WebGL.Utils.checkShaderMax is a new function, used internally by the renderer, to determine the maximum number of texture units the GPU + browser supports.

src/renderer/webgl/CheckShaderMax.js

@@ -1,58 +0,0 @@
-//  From Pixi v5
-
-function GenerateSrc (maxIfs)
-{
-    var src = '';
-
-    for (var i = 0; i < maxIfs; ++i)
-    {
-        if (i > 0)
-        {
-            src += '\nelse ';
-        }
-
-        if (i < maxIfs - 1)
-        {
-            src += 'if(test == ' + i + '.0){}';
-        }
-    }
-
-    return src;
-}
-
-var CheckShaderMax = function (gl, maxIfs)
-{
-    var shader = gl.createShader(gl.FRAGMENT_SHADER);
-
-    var fragTemplate = [
-        'precision mediump float;',
-        'void main(void){',
-        'float test = 0.1;',
-        '%forloop%',
-        'gl_FragColor = vec4(0.0);',
-        '}'
-    ].join('\n');
-
-    // eslint-disable-next-line no-constant-condition
-    while (true)
-    {
-        var fragmentSrc = fragTemplate.replace(/%forloop%/gi, GenerateSrc(maxIfs));
-
-        gl.shaderSource(shader, fragmentSrc);
-        gl.compileShader(shader);
-
-        if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
-        {
-            maxIfs = (maxIfs / 2) | 0;
-        }
-        else
-        {
-            // valid!
-            break;
-        }
-    }
-
-    return maxIfs;
-};
-
-module.exports = CheckShaderMax;

src/renderer/webgl/Utils.js

@@ -1,10 +1,37 @@
 /**
  * @author       Richard Davey <rich@photonstorm.com>
  * @author       Felipe Alfonso <@bitnenfer>
+ * @author       Matthew Groves <@doormat>
  * @copyright    2020 Photon Storm Ltd.
  * @license      {@link https://opensource.org/licenses/MIT|MIT License}
  */
 
+/**
+ * Generate shader source to test maximum ifs.
+ *
+ * @private
+ * @param {number} maxIfs - The number of if statements to generate
+ */
+function GenerateSrc (maxIfs)
+{
+    var src = '';
+
+    for (var i = 0; i < maxIfs; ++i)
+    {
+        if (i > 0)
+        {
+            src += '\nelse ';
+        }
+
+        if (i < maxIfs - 1)
+        {
+            src += 'if(test == ' + i + '.0){}';
+        }
+    }
+
+    return src;
+}
+
 /**
  * @namespace Phaser.Renderer.WebGL.Utils
  * @since 3.0.0
@@ -124,6 +151,58 @@ module.exports = {
         }
 
         return count;
+    },
+
+    /**
+     * Check to see how many texture units the GPU supports, based on the given config value.
+     * Then tests this against the maximum number of iterations GLSL can support.
+     *
+     * @function Phaser.Renderer.WebGL.Utils.checkShaderMax
+     * @since 3.25.0
+     *
+     * @param {WebGLRenderingContext} gl - The WebGLContext used to create the shaders.
+     * @param {number} maxTextures - The Game Config maxTextures value.
+     *
+     * @return {number} The number of texture units that is supported by this browser and GPU.
+     */
+    checkShaderMax: function (gl, maxTextures)
+    {
+        if (!maxTextures || maxTextures === -1)
+        {
+            maxTextures = gl.getParameter(gl.MAX_TEXTURE_IMAGE_UNITS);
+        }
+
+        var shader = gl.createShader(gl.FRAGMENT_SHADER);
+
+        var fragTemplate = [
+            'precision mediump float;',
+            'void main(void){',
+            'float test = 0.1;',
+            '%forloop%',
+            'gl_FragColor = vec4(0.0);',
+            '}'
+        ].join('\n');
+
+        // eslint-disable-next-line no-constant-condition
+        while (true)
+        {
+            var fragmentSrc = fragTemplate.replace(/%forloop%/gi, GenerateSrc(maxTextures));
+
+            gl.shaderSource(shader, fragmentSrc);
+            gl.compileShader(shader);
+
+            if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
+            {
+                maxTextures = (maxTextures / 2) | 0;
+            }
+            else
+            {
+                // valid!
+                break;
+            }
+        }
+
+        return maxTextures;
     }
 
 };