From d837166a1ba012d538d29fb153f0733de15e25c3 Mon Sep 17 00:00:00 2001
From: Olivier Guyot <olivier.guyot@camptocamp.com>
Date: Tue, 22 Oct 2019 22:44:11 +0200
Subject: [PATCH] Literal Style / add new math operators

---
 src/ol/style/LiteralStyle.js             |  4 ++++
 src/ol/webgl/ShaderBuilder.js            | 17 +++++++++++++++--
 test/spec/ol/webgl/shaderbuilder.test.js |  4 ++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/ol/style/LiteralStyle.js b/src/ol/style/LiteralStyle.js
index b4cb84e320..c0ee1e085a 100644
--- a/src/ol/style/LiteralStyle.js
+++ b/src/ol/style/LiteralStyle.js
@@ -18,10 +18,14 @@
  *
  * * Math operators:
  *   * `['*', value1, value1]` multiplies `value1` by `value2`
+ *   * `['/', value1, value1]` divides `value1` by `value2`
  *   * `['+', value1, value1]` adds `value1` and `value2`
+ *   * `['-', value1, value1]` subtracts `value2` from `value1`
  *   * `['clamp', value, low, high]` clamps `value` between `low` and `high`
  *   * `['stretch', value, low1, high1, low2, high2]` maps `value` from [`low1`, `high1`] range to
  *     [`low2`, `high2`] range, clamping values along the way
+ *   * `['mod', value1, value1]` returns the result of `value1 % value2` (modulo)
+ *   * `['pow', value1, value1]` returns the value of `value1` raised to the `value2` power
  *
  * * Color operators:
  *   * `['interpolate', ratio, color1, color2]` returns a color through interpolation between `color1` and
diff --git a/src/ol/webgl/ShaderBuilder.js b/src/ol/webgl/ShaderBuilder.js
index 1b2efde7c2..2c58fd70b5 100644
--- a/src/ol/webgl/ShaderBuilder.js
+++ b/src/ol/webgl/ShaderBuilder.js
@@ -87,9 +87,13 @@ function getValueType(value) {
     case 'var':
     case 'time':
     case '*':
+    case '/':
     case '+':
+    case '-':
     case 'clamp':
     case 'stretch':
+    case 'mod':
+    case 'pow':
     case '>':
     case '>=':
     case '<':
@@ -172,7 +176,11 @@ export function check(value) {
       case 'time':
         break;
       case '*':
+      case '/':
       case '+':
+      case '-':
+      case 'mod':
+      case 'pow':
         checkNumber(v[1]);
         checkNumber(v[2]);
         break;
@@ -271,8 +279,11 @@ export function parse(value, attributes, attributePrefix, variables, typeHint) {
         return 'u_time';
 
       // math operators
-      case '*': return `(${p(v[1])} * ${p(v[2])})`;
-      case '+': return `(${p(v[1])} + ${p(v[2])})`;
+      case '*':
+      case '/':
+      case '+':
+      case '-':
+        return `(${p(v[1])} ${v[0]} ${p(v[2])})`;
       case 'clamp': return `clamp(${p(v[1])}, ${p(v[2])}, ${p(v[3])})`;
       case 'stretch':
         const low1 = p(v[2]);
@@ -280,6 +291,8 @@ export function parse(value, attributes, attributePrefix, variables, typeHint) {
         const low2 = p(v[4]);
         const high2 = p(v[5]);
         return `((clamp(${p(v[1])}, ${low1}, ${high1}) - ${low1}) * ((${high2} - ${low2}) / (${high1} - ${low1})) + ${low2})`;
+      case 'mod': return `mod(${p(v[1])}, ${p(v[2])})`;
+      case 'pow': return `pow(${p(v[1])}, ${p(v[2])})`;
 
       // color operators
       case 'interpolate':
diff --git a/test/spec/ol/webgl/shaderbuilder.test.js b/test/spec/ol/webgl/shaderbuilder.test.js
index 86ed2c9b48..bc94e59bdc 100644
--- a/test/spec/ol/webgl/shaderbuilder.test.js
+++ b/test/spec/ol/webgl/shaderbuilder.test.js
@@ -279,8 +279,10 @@ void main(void) {
       check(['var', 'myValue']);
       check(['time']);
       check(['+', ['*', ['get', 'size'], 0.001], 12]);
+      check(['/', ['-', ['get', 'size'], 0.001], 12]);
       check(['clamp', ['get', 'attr2'], ['get', 'attr3'], 20]);
       check(['stretch', ['get', 'size'], 10, 100, 4, 8]);
+      check(['mod', ['pow', ['get', 'size'], 0.5], 12]);
       check(['>', 10, ['get', 'attr4']]);
       check(['>=', 10, ['get', 'attr4']]);
       check(['<', 10, ['get', 'attr4']]);
@@ -381,8 +383,10 @@ void main(void) {
       expect(parseFn(['var', 'myValue'])).to.eql('u_myValue');
       expect(parseFn(['time'])).to.eql('u_time');
       expect(parseFn(['+', ['*', ['get', 'size'], 0.001], 12])).to.eql('((a_size * 0.001) + 12.0)');
+      expect(parseFn(['/', ['-', ['get', 'size'], 20], 100])).to.eql('((a_size - 20.0) / 100.0)');
       expect(parseFn(['clamp', ['get', 'attr2'], ['get', 'attr3'], 20])).to.eql('clamp(a_attr2, a_attr3, 20.0)');
       expect(parseFn(['stretch', ['get', 'size'], 10, 100, 4, 8])).to.eql('((clamp(a_size, 10.0, 100.0) - 10.0) * ((8.0 - 4.0) / (100.0 - 10.0)) + 4.0)');
+      expect(parseFn(['pow', ['mod', ['time'], 10], 2])).to.eql('pow(mod(u_time, 10.0), 2.0)');
       expect(parseFn(['>', 10, ['get', 'attr4']])).to.eql('(10.0 > a_attr4 ? 1.0 : 0.0)');
       expect(parseFn(['>=', 10, ['get', 'attr4']])).to.eql('(10.0 >= a_attr4 ? 1.0 : 0.0)');
       expect(parseFn(['<', 10, ['get', 'attr4']])).to.eql('(10.0 < a_attr4 ? 1.0 : 0.0)');