feat(cameras): base camera

src/cameras/Camera.ts

@@ -0,0 +1,150 @@
+import Object3D from '../objects/Object3D';
+import ProjectionMatrix from '../math/ProjectionMatrix';
+import Matrix4 from '../math/Matrix4';
+import Vector3 from '../math/Vector3';
+
+export type CameraType = 'perspective' | 'orthographic';
+
+export interface CameraOptions {
+  near: number;
+  far: number;
+  fov?: number;
+  aspect?: number;
+  bounds?: {
+    left: number;
+    right: number;
+    top: number;
+    bottom: number;
+  };
+  zoom?: number;
+}
+
+const tempMat4 = new Matrix4();
+
+const ERR_CAMERA_METHOD_UNDEFINED = 'Camera subclass must define virtual methods';
+
+/**
+ * 相机基类
+ */
+export default class Camera extends Object3D {
+
+  /**
+   * 相机类型（默认有两种相机：perspective和orthographic）
+   */
+  public cameraType: CameraType;
+
+  public projectionMatrix: ProjectionMatrix;
+
+  public viewMatrix: Matrix4;
+
+  public projectionViewMatrix: ProjectionMatrix;
+
+  public worldPosition: Vector3;
+
+  public near: number;
+
+  public far: number;
+
+  public fov: number;
+
+  public aspect: number;
+
+  public zoom: number;
+
+  public bounds: any;
+
+  constructor({
+    near = 0.1,
+    far = 100,
+    fov = 45,
+    aspect = 1,
+    bounds,
+    zoom = 1,
+  }: CameraOptions = {} as CameraOptions) {
+    super();
+    this.cameraType = 'perspective';
+    this.projectionMatrix = new ProjectionMatrix();
+    this.viewMatrix = new Matrix4();
+    this.projectionViewMatrix = new ProjectionMatrix();
+    this.worldPosition = new Vector3();
+    this.near = near;
+    this.far = far;
+    this.fov = fov;
+    this.aspect = aspect;
+    this.bounds = bounds;
+    this.zoom = zoom;
+    const {
+      left,
+      right,
+      top,
+      bottom,
+    } = bounds || {};
+    this.cameraType = left || right ? 'orthographic' : 'perspective';
+    if (this.cameraType === 'orthographic') {
+      this.orthographic(left, right, top, bottom, near, far, zoom);
+    } else {
+      this.perspective(fov, aspect, near, far);
+    }
+  }
+
+  perspective(fov, aspect, near, far) {
+    this.fov = fov;
+    this.aspect = aspect;
+    this.near = near;
+    this.far = far;
+    this.projectionMatrix.fromPerspective(fov, aspect, near, far);
+    this.cameraType = 'perspective';
+  }
+
+  orthographic(left, right, top, bottom, near, far, zoom = 1) {
+    this.bounds = {
+      left,
+      right,
+      top,
+      bottom,
+    };
+    this.near = near;
+    this.far = far;
+    this.projectionMatrix.orthographic(
+      left / zoom,
+      right / zoom,
+      top / zoom,
+      bottom / zoom,
+      near,
+      far,
+    );
+    this.cameraType = 'orthographic';
+  }
+
+  lookAt(t) {
+    super.lookAt(t, true);
+    return this;
+  }
+
+  updateMatrixWorld() {
+    super.updateMatrixWorld();
+    this.viewMatrix.invert(this.worldMatrix);
+    this.worldMatrix.getTranslation(this.worldPosition);
+    this.projectionViewMatrix.multiply(this.projectionMatrix, this.viewMatrix);
+    return this;
+  }
+
+  project(v) {
+    v.applyMatrix4(this.viewMatrix);
+    v.applyMatrix4(this.projectionMatrix);
+    return this;
+  }
+
+  unproject(v) {
+    v.applyMatrix4(tempMat4.invert(this.projectionMatrix));
+    v.applyMatrix4(this.worldMatrix);
+    return this;
+  }
+
+  /**
+   * 更新摄像机投影矩阵，必须由子类实现
+   */
+  updateProjectionMatrix() {
+    throw new Error(ERR_CAMERA_METHOD_UNDEFINED);
+  }
+}