Allow more flexibility in the Engine.createEffectForParticles method

src/Particles/particleSystem.ts

@@ -1575,14 +1575,7 @@ export class ParticleSystem extends BaseParticleSystem implements IDisposable, I
         return effectCreationOption;
     }
 
-    /** @hidden */
-    private _getEffect(blendMode: number): Effect {
-        if (this._customEffect) {
-            return this._customEffect;
-        }
-
-        var defines = [];
-
+    public fillDefines(defines: Array<string>, blendMode: number) {
         if (this._scene.clipPlane) {
             defines.push("#define CLIPPLANE");
         }
@@ -1639,21 +1632,41 @@ export class ParticleSystem extends BaseParticleSystem implements IDisposable, I
             this._imageProcessingConfiguration.prepareDefines(this._imageProcessingConfigurationDefines);
             defines.push(this._imageProcessingConfigurationDefines.toString());
         }
+    }
+
+    public fillUniformsAttributesAndSamplerNames(uniforms: Array<string>, attributes: Array<string>, samplers: Array<string>) {
+        attributes.push(...ParticleSystem._GetAttributeNamesOrOptions(this._isAnimationSheetEnabled, this._isBillboardBased && this.billboardMode !== ParticleSystem.BILLBOARDMODE_STRETCHED, this._useRampGradients));
+
+        uniforms.push(...ParticleSystem._GetEffectCreationOptions(this._isAnimationSheetEnabled));
+
+        samplers.push("diffuseSampler", "rampSampler");
+
+        if (this._imageProcessingConfiguration) {
+            ImageProcessingConfiguration.PrepareUniforms(uniforms, this._imageProcessingConfigurationDefines);
+            ImageProcessingConfiguration.PrepareSamplers(samplers, this._imageProcessingConfigurationDefines);
+        }
+    }
+
+    /** @hidden */
+    private _getEffect(blendMode: number): Effect {
+        if (this._customEffect) {
+            return this._customEffect;
+        }
+
+        var defines: Array<string> = [];
+
+        this.fillDefines(defines, blendMode);
 
         // Effect
         var join = defines.join("\n");
         if (this._cachedDefines !== join) {
             this._cachedDefines = join;
 
-            var attributesNamesOrOptions = ParticleSystem._GetAttributeNamesOrOptions(this._isAnimationSheetEnabled, this._isBillboardBased && this.billboardMode !== ParticleSystem.BILLBOARDMODE_STRETCHED, this._useRampGradients);
-            var effectCreationOption = ParticleSystem._GetEffectCreationOptions(this._isAnimationSheetEnabled);
-
-            var samplers = ["diffuseSampler", "rampSampler"];
+            var attributesNamesOrOptions: Array<string> = [];
+            var effectCreationOption: Array<string> = [];
+            var samplers: Array<string> = [];
 
-            if (ImageProcessingConfiguration) {
-                ImageProcessingConfiguration.PrepareUniforms(effectCreationOption, this._imageProcessingConfigurationDefines);
-                ImageProcessingConfiguration.PrepareSamplers(samplers, this._imageProcessingConfigurationDefines);
-            }
+            this.fillUniformsAttributesAndSamplerNames(effectCreationOption, attributesNamesOrOptions, samplers);
 
             this._effect = this._scene.getEngine().createEffect(
                 "particles",

src/Particles/particleSystemComponent.ts

@@ -44,7 +44,8 @@ declare module "../Engines/engine" {
     export interface Engine {
         /**
          * Create an effect to use with particle systems.
-         * Please note that some parameters like animation sheets or not being billboard are not supported in this configuration
+         * Please note that some parameters like animation sheets or not being billboard are not supported in this configuration, except if you pass
+         * the particle system for which you want to create a custom effect in the last parameter
          * @param fragmentName defines the base name of the effect (The name of file without .fragment.fx)
          * @param uniformsNames defines a list of attribute names
          * @param samplers defines an array of string used to represent textures
@@ -52,18 +53,27 @@ declare module "../Engines/engine" {
          * @param fallbacks defines the list of potential fallbacks to use if shader conmpilation fails
          * @param onCompiled defines a function to call when the effect creation is successful
          * @param onError defines a function to call when the effect creation has failed
+         * @param particleSystem the particle system you want to create the effect for
          * @returns the new Effect
          */
         createEffectForParticles(fragmentName: string, uniformsNames: string[], samplers: string[], defines: string, fallbacks?: EffectFallbacks,
-            onCompiled?: (effect: Effect) => void, onError?: (effect: Effect, errors: string) => void): Effect;
+            onCompiled?: (effect: Effect) => void, onError?: (effect: Effect, errors: string) => void, particleSystem?: ParticleSystem): Effect;
     }
 }
 
 Engine.prototype.createEffectForParticles = function(fragmentName: string, uniformsNames: string[] = [], samplers: string[] = [], defines = "", fallbacks?: EffectFallbacks,
-    onCompiled?: (effect: Effect) => void, onError?: (effect: Effect, errors: string) => void): Effect {
+    onCompiled?: (effect: Effect) => void, onError?: (effect: Effect, errors: string) => void, particleSystem?: ParticleSystem): Effect {
 
-    var attributesNamesOrOptions = ParticleSystem._GetAttributeNamesOrOptions();
-    var effectCreationOption = ParticleSystem._GetEffectCreationOptions();
+    var attributesNamesOrOptions: Array<string> = [];
+    var effectCreationOption: Array<string> = [];
+    var allSamplers: Array<string> = [];
+
+    if (particleSystem) {
+        particleSystem.fillUniformsAttributesAndSamplerNames(effectCreationOption, attributesNamesOrOptions, allSamplers);
+    } else {
+        attributesNamesOrOptions = ParticleSystem._GetAttributeNamesOrOptions();
+        effectCreationOption = ParticleSystem._GetEffectCreationOptions();
+    }
 
     if (defines.indexOf(" BILLBOARD") === -1) {
         defines += "\n#define BILLBOARD\n";
@@ -80,7 +90,7 @@ Engine.prototype.createEffectForParticles = function(fragmentName: string, unifo
         },
         attributesNamesOrOptions,
         effectCreationOption.concat(uniformsNames),
-        samplers, defines, fallbacks, onCompiled, onError);
+        allSamplers.concat(samplers), defines, fallbacks, onCompiled, onError);
 };
 
 declare module "../Meshes/mesh" {