perf(EffectComposer): lower default multisampling to 4

docs/effect-composer.mdx

@@ -14,6 +14,7 @@ The `EffectComposer` must wrap all your effects. It will manage them for you.
   autoClear?: boolean
   /** Whether the last pass automatically renders to the screen. Set to `false` when rendering to a target of your own (e.g. via a trailing CopyPass) instead. */
   autoRenderToScreen?: boolean
+  /** MSAA sample count, default 4. Set to 0 to disable it, e.g. when using SMAA or FXAA instead. */
   multisampling?: number
   frameBufferType?: TextureDataType
   /** For effects that support DepthDownsamplingPass */

src/EffectComposer.tsx

@@ -200,7 +200,7 @@ export const EffectComposer = /* @__PURE__ */ memo(function EffectComposer({
   depthBuffer,
   enableNormalPass,
   stencilBuffer,
-  multisampling = 8,
+  multisampling = 4,
   frameBufferType = HalfFloatType,
   renderPass = defaultRenderPass,
   mergeMode = 'auto',

src/tests/EffectComposer.test.tsx

@@ -1529,4 +1529,32 @@ describe('EffectComposer', () => {
       expect(composer.outputBuffer.width).toBe(cssSize.width)
     })
   })
+
+  describe('defaults', () => {
+    it('uses 4 MSAA samples unless multisampling is set', async () => {
+      const ref = React.createRef<EffectComposerImpl>()
+
+      await React.act(async () =>
+        root.render(
+          <EffectComposer ref={ref}>
+            <WrappedEffectA />
+          </EffectComposer>
+        )
+      )
+      const composer = await waitForComposer(ref)
+      expect(composer.multisampling).toBe(4)
+
+      await React.act(async () =>
+        root.render(
+          <EffectComposer ref={ref} multisampling={0}>
+            <WrappedEffectA />
+          </EffectComposer>
+        )
+      )
+      const next = await waitForNewComposer(ref, composer)
+      expect(next.multisampling).toBe(0)
+
+      await React.act(async () => root.render(null))
+    })
+  })
 })