From abfb7a20bcba3594e0c4fd722332383cf8ac17f4 Mon Sep 17 00:00:00 2001
From: zenoamaro <zenoamaro@gmail.com>
Date: Sun, 30 Jun 2019 02:56:18 +0200
Subject: [PATCH] Multiple skies

---
 constants.js |  9 +++++++++
 math.js      |  4 ++++
 sky.js       | 14 +++++++++-----
 terrain.js   |  2 +-
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/constants.js b/constants.js
index 990c284..9398b1c 100644
--- a/constants.js
+++ b/constants.js
@@ -13,6 +13,15 @@ export const PLAYER_COLORS = [
   'darkorchid',
 ];
 
+export const SKY_COLORS = [
+  {from:[42, 78, 108], to:[0, 0, 0]},
+  {from:[82, 120, 187], to:[201, 218, 236]},
+  {from:[94, 171, 184], to:[225, 172, 139]},
+  {from:[49, 76, 148], to:[242, 171, 85]},
+  {from:[51, 89, 135], to:[163, 198, 220]},
+  {from:[105, 95, 108], to:[223, 183, 110]},
+];
+
 export const MAX_WIND = 25;
 
 export const PLAYER_MAX_ENERGY = 100;
diff --git a/math.js b/math.js
index 5c91d7d..1737db2 100644
--- a/math.js
+++ b/math.js
@@ -11,6 +11,10 @@ export function coords2index(width, x, y) {
   return y * width + x;
 }
 
+export function gradient(from, to, i) {
+  return from + (to-from) * i;
+}
+
 export function random(min, max) {
   return min + Math.random() * (max-min);
 }
diff --git a/sky.js b/sky.js
index fc61024..c9a259f 100644
--- a/sky.js
+++ b/sky.js
@@ -1,5 +1,7 @@
 import {createCanvas, drawRect, clipCanvas, plot} from './gfx.js';
-import {randomInt} from './math.js';
+import {randomInt, gradient} from './math.js';
+import {SKY_COLORS} from './constants.js';
+import {sample} from './utils.js';
 
 export function createSky(width, height) {
   const ctx = createCanvas(width, height);
@@ -9,11 +11,13 @@ export function createSky(width, height) {
 
 export function generateSky(ctx) {
   const {width, height} = ctx.canvas;
-  const [r, g, b] = [70*0.6, 130*0.6, 180*0.6];
+  const {from, to} = sample(SKY_COLORS);
 
   for (let y=0; y<height; y++) {
-    const darken = 1 - (1/height*y);
-    const [dr, dg, db] = [r*darken, g*darken, b*darken];
-    drawRect(ctx, 0, y, width, 1, `rgb(${dr},${dg},${db})`);
+    const f = y / height;
+    const r = gradient(from[0], to[0], f);
+    const g = gradient(from[1], to[1], f);
+    const b = gradient(from[2], to[2], f);
+    drawRect(ctx, 0, y, width, 1, `rgb(${r},${g},${b})`);
   }
 }
diff --git a/terrain.js b/terrain.js
index 14893b7..f51c0b7 100644
--- a/terrain.js
+++ b/terrain.js
@@ -39,7 +39,7 @@ const TERRAIN_TYPES = {
   },
 
   sand(ctx) {
-    ctx.color = 'burlywood'; // FIXME
+    ctx.color = 'wheat';
     const {width, height} = ctx.canvas;
     const stepCount = 16;
     const stepSize = width / stepCount;