1 前言
Filament环境搭建中介绍了 Filament 的 Windows 和 Android 环境搭建，本文将使用 Filament 绘制纯色和彩色三角形。
1.1 Filament 类图
1.2 图元
Filament 中图形的绘制都是基于三角形实现，三角形是构成复杂图形的最小基本单元。Filament 中输入模型信息的代码如下。其中，primitiveType 为图元类型，vertexCount 为顶点个数，mBox 为渲染区域，mVertexBuffer 为顶点属性缓存（顶点属性包含位置、颜色、纹理坐标、法线向量等），mIndexBuffer 是顶点索引缓存，mMaterial 是模型材质。
private int getRenderable(PrimitiveType primitiveType, int vertexCount) { // 获取渲染id
int renderable = EntityManager.get().create();
new RenderableManager.Builder(1)
.boundingBox(mBox)
.geometry(0, primitiveType, mVertexBuffer, mIndexBuffer, 0, vertexCount)
.material(0, mMaterial.getDefaultInstance())
.build(mEngine, renderable);
return renderable;
}
private void setupScene() {
int renderable = getRenderable(PrimitiveType.TRIANGLES, mIndex.length);
mScene.addEntity(renderable);
}
primitiveType 取值主要有：POINTS（点）、LINES（线）、LINE_STRIP（线带）、TRIANGLES（三角形）、TRIANGLE_STRIP（三角形带），OpenGL ES 与之不同的是：除了有这些图元的外，还有 LINE_LOOP（线圈）、TRIANGLE_FAN（三角形扇），详见 → 【OpenGL ES】渲染管线。
对于线段类型图元，输入顶点序列 abcdef，根据图元类型，组装成的线段如下：
对于三角形类型图元，输入顶点序列 abcdef，根据图元类型，组装成的三角形如下：
2 绘制三角形
本文项目结构如下，完整代码资源 → Filament绘制三角形。
2.1 自定义基类
为方便读者将注意力聚焦在 Filament 的输入上，轻松配置复杂的环境依赖逻辑，笔者仿照 OpenGL ES 的写法，抽出了 FLSurfaceView 和 BaseModel 类。FLSurfaceView 与 GLSurfaceView 的功能类似，承载了渲染环境配置；BaseModel 中提供了一些 VertexBuffer、IndexBuffer、Material、Renderable 相关的工具类，方便子类直接使用这些工具类。
build.gradle
...
android {
...
aaptOptions { // 在应用程序打包过程中不压缩的文件
noCompress 'filamat', 'ktx'
}
}
dependencies {
implementation fileTree(dir: '../libs', include: ['*.aar'])
...
}
说明：在项目根目录下的 libs 目录中，需要放入以下 aar 文件，它们源自Filament环境搭建中编译生成的 aar。
FLSurfaceView.java
package com.zhyan8.triangle.filament;
import android.content.Context;
import android.graphics.Point;
import android.view.Choreographer;
import android.view.Surface;
import android.view.SurfaceView;
import com.google.android.filament.Camera;
import com.google.android.filament.Engine;
import com.google.android.filament.EntityManager;
import com.google.android.filament.Filament;
import com.google.android.filament.Renderer;
import com.google.android.filament.Scene;
import com.google.android.filament.Skybox;
import com.google.android.filament.SwapChain;
import com.google.android.filament.View;
import com.google.android.filament.Viewport;
import com.google.android.filament.android.DisplayHelper;
import com.google.android.filament.android.FilamentHelper;
import com.google.android.filament.android.UiHelper;
/*
* Filament中待渲染的SurfaceView
* 功能可以类比OpenGL ES中的GLSurfaceView
* 用于创建Filament的渲染环境
*/
public class FLSurfaceView extends SurfaceView {
public static int RENDERMODE_WHEN_DIRTY = 0; // 用户请求渲染才渲染一帧
public static int RENDERMODE_CONTINUOUSLY = 1; // 持续渲染
protected int mRenderMode = RENDERMODE_CONTINUOUSLY; // 渲染模式
protected Choreographer mChoreographer; // 消息控制
protected DisplayHelper mDisplayHelper; // 管理Display(可以监听分辨率或刷新率的变化)
protected UiHelper mUiHelper; // 管理SurfaceView、TextureView、SurfaceHolder
protected Engine mEngine; // 引擎(跟踪用户创建的资源, 管理渲染线程和硬件渲染器)
protected Renderer mRenderer; // 渲染器(用于操作系统窗口, 生成绘制命令, 管理帧延时)
protected Scene mScene; // 场景(管理渲染对象、灯光)
protected View mView; // 存储渲染数据(View是Renderer操作的对象)
protected Camera mCamera; // 相机(视角管理)
protected Point mDesiredSize; // 渲染分辨率
protected float[] mSkyboxColor; // 背景颜色
protected SwapChain mSwapChain; // 操作系统的本地可渲染表面(native renderable surface, 通常是一个window或view)
protected FrameCallback mFrameCallback = new FrameCallback(); // 帧回调
static {
Filament.init();
}
public FLSurfaceView(Context context) {
super(context);
mChoreographer = Choreographer.getInstance();
mDisplayHelper = new DisplayHelper(context);
}
public void init() { // 初始化
setupSurfaceView();
setupFilament();
setupView();
setupScene();
}
public void setRenderMode(int renderMode) { // 设置渲染模式
mRenderMode = renderMode;
}
public void requestRender() { // 请求渲染
mChoreographer.postFrameCallback(mFrameCallback);
}
public void onResume() { // 恢复
mChoreographer.postFrameCallback(mFrameCallback);
}
public void onPause() { // 暂停
mChoreographer.removeFrameCallback(mFrameCallback);
}
public void onDestroy() { // 销毁Filament环境
mChoreographer.removeFrameCallback(mFrameCallback);
mUiHelper.detach();
mEngine.destroyRenderer(mRenderer);
mEngine.destroyView(mView);
mEngine.destroyScene(mScene);
mEngine.destroyCameraComponent(mCamera.getEntity());
EntityManager entityManager = EntityManager.get();
entityManager.destroy(mCamera.getEntity());
mEngine.destroy();
}
protected void setupScene() { // 设置Scene参数
}
protected void onResized(int width, int height) { // Surface尺寸变化时回调
double zoom = 1;
double aspect = (double) width / (double) height;
mCamera.setProjection(Camera.Projection.ORTHO,
-aspect * zoom, aspect * zoom, -zoom, zoom, 0, 1000);
}
private void setupSurfaceView() { // 设置SurfaceView
mUiHelper = new UiHelper(UiHelper.ContextErrorPolicy.DONT_CHECK);
mUiHelper.setRenderCallback(new SurfaceCallback());
if (mDesiredSize != null) {
mUiHelper.setDesiredSize(mDesiredSize.x, mDesiredSize.y);
}
mUiHelper.attachTo(this);
}
private void setupFilament() { // 设置Filament参数
mEngine = Engine.create();
// mEngine = (new Engine.Builder()).featureLevel(Engine.FeatureLevel.FEATURE_LEVEL_0).build();
mRenderer = mEngine.createRenderer();
mScene = mEngine.createScene();
mView = mEngine.createView();
mCamera = mEngine.createCamera(mEngine.getEntityManager().create());
}
private void setupView() { // 设置View参数
float[] color = mSkyboxColor != null ? mSkyboxColor : new float[] {0, 0, 0, 1};
Skybox skybox = (new Skybox.Builder()).color(color).build(mEngine);
mScene.setSkybox(skybox);
if (mEngine.getActiveFeatureLevel() == Engine.FeatureLevel.FEATURE_LEVEL_0) {
mView.setPostProcessingEnabled(false); // FEATURE_LEVEL_0不支持post-processing
}
mView.setCamera(mCamera);
mView.setScene(mScene);
}
/*
* 帧回调
*/
private class FrameCallback implements Choreographer.FrameCallback {
@Override
public void doFrame(long frameTimeNanos) { // 渲染每帧数据
if (mRenderMode == RENDERMODE_CONTINUOUSLY) {
mChoreographer.postFrameCallback(this); // 请求下一帧
}
if (mUiHelper.isReadyToRender()) {
if (mRenderer.beginFrame(mSwapChain, frameTimeNanos)) {
mRenderer.render(mView);
mRenderer.endFrame();
}
}
}
}
/*
* Surface回调
*/
private class SurfaceCallback implements UiHelper.RendererCallback {
@Override
public void onNativeWindowChanged(Surface surface) { // Native窗口改变时回调
if (mSwapChain != null) {
mEngine.destroySwapChain(mSwapChain);
}
long flags = mUiHelper.getSwapChainFlags();
if (mEngine.getActiveFeatureLevel() == Engine.FeatureLevel.FEATURE_LEVEL_0) {
if (SwapChain.isSRGBSwapChainSupported(mEngine)) {
flags = flags | SwapChain.CONFIG_SRGB_COLORSPACE;
}
}
mSwapChain = mEngine.createSwapChain(surface, flags);
mDisplayHelper.attach(mRenderer, getDisplay());
}
@Override
public void onDetachedFromSurface() { // 解绑Surface时回调
mDisplayHelper.detach();
if (mSwapChain != null) {
mEngine.destroySwapChain(mSwapChain);
mEngine.flushAndWait();
mSwapChain = null;
}
}
@Override
public void onResized(int width, int height) { // Surface尺寸变化时回调
mView.setViewport(new Viewport(0, 0, width, height));
FilamentHelper.synchronizePendingFrames(mEngine);
FLSurfaceView.this.onResized(width, height);
}
}
}
BaseModel.java
package com.zhyan8.triangle.filament;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import com.google.android.filament.Box;
import com.google.android.filament.Engine;
import com.google.android.filament.EntityManager;
import com.google.android.filament.IndexBuffer;
import com.google.android.filament.Material;
import com.google.android.filament.RenderableManager;
import com.google.android.filament.RenderableManager.PrimitiveType;
import com.google.android.filament.VertexBuffer;
import com.google.android.filament.VertexBuffer.AttributeType;
import com.google.android.filament.VertexBuffer.VertexAttribute;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
/*
* 模型基类
* 管理模型的材质、顶点属性、顶点索引、渲染id
*/
public class BaseModel {
private static String TAG = "BaseModel";
protected AssetManager mAssetManager; // 资源管理器
protected Engine mEngine; // Filament引擎
protected Material mMaterial; // 模型材质
protected VertexBuffer mVertexBuffer; // 顶点属性缓存
protected IndexBuffer mIndexBuffer; // 顶点索引缓存
protected int mRenderable; // 渲染id
protected Box mBox; // 渲染区域
public BaseModel(AssetManager assetManager, Engine engine) {
mAssetManager = assetManager;
mEngine = engine;
}
public Material getMaterial() { // 获取材质
return mMaterial;
}
public VertexBuffer getVertexBuffer() { // 获取顶点属性缓存
return mVertexBuffer;
}
public IndexBuffer getIndexBuffer() { // 获取顶点索引缓存
return mIndexBuffer;
}
public int getRenderable() { // 获取渲染id
return mRenderable;
}
public void destroy() { // 销毁模型
mEngine.destroyEntity(mRenderable);
mEngine.destroyVertexBuffer(mVertexBuffer);
mEngine.destroyIndexBuffer(mIndexBuffer);
mEngine.destroyMaterial(mMaterial);
EntityManager entityManager = EntityManager.get();
entityManager.destroy(mRenderable);
}
protected Material loadMaterial(String materialPath) { // 加载材质
Buffer buffer = readUncompressedAsset(mAssetManager, materialPath);
if (buffer != null) {
Material material = (new Material.Builder()).payload(buffer, buffer.remaining()).build(mEngine);
material.compile(
Material.CompilerPriorityQueue.HIGH,
Material.UserVariantFilterBit.ALL,
new Handler(Looper.getMainLooper()),
() -> Log.i(TAG, "Material " + material.getName() + " compiled."));
mEngine.flush();
return material;
}
return null;
}
protected VertexBuffer getVertexBuffer(float[] values) { // 获取顶点属性缓存
ByteBuffer vertexData = getByteBuffer(values);
int vertexCount = values.length / 3;
int vertexSize = Float.BYTES * 3;
VertexBuffer vertexBuffer = new VertexBuffer.Builder()
.bufferCount(1)
.vertexCount(vertexCount)
.attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
.build(mEngine);
vertexBuffer.setBufferAt(mEngine, 0, vertexData);
return vertexBuffer;
}
protected VertexBuffer getVertexBuffer(Vertex[] values) { // 获取顶点属性缓存
ByteBuffer vertexData = getByteBuffer(values);
int vertexCount = values.length;
int vertexSize = Vertex.BYTES;
VertexBuffer vertexBuffer = new VertexBuffer.Builder()
.bufferCount(1)
.vertexCount(vertexCount)
.attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
.attribute(VertexAttribute.COLOR, 0, AttributeType.UBYTE4, 3 * Float.BYTES, vertexSize)
.normalized(VertexAttribute.COLOR)
.build(mEngine);
vertexBuffer.setBufferAt(mEngine, 0, vertexData);
return vertexBuffer;
}
protected IndexBuffer getIndexBuffer(short[] values) { // 获取顶点索引缓存
ByteBuffer indexData = getByteBuffer(values);
int indexCount = values.length;
IndexBuffer indexBuffer = new IndexBuffer.Builder()
.indexCount(indexCount)
.bufferType(IndexBuffer.Builder.IndexType.USHORT)
.build(mEngine);
indexBuffer.setBuffer(mEngine, indexData);
return indexBuffer;
}
protected int getRenderable(PrimitiveType primitiveType, int vertexCount) { // 获取渲染id
int renderable = EntityManager.get().create();
new RenderableManager.Builder(1)
.boundingBox(mBox)
.geometry(0, primitiveType, mVertexBuffer, mIndexBuffer, 0, vertexCount)
.material(0, mMaterial.getDefaultInstance())
.build(mEngine, renderable);
return renderable;
}
private Buffer readUncompressedAsset(AssetManager assetManager, String assetPath) { // 加载资源
ByteBuffer dist = null;
try {
AssetFileDescriptor fd = assetManager.openFd(assetPath);
try(FileInputStream fis = fd.createInputStream()) {
dist = ByteBuffer.allocate((int) fd.getLength());
try (ReadableByteChannel src = Channels.newChannel(fis)) {
src.read(dist);
}
}
} catch (IOException e) {
e.printStackTrace();
}
if (dist != null) {
return dist.rewind();
}
return null;
}
private ByteBuffer getByteBuffer(float[] values) { // float数组转换为ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Float.BYTES);
byteBuffer.order(ByteOrder.nativeOrder());
for (int i = 0; i < values.length; i++) {
byteBuffer.putFloat(values[i]);
}
byteBuffer.flip();
return byteBuffer;
}
private ByteBuffer getByteBuffer(short[] values) { // short数组转换为ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Short.BYTES);
byteBuffer.order(ByteOrder.nativeOrder());
for (int i = 0; i < values.length; i++) {
byteBuffer.putShort(values[i]);
}
byteBuffer.flip();
return byteBuffer;
}
private ByteBuffer getByteBuffer(Vertex[] values) { // Vertex数组转换为ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Vertex.BYTES);
byteBuffer.order(ByteOrder.nativeOrder());
for (int i = 0; i < values.length; i++) {
values[i].put(byteBuffer);
}
byteBuffer.flip();
return byteBuffer;
}
/*
* 顶点数据
* 包含顶点位置和颜色
*/
public static class Vertex {
public static int BYTES = 16;
public float x;
public float y;
public float z;
public int color;
public Vertex() {}
public Vertex(float x, float y, float z, int color) {
this.x = x;
this.y = y;
this.z = z;
this.color = color;
}
public ByteBuffer put(ByteBuffer buffer) { // Vertex转换为ByteBuffer
buffer.putFloat(x);
buffer.putFloat(y);
buffer.putFloat(z);
buffer.putInt(color);
return buffer;
}
}
}
2.2 绘制纯色三角形
MainActivity.java
package com.zhyan8.triangle;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import com.zhyan8.triangle.filament.FLSurfaceView;
public class MainActivity extends AppCompatActivity {
private FLSurfaceView mFLSurfaceView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mFLSurfaceView = new MyFLSurfaceView(this);
setContentView(mFLSurfaceView);
mFLSurfaceView.init();
mFLSurfaceView.setRenderMode(FLSurfaceView.RENDERMODE_CONTINUOUSLY);
}
@Override
public void onResume() {
super.onResume();
mFLSurfaceView.onResume();
}
@Override
public void onPause() {
super.onPause();
mFLSurfaceView.onPause();
}
@Override
public void onDestroy() {
super.onDestroy();
mFLSurfaceView.onDestroy();
}
}
MyFLSurfaceView.java
package com.zhyan8.triangle;
import android.content.Context;
import com.google.android.filament.Camera;
import com.zhyan8.triangle.filament.BaseModel;
import com.zhyan8.triangle.filament.FLSurfaceView;
public class MyFLSurfaceView extends FLSurfaceView {
private BaseModel mMyModel;
public MyFLSurfaceView(Context context) {
super(context);
}
public void init() {
mSkyboxColor = new float[] {0.965f, 0.941f, 0.887f, 1};
super.init();
}
@Override
public void onDestroy() {
mMyModel.destroy();
super.onDestroy();
}
@Override
protected void setupScene() { // 设置Scene参数
mMyModel = new Triangle1(getContext().getAssets(), mEngine);
mScene.addEntity(mMyModel.getRenderable());
}
@Override
protected void onResized(int width, int height) {
double zoom = 1.5;
double aspect = (double) width / (double) height;
mCamera.setProjection(Camera.Projection.ORTHO,
-aspect * zoom, aspect * zoom, -zoom, zoom, 0, 10);
}
}
Triangle1.java
package com.zhyan8.triangle;
import android.content.res.AssetManager;
import com.google.android.filament.Box;
import com.google.android.filament.Engine;
import com.google.android.filament.RenderableManager.PrimitiveType;
import com.zhyan8.triangle.filament.BaseModel;
public class Triangle1 extends BaseModel {
private String materialPath = "materials/triangle1.filamat";
private float[] mVertices = new float[] {
-0.5f, -0.5f, 0f,
0.5f, -0.5f, 0f,
0f, 0.5f, 0f
};
private short[] mIndex = new short[] {0, 1, 2};
public Triangle1(AssetManager assetManager, Engine engine) {
super(assetManager, engine);
init();
}
private void init() {
mBox = new Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.01f);
mMaterial = loadMaterial(materialPath);
mVertexBuffer = getVertexBuffer(mVertices);
mIndexBuffer = getIndexBuffer(mIndex);
mRenderable = getRenderable(PrimitiveType.TRIANGLES, mIndex.length);
}
}
triangle1.mat
material {
name : triangle,
// 禁用所有lighting
shadingModel : unlit,
featureLevel : 0
}
fragment {
void material(inout MaterialInputs material) {
prepareMaterial(material); // 在方法返回前必须回调该函数
material.baseColor = vec4(1, 0, 0, 1);
}
}
mat 文件需要使用通过 matc.exe 工具转换为 filamat 文件。
transform.bat
@echo off
setlocal enabledelayedexpansion
set "srcFolder=../src/main/materials"
set "distFolder=../src/main/assets/materials"
for %%f in ("%srcFolder%\*.mat") do (
set "matfile=%%~nf"
matc -p mobile -a opengl -o "!matfile!.filamat" "%%f"
move "!matfile!.filamat" "%distFolder%\!matfile!.filamat"
)
echo Processing complete.
pause
说明：需要将 matc.exe 文件与 transform.bat 文件放在同一个目录下面，matc.exe 源自Filament环境搭建中编译生成的 exe 文件。双击 transform.bat 文件，会自动将 /src/main/materials/ 下面的所有 mat 文件全部转换为 filamat 文件，并移到 /src/main/assets/materials/ 目录下面。
运行效果如下。
2.3 绘制彩色三角形
MyFLSurfaceView.java
package com.zhyan8.triangle;
import android.content.Context;
import com.google.android.filament.Camera;
import com.zhyan8.triangle.filament.BaseModel;
import com.zhyan8.triangle.filament.FLSurfaceView;
public class MyFLSurfaceView extends FLSurfaceView {
private BaseModel mMyModel;
public MyFLSurfaceView(Context context) {
super(context);
}
public void init() {
mSkyboxColor = new float[] {0.965f, 0.941f, 0.887f, 1};
super.init();
}
@Override
public void onDestroy() {
mMyModel.destroy();
super.onDestroy();
}
@Override
protected void setupScene() { // 设置Scene参数
mMyModel = new Triangle2(getContext().getAssets(), mEngine);
mScene.addEntity(mMyModel.getRenderable());
}
@Override
protected void onResized(int width, int height) {
double zoom = 1.5;
double aspect = (double) width / (double) height;
mCamera.setProjection(Camera.Projection.ORTHO,
-aspect * zoom, aspect * zoom, -zoom, zoom, 0, 10);
}
}
Triangle2.java
package com.zhyan8.triangle;
import android.content.res.AssetManager;
import com.google.android.filament.Box;
import com.google.android.filament.Engine;
import com.google.android.filament.RenderableManager.PrimitiveType;
import com.zhyan8.triangle.filament.BaseModel;
public class Triangle2 extends BaseModel {
private String materialPath = "materials/triangle2.filamat";
private Vertex[] mVertices = new Vertex[] {
new Vertex(-0.5f, -0.5f, 0f, 0xffff0000),
new Vertex(0.5f, -0.5f, 0f, 0xff00ff00),
new Vertex(0f, 0.5f, 0f, 0xff0000ff),
};
private short[] mIndex = new short[] {0, 1, 2};
public Triangle2(AssetManager assetManager, Engine engine) {
super(assetManager, engine);
init();
}
private void init() {
mBox = new Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.01f);
mMaterial = loadMaterial(materialPath);
mVertexBuffer = getVertexBuffer(mVertices);
mIndexBuffer = getIndexBuffer(mIndex);
mRenderable = getRenderable(PrimitiveType.TRIANGLES, mIndex.length);
}
}
triangle2.mat
material {
name : triangle,
// 顶点着色器入参MaterialVertexInputs中需要的顶点属性
requires : [
color
],
// 禁用所有lighting
shadingModel : unlit,
featureLevel : 0
}
fragment {
void material(inout MaterialInputs material) {
prepareMaterial(material); // 在方法返回前必须回调该函数
material.baseColor = getColor();
}
}
运行效果如下。
声明：本文转自【Filament】绘制三角形。
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