(cat(3,238,236,214).*(1-.14*(sin(x*.9+1)+sin(y*1.2) > 1))-B);
% Fade in the stars; make them twinkle
B = B+p*St.*(.7+.3*sin(3*T+X.*Y));
% Drift two cloud layers across the open sky; move the first by fractions of a cell
c = floor(2*T)+(0:199);
q = 2*T-floor(2*T);
g = g+cat(3,219-170*p,107-55*p,102-20*p);
B = B+O.*((1-q)*C(:,mod(c,200)+1)+q*C(:,mod(c+1,200)+1)).*(g-B);
B = B+.5*O.*C(:,mod(floor(T/2)+(200:-1:1),200)+1).*(g-B);
% Drift the mist in front of the headland
c = floor(.7*T)+(0:199);
q = .7*T-floor(.7*T);
B = B+(Y < 109).*((1-q)*Mi(:,mod(c,200)+1)+q*Mi(:,mod(c+1,200)+1)).*(cat(3,200-140*p,160-100*p,175-75*p)-B);
% Light the lighthouse lamp; sweep its beam across the open sky
B = B+p*(E(:,:,1)+E(:,:,2).*exp(40*cos(A-T)-40)).*cat(3,1,.9,.6);
% Append the light on the sea
B = cat(3,B,G);
end

function m = pack(m,n)
% Pack the damp sand into walls with battlements, n grains per bay
for k = 1:n
    for b = find(any(reshape(any(m(:,5:193) == 6),7,27)))
        c = 7*b-2+(0:6);
        e = m(:,c);
        i = find(e' == 6);
        if ~isempty(i)
            % Find the highest damp grain of the bay
            y = ceil(i(1)/7);
            z = mod(i(1)-1,7)+1;
            % Find the lowest free place on the packed sand; fill the gap columns of the battlements last
            g = mod(c,2);
            r = sum(cumsum(e > 6) == 0);
            v = r-g;
            [~,j] = max(v+g/99);
            if max(v) < 43
                % Turn the damp sand loose above the height limit
                e(e == 6) = 5;
            elseif numel(i) > 6 || any(v ~= v(1))
                % Pack the grain at that place; a complete top waits until seven grains have gathered
                e(y,z) = 6-4*(e(r(j),j) ~= 6);
                e(r(j),j) = 7;
            end
            m(:,c) = e;
        end
    end
end
end

function v = F(a),[v{1:3}] = find(a);end
function v = MG(a,b),[v{1:2}] = meshgrid(a,b);end
function a = A(a,v,varargin),a(varargin{:}) = v;end
Play Game
Preview

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