buffer update opt: New android sample for material instance stress test (#9396)

2025-11-05 11:24:56 +08:00
parent dc1de994e0
commit 84fdf36ed9
23 changed files with 904 additions and 0 deletions
--- a/android/samples/sample-material-instance-stress/.gitignore
+++ b/android/samples/sample-material-instance-stress/.gitignore
@@ -0,0 +1,12 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+/.idea/caches
+/.idea/gradle.xml
+.DS_Store
+/build
+/captures
+/src/main/assets
+.externalNativeBuild
--- a/android/samples/sample-material-instance-stress/build.gradle
+++ b/android/samples/sample-material-instance-stress/build.gradle
@@ -0,0 +1,52 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+    id 'filament-tools-plugin'
+}
+
+project.ext.isSample = true
+
+kotlin {
+    jvmToolchain(versions.jdk)
+}
+
+filamentTools {
+    materialInputDir = project.layout.projectDirectory.dir("src/main/materials")
+    materialOutputDir = project.layout.projectDirectory.dir("src/main/assets/materials")
+}
+
+clean.doFirst {
+    delete "src/main/assets"
+}
+android {
+    namespace 'com.google.android.filament.materialinstancestress'
+
+    compileSdkVersion versions.compileSdk
+    defaultConfig {
+        applicationId "com.google.android.filament.materialinstancestress"
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
+    }
+
+    // NOTE: This is a workaround required because the AGP task collectReleaseDependencies
+    //       is not configuration-cache friendly yet; this is only useful for Play publication
+    dependenciesInfo {
+        includeInApk = false
+    }
+
+    // We use the .filamat extension for materials compiled with matc
+    // Telling aapt to not compress them allows to load them efficiently
+    aaptOptions {
+        noCompress 'filamat', 'ktx'
+    }
+
+    compileOptions {
+        sourceCompatibility versions.jdk
+        targetCompatibility versions.jdk
+    }
+}
+
+dependencies {
+    implementation deps.kotlin
+    implementation project(':filament-android')
+}
--- a/android/samples/sample-material-instance-stress/src/main/AndroidManifest.xml
+++ b/android/samples/sample-material-instance-stress/src/main/AndroidManifest.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <application
+      android:allowBackup="true"
+      android:icon="@mipmap/ic_launcher"
+      android:label="@string/app_name"
+      android:roundIcon="@mipmap/ic_launcher_round"
+      android:supportsRtl="true"
+      android:theme="@style/AppTheme">
+    <activity
+        android:exported="true"
+        android:name=".MainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN"/>
+
+        <category android:name="android.intent.category.LAUNCHER"/>
+      </intent-filter>
+    </activity>
+  </application>
+
+</manifest>
--- a/android/samples/sample-material-instance-stress/src/main/java/com/google/android/filament/materialinstancestress/MainActivity.kt
+++ b/android/samples/sample-material-instance-stress/src/main/java/com/google/android/filament/materialinstancestress/MainActivity.kt
@@ -0,0 +1,532 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.filament.materialinstancestress
+
+import android.animation.ValueAnimator
+import android.app.Activity
+import android.opengl.Matrix
+import android.os.Bundle
+import android.view.Choreographer
+import android.view.Surface
+import android.view.SurfaceView
+import android.view.animation.LinearInterpolator
+
+import com.google.android.filament.*
+import com.google.android.filament.RenderableManager.*
+import com.google.android.filament.VertexBuffer.*
+import com.google.android.filament.android.DisplayHelper
+import com.google.android.filament.android.FilamentHelper
+import com.google.android.filament.android.UiHelper
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.nio.channels.Channels
+import kotlin.math.cos
+import kotlin.math.sin
+
+class MainActivity : Activity() {
+    // Make sure to initialize Filament first
+    // This loads the JNI library needed by most API calls
+    companion object {
+        init {
+            Filament.init()
+        }
+
+        private const val NUM_CUBES = 1000
+        private const val GRID_SIZE = 10
+        private const val SPACING = 2.5f
+    }
+
+    // The View we want to render into
+    private lateinit var surfaceView: SurfaceView
+    // UiHelper is provided by Filament to manage SurfaceView and SurfaceTexture
+    private lateinit var uiHelper: UiHelper
+    // DisplayHelper is provided by Filament to manage the display
+    private lateinit var displayHelper: DisplayHelper
+    // Choreographer is used to schedule new frames
+    private lateinit var choreographer: Choreographer
+
+    // Engine creates and destroys Filament resources
+    // Each engine must be accessed from a single thread of your choosing
+    // Resources cannot be shared across engines
+    private lateinit var engine: Engine
+    // A renderer instance is tied to a single surface (SurfaceView, TextureView, etc.)
+    private lateinit var renderer: Renderer
+    // A scene holds all the renderable, lights, etc. to be drawn
+    private lateinit var scene: Scene
+    // A view defines a viewport, a scene and a camera for rendering
+    private lateinit var view: View
+    // Should be pretty obvious :)
+    private lateinit var camera: Camera
+
+    private lateinit var material: Material
+    private lateinit var vertexBuffer: VertexBuffer
+    private lateinit var indexBuffer: IndexBuffer
+
+    // Filament entity representing a renderable object
+    @Entity private val renderables = IntArray(NUM_CUBES)
+    private val materialInstances = arrayOfNulls<MaterialInstance>(NUM_CUBES)
+    private val translationMatrices = Array(NUM_CUBES) { FloatArray(16) }
+
+    @Entity private var light = 0
+
+    // A swap chain is Filament's representation of a surface
+    private var swapChain: SwapChain? = null
+
+    private var cameraRadius = 42.7f // Initial distance (calculated from original 15Y, 40Z)
+    private var cameraTheta = 0.0f  // Azimuth (horizontal) in radians
+    private var cameraPhi = 0.358f  // Elevation (vertical) in radians (from original 15Y, 40Z)
+
+    private var mLastX = 0.0f
+    private var mLastY = 0.0f
+    private val DRAG_SPEED = 0.005f
+
+    // Performs the rendering and schedules new frames
+    private val frameScheduler = FrameCallback()
+
+    private val animator = ValueAnimator.ofFloat(0.0f, 360.0f)
+
+    private val animatorListener = object : ValueAnimator.AnimatorUpdateListener {
+        // Pre-allocate matrix to avoid GC churn
+        private val transformMatrix = FloatArray(16)
+
+        override fun onAnimationUpdate(a: ValueAnimator) {
+            val tcm = engine.transformManager
+            val time = a.animatedFraction // 0.0 to 1.0
+
+            // Calculate the sine wave scale factor.
+            // sin(time * 2 * PI) oscillates between -1.0 and 1.0.
+            // We multiply by 0.5f (so it's -0.5 to 0.5) and add 1.0f.
+            // This makes the final 'scale' oscillate between 0.5 and 1.5.
+            val scale = 1.0f + sin(time * 2.0 * Math.PI).toFloat() * 0.5f
+
+            val localScale = (scale - 0.5f) * 0.5f + 0.5f
+
+            for (i in 0 until NUM_CUBES) {
+                val inst = tcm.getInstance(renderables[i])
+                val materialInst = materialInstances[i] ?: continue
+
+                // Get the cube's base position from its stored matrix
+                // The translation is in elements 12 (x), 13 (y), and 14 (z)
+                val baseX = translationMatrices[i][12]
+                val baseY = translationMatrices[i][13]
+                val baseZ = translationMatrices[i][14]
+
+                // Set the transformMatrix to a new translation matrix,
+                // scaled from the center (0,0,0)
+                Matrix.setIdentityM(transformMatrix, 0)
+                Matrix.translateM(transformMatrix, 0,
+                        baseX * scale,
+                        baseY * scale,
+                        baseZ * scale)
+                Matrix.scaleM(transformMatrix, 0, localScale, localScale, localScale)
+
+                tcm.setTransform(inst, transformMatrix)
+
+                // Vary roughness
+                val roughness = 0.5f + 0.5f * sin(time * 2.0 * Math.PI + i * 0.1).toFloat()
+                materialInst.setParameter("roughness", roughness)
+
+                // Vary color (using linear RGB)
+                val r = 0.5f + 0.5f * cos(time * 2.0 * Math.PI + i * 0.5).toFloat()
+                val g = 0.5f + 0.5f * sin(time * 2.0 * Math.PI + i * 0.3).toFloat()
+                val b = 0.5f + 0.5f * cos(time * 2.0 * Math.PI + i * 0.1).toFloat()
+                materialInst.setParameter("baseColor", Colors.RgbType.LINEAR, r, g, b)
+            }
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        surfaceView = SurfaceView(this)
+        setContentView(surfaceView)
+
+        surfaceView.setOnTouchListener(touchListener)
+        choreographer = Choreographer.getInstance()
+
+        displayHelper = DisplayHelper(this)
+
+        setupSurfaceView()
+        setupFilament()
+        setupView()
+        setupScene()
+    }
+
+    private fun setupSurfaceView() {
+        uiHelper = UiHelper(UiHelper.ContextErrorPolicy.DONT_CHECK)
+        uiHelper.renderCallback = SurfaceCallback()
+        uiHelper.attachTo(surfaceView)
+    }
+
+    private fun setupFilament() {
+        engine = Engine.create()
+        renderer = engine.createRenderer()
+        scene = engine.createScene()
+        view = engine.createView()
+        camera = engine.createCamera(engine.entityManager.create())
+    }
+
+    private fun setupView() {
+        scene.skybox = Skybox.Builder().color(0.035f, 0.035f, 0.035f, 1.0f).build(engine)
+        view.camera = camera
+        view.scene = scene
+    }
+
+    private fun setupScene() {
+        loadMaterial()
+        createMesh()
+
+        val tcm = engine.transformManager
+        val center = (GRID_SIZE - 1) * 0.5f
+
+        for (i in 0 until NUM_CUBES) {
+            // Calculate grid position
+            val x = (i % GRID_SIZE) - center
+            val y = ((i / GRID_SIZE) % GRID_SIZE) - center
+            val z = (i / (GRID_SIZE * GRID_SIZE)) - center
+
+            val posX = x * SPACING
+            val posY = y * SPACING
+            val posZ = z * SPACING
+
+            // Create material instance for this cube
+            materialInstances[i] = material.createInstance()
+
+            // Set initial parameters (will be overwritten by animator, but good practice)
+            materialInstances[i]?.setParameter("baseColor", Colors.RgbType.SRGB, 1.0f, 0.85f, 0.57f)
+            materialInstances[i]?.setParameter("metallic", 0.0f)
+            materialInstances[i]?.setParameter("roughness", 0.3f)
+
+            // Create the renderable entity
+            renderables[i] = EntityManager.get().create()
+
+            // Create the renderable component
+            RenderableManager.Builder(1)
+                .boundingBox(Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f))
+                .geometry(0, PrimitiveType.TRIANGLES, vertexBuffer, indexBuffer, 0, 6 * 6)
+                .material(0, materialInstances[i]!!)
+                .build(engine, renderables[i])
+
+            // Add to scene
+            scene.addEntity(renderables[i])
+
+            // Set its initial transform
+            // Store the base translation matrix
+            Matrix.setIdentityM(translationMatrices[i], 0)
+            Matrix.translateM(translationMatrices[i], 0, posX, posY, posZ)
+
+            // Get the transform component instance
+            val inst = tcm.getInstance(renderables[i])
+            tcm.setTransform(inst, translationMatrices[i])
+        }
+
+        // We now need a light, let's create a directional light
+        light = EntityManager.get().create()
+
+        val (r, g, b) = Colors.cct(5_500.0f)
+        LightManager.Builder(LightManager.Type.DIRECTIONAL)
+                .color(r, g, b)
+                .intensity(110_000.0f)
+                .direction(0.0f, -0.5f, -1.0f)
+                .castShadows(true)
+                .build(engine, light)
+
+        scene.addEntity(light)
+
+        camera.setExposure(16.0f, 1.0f / 125.0f, 100.0f)
+
+        updateCamera()
+
+        startAnimation()
+    }
+
+    private fun loadMaterial() {
+        readUncompressedAsset("materials/lit.filamat").let {
+            material = Material.Builder().payload(it, it.remaining()).build(engine)
+        }
+    }
+
+    private fun createMesh() {
+        val floatSize = 4
+        val shortSize = 2
+        val vertexSize = 3 * floatSize + 4 * floatSize
+
+        // A vertex is a position + a tangent frame:
+        // 3 floats for XYZ position, 4 floats for normal+tangents (quaternion)
+        @Suppress("ArrayInDataClass")
+        data class Vertex(val x: Float, val y: Float, val z: Float, val tangents: FloatArray)
+        fun ByteBuffer.put(v: Vertex): ByteBuffer {
+            putFloat(v.x)
+            putFloat(v.y)
+            putFloat(v.z)
+            v.tangents.forEach { putFloat(it) }
+            return this
+        }
+
+        // 6 faces, 4 vertices per face
+        val vertexCount = 6 * 4
+
+        // Create tangent frames, one per face
+        val tfPX = FloatArray(4)
+        val tfNX = FloatArray(4)
+        val tfPY = FloatArray(4)
+        val tfNY = FloatArray(4)
+        val tfPZ = FloatArray(4)
+        val tfNZ = FloatArray(4)
+
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 0.0f, 0.0f, -1.0f,  1.0f,  0.0f,  0.0f, tfPX)
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 0.0f, 0.0f, -1.0f, -1.0f,  0.0f,  0.0f, tfNX)
+        MathUtils.packTangentFrame(-1.0f,  0.0f, 0.0f, 0.0f, 0.0f, -1.0f,  0.0f,  1.0f,  0.0f, tfPY)
+        MathUtils.packTangentFrame(-1.0f,  0.0f, 0.0f, 0.0f, 0.0f,  1.0f,  0.0f, -1.0f,  0.0f, tfNY)
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 1.0f, 0.0f,  0.0f,  0.0f,  0.0f,  1.0f, tfPZ)
+        MathUtils.packTangentFrame( 0.0f, -1.0f, 0.0f, 1.0f, 0.0f,  0.0f,  0.0f,  0.0f, -1.0f, tfNZ)
+
+        val vertexData = ByteBuffer.allocate(vertexCount * vertexSize)
+                // It is important to respect the native byte order
+                .order(ByteOrder.nativeOrder())
+                // Face -Z
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNZ))
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfNZ))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfNZ))
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfNZ))
+                // Face +X
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfPX))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfPX))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPX))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfPX))
+                // Face +Z
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfPZ))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfPZ))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPZ))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfPZ))
+                // Face -X
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfNX))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfNX))
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfNX))
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNX))
+                // Face -Y
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfNY))
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNY))
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfNY))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfNY))
+                // Face +Y
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfPY))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfPY))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPY))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfPY))
+                // Make sure the cursor is pointing in the right place in the byte buffer
+                .flip()
+
+        // Declare the layout of our mesh
+        vertexBuffer = VertexBuffer.Builder()
+                .bufferCount(1)
+                .vertexCount(vertexCount)
+                // Because we interleave position and color data we must specify offset and stride
+                // We could use de-interleaved data by declaring two buffers and giving each
+                // attribute a different buffer index
+                .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0,             vertexSize)
+                .attribute(VertexAttribute.TANGENTS, 0, AttributeType.FLOAT4, 3 * floatSize, vertexSize)
+                .build(engine)
+
+        // Feed the vertex data to the mesh
+        // We only set 1 buffer because the data is interleaved
+        vertexBuffer.setBufferAt(engine, 0, vertexData)
+
+        // Create the indices
+        val indexData = ByteBuffer.allocate(6 * 2 * 3 * shortSize)
+                .order(ByteOrder.nativeOrder())
+        repeat(6) {
+            val i = (it * 4).toShort()
+            indexData
+                    .putShort(i).putShort((i + 1).toShort()).putShort((i + 2).toShort())
+                    .putShort(i).putShort((i + 2).toShort()).putShort((i + 3).toShort())
+        }
+        indexData.flip()
+
+        // 6 faces, 2 triangles per face,
+        indexBuffer = IndexBuffer.Builder()
+                .indexCount(vertexCount * 2)
+                .bufferType(IndexBuffer.Builder.IndexType.USHORT)
+                .build(engine)
+        indexBuffer.setBuffer(engine, indexData)
+    }
+
+    private fun updateCamera() {
+        // Calculate eye position from spherical coordinates
+        val eyeY = cameraRadius * sin(cameraPhi)
+        val horizontalRadius = cameraRadius * cos(cameraPhi)
+        val eyeX = horizontalRadius * sin(cameraTheta)
+        val eyeZ = horizontalRadius * cos(cameraTheta)
+
+        // Point the camera at the center (0,0,0)
+        camera.lookAt(eyeX.toDouble(), eyeY.toDouble(), eyeZ.toDouble(), // eye
+                0.0, 0.0, 0.0, // center
+                0.0, 1.0, 0.0) // up
+    }
+
+    private val touchListener = object : android.view.View.OnTouchListener {
+        override fun onTouch(v: android.view.View?, event: android.view.MotionEvent?): Boolean {
+            if (event == null) return false
+            when (event.action) {
+                android.view.MotionEvent.ACTION_DOWN -> {
+                    mLastX = event.x
+                    mLastY = event.y
+                    return true
+                }
+                android.view.MotionEvent.ACTION_MOVE -> {
+                    val dx = event.x - mLastX
+                    val dy = event.y - mLastY
+
+                    cameraTheta -= dx * DRAG_SPEED
+                    cameraPhi += dy * DRAG_SPEED
+
+                    // Clamp vertical angle to avoid flipping over
+                    cameraPhi = cameraPhi.coerceIn(-1.5f, 1.5f)
+
+                    updateCamera()
+
+                    mLastX = event.x
+                    mLastY = event.y
+                    return true
+                }
+            }
+            return v?.onTouchEvent(event) ?: false
+        }
+    }
+
+    private fun startAnimation() {
+        animator.interpolator = LinearInterpolator()
+        animator.duration = 6000
+        animator.repeatMode = ValueAnimator.RESTART
+        animator.repeatCount = ValueAnimator.INFINITE
+        animator.addUpdateListener(animatorListener)
+        animator.start()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        choreographer.postFrameCallback(frameScheduler)
+        animator.start()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+
+        // Stop the animation and any pending frame
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel();
+
+        // Always detach the surface before destroying the engine
+        uiHelper.detach()
+
+        // Cleanup all resources
+        engine.destroyEntity(light)
+
+        // Destroy all 1000 entities and material instances
+        for (i in 0 until NUM_CUBES) {
+            engine.destroyEntity(renderables[i])
+            materialInstances[i]?.let { engine.destroyMaterialInstance(it) }
+        }
+
+        engine.destroyRenderer(renderer)
+        engine.destroyVertexBuffer(vertexBuffer)
+        engine.destroyIndexBuffer(indexBuffer)
+        engine.destroyMaterial(material)
+        engine.destroyView(view)
+        engine.destroyScene(scene)
+        engine.destroyCameraComponent(camera.entity)
+
+        // Engine.destroyEntity() destroys Filament related resources only
+        // (components), not the entity itself
+        val entityManager = EntityManager.get()
+        entityManager.destroy(light)
+        for (entity in renderables) {
+            entityManager.destroy(entity)
+        }
+        entityManager.destroy(camera.entity)
+
+        // Destroying the engine will free up any resource you may have forgotten
+        // to destroy, but it's recommended to do the cleanup properly
+        engine.destroy()
+    }
+
+    inner class FrameCallback : Choreographer.FrameCallback {
+        override fun doFrame(frameTimeNanos: Long) {
+            // Schedule the next frame
+            choreographer.postFrameCallback(this)
+
+            // This check guarantees that we have a swap chain
+            if (uiHelper.isReadyToRender) {
+                // If beginFrame() returns false you should skip the frame
+                // This means you are sending frames too quickly to the GPU
+                if (renderer.beginFrame(swapChain!!, frameTimeNanos)) {
+                    renderer.render(view)
+                    renderer.endFrame()
+                }
+            }
+        }
+    }
+
+    inner class SurfaceCallback : UiHelper.RendererCallback {
+        override fun onNativeWindowChanged(surface: Surface) {
+            swapChain?.let { engine.destroySwapChain(it) }
+            swapChain = engine.createSwapChain(surface)
+            displayHelper.attach(renderer, surfaceView.display)
+        }
+
+        override fun onDetachedFromSurface() {
+            displayHelper.detach()
+            swapChain?.let {
+                engine.destroySwapChain(it)
+                // Required to ensure we don't return before Filament is done executing the
+                // destroySwapChain command, otherwise Android might destroy the Surface
+                // too early
+                engine.flushAndWait()
+                swapChain = null
+            }
+        }
+
+        override fun onResized(width: Int, height: Int) {
+            val aspect = width.toDouble() / height.toDouble()
+            camera.setProjection(45.0, aspect, 0.1, 100.0, Camera.Fov.VERTICAL)
+
+            view.viewport = Viewport(0, 0, width, height)
+
+            FilamentHelper.synchronizePendingFrames(engine)
+        }
+    }
+
+    private fun readUncompressedAsset(assetName: String): ByteBuffer {
+        assets.openFd(assetName).use { fd ->
+            val input = fd.createInputStream()
+            val dst = ByteBuffer.allocate(fd.length.toInt())
+
+            val src = Channels.newChannel(input)
+            src.read(dst)
+            src.close()
+
+            return dst.apply { rewind() }
+        }
+    }
+}
--- a/android/samples/sample-material-instance-stress/src/main/materials/lit.mat
+++ b/android/samples/sample-material-instance-stress/src/main/materials/lit.mat
@@ -0,0 +1,53 @@
+// Simple lit material that defines 3 parameters:
+// - baseColor
+// - roughness
+// - metallic
+//
+// These parameters can be used by the application to change the appearance of the material.
+//
+// This source material must be compiled to a binary material using the matc tool.
+// The command used to compile this material is:
+// matc -p mobile -a opengl -o app/src/main/assets/lit.filamat app/src/materials/lit.mat
+//
+// See build.gradle for an example of how to compile materials automatically
+// Please refer to the documentation for more information about matc and the materials system.
+
+material {
+    name : lit,
+
+    // Dynamic lighting is enabled on this material
+    shadingModel : lit,
+
+    // We don't need to declare a "requires" array, lit materials
+    // always requires the "tangents" vertex attribute (the normal
+    // is required for lighting, tangent/bitangent for normal mapping
+    // and anisotropy)
+
+    // List of parameters exposed by this material
+    parameters : [
+        // The color must be passed in linear space, not sRGB
+        {
+            type : float3,
+            name : baseColor
+        },
+        {
+            type : float,
+            name : roughness
+        },
+        {
+            type : float,
+            name : metallic
+        }
+    ],
+}
+
+fragment {
+    void material(inout MaterialInputs material) {
+        prepareMaterial(material);
+
+        // Nothing fancy here, we simply copy the parameters
+        material.baseColor.rgb = materialParams.baseColor;
+        material.roughness = materialParams.roughness;
+        material.metallic = materialParams.metallic;
+    }
+}
--- a/android/samples/sample-material-instance-stress/src/main/res/drawable-v24/ic_launcher_foreground.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/drawable-v24/ic_launcher_foreground.xml
@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillType="evenOdd"
+      android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1">
+    <aapt:attr name="android:fillColor">
+      <gradient
+          android:endX="78.5885"
+          android:endY="90.9159"
+          android:startX="48.7653"
+          android:startY="61.0927"
+          android:type="linear">
+        <item
+            android:color="#44000000"
+            android:offset="0.0"/>
+        <item
+            android:color="#00000000"
+            android:offset="1.0"/>
+      </gradient>
+    </aapt:attr>
+  </path>
+  <path
+      android:fillColor="#FFFFFF"
+      android:fillType="nonZero"
+      android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1"/>
+</vector>
--- a/android/samples/sample-material-instance-stress/src/main/res/drawable/ic_launcher_background.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/drawable/ic_launcher_background.xml
@@ -0,0 +1,171 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillColor="#26A69A"
+      android:pathData="M0,0h108v108h-108z"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M9,0L9,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,0L19,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,0L29,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,0L39,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,0L49,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,0L59,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,0L69,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,0L79,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M89,0L89,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M99,0L99,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,9L108,9"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,19L108,19"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,29L108,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,39L108,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,49L108,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,59L108,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,69L108,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,79L108,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,89L108,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,99L108,99"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,29L89,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,39L89,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,49L89,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,59L89,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,69L89,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,79L89,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,19L29,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,19L39,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,19L49,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,19L59,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,19L69,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,19L79,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+</vector>
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-hdpi/ic_launcher.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-hdpi/ic_launcher.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-hdpi/ic_launcher_round.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-hdpi/ic_launcher_round.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-mdpi/ic_launcher.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-mdpi/ic_launcher.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-mdpi/ic_launcher_round.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-mdpi/ic_launcher_round.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xhdpi/ic_launcher.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xhdpi/ic_launcher.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xhdpi/ic_launcher_round.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xhdpi/ic_launcher_round.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxhdpi/ic_launcher.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxhdpi/ic_launcher.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxhdpi/ic_launcher_round.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxhdpi/ic_launcher_round.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxxhdpi/ic_launcher.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxxhdpi/ic_launcher.png
--- a/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxxhdpi/ic_launcher_round.png
+++ b/android/samples/sample-material-instance-stress/src/main/res/mipmap-xxxhdpi/ic_launcher_round.png
--- a/android/samples/sample-material-instance-stress/src/main/res/values/colors.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/values/colors.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+  <color name="colorPrimary">#3F51B5</color>
+  <color name="colorPrimaryDark">#303F9F</color>
+  <color name="colorAccent">#FF4081</color>
+</resources>
--- a/android/samples/sample-material-instance-stress/src/main/res/values/strings.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/values/strings.xml
@@ -0,0 +1,3 @@
+<resources>
+  <string name="app_name">Material Instance Stress</string>
+</resources>
--- a/android/samples/sample-material-instance-stress/src/main/res/values/styles.xml
+++ b/android/samples/sample-material-instance-stress/src/main/res/values/styles.xml
@@ -0,0 +1,8 @@
+<resources>
+
+  <!-- Base application theme. -->
+  <style name="AppTheme" parent="android:Theme.Material.Light.DarkActionBar">
+    <!-- Customize your theme here. -->
+  </style>
+
+</resources>
--- a/android/settings.gradle
+++ b/android/settings.gradle
@@ -12,6 +12,7 @@ include ':samples:sample-image-based-lighting'
 include ':samples:sample-lit-cube'
 include ':samples:sample-live-wallpaper'
 include ':samples:sample-material-builder'
+include ':samples:sample-material-instance-stress'
 include ':samples:sample-multi-view'
 include ':samples:sample-page-curl'
 include ':samples:sample-stream-test'