From e5e03d46a0ce92655f96077d679ec01977ebc37f Mon Sep 17 00:00:00 2001
From: Olivier Guyot <olivier.guyot@camptocamp.com>
Date: Thu, 31 Oct 2019 10:50:24 +0100
Subject: [PATCH] Webgl points renderer / more optimizations

Simplify calls in the attributes callback, also less stress
on garbage collection.
---
 src/ol/style/expressions.js   | 18 ++++++++++++++----
 src/ol/webgl/ShaderBuilder.js | 10 +++++-----
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/ol/style/expressions.js b/src/ol/style/expressions.js
index 889e33b921..6527164bf2 100644
--- a/src/ol/style/expressions.js
+++ b/src/ol/style/expressions.js
@@ -203,6 +203,19 @@ export function colorToGlsl(color) {
   );
 }
 
+/**
+ * Returns a stable equivalent number for the string literal.
+ * @param {ParsingContext} context Parsing context
+ * @param {string} string String literal value
+ * @returns {number} Number equivalent
+ */
+export function getStringNumberEquivalent(context, string) {
+  if (context.stringLiteralsMap[string] === undefined) {
+    context.stringLiteralsMap[string] = Object.keys(context.stringLiteralsMap).length;
+  }
+  return context.stringLiteralsMap[string];
+}
+
 /**
  * Returns a stable equivalent number for the string literal, for use in shaders. This number is then
  * converted to be a GLSL-compatible string.
@@ -211,10 +224,7 @@ export function colorToGlsl(color) {
  * @returns {string} GLSL-compatible string containing a number
  */
 export function stringToGlsl(context, string) {
-  if (context.stringLiteralsMap[string] === undefined) {
-    context.stringLiteralsMap[string] = Object.keys(context.stringLiteralsMap).length;
-  }
-  return numberToGlsl(context.stringLiteralsMap[string]);
+  return numberToGlsl(getStringNumberEquivalent(context, string));
 }
 
 /**
diff --git a/src/ol/webgl/ShaderBuilder.js b/src/ol/webgl/ShaderBuilder.js
index bea9a05926..1ccd598583 100644
--- a/src/ol/webgl/ShaderBuilder.js
+++ b/src/ol/webgl/ShaderBuilder.js
@@ -3,7 +3,7 @@
  * @module ol/webgl/ShaderBuilder
  */
 
-import {expressionToGlsl, stringToGlsl, ValueTypes} from '../style/expressions.js';
+import {expressionToGlsl, getStringNumberEquivalent, ValueTypes} from '../style/expressions.js';
 
 /**
  * @typedef {Object} VaryingDescription
@@ -450,7 +450,7 @@ export function parseLiteralStyle(style) {
       }
       let value = style.variables[varName];
       if (typeof value === 'string') {
-        value = parseFloat(stringToGlsl(vertContext, value));
+        value = getStringNumberEquivalent(vertContext, value);
       }
       return value !== undefined ? value : -9999999; // to avoid matching with the first string literal
     };
@@ -484,10 +484,10 @@ export function parseLiteralStyle(style) {
     attributes: vertContext.attributes.map(function(attributeName) {
       return {
         name: attributeName,
-        callback: function(feature) {
-          let value = feature.get(attributeName);
+        callback: function(feature, props) {
+          let value = props[attributeName];
           if (typeof value === 'string') {
-            value = parseFloat(stringToGlsl(vertContext, value));
+            value = getStringNumberEquivalent(vertContext, value);
           }
           return value !== undefined ? value : -9999999; // to avoid matching with the first string literal
         }