feat(GLTFImporter): add GLTFImporter

Author: daker

Documentation/content/docs/gallery/GLTFImporter.jpg

@@ -0,0 +1,253 @@
+import macro from 'vtk.js/Sources/macros';
+import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';
+import { quat, vec3 } from 'gl-matrix';
+
+const { vtkDebugMacro, vtkWarningMacro } = macro;
+
+/**
+ * Create an animation channel
+ * @param {*} glTFChannel
+ * @returns
+ */
+function createAnimationChannel(glTFChannel, glTFSamplers) {
+  const path = glTFChannel.target.path;
+  const node = glTFChannel.target.node;
+
+  function applyAnimation(value) {
+    let axisAngle;
+    let w;
+    let nq;
+    switch (path) {
+      case 'translation':
+        node.setPosition(value[0], value[1], value[2]);
+        break;
+      case 'rotation':
+        // Convert quaternion to axis-angle representation
+        nq = quat.normalize(quat.create(), value);
+        axisAngle = new Float64Array(3);
+        w = quat.getAxisAngle(axisAngle, nq);
+        // Apply rotation using rotateWXYZ
+        node.rotateWXYZ(
+          vtkMath.degreesFromRadians(w),
+          axisAngle[0],
+          axisAngle[1],
+          axisAngle[2]
+        );
+        break;
+      case 'scale':
+        node.setScale(value[0], value[1], value[2]);
+        break;
+      default:
+        vtkWarningMacro(`Unsupported animation path: ${path}`);
+    }
+  }
+
+  function animate(currentTime) {
+    const sampler = glTFSamplers[glTFChannel.sampler];
+    const value = sampler.evaluate(currentTime, path);
+    applyAnimation(value);
+  }
+
+  return { ...glTFChannel, animate };
+}
+
+/**
+ * Create an animation sampler
+ * @param {glTFSampler} glTFSampler
+ * @returns
+ */
+function createAnimationSampler(glTFSampler) {
+  let lastKeyframeIndex = 0;
+
+  function findKeyframes(time) {
+    let i1 = lastKeyframeIndex;
+    while (i1 < glTFSampler.input.length - 1 && glTFSampler.input[i1] <= time) {
+      i1++;
+    }
+    const i0 = Math.max(0, i1 - 1);
+    lastKeyframeIndex = i0;
+    return [glTFSampler.input[i0], glTFSampler.input[i1], i0, i1];
+  }
+
+  function stepInterpolate(path, i0) {
+    const startIndex = i0 * 3;
+    const v0 = new Array(3);
+    for (let i = 0; i < 3; ++i) {
+      v0[i] = glTFSampler.output[startIndex + i];
+    }
+
+    return v0;
+  }
+
+  function linearInterpolate(path, t0, t1, i0, i1, t) {
+    const ratio = (t - t0) / (t1 - t0);
+    const startIndex = i0 * 4;
+    const endIndex = i1 * 4;
+
+    const v0 = new Array(4);
+    const v1 = new Array(4);
+    for (let i = 0; i < 4; ++i) {
+      v0[i] = glTFSampler.output[startIndex + i];
+      v1[i] = glTFSampler.output[endIndex + i];
+    }
+
+    switch (path) {
+      case 'translation':
+      case 'scale':
+        return vec3.lerp(vec3.create(), v0, v1, ratio);
+      case 'rotation':
+        return quat.slerp(quat.create(), v0, v1, ratio);
+      default:
+        vtkWarningMacro(`Unsupported animation path: ${path}`);
+        return null;
+    }
+  }
+
+  function cubicSplineInterpolate(path, t0, t1, i0, i1, time) {
+    const dt = t1 - t0;
+    const t = (time - t0) / dt;
+    const t2 = t * t;
+    const t3 = t2 * t;
+
+    const p0 = glTFSampler.output[i0 * 3 + 1];
+    const m0 = dt * glTFSampler.output[i0 * 3 + 2];
+    const p1 = glTFSampler.output[i1 * 3 + 1];
+    const m1 = dt * glTFSampler.output[i1 * 3];
+
+    if (Array.isArray(p0)) {
+      return p0.map((v, j) => {
+        const a = 2 * t3 - 3 * t2 + 1;
+        const b = t3 - 2 * t2 + t;
+        const c = -2 * t3 + 3 * t2;
+        const d = t3 - t2;
+        return a * v + b * m0[j] + c * p1[j] + d * m1[j];
+      });
+    }
+
+    const a = 2 * t3 - 3 * t2 + 1;
+    const b = t3 - 2 * t2 + t;
+    const c = -2 * t3 + 3 * t2;
+    const d = t3 - t2;
+    return a * p0 + b * m0 + c * p1 + d * m1;
+  }
+
+  function evaluate(time, path) {
+    const [t0, t1, i0, i1] = findKeyframes(time);
+
+    let result;
+
+    switch (glTFSampler.interpolation) {
+      case 'STEP':
+        result = stepInterpolate(path, i0);
+        break;
+      case 'LINEAR':
+        result = linearInterpolate(path, t0, t1, i0, i1, time);
+        break;
+      case 'CUBICSPLINE':
+        result = cubicSplineInterpolate(path, t0, t1, i0, i1, time);
+        break;
+      default:
+        throw new Error(
+          `Unknown interpolation method: ${glTFSampler.interpolation}`
+        );
+    }
+    return result;
+  }
+
+  return { ...glTFSampler, evaluate };
+}
+
+/**
+ * Create an animation
+ * @param {glTFAnimation} glTFAnimation
+ * @returns
+ */
+function createAnimation(glTFAnimation, nodes) {
+  glTFAnimation.samplers = glTFAnimation.samplers.map((sampler) =>
+    createAnimationSampler(sampler)
+  );
+
+  glTFAnimation.channels = glTFAnimation.channels.map((channel) => {
+    channel.target.node = nodes.get(`node-${channel.target.node}`);
+    return createAnimationChannel(channel, glTFAnimation.samplers);
+  });
+
+  function update(currentTime) {
+    glTFAnimation.channels.forEach((channel) => channel.animate(currentTime));
+  }
+
+  return { ...glTFAnimation, update };
+}
+
+/**
+ * Create an animation mixer
+ * @param {*} nodes
+ * @returns
+ */
+function createAnimationMixer(nodes, accessors) {
+  const animations = new Map();
+  const activeAnimations = new Map();
+
+  function addAnimation(glTFAnimation) {
+    const annimation = createAnimation(glTFAnimation, nodes, accessors);
+    animations.set(glTFAnimation.id, annimation);
+    vtkDebugMacro(`Animation "${glTFAnimation.id}" added to mixer`);
+  }
+
+  function play(name, weight = 1) {
+    if (!animations.has(name)) {
+      vtkWarningMacro(`Animation "${name}" not found in mixer`);
+      return;
+    }
+    activeAnimations.set(name, {
+      animation: animations.get(name),
+      weight,
+      time: 0,
+    });
+    vtkDebugMacro(`Playing animation "${name}" with weight ${weight}`);
+  }
+
+  function stop(name) {
+    if (activeAnimations.delete(name)) {
+      vtkWarningMacro(`Stopped animation "${name}"`);
+    } else {
+      vtkWarningMacro(`Animation "${name}" was not playing`);
+    }
+  }
+
+  function stopAll() {
+    activeAnimations.clear();
+    vtkWarningMacro('Stopped all animations');
+  }
+
+  function update(deltaTime) {
+    // Normalize weights
+    const totalWeight = Array.from(activeAnimations.values()).reduce(
+      (sum, { weight }) => sum + weight,
+      0
+    );
+
+    activeAnimations.forEach(({ animation, weight, time }, name) => {
+      const normalizedWeight = totalWeight > 0 ? weight / totalWeight : 0;
+      const newTime = time + deltaTime;
+      activeAnimations.set(name, { animation, weight, time: newTime });
+
+      vtkDebugMacro(
+        `Updating animation "${name}" at time ${newTime.toFixed(
+          3
+        )} with normalized weight ${normalizedWeight.toFixed(3)}`
+      );
+
+      animation.update(newTime, normalizedWeight);
+    });
+  }
+
+  return { addAnimation, play, stop, stopAll, update };
+}
+
+export {
+  createAnimation,
+  createAnimationChannel,
+  createAnimationMixer,
+  createAnimationSampler,
+};

Documentation/content/examples/index.md

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+export const BINARY_HEADER_MAGIC = 'glTF';
+export const BINARY_HEADER_LENGTH = 12;
+export const BINARY_CHUNK_TYPES = { JSON: 0x4e4f534a, BIN: 0x004e4942 };
+export const BINARY_HEADER_INTS = 3;
+export const BINARY_CHUNK_HEADER_INTS = 2;
+
+export const MIN_LIGHT_ATTENUATION = 0.01;
+
+export const COMPONENTS = {
+  SCALAR: 1,
+  VEC2: 2,
+  VEC3: 3,
+  VEC4: 4,
+  MAT2: 4,
+  MAT3: 9,
+  MAT4: 16,
+};
+
+export const BYTES = {
+  5120: 1, // BYTE
+  5121: 1, // UNSIGNED_BYTE
+  5122: 2, // SHORT
+  5123: 2, // UNSIGNED_SHORT
+  5125: 4, // UNSIGNED_INT
+  5126: 4, // FLOAT
+};
+
+export const MODES = {
+  GL_POINTS: 0,
+  GL_LINES: 1,
+  GL_LINE_LOOP: 2,
+  GL_LINE_STRIP: 3,
+  GL_TRIANGLES: 4,
+  GL_TRIANGLE_STRIP: 5,
+  GL_TRIANGLE_FAN: 6,
+};
+
+export const ARRAY_TYPES = {
+  5120: Int8Array,
+  5121: Uint8Array,
+  5122: Int16Array,
+  5123: Uint16Array,
+  5125: Uint32Array,
+  5126: Float32Array,
+};
+
+export const GL_SAMPLER = {
+  NEAREST: 9728,
+  LINEAR: 9729,
+  NEAREST_MIPMAP_NEAREST: 9984,
+  LINEAR_MIPMAP_NEAREST: 9985,
+  NEAREST_MIPMAP_LINEAR: 9986,
+  LINEAR_MIPMAP_LINEAR: 9987,
+  REPEAT: 10497,
+  CLAMP_TO_EDGE: 33071,
+  MIRRORED_REPEAT: 33648,
+  TEXTURE_MAG_FILTER: 10240,
+  TEXTURE_MIN_FILTER: 10241,
+  TEXTURE_WRAP_S: 10242,
+  TEXTURE_WRAP_T: 10243,
+};
+
+export const DEFAULT_SAMPLER = {
+  magFilter: GL_SAMPLER.NEAREST,
+  minFilter: GL_SAMPLER.LINEAR_MIPMAP_LINEAR,
+  wrapS: GL_SAMPLER.REPEAT,
+  wrapT: GL_SAMPLER.REPEAT,
+};
+
+export const SEMANTIC_ATTRIBUTE_MAP = {
+  NORMAL: 'normal',
+  POSITION: 'position',
+  TEXCOORD_0: 'texcoord0',
+  TEXCOORD_1: 'texcoord1',
+  WEIGHTS_0: 'weight',
+  JOINTS_0: 'joint',
+  COLOR_0: 'color',
+  TANGENT: 'tangent',
+};
+
+export const ALPHA_MODE = {
+  OPAQUE: 'OPAQUE',
+  MASK: 'MASK',
+  BLEND: 'BLEND',
+};