【Filament】自定义Blinn Phong光照模型
2024-02-24 本文已影响0人
LittleFatSheep
1 前言
光照元素主要有环境光（ambient）、漫反射光（diffuse）、镜面反射光（specular），基础的光照模型主要有兰伯特（Lambert）光照模型、冯氏（Phong）光照模型和改进的冯氏（Blinn Phong）光照模型。
Lambert 光照模型只包含漫反射光的计算，Phong 光照模型和 Blinn Phong 光照模型都包含环境光、漫反射光、镜面反射光的计算，两者的区别在与镜面反射光的计算，Phong 光照模型根据反向量和观察向量计算镜面反射光，Blinn Phong 光照模型根据半向量和法向量计算镜面反射光。
Blinn Phong 光照模型中环境光、漫反射光、镜面反射光的计算如下。
vec3 ambientColor() { // 环境光
vec3 ambient = materialParams.ambientColor * materialParams.albedo;
return ambient;
}
vec3 diffuseColor(vec3 normal, vec3 lightDir) { // 漫反射光
float factor = max(dot(normal, lightDir), 0.0);
vec3 diffuse = factor * materialParams.lightColor * materialParams.albedo;
return diffuse;
}
vec3 specularColor(vec3 normal, vec3 lightDir, vec3 viewDire) { // 镜面反射光
vec3 halfVec = normalize(lightDir + viewDire); // 半向量
float factor = pow(max(dot(normal, halfVec), 0.0), materialParams.gloss);
vec3 specular = factor * materialParams.lightColor * materialParams.specularStrength;
return specular;
}
最终的渲染颜色由以上三种光的颜色叠加而成，如下。
material.baseColor = vec4(ambient + diffuse + specular, 1);
2 自定义光照
本文项目结构如下，完整代码资源 → Filament自定义Blinn Phong光照模型。
2.1 基础类
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、BaseModel、Mesh、MaterialUtils 和 MeshUtils 类。FLSurfaceView 与 GLSurfaceView 的功能类似，承载了渲染环境配置；BaseModel 用于管理模型的网格和材质；Mesh 用于管理模型的顶点属性；MaterialUtils 和 MeshUtils 中分别提供了一些材质和网格相关的工具。
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.customlight.filament.base;
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;
import java.util.ArrayList;
/**
* 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
protected ArrayList<RenderCallback> mRenderCallbacks; // 每一帧渲染前的回调(一般用于处理模型变换、相机变换等)
static {
Filament.init();
}
public FLSurfaceView(Context context) {
super(context);
mChoreographer = Choreographer.getInstance();
mDisplayHelper = new DisplayHelper(context);
mRenderCallbacks = new ArrayList<>();
}
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 addRenderCallback(RenderCallback renderCallback) { // 添加渲染回调
if (renderCallback != null) {
mRenderCallbacks.add(renderCallback);
}
}
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);
mRenderCallbacks.clear();
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
}
mRenderCallbacks.forEach(callback -> callback.onCall());
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);
}
}
/**
* 每一帧渲染前的回调
* 一般用于处理模型变换、相机变换等
*/
public interface RenderCallback {
void onCall();
}
}
BaseModel.java
package com.zhyan8.loadmodel.filament.base;
import android.content.Context;
import com.google.android.filament.Engine;
import com.google.android.filament.EntityManager;
import com.google.android.filament.Material;
import com.google.android.filament.MaterialInstance;
import com.google.android.filament.RenderableManager;
import com.google.android.filament.RenderableManager.PrimitiveType;
import com.google.android.filament.Texture;
import com.google.android.filament.TransformManager;
import com.zhyan8.loadmodel.filament.utils.MaterialUtils;
import com.zhyan8.loadmodel.filament.base.Mesh.Part;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* 模型基类
* 管理模型的网格、材质、渲染id
*/
public class BaseModel {
private static String TAG = "BaseModel";
protected Context mContext; // 上下文
protected Engine mEngine; // Filament引擎
protected TransformManager mTransformManager; // 模型变换管理器
protected Mesh mMesh; // 模型网格
protected Material[] mMaterials; // 模型材质
protected MaterialInstance[] mMaterialInstances; // 模型材质实例
protected Map<String, MaterialInstance> mMaterialMap = new HashMap<>(); // 材质名->材质
protected Texture[] mTextures; // 纹理
protected int mRenderable; // 渲染id
protected int mTransformComponent; // 模型变换组件的id
protected FLSurfaceView.RenderCallback mRenderCallback; // 每一帧渲染前的回调(一般用于处理模型变换、相机变换等)
public BaseModel(Context context, Engine engine) {
mContext = context;
mEngine = engine;
mTransformManager = mEngine.getTransformManager();
}
public int getRenderable() { // 获取渲染id
return mRenderable;
}
public FLSurfaceView.RenderCallback getRenderCallback() { // 获取渲染回调
return mRenderCallback;
}
public void destroy() { // 销毁模型
mMaterialMap.clear();
mEngine.destroyEntity(mRenderable);
if (mMesh != null) {
mMesh.destroy();
}
if (mTextures != null) {
for (int i = 0; i < mTextures.length; i++) {
mEngine.destroyTexture(mTextures[i]);
}
}
if (mMaterialInstances != null) {
for (int i = 0; i < mMaterialInstances.length; i++) {
mEngine.destroyMaterialInstance(mMaterialInstances[i]);
}
}
if (mMaterials != null) {
for (int i = 0; i < mMaterials.length; i++) {
mEngine.destroyMaterial(mMaterials[i]);
}
}
EntityManager entityManager = EntityManager.get();
entityManager.destroy(mRenderable);
}
protected int getRenderable(PrimitiveType primitiveType) { // 获取渲染id
int renderable = EntityManager.get().create();
List<Part> parts = mMesh.getParts();
List<String> materialNames = mMesh.getMaterialNames();
RenderableManager.Builder builder = new RenderableManager.Builder(parts.size()).boundingBox(mMesh.getBox());
for (int i = 0; i < parts.size(); i++) {
Part part = parts.get(i);
builder.geometry(i, primitiveType, mMesh.getVertexBuffer(), mMesh.getIndexBuffer(),
part.offset, part.minIndex, part.maxIndex, part.indexCount);
MaterialInstance material = getMaterialInstance(materialNames, part.materialID);
builder.material(i, material);
}
builder.build(mEngine, renderable);
return renderable;
}
protected Material[] loadMaterials(String materialPath) { // 加载材质
Material material = MaterialUtils.loadMaterial(mContext, mEngine, materialPath);
if (material != null) {
return new Material[] {material};
}
return null;
}
protected Material[] loadMaterials(String[] materialPaths) { // 加载材质
Material[] materials = new Material[materialPaths.length];
for (int i = 0; i < materials.length; i++) {
materials[i] = MaterialUtils.loadMaterial(mContext, mEngine, materialPaths[i]);
}
return materials;
}
protected MaterialInstance[] getMaterialInstance(Material[] materials) { // 获取材质实例
MaterialInstance[] materialInstances = new MaterialInstance[materials.length];
for (int i = 0; i < materials.length; i++) {
materialInstances[i] = materials[i].createInstance();
}
return materialInstances;
}
protected MaterialInstance[] getMaterialInstance(Material material, int count) { // 获取材质实例
MaterialInstance[] materialInstances = new MaterialInstance[count];
for (int i = 0; i < count; i++) {
materialInstances[i] = material.createInstance();
}
return materialInstances;
}
private MaterialInstance getMaterialInstance(List<String> materialNames, int materialID) { // 获取材质
MaterialInstance material = null;
if (materialNames != null && materialNames.size() > materialID && materialID >= 0) {
String name = materialNames.get(materialID);
if (mMaterialMap.containsKey(name)) {
material = mMaterialMap.get(name);
}
}
if (material == null && mMaterialMap.containsKey("DefaultMaterial")) {
material = mMaterialMap.get("DefaultMaterial");
}
return material;
}
}
Mesh.java
package com.zhyan8.customlight.filament.base;
import com.google.android.filament.Box;
import com.google.android.filament.Engine;
import com.google.android.filament.IndexBuffer;
import com.google.android.filament.VertexBuffer;
import com.google.android.filament.VertexBuffer.AttributeType;
import com.google.android.filament.VertexBuffer.VertexAttribute;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.List;
/**
* 网格
* 用于管理模型的顶点属性和顶点索引
*/
public class Mesh {
private Engine mEngine; // Filament引擎
private VertexBuffer mVertexBuffer; // 顶点属性缓存
private IndexBuffer mIndexBuffer; // 顶点索引缓存
private List<Part> mParts; // 子网格信息
private Box mBox; // 渲染区域
private List<String> mMaterialNames; // 材质名
public Mesh(Engine engine) {
mEngine = engine;
}
public Mesh(Engine engine, float[] vertices, short[] indices, List<Part> parts, Box box, List<String> materialNames) {
mEngine = engine;
setVertices(vertices);
setIndices(indices);
setParts(parts, indices.length);
setBox(box);
mMaterialNames = materialNames;
}
public Mesh(Engine engine, VertexBuffer vrtexBuffer, IndexBuffer indexBuffer, List<Part> parts, Box box, List<String> materialNames) {
mEngine = engine;
mVertexBuffer = vrtexBuffer;
mIndexBuffer = indexBuffer;
mParts = parts;
setBox(box);
mMaterialNames = materialNames;
}
public Mesh(Engine engine, VertexPosCol[] vertices, short[] indices, List<Part> parts, Box box, List<String> materialNames) {
mEngine = engine;
setVertices(vertices);
setIndices(indices);
setParts(parts, indices.length);
setBox(box);
mMaterialNames = materialNames;
}
public Mesh(Engine engine, VertexPosUV[] vertices, short[] indices, List<Part> parts, Box box, List<String> materialNames) {
mEngine = engine;
setVertices(vertices);
setIndices(indices);
setParts(parts, indices.length);
setBox(box);
mMaterialNames = materialNames;
}
public void setVertices(float[] vertices) { // 设置顶点属性
mVertexBuffer = getVertexBuffer(vertices);
}
public void setVertices(VertexPosCol[] vertices) { // 设置顶点属性
mVertexBuffer = getVertexBuffer(vertices);
}
public void setVertices(VertexPosUV[] vertices) { // 设置顶点属性
mVertexBuffer = getVertexBuffer(vertices);
}
public void setIndices(short[] indices) { // 设置顶点索引
mIndexBuffer = getIndexBuffer(indices);
}
public void setParts(List<Part> parts, int count) { // 设置顶点索引
if (parts == null || parts.size() == 0) {
mParts = new ArrayList<>();
mParts.add(new Part(0, count, 0, count - 1));
} else {
mParts = parts;
}
}
public void setBox(Box box) { // 渲染区域
if (box == null) {
mBox = new Box(0, 0, 0, 1, 1, 1);
} else {
mBox = box;
}
}
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 List<Part> getParts() { // 获取顶点索引缓存
return mParts;
}
public Box getBox() {
return mBox;
}
public List<String> getMaterialNames() {
return mMaterialNames;
}
public void destroy() {
mEngine.destroyVertexBuffer(mVertexBuffer);
mEngine.destroyIndexBuffer(mIndexBuffer);
if (mParts != null) {
mParts.clear();
}
if (mMaterialNames != null) {
mMaterialNames.clear();
}
}
private 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;
}
private VertexBuffer getVertexBuffer(VertexPosCol[] values) { // 获取顶点属性缓存
ByteBuffer vertexData = getByteBuffer(values);
int vertexCount = values.length;
int vertexSize = VertexPosCol.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;
}
private VertexBuffer getVertexBuffer(VertexPosUV[] values) { // 获取顶点属性缓存
ByteBuffer vertexData = getByteBuffer(values);
int vertexCount = values.length;
int vertexSize = VertexPosUV.BYTES;
VertexBuffer vertexBuffer = new VertexBuffer.Builder()
.bufferCount(1)
.vertexCount(vertexCount)
.attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
.attribute(VertexAttribute.UV0, 0, AttributeType.FLOAT2, 3 * Float.BYTES, vertexSize)
.build(mEngine);
vertexBuffer.setBufferAt(mEngine, 0, vertexData);
return vertexBuffer;
}
private 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;
}
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(VertexPosCol[] values) { // VertexPosCol数组转换为ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * VertexPosCol.BYTES);
byteBuffer.order(ByteOrder.nativeOrder());
for (int i = 0; i < values.length; i++) {
values[i].put(byteBuffer);
}
byteBuffer.flip();
return byteBuffer;
}
private ByteBuffer getByteBuffer(VertexPosUV[] values) { // VertexPosUV数组转换为ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * VertexPosUV.BYTES);
byteBuffer.order(ByteOrder.nativeOrder());
for (int i = 0; i < values.length; i++) {
values[i].put(byteBuffer);
}
byteBuffer.flip();
return byteBuffer;
}
/**
* 子网格信息
*/
public static class Part {
public int offset = 0;
public int indexCount = 0;
public int minIndex = 0;
public int maxIndex = 0;
public int materialID = -1;
public Box aabb = new Box();
public Part() {}
public Part(int offset, int indexCount, int minIndex, int maxIndex) {
this.offset = offset;
this.indexCount = indexCount;
this.minIndex = minIndex;
this.maxIndex = maxIndex;
}
public Part(int offset, int indexCount, int minIndex, int maxIndex, int materialID, Box aabb) {
this.offset = offset;
this.indexCount = indexCount;
this.minIndex = minIndex;
this.maxIndex = maxIndex;
this.materialID = materialID;
this.aabb = aabb;
}
}
/**
* 顶点数据(位置+颜色)
* 包含顶点位置和颜色
*/
public static class VertexPosCol {
public static int BYTES = 16;
public float x;
public float y;
public float z;
public int color;
public VertexPosCol() {}
public VertexPosCol(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) { // VertexPosCol转换为ByteBuffer
buffer.putFloat(x);
buffer.putFloat(y);
buffer.putFloat(z);
buffer.putInt(color);
return buffer;
}
}
/**
* 顶点数据(位置+纹理坐标)
* 包含顶点位置和纹理坐标
*/
public static class VertexPosUV {
public static int BYTES = 20;
public float x;
public float y;
public float z;
public float u;
public float v;
public VertexPosUV() {}
public VertexPosUV(float x, float y, float z, float u, float v) {
this.x = x;
this.y = y;
this.z = z;
this.u = u;
this.v = v;
}
public ByteBuffer put(ByteBuffer buffer) { // VertexPosUV转换为ByteBuffer
buffer.putFloat(x);
buffer.putFloat(y);
buffer.putFloat(z);
buffer.putFloat(u);
buffer.putFloat(v);
return buffer;
}
}
}
MaterialUtils.java
package com.zhyan8.customlight.filament.utils;
import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import com.google.android.filament.Engine;
import com.google.android.filament.Material;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
/**
* 材质工具类
*/
public class MaterialUtils {
private static String TAG = "MaterialUtils";
public static Material loadMaterial(Context context, Engine engine, String materialPath) { // 加载材质
Buffer buffer = readUncompressedAsset(context, materialPath);
if (buffer != null) {
Material material = (new Material.Builder()).payload(buffer, buffer.remaining()).build(engine);
material.compile(
Material.CompilerPriorityQueue.HIGH,
Material.UserVariantFilterBit.ALL,
new Handler(Looper.getMainLooper()),
() -> Log.i(TAG, "Material " + material.getName() + " compiled."));
engine.flush();
return material;
}
return null;
}
private static Buffer readUncompressedAsset(Context context, String assetPath) { // 加载资源
ByteBuffer dist = null;
try {
AssetFileDescriptor fd = context.getAssets().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;
}
}
MeshUtils.java
package com.zhyan8.customlight.filament.utils;
import android.content.Context;
import android.util.Log;
import com.google.android.filament.Box;
import com.google.android.filament.Engine;
import com.google.android.filament.IndexBuffer;
import com.google.android.filament.VertexBuffer;
import com.google.android.filament.VertexBuffer.AttributeType;
import com.google.android.filament.VertexBuffer.VertexAttribute;
import com.zhyan8.customlight.filament.base.Mesh;
import com.zhyan8.customlight.filament.base.Mesh.Part;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
/**
* 网格工具类
*/
public class MeshUtils {
private static final String FILAMESH_FILE_IDENTIFIER = "FILAMESH";
private static final long HEADER_FLAG_SNORM16_UV = 0x2L;
private static final long MAX_UINT32 = 4294967295L;
public static Mesh loadMesh(Context context, Engine engine, String meshPath) {
try (InputStream inputStream = context.getAssets().open(meshPath)) {
Header header = readHeader(inputStream);
ReadableByteChannel channel = Channels.newChannel(inputStream);
ByteBuffer vertexBufferData = readSizedData(channel, header.verticesSizeInBytes);
ByteBuffer indexBufferData = readSizedData(channel, header.indicesSizeInBytes);
List<Part> parts = readParts(header, inputStream);
List<String> materialNames = readMaterials(inputStream);
VertexBuffer vertexBuffer = createVertexBuffer(engine, header, vertexBufferData);
IndexBuffer indexBuffer = createIndexBuffer(engine, header, indexBufferData);
return new Mesh(engine, vertexBuffer, indexBuffer, parts, header.aabb, materialNames);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private static Header readHeader(InputStream input) { // 读取文件头信息
Header header = new Header();
if (!readMagicNumber(input)) {
Log.e("Filament", "Invalid filamesh file.");
return header;
}
header.versionNumber = readUIntLE(input);
header.parts = readUIntLE(input);
header.aabb = new Box(
readFloat32LE(input), readFloat32LE(input), readFloat32LE(input),
readFloat32LE(input), readFloat32LE(input), readFloat32LE(input));
header.flags = readUIntLE(input);
header.posOffset = readUIntLE(input);
header.positionStride = readUIntLE(input);
header.tangentOffset = readUIntLE(input);
header.tangentStride = readUIntLE(input);
header.colorOffset = readUIntLE(input);
header.colorStride = readUIntLE(input);
header.uv0Offset = readUIntLE(input);
header.uv0Stride = readUIntLE(input);
header.uv1Offset = readUIntLE(input);
header.uv1Stride = readUIntLE(input);
header.totalVertices = readUIntLE(input);
header.verticesSizeInBytes = readUIntLE(input);
header.indices16Bit = readUIntLE(input);
header.totalIndices = readUIntLE(input);
header.indicesSizeInBytes = readUIntLE(input);
header.valid = true;
return header;
}
private static ByteBuffer readSizedData(ReadableByteChannel channel, int sizeInBytes) { // 读取模型顶点数据
ByteBuffer buffer = ByteBuffer.allocateDirect(sizeInBytes);
buffer.order(ByteOrder.LITTLE_ENDIAN);
try {
channel.read(buffer);
} catch (IOException e) {
e.printStackTrace();
}
buffer.flip();
return buffer;
}
private static List<Part> readParts(Header header, InputStream input) { // 读取子网格属性
List<Part> parts = new ArrayList<>(header.parts);
for (int i = 0; i < header.parts; i++) {
Part p = new Part();
p.offset = readUIntLE(input);
p.indexCount = readUIntLE(input);
p.minIndex = readUIntLE(input);
p.maxIndex = readUIntLE(input);
p.materialID = readUIntLE(input);
float minX = readFloat32LE(input);
float minY = readFloat32LE(input);
float minZ = readFloat32LE(input);
float maxX = readFloat32LE(input);
float maxY = readFloat32LE(input);
float maxZ = readFloat32LE(input);
p.aabb = new Box(minX, minY, minZ, maxX, maxY, maxZ);
parts.add(p);
}
return parts;
}
private static boolean readMagicNumber(InputStream input) { // 读取魔法数字, 用于判断是否是有效的filamesh文件
byte[] temp = new byte[FILAMESH_FILE_IDENTIFIER.length()];
int bytesRead = 0;
try {
bytesRead = input.read(temp);
} catch (IOException e) {
throw new RuntimeException(e);
}
if (bytesRead != FILAMESH_FILE_IDENTIFIER.length()) {
return false;
}
String tempS = new String(temp, Charset.forName("UTF-8"));
return tempS.equals(FILAMESH_FILE_IDENTIFIER);
}
private static List<String> readMaterials(InputStream input) { // 读取材质
int numMaterials = readUIntLE(input);
List<String> materials = new ArrayList<>(numMaterials);
for (int i = 0; i < numMaterials; i++) {
int dataLength = readUIntLE(input);
byte[] data = new byte[dataLength];
try {
input.read(data);
} catch (IOException e) {
e.printStackTrace();
}
try {
input.skip(1);
} catch (IOException e) {
e.printStackTrace();
}
materials.add(new String(data, Charset.forName("UTF-8")));
}
return materials;
}
private static IndexBuffer createIndexBuffer(Engine engine, Header header, ByteBuffer data) { // 创建顶点索引缓冲
IndexBuffer.Builder.IndexType indexType = (header.indices16Bit != 0) ?
IndexBuffer.Builder.IndexType.USHORT : IndexBuffer.Builder.IndexType.UINT;
IndexBuffer buffer = new IndexBuffer.Builder()
.bufferType(indexType)
.indexCount(header.totalIndices)
.build(engine);
buffer.setBuffer(engine, data);
return buffer;
}
private static VertexBuffer createVertexBuffer(Engine engine, Header header, ByteBuffer data) { // 创建顶点属性缓冲
AttributeType uvType = uvType(header);
VertexBuffer.Builder vertexBufferBuilder = new VertexBuffer.Builder()
.bufferCount(1)
.vertexCount(header.totalVertices)
.normalized(VertexAttribute.COLOR)
.normalized(VertexAttribute.TANGENTS)
.attribute(VertexAttribute.POSITION, 0, AttributeType.HALF4, header.posOffset, header.positionStride)
.attribute(VertexAttribute.TANGENTS, 0, AttributeType.SHORT4, header.tangentOffset, header.tangentStride)
.attribute(VertexAttribute.COLOR, 0, AttributeType.UBYTE4, header.colorOffset, header.colorStride)
.attribute(VertexAttribute.UV0, 0, uvType, header.uv0Offset, header.uv0Stride)
.normalized(VertexAttribute.UV0, uvNormalized(header));
if (header.uv1Offset != MAX_UINT32 && header.uv1Stride != MAX_UINT32 && header.uv1Offset > -1 && header.uv1Stride > -1) {
vertexBufferBuilder
.attribute(VertexAttribute.UV1, 0, uvType, header.uv1Offset, header.uv1Stride)
.normalized(VertexAttribute.UV1, uvNormalized(header));
}
VertexBuffer buffer = vertexBufferBuilder.build(engine);
buffer.setBufferAt(engine, 0, data);
return buffer;
}
private static AttributeType uvType(Header header) { // UV坐标的精度类型
if (uvNormalized(header)) {
return AttributeType.SHORT2;
}
return AttributeType.HALF2;
}
private static boolean uvNormalized(Header header) { // uv坐标是否已正则化
return (header.flags & HEADER_FLAG_SNORM16_UV) != 0L;
}
private static int readIntLE(InputStream input) { // 获取输入流中Little Endian格式的整数
try {
return (input.read() & 0xff) |
((input.read() & 0xff) << 8) |
((input.read() & 0xff) << 16) |
((input.read() & 0xff) << 24);
} catch (IOException e) {
e.printStackTrace();
}
return 0;
}
private static int readUIntLE(InputStream input) { // 获取输入流中Little Endian格式的无符号整数
return (int) (readIntLE(input) & 0xFFFFFFFFL);
}
private static float readFloat32LE(InputStream input) { // 获取输入流中Little Endian格式的浮点数
byte[] bytes = new byte[4];
try {
input.read(bytes, 0, 4);
} catch (IOException e) {
e.printStackTrace();
}
return ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN).getFloat();
}
}
/**
* 网格文件头
*/
class Header {
boolean valid = false;
int versionNumber = 0;
int parts = 0;
Box aabb = new Box();
int flags = 0;
int posOffset = 0;
int positionStride = 0;
int tangentOffset = 0;
int tangentStride = 0;
int colorOffset = 0;
int colorStride = 0;
int uv0Offset = 0;
int uv0Stride = 0;
int uv1Offset = 0;
int uv1Stride = 0;
int totalVertices = 0;
int verticesSizeInBytes = 0;
int indices16Bit = 0;
int totalIndices = 0;
int indicesSizeInBytes = 0;
}
2.2 业务类
MainActivity.java
package com.zhyan8.customlight;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import com.zhyan8.customlight.filament.base.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.customlight;
import android.content.Context;
import com.google.android.filament.Camera;
import com.zhyan8.customlight.filament.base.BaseModel;
import com.zhyan8.customlight.filament.base.FLSurfaceView;
public class MyFLSurfaceView extends FLSurfaceView {
private BaseModel mMyModel;
public MyFLSurfaceView(Context context) {
super(context);
}
public void init() {
mSkyboxColor = new float[] {0.35f, 0.35f, 0.35f, 1};
super.init();
}
@Override
public void onDestroy() {
mMyModel.destroy();
super.onDestroy();
}
@Override
protected void setupScene() { // 设置Scene参数
mMyModel = new MyModel(getContext(), mEngine);
mScene.addEntity(mMyModel.getRenderable());
addRenderCallback(mMyModel.getRenderCallback());
}
@Override
protected void onResized(int width, int height) {
double aspect = (double) width / (double) height;
mCamera.setProjection(45.0, aspect, 0.1, 1000.0, Camera.Fov.VERTICAL);
float[] eye = new float[] {1.5f, 1f, 7.5f}; // cube
//float[] eye = new float[] {1.5f, 1f, 500f}; // spider_bot
//float[] eye = new float[] {1.5f, 1f, 10f}; // shader_ball
float[] center = new float[] {0, 0, 0};
float[] up = new float[] {0, 1, 0};
mCamera.lookAt(eye[0], eye[1], eye[2],center[0], center[1], center[2], up[0], up[1], up[2]);
}
}
MyModel.java
package com.zhyan8.customlight;
import android.content.Context;
import android.opengl.Matrix;
import com.google.android.filament.Engine;
import com.google.android.filament.MaterialInstance;
import com.google.android.filament.RenderableManager.PrimitiveType;
import com.zhyan8.customlight.filament.base.BaseModel;
import com.zhyan8.customlight.filament.utils.MeshUtils;
public class MyModel extends BaseModel {
private String mMaterialPath = "materials/custom_light.filamat";
private String mMeshPath = "models/cube.filamesh";
//private String mMeshPath = "models/spider_bot.filamesh";
//private String mMeshPath = "models/shader_ball.filamesh";
private float[] mModelMatrix; // 模型变换矩阵
private float[] mRotateAxis; // 旋转轴
private float mRotateAgree = 0; // 旋转角度
public MyModel(Context context, Engine engine) {
super(context, engine);
init();
}
private void init() {
mMaterials = loadMaterials(mMaterialPath);
mMaterialInstances = getMaterialInstance(mMaterials);
setupMaterial(mMaterialInstances[0]);
mMaterialMap.put("DefaultMaterial", mMaterialInstances[0]);
mMesh = MeshUtils.loadMesh(mContext, mEngine, mMeshPath);
mRenderable = getRenderable(PrimitiveType.TRIANGLES);
mTransformComponent = mTransformManager.getInstance(mRenderable);
mRenderCallback = () -> renderCallback();
mModelMatrix = new float[16];
mRotateAxis = new float[] { 0.5f, 1f, 1f };
}
private void setupMaterial(MaterialInstance materialInstance) {
materialInstance.setParameter("albedo", 0.7f, 0.1f, 0.2f); // 模型颜色
materialInstance.setParameter("ambientColor", 0.2f, 0.2f, 0.2f); // 环境光颜色
materialInstance.setParameter("lightPos", 100f, 500f, 50f); // 灯光位置
materialInstance.setParameter("lightColor", 0.9f, 0.9f, 0.9f); // 灯光颜色
materialInstance.setParameter("specularStrength", 0.1f); // 镜面反射光强度
materialInstance.setParameter("gloss", 4f); // 镜面反射光泽度
}
private void renderCallback() {
mRotateAgree = (mRotateAgree + 1) % 360;
mRotateAxis[0] = mRotateAgree / 180f - 1;
mRotateAxis[1] = (float) Math.sin(mRotateAgree / 180f * Math.PI * 0.7f);
mRotateAxis[2] = (float) Math.cos(mRotateAgree / 180f * Math.PI * 0.5f);
Matrix.setRotateM(mModelMatrix, 0, mRotateAgree, mRotateAxis[0], mRotateAxis[1], mRotateAxis[2]);
mTransformManager.setTransform(mTransformComponent, mModelMatrix);
}
}
custom_light.mat
material {
name : custom_light,
shadingModel : unlit, // 禁用所有lighting
// 自定义变量参数
parameters : [
{
type : float3,
name : albedo // 模型颜色
},
{
type : float3,
name : ambientColor // 环境光颜色
},
{
type : float3,
name : lightPos // 灯光位置
},
{
type : float3,
name : lightColor // 灯光颜色
},
{
type : float,
name : specularStrength // 镜面反射光强度
},
{
type : float,
name : gloss // 镜面反射光泽度
}
],
// 顶点着色器入参MaterialVertexInputs中需要的顶点属性
requires : [
tangents
]
}
fragment {
vec3 ambientColor() { // 环境光
vec3 ambient = materialParams.ambientColor * materialParams.albedo;
return ambient;
}
vec3 diffuseColor(vec3 normal, vec3 lightDir) { // 漫反射光
float factor = max(dot(normal, lightDir), 0.0);
vec3 diffuse = factor * materialParams.lightColor * materialParams.albedo;
return diffuse;
}
vec3 specularColor(vec3 normal, vec3 lightDir, vec3 viewDire) { // 镜面反射光(Blinn Phong 光照模型)
vec3 halfVec = normalize(lightDir + viewDire); // 半向量
float factor = pow(max(dot(normal, halfVec), 0.0), materialParams.gloss);
vec3 specular = factor * materialParams.lightColor * materialParams.specularStrength;
return specular;
}
void material(inout MaterialInputs material) {
prepareMaterial(material); // 在方法返回前必须回调该函数
vec3 pos = getWorldPosition(); // 顶点的世界坐标
vec3 normal = normalize(getWorldNormalVector()); // 法线向量
vec3 lightDir = normalize(materialParams.lightPos - pos); // 顶点指向光源的向量
vec3 viewDire = normalize(getWorldCameraPosition() - pos); // 顶点指向相机的向量
vec3 ambient = ambientColor();
vec3 diffuse = diffuseColor(normal, lightDir);
vec3 specular = specularColor(normal, lightDir, viewDire);
material.baseColor = vec4(ambient + diffuse + specular, 1);
}
}
说明：custom_light 材质实现了 Blinn Phong 光照模型。
cube.obj
# 正方体模型
# 顶点位置
v 1.0 1.0 -1.0 # V1
v 1.0 -1.0 -1.0 # V2
v 1.0 1.0 1.0 # V3
v 1.0 -1.0 1.0 # V4
v -1.0 1.0 -1.0 # V5
v -1.0 -1.0 -1.0 # V6
v -1.0 1.0 1.0 # V7
v -1.0 -1.0 1.0 # V8
# 纹理坐标
vt 0.0 0.0 # VT1
vt 1.0 0.0 # VT2
vt 1.0 1.0 # VT3
vt 0.0 1.0 # VT4
# 法线
vn 0.0 1.0 0.0 # VN1 (上面法线)
vn 0.0 0.0 1.0 # VN2 (背面法线)
vn -1.0 0.0 0.0 # VN3 (左面法线)
vn 0.0 -1.0 0.0 # VN4 (下面法线)
vn 1.0 0.0 0.0 # VN5 (右面法线)
vn 0.0 0.0 -1.0 # VN6 (前面法线)
# 面（v/vt/vn）
f 1/1/1 5/2/1 7/3/1
f 1/1/1 7/3/1 3/4/1
f 4/1/2 3/2/2 7/3/2
f 4/1/2 7/3/2 8/4/2
f 8/1/3 7/2/3 5/3/3
f 8/1/3 5/3/3 6/4/3
f 6/1/4 2/2/4 4/3/4
f 6/1/4 4/3/4 8/4/4
f 2/1/5 1/2/5 3/3/5
f 2/1/5 3/3/5 4/4/5
f 6/1/6 5/2/6 1/3/6
f 6/1/6 1/3/6 2/4/6
transform.bat
@echo off
setlocal enabledelayedexpansion
echo transform materials
set "srcMatDir=../src/main/raw/materials"
set "distMatDir=../src/main/assets/materials"
for %%f in ("%srcMatDir%\*.mat") do (
set "matfile=%%~nf"
matc -p mobile -a opengl -o "!matfile!.filamat" "%%f"
move "!matfile!.filamat" "%distMatDir%\!matfile!.filamat"
)
echo transform mesh
set "srcMeshDir=../src/main/raw/models"
set "distMeshDir=../src/main/assets/models"
for %%f in ("%srcMeshDir%\*.obj" "%srcMeshDir%\*.fbx") do (
set "meshfile=%%~nf"
filamesh "%%f" "!meshfile!.filamesh"
move "!meshfile!.filamesh" "%distMeshDir%\!meshfile!.filamesh"
)
echo Processing complete.
pause
说明：需要将 matc.exe 文件、filamesh.exe 文件与 transform.bat 文件放在同一个目录下面，matc.exe 和 filamesh.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/raw/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，同时自动将 /src/main/raw/models下面的所有 obj 或 fbx 文件全部转换为 filamesh 文件，并移到 /src/main/assets/models/ 目录下面。
加载 cube 模型运行效果如下。
加载 spider_bot 模型运行效果如下。
加载 shader_ball 模型运行效果如下。
声明：本文转自【Filament】自定义Blinn Phong光照模型。
