火箭降落 | JavaScript Programming Project | OrangeApple Learning Platform

{"id":7216,"student_id":10,"content":"setBackdrop(\"bg.jpg\");\n\nvar platform = createSprite(\"platform.png\");\nplatform.moveTo(500, 200);\n\nvar life = 0;\nvar rockets = [];\n\nfor (var i=0; i\u003c20; i++) {\n    var dna = randomDNA();\n    var rocket = createSprite(\"rocket.png\");\n    rocket.direction = 0;\n    rocket.reset = function () {\n        this.x = 50;\n        this.y = 400;\n        this.vx = 0;\n        this.vy = 0;\n        this.fuel = 300;\n        this.active = true;\n    }\n    rocket.forever(function () {\n        this.direction = this.vx*3;\n    });\n    rocket.on(\"touch\", platform, function(){\n        if (this.y \u003e platform.y - this.height/2 || this.vx \u003e 0.2 || this.vx \u003c -0.2 || this.vy \u003e 0.2 || this.vy \u003c -0.2) {\n            this.hidden = true;\n        } else {\n            this.active = false;\n        }\n    });\n    rocket.reset();\n    rocket.dna = dna\n    rockets.push(rocket);\n}\n\nfunction randomDNA () {\n    var dna = '';\n    for (var i=0; i\u003c500; i++) {\n        dna += Math.floor(Math.random()*4);\n    }\n    return dna;\n}\n\nfunction crossover (a, b) {\n    var newDNA = '';\n    for (var i=0; i\u003ca.length; i++) {\n        newDNA += Math.random() \u003e 0.5 ? a[i] : b[i];\n    }\n    return mutation(newDNA);\n}\n\nfunction mutation (dna) {\n    var newDNA = '';\n    for (var i=0; i\u003cdna.length; i++) {\n        newDNA += Math.random() \u003e 0.05 ? dna[i] : Math.floor(Math.random()*4);\n    }\n    return newDNA;\n}\n\nfunction nextGeneration () {\n    rockets.sort(function (a, b) {\n        return fitness(a) - fitness(b);\n    });\n\n    var pops = [];\n    for (var i=0; i\u003c16; i++) {\n        var rand1 = Math.floor(Math.sqrt(Math.random()*400));\n        var rand2 = Math.floor(Math.sqrt(Math.random()*400));\n        var newGen = crossover(rockets[rand1].dna, rockets[rand2].dna);\n        pops.push(newGen);\n    }\n    pops.push(randomDNA());\n    pops.push(rockets[19].dna);\n    pops.push(rockets[18].dna);\n    pops.push(rockets[17].dna);\n    \n    rockets.forEach(r =\u003e r.reset());\n\n    for (var i=0; i\u003c20; i++) {\n        rockets[i].dna = pops[i];\n    }\n}\n\nfunction fitness (rocket) {\n    var d = rocket.distanceTo(platform.x, platform.y - 50);\n    if (rocket.hidden) d += 400;\n    return -d;\n}\n\nforever(function(){\n\n    if (life \u003e= 500) {\n        nextGeneration();\n        life = 0;\n    } else {\n        for (var i=0; i\u003crockets.length; i++) {\n            rocket = rockets[i];\n            rocket.vy += 0.05;\n            var d = rocket.dna[life];\n            if (rocket.fuel \u003e 0) {\n                if (d == '0') rocket.vx += 0.1;\n                if (d == '1') rocket.vx -= 0.1;\n                if (d == '2') rocket.vy -= 0.3;\n                rocket.fuel -= 1;\n            }\n\n            if (rocket.hidden != true \u0026\u0026 rocket.active)\n                rocket.move(rocket.vx, rocket.vy);\n        }\n    }\n    life++;\n});","created_at":"2017-03-01T20:52:04.729+08:00","updated_at":"2019-11-08T02:54:00.062+08:00","name":"火箭降落","language":"javascript","screenshot":{"url":"/uploads/project/screenshot/7216/ed1bf956dab6995310ccf93f64934731.jpg"},"parent_id":2,"plugin":"\n\n","description":null,"note":null,"status":"public","like_student_ids":[],"is_featured":false,"views":568,"hashid":"2pds85z","is_content_changed":false,"review_status":"unsubmitted","submitted_at":null,"reviewed_at":null,"advise":null,"is_deleted":false}