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Revert "Generate tangents with MikkTSpace"
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@UX3D-haertl
UX3D-haertl authored Jul 13, 2023
1 parent 6e096a3 commit c33d91e
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Showing 4 changed files with 4 additions and 507 deletions.
12 changes: 3 additions & 9 deletions app_web/src/main.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,14 +7,8 @@ import { Observable, Subject, from, merge } from 'rxjs';
import { mergeMap, filter, map, multicast } from 'rxjs/operators';
import { gltfModelPathProvider, fillEnvironmentWithPaths } from './model_path_provider.js';


import mikktspaceWasm from '../../source/libs/mikktspace_module.js';

let mikktspace = null;

async function main() {
mikktspace = await mikktspaceWasm("libs/mikktspace_module_bg.wasm");

async function main()
{
const canvas = document.getElementById("canvas");
const context = canvas.getContext("webgl2", { alpha: false, antialias: true });
const ui = document.getElementById("app");
Expand Down Expand Up @@ -369,4 +363,4 @@ async function main() {
window.requestAnimationFrame(update);
}

export { main, mikktspace };
export { main };
139 changes: 1 addition & 138 deletions source/gltf/primitive.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
import { initGlForMembers } from './utils.js';
import { GltfObject } from './gltf_object.js';
import { gltfBuffer } from './buffer.js';
import { gltfAccessor } from './accessor.js';
import { gltfImage } from './image.js';
import { ImageMimeType } from './image_mime_type.js';
import { gltfTexture } from './texture.js';
Expand All @@ -10,14 +9,13 @@ import { gltfSampler } from './sampler.js';
import { gltfBufferView } from './buffer_view.js';
import { DracoDecoder } from '../ResourceLoader/draco.js';
import { GL } from '../Renderer/webgl.js';
import { mikktspace } from '../../app_web/src/main.js';

class gltfPrimitive extends GltfObject
{
constructor()
{
super();
this.attributes = {};
this.attributes = [];
this.targets = [];
this.indices = undefined;
this.material = undefined;
Expand Down Expand Up @@ -55,7 +53,6 @@ class gltfPrimitive extends GltfObject

if (this.extensions !== undefined)
{
// Decode Draco compressed mesh:
if (this.extensions.KHR_draco_mesh_compression !== undefined)
{
const dracoDecoder = new DracoDecoder();
Expand All @@ -72,15 +69,6 @@ class gltfPrimitive extends GltfObject
}
}

if (this.attributes.TANGENT === undefined)
{
console.info("Generating tangents using the MikkTSpace algorithm.");
console.time("Tangent generation");
this.unweld(gltf);
this.generateTangents(gltf);
console.timeEnd("Tangent generation");
}

// VERTEX ATTRIBUTES
for (const attribute of Object.keys(this.attributes))
{
Expand Down Expand Up @@ -734,131 +722,6 @@ class gltfPrimitive extends GltfObject
};

}

/**
* Unwelds this primitive, i.e. applies the index mapping.
* This is required for generating tangents using the MikkTSpace algorithm,
* because the same vertex might be mapped to different tangents.
* @param {*} gltf The glTF document.
*/
unweld(gltf) {
// Unwelding is an idempotent operation.
if (this.indices === undefined) {
return;
}

const indices = gltf.accessors[this.indices].getTypedView(gltf);

// Unweld attributes:
for (const [attribute, accessorIndex] of Object.entries(this.attributes)) {
this.attributes[attribute] = this.unweldAccessor(gltf, gltf.accessors[accessorIndex], indices);
}

// Unweld morph targets:
for (const target of this.targets) {
for (const [attribute, accessorIndex] of Object.entries(target)) {
target[attribute] = this.unweldAccessor(gltf, gltf.accessors[accessorIndex], indices);
}
}

// Dipose the indices:
this.indices = undefined;
}

/**
* Unwelds a single accessor. Used by {@link unweld}.
* @param {*} gltf The glTF document.
* @param {*} accessor The accessor to unweld.
* @param {*} typedIndexView A typed view of the indices.
* @returns A new accessor index containing the unwelded attribute.
*/
unweldAccessor(gltf, accessor, typedIndexView) {
const stride = accessor.getComponentCount(accessor.type);

const weldedAttribute = accessor.getTypedView(gltf);
const unweldedAttribute = new Float32Array(gltf.accessors[this.indices].count * stride);

// Apply the index mapping.
for (let i = 0; i < typedIndexView.length; i++) {
for (let j = 0; j < stride; j++) {
unweldedAttribute[i * stride + j] = weldedAttribute[typedIndexView[i] * stride + j];
}
}

// Create a new buffer and buffer view for the unwelded attribute:
const unweldedBuffer = new gltfBuffer();
unweldedBuffer.byteLength = unweldedAttribute.byteLength;
unweldedBuffer.buffer = unweldedAttribute.buffer;
gltf.buffers.push(unweldedBuffer);

const unweldedBufferView = new gltfBufferView();
unweldedBufferView.buffer = gltf.buffers.length - 1;
unweldedBufferView.byteLength = unweldedAttribute.byteLength;
unweldedBufferView.target = GL.ARRAY_BUFFER;
gltf.bufferViews.push(unweldedBufferView);

// Create a new accessor for the unwelded attribute:
const unweldedAccessor = new gltfAccessor();
unweldedAccessor.bufferView = gltf.bufferViews.length - 1;
unweldedAccessor.byteOffset = 0;
unweldedAccessor.count = typedIndexView.length;
unweldedAccessor.type = accessor.type;
unweldedAccessor.componentType = accessor.componentType;
unweldedAccessor.min = gltf.accessors[this.attributes.POSITION].min;
unweldedAccessor.max = gltf.accessors[this.attributes.POSITION].max;
gltf.accessors.push(unweldedAccessor);

// Update the primitive to use the unwelded attribute:
return gltf.accessors.length - 1;
}

generateTangents(gltf) {
const positions = gltf.accessors[this.attributes.POSITION].getTypedView(gltf);
const normals = gltf.accessors[this.attributes.NORMAL].getTypedView(gltf);
const texcoords = gltf.accessors[this.attributes.TEXCOORD_0].getTypedView(gltf);
for (let i = 0; i < positions.length; i += 3) {
mikktspace.writeFace(
positions[i], positions[i + 1], positions[i + 2],
normals[i], normals[i + 1], normals[i + 2],
texcoords[i], texcoords[i + 1]
);
}

mikktspace.generateTangents();

const tangents = new Float32Array(4 * positions.length / 3);
for (let i = 0; i < tangents.length; i++) {
let t = mikktspace.readTangent(i);
tangents[i] = t;
}

// Create a new buffer and buffer view for the tangents:
const tangentBuffer = new gltfBuffer();
tangentBuffer.byteLength = tangents.byteLength;
tangentBuffer.buffer = tangents.buffer;
gltf.buffers.push(tangentBuffer);

const tangentBufferView = new gltfBufferView();
tangentBufferView.buffer = gltf.buffers.length - 1;
tangentBufferView.byteLength = tangents.byteLength;
tangentBufferView.target = GL.ARRAY_BUFFER;
gltf.bufferViews.push(tangentBufferView);

// Create a new accessor for the tangents:
const tangentAccessor = new gltfAccessor();
tangentAccessor.bufferView = gltf.bufferViews.length - 1;
tangentAccessor.byteOffset = 0;
tangentAccessor.count = tangents.length / 4;
tangentAccessor.type = "VEC4";
tangentAccessor.componentType = GL.FLOAT;

// Update the primitive to use the tangents:
this.attributes.TANGENT = gltf.accessors.length;
gltf.accessors.push(tangentAccessor);

// Update the primitive to use the tangents:
this.attributes.TANGENT = gltf.accessors.length - 1;
}
}

export { gltfPrimitive };
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