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【Filament】绘制圆形
来源：cnblogs　　作者：little_fat_sheep　　时间：2024/2/28 9:07:33　　对本文有异议

1 前言

? Filament环境搭建中介绍了 Filament 的 Windows 和 Android 环境搭，绘制三角形中介绍了绘制纯色和彩色三角形，绘制矩形中介绍了绘制纯色和彩色矩形，本文将使用 Filament 绘制圆形。

2 绘制圆形

? 本文项目结构如下，完整代码资源 → Filament绘制圆形。

img

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

  1. ...
  2. android {
  3.     ...
  4.     aaptOptions { // 在应用程序打包过程中不压缩的文件
  5.         noCompress 'filamat', 'ktx'
  6.     }
  7. }
  8.  
  9. dependencies {
  10.     implementation fileTree(dir: '../libs', include: ['*.aar'])
  11.     ...
  12. }

? 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。

img

? FLSurfaceView.java

  1. package com.zhyan8.circle.filament;
  3. import android.content.Context;
  4. import android.graphics.Point;
  5. import android.view.Choreographer;
  6. import android.view.Surface;
  7. import android.view.SurfaceView;
  9. import com.google.android.filament.Camera;
  10. import com.google.android.filament.Engine;
  11. import com.google.android.filament.EntityManager;
  12. import com.google.android.filament.Filament;
  13. import com.google.android.filament.Renderer;
  14. import com.google.android.filament.Scene;
  15. import com.google.android.filament.Skybox;
  16. import com.google.android.filament.SwapChain;
  17. import com.google.android.filament.View;
  18. import com.google.android.filament.Viewport;
  19. import com.google.android.filament.android.DisplayHelper;
  20. import com.google.android.filament.android.FilamentHelper;
  21. import com.google.android.filament.android.UiHelper;
  23. /*
  24.  * Filament中待渲染的SurfaceView
  25.  * 功能可以类比OpenGL ES中的GLSurfaceView
  26.  * 用于创建Filament的渲染环境
  27.  */
  28. public class FLSurfaceView extends SurfaceView {
  29.     public static int RENDERMODE_WHEN_DIRTY = 0; // 用户请求渲染才渲染一帧
  30.     public static int RENDERMODE_CONTINUOUSLY = 1; // 持续渲染
  31.     protected int mRenderMode = RENDERMODE_CONTINUOUSLY; // 渲染模式
  32.     protected Choreographer mChoreographer; // 消息控制
  33.     protected DisplayHelper mDisplayHelper; // 管理Display(可以监听分辨率或刷新率的变化)
  34.     protected UiHelper mUiHelper; // 管理SurfaceView、TextureView、SurfaceHolder
  35.     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)
  36.     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)
  37.     protected Scene mScene; // 场景(管理渲染对象、灯光)
  38.     protected View mView; // 存储渲染数据(View是Renderer操作的对象)
  39.     protected Camera mCamera; // 相机(视角管理)
  40.     protected Point mDesiredSize; // 渲染分辨率
  41.     protected float[] mSkyboxColor; // 背景颜色
  42.     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)
  43.     protected FrameCallback mFrameCallback = new FrameCallback(); // 帧回调
  45.     static {
  46.         Filament.init();
  47.     }
  49.     public FLSurfaceView(Context context) {
  50.         super(context);
  51.         mChoreographer = Choreographer.getInstance();
  52.         mDisplayHelper = new DisplayHelper(context);
  53.     }
  55.     public void init() { // 初始化
  56.         setupSurfaceView();
  57.         setupFilament();
  58.         setupView();
  59.         setupScene();
  60.     }
  62.     public void setRenderMode(int renderMode) { // 设置渲染模式
  63.         mRenderMode = renderMode;
  64.     }
  66.     public void requestRender() { // 请求渲染
  67.         mChoreographer.postFrameCallback(mFrameCallback);
  68.     }
  70.     public void onResume() { // 恢复
  71.         mChoreographer.postFrameCallback(mFrameCallback);
  72.     }
  74.     public void onPause() { // 暂停
  75.         mChoreographer.removeFrameCallback(mFrameCallback);
  76.     }
  78.     public void onDestroy() { // 销毁Filament环境
  79.         mChoreographer.removeFrameCallback(mFrameCallback);
  80.         mUiHelper.detach();
  81.         mEngine.destroyRenderer(mRenderer);
  82.         mEngine.destroyView(mView);
  83.         mEngine.destroyScene(mScene);
  84.         mEngine.destroyCameraComponent(mCamera.getEntity());
  85.         EntityManager entityManager = EntityManager.get();
  86.         entityManager.destroy(mCamera.getEntity());
  87.         mEngine.destroy();
  88.     }
  90.     protected void setupScene() { // 设置Scene参数
  91.     }
  93.     protected void onResized(int width, int height) { // Surface尺寸变化时回调
  94.         double zoom = 1;
  95.         double aspect = (double) width / (double) height;
  96.         mCamera.setProjection(Camera.Projection.ORTHO,
  97.                 -aspect * zoom, aspect * zoom, -zoom, zoom, 0, 1000);
  98.     }
  100.     private void setupSurfaceView() { // 设置SurfaceView
  101.         mUiHelper = new UiHelper(UiHelper.ContextErrorPolicy.DONT_CHECK);
  102.         mUiHelper.setRenderCallback(new SurfaceCallback());
  103.         if (mDesiredSize != null) {
  104.             mUiHelper.setDesiredSize(mDesiredSize.x, mDesiredSize.y);
  105.         }
  106.         mUiHelper.attachTo(this);
  107.     }
  109.     private void setupFilament() { // 设置Filament参数
  110.         mEngine = Engine.create();
  111.         // mEngine = (new Engine.Builder()).featureLevel(Engine.FeatureLevel.FEATURE_LEVEL_0).build();
  112.         mRenderer = mEngine.createRenderer();
  113.         mScene = mEngine.createScene();
  114.         mView = mEngine.createView();
  115.         mCamera = mEngine.createCamera(mEngine.getEntityManager().create());
  116.     }
  118.     private void setupView() { // 设置View参数
  119.         float[] color = mSkyboxColor != null ? mSkyboxColor : new float[] {0, 0, 0, 1};
  120.         Skybox skybox = (new Skybox.Builder()).color(color).build(mEngine);
  121.         mScene.setSkybox(skybox);
  122.         if (mEngine.getActiveFeatureLevel() == Engine.FeatureLevel.FEATURE_LEVEL_0) {
  123.             mView.setPostProcessingEnabled(false); // FEATURE_LEVEL_0不支持post-processing
  124.         }
  125.         mView.setCamera(mCamera);
  126.         mView.setScene(mScene);
  127.     }
  129.     /*
  130.      * 帧回调
  131.      */
  132.     private class FrameCallback implements Choreographer.FrameCallback {
  133.         @Override
  134.         public void doFrame(long frameTimeNanos) { // 渲染每帧数据
  135.             if (mRenderMode == RENDERMODE_CONTINUOUSLY) {
  136.                 mChoreographer.postFrameCallback(this); // 请求下一帧
  137.             }
  138.             if (mUiHelper.isReadyToRender()) {
  139.                 if (mRenderer.beginFrame(mSwapChain, frameTimeNanos)) {
  140.                     mRenderer.render(mView);
  141.                     mRenderer.endFrame();
  142.                 }
  143.             }
  144.         }
  145.     }
  147.     /*
  148.      * Surface回调
  149.      */
  150.     private class SurfaceCallback implements UiHelper.RendererCallback {
  151.         @Override
  152.         public void onNativeWindowChanged(Surface surface) { // Native窗口改变时回调
  153.             if (mSwapChain != null) {
  154.                 mEngine.destroySwapChain(mSwapChain);
  155.             }
  156.             long flags = mUiHelper.getSwapChainFlags();
  157.             if (mEngine.getActiveFeatureLevel() == Engine.FeatureLevel.FEATURE_LEVEL_0) {
  158.                 if (SwapChain.isSRGBSwapChainSupported(mEngine)) {
  159.                     flags = flags | SwapChain.CONFIG_SRGB_COLORSPACE;
  160.                 }
  161.             }
  162.             mSwapChain = mEngine.createSwapChain(surface, flags);
  163.             mDisplayHelper.attach(mRenderer, getDisplay());
  164.         }
  166.         @Override
  167.         public void onDetachedFromSurface() { // 解绑Surface时回调
  168.             mDisplayHelper.detach();
  169.             if (mSwapChain != null) {
  170.                 mEngine.destroySwapChain(mSwapChain);
  171.                 mEngine.flushAndWait();
  172.                 mSwapChain = null;
  173.             }
  174.         }
  176.         @Override
  177.         public void onResized(int width, int height) { // Surface尺寸变化时回调
  178.             mView.setViewport(new Viewport(0, 0, width, height));
  179.             FilamentHelper.synchronizePendingFrames(mEngine);
  180.             FLSurfaceView.this.onResized(width, height);
  181.         }
  182.     }
  183. }

? BaseModel.java

  1. package com.zhyan8.circle.filament;
  3. import android.content.res.AssetFileDescriptor;
  4. import android.content.res.AssetManager;
  5. import android.os.Handler;
  6. import android.os.Looper;
  7. import android.util.Log;
  9. import com.google.android.filament.Box;
  10. import com.google.android.filament.Engine;
  11. import com.google.android.filament.EntityManager;
  12. import com.google.android.filament.IndexBuffer;
  13. import com.google.android.filament.Material;
  14. import com.google.android.filament.MaterialInstance;
  15. import com.google.android.filament.RenderableManager;
  16. import com.google.android.filament.RenderableManager.PrimitiveType;
  17. import com.google.android.filament.VertexBuffer;
  18. import com.google.android.filament.VertexBuffer.AttributeType;
  19. import com.google.android.filament.VertexBuffer.VertexAttribute;
  21. import java.io.FileInputStream;
  22. import java.io.IOException;
  23. import java.nio.Buffer;
  24. import java.nio.ByteBuffer;
  25. import java.nio.ByteOrder;
  26. import java.nio.channels.Channels;
  27. import java.nio.channels.ReadableByteChannel;
  29. /*
  30.  * 模型基类
  31.  * 管理模型的材质、顶点属性、顶点索引、渲染id
  32.  */
  33. public class BaseModel {
  34.     private static String TAG = "BaseModel";
  35.     protected AssetManager mAssetManager; // 资源管理器
  36.     protected Engine mEngine; // Filament引擎
  37.     protected Material mMaterial; // 模型材质
  38.     protected MaterialInstance mMaterialInstance; // 模型材质实例
  39.     protected VertexBuffer mVertexBuffer; // 顶点属性缓存
  40.     protected IndexBuffer mIndexBuffer; // 顶点索引缓存
  41.     protected int mRenderable; // 渲染id
  42.     protected Box mBox; // 渲染区域
  44.     public BaseModel(AssetManager assetManager, Engine engine) {
  45.         mAssetManager = assetManager;
  46.         mEngine = engine;
  47.     }
  49.     public Material getMaterial() { // 获取材质
  50.         return mMaterial;
  51.     }
  53.     public VertexBuffer getVertexBuffer() { // 获取顶点属性缓存
  54.         return mVertexBuffer;
  55.     }
  57.     public IndexBuffer getIndexBuffer() { // 获取顶点索引缓存
  58.         return mIndexBuffer;
  59.     }
  61.     public int getRenderable() { // 获取渲染id
  62.         return mRenderable;
  63.     }
  65.     public void destroy() { // 销毁模型
  66.         mEngine.destroyEntity(mRenderable);
  67.         mEngine.destroyVertexBuffer(mVertexBuffer);
  68.         mEngine.destroyIndexBuffer(mIndexBuffer);
  69.         mEngine.destroyMaterialInstance(mMaterialInstance);
  70.         mEngine.destroyMaterial(mMaterial);
  71.         EntityManager entityManager = EntityManager.get();
  72.         entityManager.destroy(mRenderable);
  73.     }
  75.     protected Material loadMaterial(String materialPath) { // 加载材质
  76.         Buffer buffer = readUncompressedAsset(mAssetManager, materialPath);
  77.         if (buffer != null) {
  78.             Material material = (new Material.Builder()).payload(buffer, buffer.remaining()).build(mEngine);
  79.             mMaterialInstance = material.createInstance();
  80.             material.compile(
  81.                     Material.CompilerPriorityQueue.HIGH,
  82.                     Material.UserVariantFilterBit.ALL,
  83.                     new Handler(Looper.getMainLooper()),
  84.                     () -> Log.i(TAG, "Material " + material.getName() + " compiled."));
  85.             mEngine.flush();
  86.             return material;
  87.         }
  88.         return null;
  89.     }
  91.     protected VertexBuffer getVertexBuffer(float[] values) { // 获取顶点属性缓存
  92.         ByteBuffer vertexData = getByteBuffer(values);
  93.         int vertexCount = values.length / 3;
  94.         int vertexSize = Float.BYTES * 3;
  95.         VertexBuffer vertexBuffer = new VertexBuffer.Builder()
  96.                 .bufferCount(1)
  97.                 .vertexCount(vertexCount)
  98.                 .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
  99.                 .build(mEngine);
  100.         vertexBuffer.setBufferAt(mEngine, 0, vertexData);
  101.         return vertexBuffer;
  102.     }
  104.     protected VertexBuffer getVertexBuffer(Vertex[] values) { // 获取顶点属性缓存
  105.         ByteBuffer vertexData = getByteBuffer(values);
  106.         int vertexCount = values.length;
  107.         int vertexSize = Vertex.BYTES;
  108.         VertexBuffer vertexBuffer = new VertexBuffer.Builder()
  109.                 .bufferCount(1)
  110.                 .vertexCount(vertexCount)
  111.                 .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
  112.                 .attribute(VertexAttribute.COLOR,    0, AttributeType.UBYTE4, 3 * Float.BYTES, vertexSize)
  113.                 .normalized(VertexAttribute.COLOR)
  114.                 .build(mEngine);
  115.         vertexBuffer.setBufferAt(mEngine, 0, vertexData);
  116.         return vertexBuffer;
  117.     }
  119.     protected IndexBuffer getIndexBuffer(short[] values) { // 获取顶点索引缓存
  120.         ByteBuffer indexData = getByteBuffer(values);
  121.         int indexCount = values.length;
  122.         IndexBuffer indexBuffer = new IndexBuffer.Builder()
  123.                 .indexCount(indexCount)
  124.                 .bufferType(IndexBuffer.Builder.IndexType.USHORT)
  125.                 .build(mEngine);
  126.         indexBuffer.setBuffer(mEngine, indexData);
  127.         return indexBuffer;
  128.     }
  130.     protected int getRenderable(PrimitiveType primitiveType, int vertexCount) { // 获取渲染id
  131.         int renderable = EntityManager.get().create();
  132.         new RenderableManager.Builder(1)
  133.                 .boundingBox(mBox)
  134.                 .geometry(0, primitiveType, mVertexBuffer, mIndexBuffer, 0, vertexCount)
  135.                 .material(0, mMaterialInstance)
  136.                 .build(mEngine, renderable);
  137.         return renderable;
  138.     }
  140.     private Buffer readUncompressedAsset(AssetManager assetManager, String assetPath) { // 加载资源
  141.         ByteBuffer dist = null;
  142.         try {
  143.             AssetFileDescriptor fd = assetManager.openFd(assetPath);
  144.             try(FileInputStream fis = fd.createInputStream()) {
  145.                 dist = ByteBuffer.allocate((int) fd.getLength());
  146.                 try (ReadableByteChannel src = Channels.newChannel(fis)) {
  147.                     src.read(dist);
  148.                 }
  149.             }
  150.         } catch (IOException e) {
  151.             e.printStackTrace();
  152.         }
  153.         if (dist != null) {
  154.             return dist.rewind();
  155.         }
  156.         return null;
  157.     }
  159.     private ByteBuffer getByteBuffer(float[] values) { // float数组转换为ByteBuffer
  160.         ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Float.BYTES);
  161.         byteBuffer.order(ByteOrder.nativeOrder());
  162.         for (int i = 0; i < values.length; i++) {
  163.             byteBuffer.putFloat(values[i]);
  164.         }
  165.         byteBuffer.flip();
  166.         return byteBuffer;
  167.     }
  169.     private ByteBuffer getByteBuffer(short[] values) { // short数组转换为ByteBuffer
  170.         ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Short.BYTES);
  171.         byteBuffer.order(ByteOrder.nativeOrder());
  172.         for (int i = 0; i < values.length; i++) {
  173.             byteBuffer.putShort(values[i]);
  174.         }
  175.         byteBuffer.flip();
  176.         return byteBuffer;
  177.     }
  179.     private ByteBuffer getByteBuffer(Vertex[] values) { // Vertex数组转换为ByteBuffer
  180.         ByteBuffer byteBuffer = ByteBuffer.allocate(values.length * Vertex.BYTES);
  181.         byteBuffer.order(ByteOrder.nativeOrder());
  182.         for (int i = 0; i < values.length; i++) {
  183.             values[i].put(byteBuffer);
  184.         }
  185.         byteBuffer.flip();
  186.         return byteBuffer;
  187.     }
  189.     /*
  190.      * 顶点数据
  191.      * 包含顶点位置和颜色
  192.      */
  193.     public static class Vertex {
  194.         public static int BYTES = 16;
  195.         public float x;
  196.         public float y;
  197.         public float z;
  198.         public int color;
  199.         public Vertex() {}
  200.         public Vertex(float x, float y, float z, int color) {
  201.             this.x = x;
  202.             this.y = y;
  203.             this.z = z;
  204.             this.color = color;
  205.         }
  207.         public ByteBuffer put(ByteBuffer buffer) { // Vertex转换为ByteBuffer
  208.             buffer.putFloat(x);
  209.             buffer.putFloat(y);
  210.             buffer.putFloat(z);
  211.             buffer.putInt(color);
  212.             return buffer;
  213.         }
  214.     }
  215. }

2.2 绘制纯色圆形（固定材质颜色）

? MainActivity.java

  1. package com.zhyan8.circle;
  3. import androidx.appcompat.app.AppCompatActivity;
  5. import android.os.Bundle;
  7. import com.zhyan8.circle.filament.FLSurfaceView;
  9. public class MainActivity extends AppCompatActivity {
  10.     private FLSurfaceView mFLSurfaceView;
  12.     @Override
  13.     protected void onCreate(Bundle savedInstanceState) {
  14.         super.onCreate(savedInstanceState);
  15.         mFLSurfaceView = new MyFLSurfaceView(this);
  16.         setContentView(mFLSurfaceView);
  17.         mFLSurfaceView.init();
  18.         mFLSurfaceView.setRenderMode(FLSurfaceView.RENDERMODE_CONTINUOUSLY);
  19.     }
  21.     @Override
  22.     public void onResume() {
  23.         super.onResume();
  24.         mFLSurfaceView.onResume();
  25.     }
  27.     @Override
  28.     public void onPause() {
  29.         super.onPause();
  30.         mFLSurfaceView.onPause();
  31.     }
  33.     @Override
  34.     public void onDestroy() {
  35.         super.onDestroy();
  36.         mFLSurfaceView.onDestroy();
  37.     }
  38. }

? MyFLSurfaceView.java

  1. package com.zhyan8.circle;
  3. import android.content.Context;
  5. import com.google.android.filament.Camera;
  6. import com.zhyan8.circle.filament.BaseModel;
  7. import com.zhyan8.circle.filament.FLSurfaceView;
  9. public class MyFLSurfaceView extends FLSurfaceView {
  10.     private BaseModel mMyModel;
  11.     public MyFLSurfaceView(Context context) {
  12.         super(context);
  13.     }
  15.     public void init() {
  16.         mSkyboxColor = new float[] {0.965f, 0.941f, 0.887f, 1};
  17.         super.init();
  18.     }
  20.     @Override
  21.     public void onDestroy() {
  22.         mMyModel.destroy();
  23.         super.onDestroy();
  24.     }
  26.     @Override
  27.     protected void setupScene() { // 设置Scene参数
  28.         mMyModel = new Circle1(getContext().getAssets(), mEngine);
  29.         mScene.addEntity(mMyModel.getRenderable());
  30.     }
  32.     @Override
  33.     protected void onResized(int width, int height) {
  34.         double zoom = 1.5;
  35.         double aspect = (double) width / (double) height;
  36.         mCamera.setProjection(Camera.Projection.ORTHO,
  37.                 -aspect * zoom, aspect * zoom, -zoom, zoom, 0, 10);
  38.     }
  39. }

? Circle1.java

  1. package com.zhyan8.circle;
  3. import android.content.res.AssetManager;
  5. import com.google.android.filament.Box;
  6. import com.google.android.filament.Engine;
  7. import com.google.android.filament.RenderableManager.PrimitiveType;
  8. import com.zhyan8.circle.filament.BaseModel;
  10. public class Circle1 extends BaseModel {
  11.     private String materialPath = "materials/circle1.filamat";
  12.     private float[] mVertices;
  13.     private short[] mIndex;
  15.     public Circle1(AssetManager assetManager, Engine engine) {
  16.         super(assetManager, engine);
  17.         init();
  18.     }
  20.     private void init() {
  21.         int num = 50;
  22.         mVertices = getCircle(0, 0, 0.5f, num);
  23.         mIndex = getIndices(num);
  24.         mBox = new Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.01f);
  25.         mMaterial = loadMaterial(materialPath);
  26.         mVertexBuffer = getVertexBuffer(mVertices);
  27.         mIndexBuffer = getIndexBuffer(mIndex);
  28.         mRenderable = getRenderable(PrimitiveType.TRIANGLES, mIndex.length);
  29.     }
  31.     private float[] getCircle(float centerX, float centerY, float radius, int num) {
  32.         float unit = (float) (2 * Math.PI / num);
  33.         float[] coords = new float[(num + 1) * 3];
  34.         int index = 0;
  35.         for (int i = 0; i < num; i++) {
  36.             coords[index++] = (float)(centerX + radius * Math.cos(unit * i));
  37.             coords[index++] = (float)(centerY + radius * Math.sin(unit * i));
  38.             coords[index++] = 0;
  39.         }
  40.         coords[index++] = centerX;
  41.         coords[index++] = centerY;
  42.         coords[index] = 0;
  43.         return coords;
  44.     }
  46.     private short[] getIndices(int num) {
  47.         short[] indices = new short[num * 3];
  48.         short centerIndex = (short) num;
  49.         short index = 0;
  50.         for (short i = 0; i < num - 1; i++) {
  51.             indices[index++] = centerIndex;
  52.             indices[index++] = i;
  53.             indices[index++] = (short)(i + 1);
  54.         }
  55.         indices[index++] = centerIndex;
  56.         indices[index++] = (short) (num - 1);
  57.         indices[index] = 0;
  58.         return indices;
  59.     }
  60. }

? circle1.mat

  1. material {
  2.     name : circle,
  4.     // 禁用所有lighting
  5.     shadingModel : unlit,
  6.     featureLevel : 0
  7. }
  9. fragment {
  10.     vec3 sRGB_to_linear(vec3 color) { // gamma解码, 转换到线下空间
  11.         color.x = pow(color.r, 2.2);
  12.         color.y = pow(color.g, 2.2);
  13.         color.z = pow(color.b, 2.2);
  14.         return color;
  15.     }
  17.     void material(inout MaterialInputs material) {
  18.         prepareMaterial(material); // 在方法返回前必须回调该函数
  19.         vec3 color = vec3(0.455, 0.725, 1.0);
  20.         color = sRGB_to_linear(color);
  21.         material.baseColor = vec4(color, 1.0);
  22.     }
  23. }

? 说明：这里需要进行伽马解码处理，将颜色空间转换到线性空间中，否则显示的颜色将会偏亮，伽马编码原理详见 → 【Unity3D】伽马校正。

? transform.bat

  1. @echo off
  2. setlocal enabledelayedexpansion
  3. set "srcFolder=../src/main/materials"
  4. set "distFolder=../src/main/assets/materials"
  6. for %%f in ("%srcFolder%\*.mat") do (
  7. 	set "matfile=%%~nf"
  8. 	matc -p mobile -a opengl -o "!matfile!.filamat" "%%f"
  9.     move "!matfile!.filamat" "%distFolder%\!matfile!.filamat"
  10. )
  12. echo Processing complete.
  13. 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。

img

2.3 绘制纯色圆形（传递材质颜色）

? MyFLSurfaceView.java

  1. package com.zhyan8.circle;
  3. import android.content.Context;
  5. import com.google.android.filament.Camera;
  6. import com.zhyan8.circle.filament.BaseModel;
  7. import com.zhyan8.circle.filament.FLSurfaceView;
  9. public class MyFLSurfaceView extends FLSurfaceView {
  10.     private BaseModel mMyModel;
  11.     public MyFLSurfaceView(Context context) {
  12.         super(context);
  13.     }
  15.     public void init() {
  16.         mSkyboxColor = new float[] {0.965f, 0.941f, 0.887f, 1};
  17.         super.init();
  18.     }
  20.     @Override
  21.     public void onDestroy() {
  22.         mMyModel.destroy();
  23.         super.onDestroy();
  24.     }
  26.     @Override
  27.     protected void setupScene() { // 设置Scene参数
  28.         mMyModel = new Circle2(getContext().getAssets(), mEngine);
  29.         mScene.addEntity(mMyModel.getRenderable());
  30.     }
  32.     @Override
  33.     protected void onResized(int width, int height) {
  34.         double zoom = 1.5;
  35.         double aspect = (double) width / (double) height;
  36.         mCamera.setProjection(Camera.Projection.ORTHO,
  37.                 -aspect * zoom, aspect * zoom, -zoom, zoom, 0, 10);
  38.     }
  39. }

? Circle2.java

  1. package com.zhyan8.circle;
  3. import android.content.res.AssetManager;
  5. import com.google.android.filament.Box;
  6. import com.google.android.filament.Colors;
  7. import com.google.android.filament.Engine;
  8. import com.google.android.filament.RenderableManager.PrimitiveType;
  9. import com.zhyan8.circle.filament.BaseModel;
  11. public class Circle2 extends BaseModel {
  12.     private String materialPath = "materials/circle2.filamat";
  13.     private float[] mVertices;
  14.     private short[] mIndex;
  16.     public Circle2(AssetManager assetManager, Engine engine) {
  17.         super(assetManager, engine);
  18.         init();
  19.     }
  21.     private void init() {
  22.         int num = 50;
  23.         mVertices = getCircle(0, 0, 0.5f, num);
  24.         mIndex = getIndices(num);
  25.         mBox = new Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.01f);
  26.         mMaterial = loadMaterial(materialPath);
  27.         mMaterialInstance.setParameter("baseColor", Colors.RgbType.SRGB, 0.455f, 0.725f, 1.0f);
  28.         mVertexBuffer = getVertexBuffer(mVertices);
  29.         mIndexBuffer = getIndexBuffer(mIndex);
  30.         mRenderable = getRenderable(PrimitiveType.TRIANGLES, mIndex.length);
  31.     }
  33.     private float[] getCircle(float centerX, float centerY, float radius, int num) {
  34.         float unit = (float) (2 * Math.PI / num);
  35.         float[] coords = new float[(num + 1) * 3];
  36.         int index = 0;
  37.         for (int i = 0; i < num; i++) {
  38.             coords[index++] = (float)(centerX + radius * Math.cos(unit * i));
  39.             coords[index++] = (float)(centerY + radius * Math.sin(unit * i));
  40.             coords[index++] = 0;
  41.         }
  42.         coords[index++] = centerX;
  43.         coords[index++] = centerY;
  44.         coords[index] = 0;
  45.         return coords;
  46.     }
  48.     private short[] getIndices(int num) {
  49.         short[] indices = new short[num * 3];
  50.         short centerIndex = (short) num;
  51.         short index = 0;
  52.         for (short i = 0; i < num - 1; i++) {
  53.             indices[index++] = centerIndex;
  54.             indices[index++] = i;
  55.             indices[index++] = (short)(i + 1);
  56.         }
  57.         indices[index++] = centerIndex;
  58.         indices[index++] = (short) (num - 1);
  59.         indices[index] = 0;
  60.         return indices;
  61.     }
  62. }

? circle2.mat

  1. material {
  2.     name : circle,
  4.     // 禁用所有lighting
  5.     shadingModel : unlit,
  6.     featureLevel : 0,
  7.     parameters : [
  8.         { // 颜色必须在线性空间中传递, 而不是sRGB空间
  9.             type : float3,
  10.             name : baseColor
  11.         }
  12.     ]
  13. }
  15. fragment {
  16.     void material(inout MaterialInputs material) {
  17.         prepareMaterial(material); // 在方法返回前必须回调该函数
  18.         material.baseColor.rgb = materialParams.baseColor;
  19.     }
  20. }

? 运行效果如下，可以看到，与 2.2 节中进行伽马校正后的颜色是一样的。

img

? 声明：本文转自【Filament】绘制圆形。

原文链接：https://www.cnblogs.com/zhyan8/p/18024345

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