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river generator - subs confluence to select main stem

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Azgaar 2021-07-21 00:15:05 +03:00
parent 5c0b92c542
commit 77f371e28f
2 changed files with 25 additions and 12 deletions
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35
modules/river-generator.js
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@ -31,7 +31,11 @@
const land = cells.i.filter(i => h[i] >= 20).sort((a, b) => h[b] - h[a]);
const lakeOutCells = Lakes.setClimateData(h);
let step = 0;
land.forEach(function (i) {
step++;
cells.fl[i] += grid.cells.prec[cells.g[i]]; // flux from precipitation
const [x, y] = p[i];
@ -59,7 +63,7 @@
}
lake.outlet = cells.r[lakeCell];
flowDown(i, cells.fl[i], cells.fl[lakeCell], lake.outlet);
flowDown(i, cells.fl[lakeCell], lake.outlet);
}
// assign all tributary rivers to outlet basin
@ -100,15 +104,24 @@
riverNext++;
}
flowDown(min, cells.fl[min], cells.fl[i], cells.r[i], i);
flowDown(min, cells.fl[i], cells.r[i], i, step);
});
}
function flowDown(toCell, toFlux, fromFlux, river, fromCell = 0) {
function flowDown(toCell, fromFlux, river, fromCell, step) {
const toFlux = cells.fl[toCell] - cells.conf[toCell];
// prettier-ignore
if (step) debug.append("text")
.attr("x", pack.cells.p[fromCell][0])
.attr("y", pack.cells.p[fromCell][1])
.text(`${step}: ${fromFlux} -> ${toFlux}`)
.attr("font-size", "1.5px");
if (cells.r[toCell]) {
// downhill cell already has river assigned
if (toFlux < fromFlux) {
cells.conf[toCell] = cells.fl[toCell]; // mark confluence
if (fromFlux > toFlux) {
cells.conf[toCell] += cells.fl[toCell]; // mark confluence
if (h[toCell] >= 20) riversData.find(r => r.river === cells.r[toCell]).parent = river; // min river is a tributary of current river
cells.r[toCell] = river; // re-assign river if downhill part has less flux
} else {
@ -155,16 +168,16 @@
const source = riverPoints[0].cell;
const mouth = riverPoints[riverPoints.length - 2].cell;
const parent = riverPoints[0].parent || 0;
const widthFactor = rn(0.8 + Math.random() * 0.4, 1); // river width modifier [.8, 1.2]
const sourceWidth = cells.h[source] >= 20 ? 0.1 : rn(Math.min(Math.max((cells.fl[source] / 500) ** 0.4, 0.5), 1.7), 2);
const widthFactor = parent ? 1 : 1.4;
const sourceWidth = cells.h[source] >= 20 ? 0.1 : rn(Math.min(Math.max((cells.fl[source] / 500) ** 0.4, 0.5), 1.6), 2);
const riverCells = riverPoints.map(point => point.cell);
const riverMeandered = addMeandering(riverCells, sourceWidth * 10, 0.5);
const [path, length, offset] = getPath(riverMeandered, widthFactor, sourceWidth);
riverPaths.push([path, r]);
const parent = riverPoints[0].parent || 0;
const width = rn(offset ** 2, 2); // mounth width in km
const discharge = last(riverPoints).flux; // in m3/s
@ -295,7 +308,7 @@
const factor = riverLength / points.length;
let offset;
// store points on both sides to build a valid polygon
// store points on both sides to build a polygon
const riverPointsLeft = [];
const riverPointsRight = [];
@ -316,12 +329,12 @@
const cosOffset = Math.cos(angle) * offset;
riverPointsLeft.push([x1 - sinOffset, y1 + cosOffset]);
riverPointsRight.unshift([x1 + sinOffset, y1 - cosOffset]);
riverPointsRight.push([x1 + sinOffset, y1 - cosOffset]);
}
// generate polygon path and return
lineGen.curve(d3.curveCatmullRom.alpha(0.1));
const right = lineGen(riverPointsRight);
const right = lineGen(riverPointsRight.reverse());
let left = lineGen(riverPointsLeft);
left = left.substring(left.indexOf("C"));