Coding Pong from Scratch ● Live Stream Transcription

ball = Table[{0.,0.}, {2}];
integrate[ball_, a_:{0.,0.}, \[Delta]t_:0.01] := {
  (*TB[*)Indexed[(*|*)ball(*|*), {(*|*)2(*|*)}](*|*)(*1:eJxTTMoPSmMAgmIuIOGZl5JakZrilF8BAECTBhI=*)(*]TB*), 2 (*TB[*)Indexed[(*|*)ball(*|*), {(*|*)2(*|*)}](*|*)(*1:eJxTTMoPSmMAgmIuIOGZl5JakZrilF8BAECTBhI=*)(*]TB*) - (*TB[*)Indexed[(*|*)ball(*|*), {(*|*)1(*|*)}](*|*)(*1:eJxTTMoPSmMAgmIuIOGZl5JakZrilF8BAECTBhI=*)(*]TB*) + (*SpB[*)Power[\[Delta]t(*|*),(*|*)2](*]SpB*) a
}

Graphics[{
  Black, Disk[ball[[2]] // Offload, Offset[{10,10}]]
}, AspectRatio->1, ImageSize->200, PlotRange->1]//Framed 

%28%2AVB%5B%2A%29%28CoffeeLiqueur%60Extensions%60Video%60Internal%60imgSymbol%24457660%29%28%2A%2C%2A%29%28%2A%221%3AeJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJJ5sbmxuZpJjrpqYmmemaGCQa6VokmRvqGhtZJJmYp6RYmpolAgCX1BXB%22%2A%29%28%2A%5DVB%2A%29

ball = 0.0 ball;
ball[[2]] = {-0.01,-0.02};

Do[
  If[Abs[ball[[2,1]]] >= 1, 
    ball[[{1,2}, 1]] = ball[[{2,1}, 1]];
  ];

  If[Abs[ball[[2,2]]] >= 1, 
    ball[[{1,2}, 2]] = ball[[{2,1}, 2]];
  ];  
  
  ball = integrate[ball, {0.,0.}, 0.1];
  Pause[1/60.0];
, {300}];

paddles = {{-0.75,0.}, {0.75,0.}};
$paddles = 2{0.02, 0.21};

handler[_] := With[{},
  If[Abs[ball[[2,1]]] >= 1, 
    ball[[{1,2}, 1]] = ball[[{2,1}, 1]];
  ];

  If[Abs[ball[[2,2]]] >= 1, 
    ball[[{1,2}, 2]] = ball[[{2,1}, 2]];
  ];  
  
  ball = integrate[ball, {0.,0.}, 0.1];
  paddles = paddles;
];

EventHandler[Graphics[{
  Pink, Disk[ball[[2]] // Offload, Offset[{5,5}]],
  Black, 
  Translate[Rectangle[
    -$paddles/2,$paddles/2, RoundingRadius->0.02
  ], paddles[[1]]//Offload],
  Translate[Rectangle[
    -$paddles/2,$paddles/2, RoundingRadius->0.02
  ], paddles[[2]]//Offload],
  Dashed, Line[{{0.0, -0.75}, {0.0,0.75}}],
  
  EventHandler[
    AnimationFrameListener[ball//Offload],
    handler
  ]
}, AspectRatio->1, ImageSize->200, PlotRange->1], {
  "mousemove" -> Function[xy,
    paddles[[1,2]] = xy[[2]];
  ]
}]//Framed 

handler[_] := Null;

Play[Sin[15000.0 x ]Exp[-30.0 x], {x,0,Pi/32}] 

(*VB[*)(FrontEndRef["F2a567631-f7b0-476e-b172-7f9c0a39f5b0"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJGyWampmbGRvqppknGeiamJul6iYZmhvpmqdZJhskGlummSYZAACPTRWN"*)(*]VB*)

{
  AudioPlot[%, PlotRange->{0, 0.01}],
  Periodogram[%, PlotRange->Full, Frame->True]
} // Column // Deploy 

(*GB[*){{(*VB[*)(FrontEndRef["Fe687ab49-d886-4ad0-9eaf-496526ffa5c7"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJp5pZmCcmmVjqplhYmOmaJKYY6FqmJqbpmliamRqZpaUlmiabAwCfHxY4"*)(*]VB*)}(*||*),(*||*){(*VB[*)(FrontEndRef["Fe2534287-28c4-4f43-92ad-811828c38100"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJpxqZGpsYWZjrGlkkm+iapJkY61oaJaboWhgaWgCFjC0MDQwAiGsUyw=="*)(*]VB*)}}(*||*)(*1:eJxTTMoPSmNmYGAo5gUSYZmp5S6pyflFiSX5RcEsQBH3osyUNCaQPIgXVJqTWiwAFXbKr3DMyUzPy03NK0ljhCnxySwuQdUQzA5kOOfnlObmFaOpQ+FBGKlpaNqLuYCM4NSc1OSSxCQglxXIdUvMKU4FAOS6Kv4=*)(*]GB*)

SFXPaddle = Play[Sum[Sin[15000.0 x n ], {n,1,4,2}]Exp[-30.0 x], {x,0,Pi/32}]

(*VB[*)(FrontEndRef["Fb43842bd-108f-4536-b5dc-dc219655031c"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJJ5kYW5gYJaXoGhpYpOmamBqb6SaZpiTrpiQbGVqamZoaGBsmAwCUoRWA"*)(*]VB*)

{
  AudioPlot[%, PlotRange->{0, 0.01}],
  Periodogram[%, PlotRange->Full, Frame->True]
} // Column // Deploy 

(*GB[*){{(*VB[*)(FrontEndRef["Ff4164d19-9ba4-4e2e-9191-1b8f17cded33"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJp5kYmpmkGFrqWiYlmuiapBql6loaWhrqGiZZpBmaJ6ekphgbAwCXIxXw"*)(*]VB*)}(*||*),(*||*){(*VB[*)(FrontEndRef["F3bae19f4-9b8e-422a-ae18-87549ea966b4"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJGyclphpappnoWiZZpOqaGBkl6gIFLHQtzE1NLFMTLc3MkkwAoQEV+w=="*)(*]VB*)}}(*||*)(*1:eJxTTMoPSmNmYGAo5gUSYZmp5S6pyflFiSX5RcEsQBH3osyUNCaQPIgXVJqTWiwAFXbKr3DMyUzPy03NK0ljhCnxySwuQdUQzA5kOOfnlObmFaOpQ+FBGKlpaNqLuYCM4NSc1OSSxCQglxXIdUvMKU4FAOS6Kv4=*)(*]GB*)

SFXLost = AudioAmplify[Play[RandomReal[{-1,1}] Exp[- 10 x], {x,0,Pi/8}], 0.2]

(*VB[*)(Audio[FrontEndRef["Fecdecb74-3dd9-44a9-ac73-4f7836e3c289"], "SignedInteger16", SampleRate->8000])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJGyWZGJiaJBrqGhgZGuiamJtZ6lqamZromlkkJ1qYGZskmyUnAQCBcxT3"*)(*]VB*)

{
  AudioPlot[%, PlotRange->{0, 0.01}],
  Periodogram[%, PlotRange->Full, Frame->True]
} // Column // Deploy 

(*GB[*){{(*VB[*)(FrontEndRef["Fe53da39b-7dca-438a-a739-a5b57cbf13e7"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJp5oapyQaWybpmqckJ+qaGFsk6iaaG1vqJpommZonJ6UZGqeaAwCm2xZ8"*)(*]VB*)}(*||*),(*||*){(*VB[*)(FrontEndRef["F4d7d125f-f1eb-44d6-ada6-50d05b2760c0"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJm6SYpxgamabpphmmJumamKSY6SamJJrpmhqkGJgmGZmbGSQbAACiBBYJ"*)(*]VB*)}}(*||*)(*1:eJxTTMoPSmNmYGAo5gUSYZmp5S6pyflFiSX5RcEsQBH3osyUNCaQPIgXVJqTWiwAFXbKr3DMyUzPy03NK0ljhCnxySwuQdUQzA5kOOfnlObmFaOpQ+FBGKlpaNqLuYCM4NSc1OSSxCQglxXIdUvMKU4FAOS6Kv4=*)(*]GB*)

Button["Boom", (*VB[*)(Audio[FrontEndRef["Fe861a778-250d-4b8f-a460-9e736a58f45a"], "SignedInteger16", SampleRate->8000])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgUJm5oaJZuZpxnqJhmZmOmamBgY6VoaGhvpJpuZJZmYm5ulWpqZAgCHVRTW"*)(*]VB*) // EmitSound]

If[
    Abs[ball[[2,1]] - paddles[[i,1]]] < $ballRadius + $paddles[[1]]/2 &&
    Abs[ball[[2,2]] - paddles[[i,2]]] < $ballRadius + $paddles[[2]]/2,
      (* reflect x-velocity *)
      ball[[{1,2}, 1]] = ball[[{2,1}, 1]];
      SFXPaddle // EmitSound;
]

\[Eta] (paddles[[1,2]]-prevPaddles[[1,2]]);

ball[[1,2]] -= \[Eta] (paddles[[1,2]]-prevPaddles[[1,2]]);

paddles = {{-0.75,0.}, {0.75,0.}};
prevPaddles = paddles;
score = {0,0};
playerTarget = 0.5;

$paddles = 2{0.02, 0.21};
$ballRadius = 0.03;
$initVel = 0.03;

\[Eta] = 0.5;  (* momentum transfer paddle->ball coeff.*)
\[Alpha] = 0.15; (* 1/sloppines of 2nd player *)
\[Beta] = 0.6;  (* paddle movement smoothing *)

(* Main animation loop *)
handler[_] := With[{},
  (* player's paddle position interpolation *)
  (* mousemove fires events every ~10-50 ms only *)
  prevPaddles = paddles;
  paddles[[1,2]] = (1 - \[Beta]) paddles[[1,2]] + \[Beta] playerTarget;

  (* if ball hit left/right wall *)
  If[Abs[ball[[2,1]]] >= 1, 
    score = score + If[ball[[2,1]] > 0, 
      {1,0}, {0,1}
    ];

    (* reset game *)
    ball[[1]] = 0.0 ball[[1]];
    ball[[2]] = 0.0 ball[[2]];
    ball[[1]] = $initVel 
      RandomChoice[{-1,1}] 
      AngleVector[RandomReal[{-1,1} Pi/3.0]];
      
    SFXLost // EmitSound;
  ];

  (* top/bottom - just reflection *)
  If[Abs[ball[[2,2]]] >= 1, 
    ball[[{1,2}, 2]] = ball[[{2,1}, 2]];
  ]; 

  (* collisions with 2 paddles *)
  Do[
    (* here we consider only left/right surfaces *)
    If[
      Abs[ball[[2,1]] - paddles[[i,1]]] < $ballRadius + $paddles[[1]]/2 &&
      Abs[ball[[2,2]] - paddles[[i,2]]] < $ballRadius + $paddles[[2]]/2,
        (* reflect x-velocity *)
        ball[[{1,2}, 1]] = ball[[{2,1}, 1]];
        (* transfer momentum to y-velocity from the paddle *)
        (* 1:43:44 Momentum transfer *)
        ball[[1,2]] -= \[Eta] (paddles[[1,2]]-prevPaddles[[1,2]]);
        
        SFXPaddle // EmitSound;
        Break[];
    ],
  {i, 2}];

  (* solve kinematic equations *)
  ball = integrate[ball, {0.,0.}, 0.1];

  (* CPU paddle aka 2nd player is just P controller *)
  paddles[[2,2]] = (1-\[Alpha]) paddles[[2,2]] + \[Alpha] ball[[2,2]];
  (* trigger sync with frontend *)
  paddles = paddles;
];

EventHandler[Graphics[{
  {Pink, 
    Opacity[0.3], (* sick trail *)
    Disk[ball[[1]] // Offload, $ballRadius],
    Opacity[1.0],
    Disk[ball[[2]] // Offload, $ballRadius]
  },
  Black, 
  Translate[Rectangle[
    -$paddles/2,$paddles/2, RoundingRadius->0.02
  ], paddles[[1]]//Offload],
  Translate[Rectangle[
    -$paddles/2,$paddles/2, RoundingRadius->0.02
  ], paddles[[2]]//Offload],
  Dashed, Line[{{0.0, -0.75}, {0.0,0.75}}],

  Black,
  Directive[FontSize->18, FontFamily->"monospace"],
  Text[score[[1]]//ToString//Offload, {-0.5,0.75}, {0,0}],
  Text[score[[2]]//ToString//Offload, {0.5,0.75}, {0,0}],
  
  EventHandler[
    AnimationFrameListener[ball//Offload],
    handler
  ]
}, AspectRatio->1, ImageSize->350, 
  PlotRange->1, "TransitionType"->None], {
  "mousemove" -> Function[xy,
    playerTarget = xy[[2]];
  ]
}]//Framed