From 921952cdb937fcc3d85e6370d51fb9396e88831b Mon Sep 17 00:00:00 2001
From: Alexander <DrA1ex@users.noreply.github.com>
Date: Thu, 28 Sep 2023 23:35:16 +0500
Subject: [PATCH] Allow to specify custom texture for Gravity example

---
 examples/common/params.js |  7 ++++++-
 examples/gravity/index.js | 21 +++++++++++++++++----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/examples/common/params.js b/examples/common/params.js
index 43f0a87..0fd6b50 100644
--- a/examples/common/params.js
+++ b/examples/common/params.js
@@ -49,6 +49,8 @@ export const Parser = {
     float: (v) => parseNumber(v, Number.parseFloat),
     /** @param {Object} type */
     enum: type => parseEnum(type),
+    /** @param {*} v */
+    string: v => v?.toString(),
 }
 
 export function parse(def = {}) {
@@ -113,7 +115,10 @@ export function parseSettings(config) {
 
     const result = {}
     for (const [key, {parser, param, default: def}] of Object.entries(config)) {
-        const value = parser(params[param]) ?? def;
+        let value = parser(params[param]);
+        if (value === undefined || value === null || value === "") {
+            value = def;
+        }
 
         if (value !== null) {
             result[key] = value;
diff --git a/examples/gravity/index.js b/examples/gravity/index.js
index de0b3fc..ae6df6a 100644
--- a/examples/gravity/index.js
+++ b/examples/gravity/index.js
@@ -25,7 +25,8 @@ const BootstrapInstance = new Bootstrap(
 );
 
 const {
-    count, minSize, maxSize, gravity, particleScale, particleOpacity, worldScale, minInteractionDistance
+    count, minSize, maxSize, gravity, particleScale, particleOpacity, worldScale, minInteractionDistance,
+    particleTextureUrl, particleBlending, particleColoring
 } = Params.parseSettings({
     count: {parser: Params.Parser.int, param: "count", default: 200},
     minSize: {parser: Params.Parser.int, param: "min_size", default: 10},
@@ -35,6 +36,14 @@ const {
     particleOpacity: {parser: Params.Parser.float, param: "opacity", default: 1},
     worldScale: {parser: Params.Parser.float, param: "w_scale", default: 40},
     minInteractionDistance: {parser: Params.Parser.float, param: "scale", default: 0.01 ** 2},
+
+    particleBlending: {parser: Params.Parser.bool, param: "blend", default: true},
+    particleColoring: {parser: Params.Parser.bool, param: "color", default: true},
+    particleTextureUrl: {
+        parser: Params.Parser.string,
+        param: "tex",
+        default: new URL("./sprites/particle.png", import.meta.url)
+    }
 });
 
 
@@ -53,9 +62,11 @@ BootstrapInstance.renderer.setProjectionMatrix(projMatrix)
 BootstrapInstance.addConstraint(new InsetConstraint(WorldRect))
 BootstrapInstance.addForce(new ResistanceForce(options.resistance));
 
-BootstrapInstance.renderer.setBlending(WebGL2RenderingContext.SRC_COLOR, WebGL2RenderingContext.ONE);
+if (particleBlending) {
+    BootstrapInstance.renderer.setBlending(WebGL2RenderingContext.SRC_COLOR, WebGL2RenderingContext.ONE);
+}
 
-const particleTexture = new ImageTexture(new URL("./sprites/particle.png", import.meta.url));
+const particleTexture = new ImageTexture(particleTextureUrl);
 particleTexture.glWrapS = WebGL2RenderingContext.CLAMP_TO_EDGE;
 particleTexture.glWrapT = WebGL2RenderingContext.CLAMP_TO_EDGE;
 particleTexture.glMin = WebGL2RenderingContext.LINEAR_MIPMAP_LINEAR;
@@ -84,7 +95,9 @@ for (let i = 0; i < count; i++) {
 
     const renderer = new SpriteObject(body);
     renderer.texture = particleTexture;
-    renderer.color = Utils.randomColor(170, 255);
+    if (particleColoring) {
+        renderer.color = Utils.randomColor(170, 255);
+    }
     renderer.opacity = particleOpacity;
     renderer.scale = particleScale;