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adds contour prototype example

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Francisco Dans 2015-08-12 11:36:00 +02:00
parent 50f834c008
commit 818c705a70
1 changed files with 85 additions and 0 deletions
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<!DOCTYPE html>
<meta charset="utf-8">
<body>
<canvas id = "sample" width = "600" height = "600"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script type="text/javascript">
var grid = [[0,0,1,0,0,0,0,0,0,0,0,0,1,2,0,0],[0,0,0,1,0,2,0,1,1,1,0,0,3,0,1,3],[5,1,1,0,0,0,1,0,2,0,2,0,0,0,3,0],[0,1,2,1,1,2,0,1,0,2,2,3,0,1,1,1],[2,3,2,1,1,7,4,2,4,1,1,0,0,1,0,1],[0,2,2,2,0,1,2,2,3,0,3,0,2,2,1,2],[3,0,1,1,0,1,1,3,1,3,1,1,2,1,1,1],[2,0,4,1,1,1,4,0,1,1,1,1,0,0,7,2],[4,0,1,2,0,2,0,3,3,6,2,0,2,0,2,0],[0,1,0,0,0,0,1,6,0,1,2,0,0,0,0,2],[0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,1,5,0,3,0,1,1,0],[0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1],[0,0,0,0,0,0,0,0,0,1,0,0,1,1,1,0],[0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,4],[0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1]].reverse();
var canvas = document.getElementById("sample");
var ctx = canvas.getContext("2d");
// for (var y = 0; y < grid.length; y++){
// for (var x = 0; x < grid[0].length; x++){
// ctx.beginPath();
// ctx.arc(20 + x*20, 20 + y*20, 3, 0, 2 * Math.PI, false);
// var value = grid[y][x];
// ctx.fillStyle = "rgb("+0+", "+value * 50+", "+value * 50+")";
// if(value === 0) ctx.fillStyle = "red";
// ctx.fill();
// }
// }
var cellsX = grid[0].length-1;
var cellsY = grid.length-1;
var contourValues = [0,2];
for(var c = 0; c < contourValues.length; c++){
for (var y = 0; y < cellsY; y++){
for (var x = 0; x < cellsX; x++){
var currentCell = [grid[y][x], grid[y][x+1], grid[y+1][x+1], grid[y+1][x]];
var pipe = getPipe(currentCell, contourValues[c]);
if (pipe){
ctx.beginPath();
ctx.moveTo(20 + x*20 + 20 * pipe[0][0], 20 + y*20 + 20 * pipe[0][1]);
ctx.lineTo(20 + x*20 + 20 * pipe[1][0], 20 + y*20 + 20 * pipe[1][1]);
ctx.stroke();
if (pipe.length === 4){
ctx.beginPath();
ctx.moveTo(20 + x*20 + 20 * pipe[2][0], 20 + y*20 + 20 * pipe[2][1]);
ctx.lineTo(20 + x*20 + 20 * pipe[3][0], 20 + y*20 + 20 * pipe[3][1]);
ctx.stroke();
}
}
}
}
}
function getPipe(cell, contour){
var parsedCell = cell.map(function(cornerValue){
if (cornerValue > contour){
return "1";
}
return "0";
}).join("");
var type = parseInt(parsedCell, 2);
var N = [lerp(cell[1], cell[0], contour), 0],
S = [lerp(cell[2], cell[3], contour), 1],
E = [1, lerp(cell[2], cell[1], contour)],
W = [0, lerp(cell[3], cell[0], contour)]
// Blank
if (type === 0 || type === 15) return null;
// W - S
if (type === 1 || type === 14) return [W, S]
// S - E
if (type === 2 || type === 13) return [S, E]
// W - E
if (type === 3 || type === 12) return [W, E]
// N - E
if (type === 4 || type === 11) return [N, E]
// N - S
if (type === 6 || type === 9) return [N, S]
// W - N
if (type === 7 || type === 8) return [W, N]
// W - N / S - E
if (type === 5) return [W, N, S, E]
// W - S / N - E
if (type === 10) return [W, S, N, E]
}
// Linear interpolation
function lerp(valueA, valueB, contourValue){
return Math.max(Math.min(1 + (-0.5) * (contourValue - valueA) / (valueB - valueA), 0.8), 0.2);
}
</script>