mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
328 lines
9.5 KiB
Go
328 lines
9.5 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"fmt"
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"io"
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)
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// U3DMesh 保存静态三角面和线段的共享属性数组，索引对应原始作者几何
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type U3DMesh struct {
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Name string
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ExcludeNormals bool
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Positions, Normals [][3]float32
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Diffuse, Specular, TextureCoordinates [][4]float32
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Shadings []U3DShading
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Faces []U3DFace
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Lines []U3DLine
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Quality [3]uint32
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InverseQuantization [5]float32
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NormalCrease, NormalUpdate, NormalTolerance float32
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}
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// U3DShading 描述图元使用的颜色及纹理坐标，纹理维数依层排列
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type U3DShading struct {
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Attributes uint32
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TextureDimensions []uint32
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OriginalID uint32
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}
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// U3DFace 保存着色描述索引和依原始绕序排列的三个角点
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type U3DFace struct {
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Shading uint32
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Corners [3]U3DCorner
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}
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// U3DLine 保存着色描述及线段两端的独立属性索引
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type U3DLine struct {
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Shading uint32
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Corners [2]U3DCorner
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}
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// U3DCorner 保存各属性索引，未启用的属性不可用于访问数组
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type U3DCorner struct {
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Position, Normal, Diffuse, Specular uint32
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Texture [8]uint32
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}
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// u3dMeshDeclaration 保存基础网格或线集声明及续块接收状态
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type u3dMeshDeclaration struct {
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mesh U3DMesh
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counts [7]uint32
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decoded bool
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line *u3dLineState
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}
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// primitive 访问三角面或线段的着色编号和角点，不复制属性数组
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// 入参: index 图元下标，三角面在前，线段在后
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// 返回: uint32 着色编号, []U3DCorner 只读角点
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func (m *U3DMesh) primitive(index int) (uint32, []U3DCorner) {
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if index < len(m.Faces) {
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return m.Faces[index].Shading, m.Faces[index].Corners[:]
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}
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line := &m.Lines[index-len(m.Faces)]
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return line.Shading, line.Corners[:]
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}
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// meshDeclaration 读取完整基础网格声明，不将渐进网格当作完整模型
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// 入参: r 字段读取器, name 网格名
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// 返回: error 结构、能力或预算错误
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func (d *u3dDecoder) meshDeclaration(r *u3dValues, name string) error {
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if _, exists := d.meshes[name]; exists {
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return fmt.Errorf("duplicate U3D mesh %q", name)
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}
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index, attributes := r.u32(), r.u32()
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if index != 0 || attributes > 1 {
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return fmt.Errorf("invalid U3D mesh declaration")
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}
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decl := &u3dMeshDeclaration{mesh: U3DMesh{Name: name, ExcludeNormals: attributes == 1}}
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for index := range decl.counts {
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decl.counts[index] = r.u32()
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}
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if err := d.meshShadings(r, decl); err != nil {
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return err
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}
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minimum, maximum := r.u32(), r.u32()
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for index := range decl.mesh.Quality {
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decl.mesh.Quality[index] = r.u32()
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}
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for index := range decl.mesh.InverseQuantization {
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decl.mesh.InverseQuantization[index] = r.f32()
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}
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decl.mesh.NormalCrease, decl.mesh.NormalUpdate, decl.mesh.NormalTolerance = r.f32(), r.f32(), r.f32()
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bones := r.u32()
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if r.err != nil {
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return r.err
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}
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if minimum > maximum || maximum != decl.counts[1] {
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return fmt.Errorf("invalid U3D mesh resolution")
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}
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if minimum != maximum || bones != 0 {
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return fmt.Errorf("unsupported U3D progressive or skeletal mesh")
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}
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if minimum == 0 {
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for _, count := range decl.counts[:6] {
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if count != 0 {
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return fmt.Errorf("invalid U3D empty mesh")
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}
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}
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}
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d.meshes[name] = decl
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d.meshOrder = append(d.meshOrder, name)
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return nil
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}
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// meshShadings 读取三角面与线集共用的着色描述
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// 入参: r 字段读取器, decl 资源声明
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// 返回: error 结构或预算错误
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func (d *u3dDecoder) meshShadings(r *u3dValues, decl *u3dMeshDeclaration) error {
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if r.err != nil {
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return r.err
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}
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count := decl.counts[6]
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if uint64(count) > uint64(len(r.data)-r.pos)/12 {
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return io.ErrUnexpectedEOF
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}
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if err := d.reserve(uint64(count), 40); err != nil {
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return err
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}
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decl.mesh.Shadings = make([]U3DShading, int(count))
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for index := range decl.mesh.Shadings {
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shading := &decl.mesh.Shadings[index]
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shading.Attributes = r.u32()
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layers := r.u32()
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if shading.Attributes > 3 {
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return fmt.Errorf("invalid U3D shading attributes")
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}
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if layers > 8 {
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return fmt.Errorf("unsupported U3D texture layer count")
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}
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if err := d.reserve(uint64(layers), 4); err != nil {
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return err
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}
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shading.TextureDimensions = make([]uint32, int(layers))
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for layer := range shading.TextureDimensions {
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dimension := r.u32()
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if dimension < 1 || dimension > 4 {
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return fmt.Errorf("invalid U3D texture coordinate dimension")
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}
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shading.TextureDimensions[layer] = dimension
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}
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shading.OriginalID = r.u32()
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}
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return r.err
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}
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// baseMesh 读取基础顶点与压缩面索引，保留各角点的独立属性
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// 入参: r 字段读取器, name 网格名
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// 返回: error 结构、能力、预算或取消错误
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func (d *u3dDecoder) baseMesh(r *u3dValues, name string) error {
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decl := d.meshes[name]
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if decl == nil || decl.line != nil || decl.decoded || decl.counts[1] == 0 || r.u32() != 0 {
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return fmt.Errorf("invalid U3D base mesh reference")
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}
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var counts [6]uint32
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for index := range counts {
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counts[index] = r.u32()
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if counts[index] != decl.counts[index] {
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return fmt.Errorf("U3D base mesh does not match full resolution declaration")
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}
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}
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if r.err != nil {
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return r.err
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}
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literalBytes := (uint64(counts[1])+uint64(counts[2]))*12 + (uint64(counts[3])+uint64(counts[4])+uint64(counts[5]))*16
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if literalBytes > uint64(len(r.data)-r.pos) {
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return io.ErrUnexpectedEOF
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}
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if err := d.reserve(literalBytes, 1); err != nil {
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return err
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}
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if err := d.reserve(uint64(counts[0]), 148); err != nil {
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return err
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}
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mesh := &decl.mesh
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mesh.Positions, mesh.Normals = make([][3]float32, int(counts[1])), make([][3]float32, int(counts[2]))
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mesh.Diffuse, mesh.Specular, mesh.TextureCoordinates = make([][4]float32, int(counts[3])), make([][4]float32, int(counts[4])), make([][4]float32, int(counts[5]))
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for _, array := range [][][3]float32{mesh.Positions, mesh.Normals} {
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for index := range array {
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if index%1024 == 0 {
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if r.err != nil {
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return r.err
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}
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if err := d.ctx.Err(); err != nil {
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return err
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}
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}
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for component := range array[index] {
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array[index][component] = r.f32()
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}
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}
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}
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for _, array := range [][][4]float32{mesh.Diffuse, mesh.Specular, mesh.TextureCoordinates} {
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for index := range array {
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if index%1024 == 0 {
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if r.err != nil {
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return r.err
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}
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if err := d.ctx.Err(); err != nil {
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return err
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}
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}
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for component := range array[index] {
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array[index][component] = r.f32()
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}
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}
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}
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if r.err != nil {
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return r.err
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}
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mesh.Faces = make([]U3DFace, int(counts[0]))
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var histogram u3dHistogram
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var compressed *u3dBits
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if !d.plain && counts[0] != 0 {
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if err := d.reserve(1, 1<<20); err != nil {
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return err
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}
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compressed = newU3DBits(r.data[r.pos:])
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}
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readIndex := func(count uint32) (uint32, error) {
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var value uint32
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if compressed == nil {
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value = r.u32()
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} else {
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value = compressed.index(count)
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if compressed.err != nil {
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return 0, compressed.err
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}
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}
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if r.err != nil {
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return 0, r.err
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}
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if value >= count {
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return 0, fmt.Errorf("invalid U3D corner index")
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}
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return value, nil
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}
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for index := range mesh.Faces {
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if index%256 == 0 {
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if err := d.ctx.Err(); err != nil {
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return err
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}
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}
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face := &mesh.Faces[index]
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if compressed == nil {
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face.Shading = r.u32()
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} else {
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face.Shading = compressed.dynamic(&histogram)
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if compressed.err != nil {
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return compressed.err
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}
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}
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if r.err != nil {
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return r.err
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}
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if uint64(face.Shading) >= uint64(len(mesh.Shadings)) {
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return fmt.Errorf("invalid U3D face shading index")
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}
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shading := &mesh.Shadings[face.Shading]
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for cornerIndex := range face.Corners {
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corner := &face.Corners[cornerIndex]
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var err error
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if corner.Position, err = readIndex(counts[1]); err != nil {
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return err
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}
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if !mesh.ExcludeNormals {
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if corner.Normal, err = readIndex(counts[2]); err != nil {
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return err
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}
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}
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if shading.Attributes&1 != 0 {
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if corner.Diffuse, err = readIndex(counts[3]); err != nil {
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return err
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}
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}
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if shading.Attributes&2 != 0 {
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if corner.Specular, err = readIndex(counts[4]); err != nil {
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return err
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}
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}
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for layer := range shading.TextureDimensions {
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if corner.Texture[layer], err = readIndex(counts[5]); err != nil {
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return err
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}
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}
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}
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}
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if compressed != nil {
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if compressed.pos > uint64(len(compressed.data))*8 {
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return io.ErrUnexpectedEOF
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}
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if compressed.u32() != 0 {
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return fmt.Errorf("invalid U3D compression flush")
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}
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if compressed.err != nil {
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return compressed.err
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}
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if (compressed.pos-16+7)/8 != uint64(len(compressed.data)) {
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return fmt.Errorf("unexpected U3D compressed block data: decoded %d bits, stored %d bytes", compressed.pos-16, len(compressed.data))
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}
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r.pos = len(r.data)
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}
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decl.decoded = true
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return r.done()
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}
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