forked from g3n/engine
/
loader.go
1214 lines (1022 loc) · 32.1 KB
/
loader.go
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// Copyright 2016 The G3N Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gltf
import (
"bytes"
"encoding/base64"
"encoding/binary"
"encoding/json"
"fmt"
"image"
"image/draw"
"io"
"io/ioutil"
"os"
"path/filepath"
"strings"
"unsafe"
"github.com/g3n/engine/animation"
"github.com/g3n/engine/camera"
"github.com/g3n/engine/core"
"github.com/g3n/engine/geometry"
"github.com/g3n/engine/gls"
"github.com/g3n/engine/graphic"
"github.com/g3n/engine/material"
"github.com/g3n/engine/math32"
"github.com/g3n/engine/texture"
)
// ParseJSON parses the glTF data from the specified JSON file
// and returns a pointer to the parsed structure.
func ParseJSON(filename string) (*GLTF, error) {
// Open file
f, err := os.Open(filename)
if err != nil {
return nil, err
}
// Extract path from file
path := filepath.Dir(filename)
defer f.Close()
return ParseJSONReader(f, path)
}
// ParseJSONReader parses the glTF JSON data from the specified reader
// and returns a pointer to the parsed structure
func ParseJSONReader(r io.Reader, path string) (*GLTF, error) {
g := new(GLTF)
g.path = path
dec := json.NewDecoder(r)
err := dec.Decode(g)
if err != nil {
return nil, err
}
// TODO Check for extensions used and extensions required
return g, nil
}
// ParseBin parses the glTF data from the specified binary file
// and returns a pointer to the parsed structure.
func ParseBin(filename string) (*GLTF, error) {
// Open file
f, err := os.Open(filename)
if err != nil {
return nil, err
}
// Extract path from file
path := filepath.Dir(filename)
defer f.Close()
return ParseBinReader(f, path)
}
// ParseBinReader parses the glTF data from the specified binary reader
// and returns a pointer to the parsed structure
func ParseBinReader(r io.Reader, path string) (*GLTF, error) {
// Read header
var header GLBHeader
err := binary.Read(r, binary.LittleEndian, &header)
if err != nil {
return nil, err
}
// Check magic and version
if header.Magic != GLBMagic {
return nil, fmt.Errorf("invalid GLB Magic field")
}
if header.Version < 2 {
return nil, fmt.Errorf("GLB version:%v not supported", header.Version)
}
// Read first chunk (JSON)
buf, err := readChunk(r, GLBJson)
if err != nil {
return nil, err
}
// Parse JSON into gltf object
bb := bytes.NewBuffer(buf)
gltf, err := ParseJSONReader(bb, path)
if err != nil {
return nil, err
}
// Check for and read second chunk (binary, optional)
data, err := readChunk(r, GLBBin)
if err != nil {
return nil, err
}
gltf.data = data
return gltf, nil
}
// readChunk reads a GLB chunk with the specified type and returns the data in a byte array.
func readChunk(r io.Reader, chunkType uint32) ([]byte, error) {
// Read chunk header
var chunk GLBChunk
err := binary.Read(r, binary.LittleEndian, &chunk)
if err != nil {
if err == io.EOF {
return nil, nil
}
return nil, err
}
// Check chunk type
if chunk.Type != chunkType {
return nil, fmt.Errorf("expected GLB chunk type [%v] but found [%v]", chunkType, chunk.Type)
}
// Read chunk data
data := make([]byte, chunk.Length)
err = binary.Read(r, binary.LittleEndian, &data)
if err != nil {
return nil, err
}
return data, nil
}
// LoadScene creates a parent Node which contains all nodes contained by
// the specified scene index from the GLTF Scenes array.
func (g *GLTF) LoadScene(sceneIdx int) (core.INode, error) {
// Check if provided scene index is valid
if sceneIdx < 0 || sceneIdx >= len(g.Scenes) {
return nil, fmt.Errorf("invalid scene index")
}
log.Debug("Loading Scene %d", sceneIdx)
sceneData := g.Scenes[sceneIdx]
scene := core.NewNode()
scene.SetName(sceneData.Name)
// Load all nodes
for _, ni := range sceneData.Nodes {
child, err := g.LoadNode(ni)
if err != nil {
return nil, err
}
scene.Add(child)
}
return scene, nil
}
// LoadNode creates and returns a new Node described by the specified index
// in the decoded GLTF Nodes array.
func (g *GLTF) LoadNode(nodeIdx int) (core.INode, error) {
// Check if provided node index is valid
if nodeIdx < 0 || nodeIdx >= len(g.Nodes) {
return nil, fmt.Errorf("invalid node index")
}
nodeData := g.Nodes[nodeIdx]
// Return cached if available
if nodeData.cache != nil {
log.Debug("Fetching Node %d (cached)", nodeIdx)
return nodeData.cache, nil
}
log.Debug("Loading Node %d", nodeIdx)
var in core.INode
var err error
// Check if the node is a Mesh (triangles, lines, etc...)
if nodeData.Mesh != nil {
in, err = g.LoadMesh(*nodeData.Mesh)
if err != nil {
return nil, err
}
if nodeData.Skin != nil {
mesh, ok := in.(*graphic.Mesh)
if !ok {
children := in.GetNode().Children()
if len(children) > 1 {
return nil, fmt.Errorf("skinning/rigging meshes with more than a single primitive is not supported")
}
mesh = children[0].(*graphic.Mesh)
}
// Create RiggedMesh
rm := graphic.NewRiggedMesh(mesh)
skeleton, err := g.LoadSkin(*nodeData.Skin)
if err != nil {
return nil, err
}
rm.SetSkeleton(skeleton)
in = rm
}
// Check if the node is Camera
} else if nodeData.Camera != nil {
in, err = g.LoadCamera(*nodeData.Camera)
if err != nil {
return nil, err
}
// Other cases, return empty node
} else {
log.Debug("Empty Node")
in = core.NewNode()
}
// Get *core.Node from core.INode
node := in.GetNode()
node.SetName(nodeData.Name)
// If defined, set node local transformation matrix
if nodeData.Matrix != nil {
node.SetMatrix((*math32.Matrix4)(nodeData.Matrix))
// Otherwise, check rotation, scale and translation fields
} else {
// Rotation quaternion
if nodeData.Rotation != nil {
node.SetQuaternion(nodeData.Rotation[0], nodeData.Rotation[1], nodeData.Rotation[2], nodeData.Rotation[3])
}
// Scale
if nodeData.Scale != nil {
node.SetScale(nodeData.Scale[0], nodeData.Scale[1], nodeData.Scale[2])
}
// Translation
if nodeData.Translation != nil {
node.SetPosition(nodeData.Translation[0], nodeData.Translation[1], nodeData.Translation[2])
}
}
// Cache node
g.Nodes[nodeIdx].cache = in
// Recursively load node children and add them to the parent
for _, ci := range nodeData.Children {
child, err := g.LoadNode(ci)
if err != nil {
return nil, err
}
node.Add(child)
}
return in, nil
}
// LoadSkin loads the skin with specified index.
func (g *GLTF) LoadSkin(skinIdx int) (*graphic.Skeleton, error) {
// Check if provided skin index is valid
if skinIdx < 0 || skinIdx >= len(g.Skins) {
return nil, fmt.Errorf("invalid skin index")
}
skinData := g.Skins[skinIdx]
// Return cached if available
if skinData.cache != nil {
log.Debug("Fetching Skin %d (cached)", skinIdx)
return skinData.cache, nil
}
log.Debug("Loading Skin %d", skinIdx)
// Create Skeleton and set it on Rigged mesh
skeleton := graphic.NewSkeleton()
// Load inverseBindMatrices
ibmData, err := g.loadAccessorF32(skinData.InverseBindMatrices, "ibm", []string{MAT4}, []int{FLOAT})
if err != nil {
return nil, err
}
// Add bones
for i := range skinData.Joints {
jointNode, err := g.LoadNode(skinData.Joints[i])
if err != nil {
return nil, err
}
var ibm math32.Matrix4
ibmData.GetMatrix4(16*i, &ibm)
skeleton.AddBone(jointNode.GetNode(), &ibm)
}
// Cache skin
g.Skins[skinIdx].cache = skeleton
return skeleton, nil
}
// LoadAnimationByName loads the animations with specified name.
// If there are multiple animations with the same name it loads the first occurrence.
func (g *GLTF) LoadAnimationByName(animName string) (*animation.Animation, error) {
for i := range g.Animations {
if g.Animations[i].Name == animName {
return g.LoadAnimation(i)
}
}
return nil, fmt.Errorf("could not find animation named %v", animName)
}
// LoadAnimation creates an Animation for the specified
// animation index from the GLTF Animations array.
func (g *GLTF) LoadAnimation(animIdx int) (*animation.Animation, error) {
// Check if provided animation index is valid
if animIdx < 0 || animIdx >= len(g.Animations) {
return nil, fmt.Errorf("invalid animation index")
}
log.Debug("Loading Animation %d", animIdx)
animData := g.Animations[animIdx]
anim := animation.NewAnimation()
anim.SetName(animData.Name)
for i := 0; i < len(animData.Channels); i++ {
chData := animData.Channels[i]
target := chData.Target
sampler := animData.Samplers[chData.Sampler]
node, err := g.LoadNode(target.Node)
if err != nil {
return nil, err
}
var validTypes []string
var validComponentTypes []int
var ch animation.IChannel
if target.Path == "translation" {
validTypes = []string{VEC3}
validComponentTypes = []int{FLOAT}
ch = animation.NewPositionChannel(node)
} else if target.Path == "rotation" {
validTypes = []string{VEC4}
validComponentTypes = []int{FLOAT, BYTE, UNSIGNED_BYTE, SHORT, UNSIGNED_SHORT}
ch = animation.NewRotationChannel(node)
} else if target.Path == "scale" {
validTypes = []string{VEC3}
validComponentTypes = []int{FLOAT}
ch = animation.NewScaleChannel(node)
} else if target.Path == "weights" {
validTypes = []string{SCALAR}
validComponentTypes = []int{FLOAT, BYTE, UNSIGNED_BYTE, SHORT, UNSIGNED_SHORT}
children := node.GetNode().Children()
if len(children) > 1 {
return nil, fmt.Errorf("animating meshes with more than a single primitive is not supported")
}
morphGeom := children[0].(graphic.IGraphic).IGeometry().(*geometry.MorphGeometry)
ch = animation.NewMorphChannel(morphGeom)
}
// TODO what if Input and Output accessors are interleaved? probably de-interleave in these 2 cases
keyframes, err := g.loadAccessorF32(sampler.Input, "Input", []string{SCALAR}, []int{FLOAT})
if err != nil {
return nil, err
}
values, err := g.loadAccessorF32(sampler.Output, "Output", validTypes, validComponentTypes)
if err != nil {
return nil, err
}
ch.SetBuffers(keyframes, values)
ch.SetInterpolationType(animation.InterpolationType(sampler.Interpolation))
anim.AddChannel(ch)
}
return anim, nil
}
// LoadCamera creates and returns a Camera Node
// from the specified GLTF.Cameras index.
func (g *GLTF) LoadCamera(camIdx int) (core.INode, error) {
// Check if provided camera index is valid
if camIdx < 0 || camIdx >= len(g.Cameras) {
return nil, fmt.Errorf("invalid camera index")
}
log.Debug("Loading Camera %d", camIdx)
camData := g.Cameras[camIdx]
if camData.Type == "perspective" {
desc := camData.Perspective
fov := 360 * (desc.Yfov) / 2 * math32.Pi
aspect := float32(2) // TODO how to get the current aspect ratio of the viewport from here ?
if desc.AspectRatio != nil {
aspect = *desc.AspectRatio
}
far := float32(2E6)
if desc.Zfar != nil {
far = *desc.Zfar
}
cam := camera.NewPerspective(fov, aspect, desc.Znear, far)
return cam, nil
}
if camData.Type == "orthographic" {
desc := camData.Orthographic
cam := camera.NewOrthographic(desc.Xmag/-2, desc.Xmag/2, desc.Ymag/2, desc.Ymag/-2, desc.Znear, desc.Zfar)
return cam, nil
}
return nil, fmt.Errorf("unsupported camera type: %s", camData.Type)
}
// LoadMesh creates and returns a Graphic Node (graphic.Mesh, graphic.Lines, graphic.Points, etc)
// from the specified GLTF.Meshes index.
func (g *GLTF) LoadMesh(meshIdx int) (core.INode, error) {
// Check if provided mesh index is valid
if meshIdx < 0 || meshIdx >= len(g.Meshes) {
return nil, fmt.Errorf("invalid mesh index")
}
meshData := g.Meshes[meshIdx]
// Return cached if available
if meshData.cache != nil {
// TODO CLONE/REINSTANCE INSTEAD
//log.Debug("Instancing Mesh %d (from cached)", meshIdx)
//return meshData.cache, nil
}
log.Debug("Loading Mesh %d", meshIdx)
var err error
// Create container node
var meshNode core.INode
meshNode = core.NewNode()
for i := 0; i < len(meshData.Primitives); i++ {
// Get primitive information
p := meshData.Primitives[i]
// Indexed Geometry
indices := math32.NewArrayU32(0, 0)
if p.Indices != nil {
pidx, err := g.loadIndices(*p.Indices)
if err != nil {
return nil, err
}
indices = append(indices, pidx...)
} else {
// Non-indexed primitive
// indices array stay empty
}
// Load primitive material
var grMat material.IMaterial
if p.Material != nil {
grMat, err = g.LoadMaterial(*p.Material)
if err != nil {
return nil, err
}
} else {
grMat = g.newDefaultMaterial()
}
// Create geometry
var igeom geometry.IGeometry
igeom = geometry.NewGeometry()
geom := igeom.GetGeometry()
err = g.loadAttributes(geom, p.Attributes, indices)
if err != nil {
return nil, err
}
// If primitive has targets then the geometry should be a morph geometry
if len(p.Targets) > 0 {
morphGeom := geometry.NewMorphGeometry(geom)
// TODO Load morph target names if present in extras under "targetNames"
// TODO Update morph target weights if present in Mesh.Weights
// Load targets
for i := range p.Targets {
tGeom := geometry.NewGeometry()
attributes := p.Targets[i]
err = g.loadAttributes(tGeom, attributes, indices)
if err != nil {
return nil, err
}
morphGeom.AddMorphTargetDeltas(tGeom)
}
igeom = morphGeom
}
// Default mode is 4 (TRIANGLES)
mode := TRIANGLES
if p.Mode != nil {
mode = *p.Mode
}
// Create Mesh
// TODO materials for LINES, etc need to be different...
if mode == TRIANGLES {
meshNode.GetNode().Add(graphic.NewMesh(igeom, grMat))
} else if mode == LINES {
meshNode.GetNode().Add(graphic.NewLines(igeom, grMat))
} else if mode == LINE_STRIP {
meshNode.GetNode().Add(graphic.NewLineStrip(igeom, grMat))
} else if mode == POINTS {
meshNode.GetNode().Add(graphic.NewPoints(igeom, grMat))
} else {
return nil, fmt.Errorf("unsupported primitive:%v", mode)
}
}
children := meshNode.GetNode().Children()
if len(children) == 1 {
meshNode = children[0]
}
// Cache mesh
g.Meshes[meshIdx].cache = meshNode
return meshNode, nil
}
// loadAttributes loads the provided list of vertex attributes as VBO(s) into the specified geometry.
func (g *GLTF) loadAttributes(geom *geometry.Geometry, attributes map[string]int, indices math32.ArrayU32) error {
// Indices of buffer views
interleavedVBOs := make(map[int]*gls.VBO, 0)
// Load primitive attributes
for name, aci := range attributes {
accessor := g.Accessors[aci]
// Validate that accessor is compatible with attribute
err := g.validateAccessorAttribute(accessor, name)
if err != nil {
return err
}
// Load data and add it to geometry's VBO
if g.isInterleaved(accessor) {
bvIdx := *accessor.BufferView
// Check if we already loaded this buffer view
vbo, ok := interleavedVBOs[bvIdx]
if ok {
// Already created VBO for this buffer view
// Add attribute with correct byteOffset
g.addAttributeToVBO(vbo, name, uint32(*accessor.ByteOffset))
} else {
// Load data and create vbo
buf, err := g.loadBufferView(bvIdx)
if err != nil {
return err
}
//
// TODO: BUG HERE
// If buffer view has accessors with different component type then this will have a read alignment problem!
//
data, err := g.bytesToArrayF32(buf, accessor.ComponentType, accessor.Count*TypeSizes[accessor.Type])
if err != nil {
return err
}
vbo := gls.NewVBO(data)
g.addAttributeToVBO(vbo, name, 0)
// Save reference to VBO keyed by index of the buffer view
interleavedVBOs[bvIdx] = vbo
// Add VBO to geometry
geom.AddVBO(vbo)
}
} else {
buf, err := g.loadAccessorBytes(accessor)
if err != nil {
return err
}
data, err := g.bytesToArrayF32(buf, accessor.ComponentType, accessor.Count*TypeSizes[accessor.Type])
if err != nil {
return err
}
vbo := gls.NewVBO(data)
g.addAttributeToVBO(vbo, name, 0)
// Add VBO to geometry
geom.AddVBO(vbo)
}
}
// Set indices
if len(indices) > 0 {
geom.SetIndices(indices)
}
return nil
}
// loadIndices loads the indices stored in the specified accessor.
func (g *GLTF) loadIndices(ai int) (math32.ArrayU32, error) {
return g.loadAccessorU32(ai, "indices", []string{SCALAR}, []int{UNSIGNED_BYTE, UNSIGNED_SHORT, UNSIGNED_INT}) // TODO verify that it's ELEMENT_ARRAY_BUFFER
}
// addAttributeToVBO adds the appropriate attribute to the provided vbo based on the glTF attribute name.
func (g *GLTF) addAttributeToVBO(vbo *gls.VBO, attribName string, byteOffset uint32) {
aType, ok := AttributeName[attribName]
if !ok {
log.Warn(fmt.Sprintf("Attribute %v is not supported!", attribName))
return
}
vbo.AddAttribOffset(aType, byteOffset)
}
// validateAccessorAttribute validates the specified accessor for the given attribute name.
func (g *GLTF) validateAccessorAttribute(ac Accessor, attribName string) error {
parts := strings.Split(attribName, "_")
semantic := parts[0]
usage := "attribute " + attribName
if attribName == "POSITION" {
return g.validateAccessor(ac, usage, []string{VEC3}, []int{FLOAT})
} else if attribName == "NORMAL" {
return g.validateAccessor(ac, usage, []string{VEC3}, []int{FLOAT})
} else if attribName == "TANGENT" {
// Note that morph targets only support VEC3 whereas normal attributes only support VEC4.
return g.validateAccessor(ac, usage, []string{VEC3, VEC4}, []int{FLOAT})
} else if semantic == "TEXCOORD" {
return g.validateAccessor(ac, usage, []string{VEC2}, []int{FLOAT, UNSIGNED_BYTE, UNSIGNED_SHORT})
} else if semantic == "COLOR" {
return g.validateAccessor(ac, usage, []string{VEC3, VEC4}, []int{FLOAT, UNSIGNED_BYTE, UNSIGNED_SHORT})
} else if semantic == "JOINTS" {
return g.validateAccessor(ac, usage, []string{VEC4}, []int{UNSIGNED_BYTE, UNSIGNED_SHORT})
} else if semantic == "WEIGHTS" {
return g.validateAccessor(ac, usage, []string{VEC4}, []int{FLOAT, UNSIGNED_BYTE, UNSIGNED_SHORT})
} else {
return fmt.Errorf("attribute %v is not supported", attribName)
}
}
// validateAccessor validates the specified attribute accessor with the specified allowed types and component types.
func (g *GLTF) validateAccessor(ac Accessor, usage string, validTypes []string, validComponentTypes []int) error {
// Validate accessor type
validType := false
for _, vType := range validTypes {
if ac.Type == vType {
validType = true
break
}
}
if !validType {
return fmt.Errorf("invalid Accessor.Type %v for %s", ac.Type, usage)
}
// Validate accessor component type
validComponentType := false
for _, vComponentType := range validComponentTypes {
if ac.ComponentType == vComponentType {
validComponentType = true
break
}
}
if !validComponentType {
return fmt.Errorf("invalid Accessor.ComponentType %v for %s", ac.ComponentType, usage)
}
return nil
}
// newDefaultMaterial creates and returns the default material.
func (g *GLTF) newDefaultMaterial() material.IMaterial {
return material.NewStandard(&math32.Color{0.5, 0.5, 0.5})
}
// LoadMaterial creates and returns a new material based on the material data with the specified index.
func (g *GLTF) LoadMaterial(matIdx int) (material.IMaterial, error) {
// Check if provided material index is valid
if matIdx < 0 || matIdx >= len(g.Materials) {
return nil, fmt.Errorf("invalid material index")
}
matData := g.Materials[matIdx]
// Return cached if available
if matData.cache != nil {
log.Debug("Fetching Material %d (cached)", matIdx)
return matData.cache, nil
}
log.Debug("Loading Material %d", matIdx)
var err error
var imat material.IMaterial
// Check for material extensions
if matData.Extensions != nil {
for ext, extData := range matData.Extensions {
if ext == KhrMaterialsCommon {
imat, err = g.loadMaterialCommon(extData)
} else if ext == KhrMaterialsUnlit {
//imat, err = g.loadMaterialUnlit(matData, extData)
//} else if ext == KhrMaterialsPbrSpecularGlossiness {
} else {
return nil, fmt.Errorf("unsupported extension:%s", ext)
}
}
} else {
// Material is normally PBR
imat, err = g.loadMaterialPBR(&matData)
}
// Cache material
g.Materials[matIdx].cache = imat
return imat, err
}
// LoadTexture loads the texture specified by its index.
func (g *GLTF) LoadTexture(texIdx int) (*texture.Texture2D, error) {
// Check if provided texture index is valid
if texIdx < 0 || texIdx >= len(g.Textures) {
return nil, fmt.Errorf("invalid texture index")
}
texData := g.Textures[texIdx]
// NOTE: Textures can't be cached because they have their own uniforms
log.Debug("Loading Texture %d", texIdx)
// Load texture image
img, err := g.LoadImage(texData.Source)
if err != nil {
return nil, err
}
tex := texture.NewTexture2DFromRGBA(img)
// Get sampler and apply texture parameters
if texData.Sampler != nil {
err = g.applySampler(*texData.Sampler, tex)
if err != nil {
return nil, err
}
}
return tex, nil
}
// applySamplers applies the specified Sampler to the provided texture.
func (g *GLTF) applySampler(samplerIdx int, tex *texture.Texture2D) error {
log.Debug("Applying Sampler %d", samplerIdx)
// Check if provided sampler index is valid
if samplerIdx < 0 || samplerIdx >= len(g.Samplers) {
return fmt.Errorf("invalid sampler index")
}
sampler := g.Samplers[samplerIdx]
// Magnification filter
magFilter := gls.LINEAR
if sampler.MagFilter != nil {
magFilter = *sampler.MagFilter
}
tex.SetMagFilter(uint32(magFilter))
// Minification filter
minFilter := gls.LINEAR_MIPMAP_LINEAR
if sampler.MinFilter != nil {
minFilter = *sampler.MinFilter
}
tex.SetMinFilter(uint32(minFilter))
// S coordinate wrapping mode
wrapS := gls.REPEAT
if sampler.WrapS != nil {
wrapS = *sampler.WrapS
}
tex.SetWrapS(uint32(wrapS))
// T coordinate wrapping mode
wrapT := gls.REPEAT
if sampler.WrapT != nil {
wrapT = *sampler.WrapT
}
tex.SetWrapT(uint32(wrapT))
return nil
}
// LoadImage loads the image specified by the index of GLTF.Images.
// Image can be loaded from binary chunk file or data URI or external file..
func (g *GLTF) LoadImage(imgIdx int) (*image.RGBA, error) {
// Check if provided image index is valid
if imgIdx < 0 || imgIdx >= len(g.Images) {
return nil, fmt.Errorf("invalid image index")
}
imgData := g.Images[imgIdx]
// Return cached if available
if imgData.cache != nil {
log.Debug("Fetching Image %d (cached)", imgIdx)
return imgData.cache, nil
}
log.Debug("Loading Image %d", imgIdx)
var data []byte
var err error
// If Uri is empty, load image from GLB binary chunk
if imgData.Uri == "" {
if imgData.BufferView == nil {
return nil, fmt.Errorf("image has empty URI and no BufferView")
}
data, err = g.loadBufferView(*imgData.BufferView)
} else if isDataURL(imgData.Uri) {
// Checks if image URI is data URL
data, err = loadDataURL(imgData.Uri)
} else {
// Load image data from file
data, err = g.loadFileBytes(imgData.Uri)
}
if err != nil {
return nil, err
}
// Decodes image data
bb := bytes.NewBuffer(data)
img, _, err := image.Decode(bb)
if err != nil {
return nil, err
}
// Converts image to RGBA format
rgba := image.NewRGBA(img.Bounds())
if rgba.Stride != rgba.Rect.Size().X*4 {
return nil, fmt.Errorf("unsupported stride")
}
draw.Draw(rgba, rgba.Bounds(), img, image.Point{0, 0}, draw.Src)
// Cache image
g.Images[imgIdx].cache = rgba
return rgba, nil
}
// bytesToArrayU32 converts a byte array to ArrayU32.
func (g *GLTF) bytesToArrayU32(data []byte, componentType, count int) (math32.ArrayU32, error) {
// If component is UNSIGNED_INT nothing to do
if componentType == UNSIGNED_INT {
arr := (*[1 << 30]uint32)(unsafe.Pointer(&data[0]))[:count]
return math32.ArrayU32(arr), nil
}
// Converts UNSIGNED_SHORT or SHORT to UNSIGNED_INT
if componentType == UNSIGNED_SHORT || componentType == SHORT {
out := math32.NewArrayU32(count, count)
for i := 0; i < count; i++ {
out[i] = uint32(data[i*2]) + uint32(data[i*2+1])*256
}
return out, nil
}
// Converts UNSIGNED_BYTE or BYTE to UNSIGNED_INT
if componentType == UNSIGNED_BYTE || componentType == BYTE {
out := math32.NewArrayU32(count, count)
for i := 0; i < count; i++ {
out[i] = uint32(data[i])
}
return out, nil
}
return nil, fmt.Errorf("unsupported Accessor ComponentType:%v", componentType)
}
// bytesToArrayF32 converts a byte array to ArrayF32.
func (g *GLTF) bytesToArrayF32(data []byte, componentType, count int) (math32.ArrayF32, error) {
// If component is UNSIGNED_INT nothing to do
if componentType == UNSIGNED_INT {
arr := (*[1 << 30]float32)(unsafe.Pointer(&data[0]))[:count]
return math32.ArrayF32(arr), nil
}
// Converts UNSIGNED_SHORT or SHORT to UNSIGNED_INT
if componentType == UNSIGNED_SHORT || componentType == SHORT {
out := math32.NewArrayF32(count, count)
for i := 0; i < count; i++ {
out[i] = float32(data[i*2]) + float32(data[i*2+1])*256
}
return out, nil
}
// Converts UNSIGNED_BYTE or BYTE to UNSIGNED_INT
if componentType == UNSIGNED_BYTE || componentType == BYTE {
out := math32.NewArrayF32(count, count)
for i := 0; i < count; i++ {
out[i] = float32(data[i])
}
return out, nil
}
return (*[1 << 30]float32)(unsafe.Pointer(&data[0]))[:count], nil
}
// loadAccessorU32 loads data from the specified accessor and performs validation of the Type and ComponentType.
func (g *GLTF) loadAccessorU32(ai int, usage string, validTypes []string, validComponentTypes []int) (math32.ArrayU32, error) {
// Get Accessor for the specified index
ac := g.Accessors[ai]
if ac.BufferView == nil {
return nil, fmt.Errorf("accessor.BufferView == nil NOT SUPPORTED YET") // TODO
}
// Validate type and component type
err := g.validateAccessor(ac, usage, validTypes, validComponentTypes)
if err != nil {
return nil, err
}
// Load bytes
data, err := g.loadAccessorBytes(ac)
if err != nil {
return nil, err
}
return g.bytesToArrayU32(data, ac.ComponentType, ac.Count*TypeSizes[ac.Type])
}
// loadAccessorF32 loads data from the specified accessor and performs validation of the Type and ComponentType.
func (g *GLTF) loadAccessorF32(ai int, usage string, validTypes []string, validComponentTypes []int) (math32.ArrayF32, error) {
// Get Accessor for the specified index
ac := g.Accessors[ai]
if ac.BufferView == nil {
return nil, fmt.Errorf("accessor.BufferView == nil NOT SUPPORTED YET") // TODO
}
// Validate type and component type
err := g.validateAccessor(ac, usage, validTypes, validComponentTypes)
if err != nil {
return nil, err
}
// Load bytes
data, err := g.loadAccessorBytes(ac)
if err != nil {
return nil, err
}
return g.bytesToArrayF32(data, ac.ComponentType, ac.Count*TypeSizes[ac.Type])
}
// loadAccessorBytes returns the base byte array used by an accessor.
func (g *GLTF) loadAccessorBytes(ac Accessor) ([]byte, error) {
// Get the Accessor's BufferView
if ac.BufferView == nil {
return nil, fmt.Errorf("accessor.BufferView == nil NOT SUPPORTED YET") // TODO
}
bv := g.BufferViews[*ac.BufferView]
// Loads data from associated BufferView
data, err := g.loadBufferView(*ac.BufferView)
if err != nil {
return nil, err
}
// Accessor offset into BufferView
offset := 0
if ac.ByteOffset != nil {
offset = *ac.ByteOffset
}
data = data[offset:]
// TODO check if interleaved and de-interleave if necessary?
// Calculate the size in bytes of a complete attribute
itemSize := TypeSizes[ac.Type]
itemBytes := int(gls.FloatSize) * itemSize
// If the BufferView stride is equal to the item size, the buffer is not interleaved
if (bv.ByteStride != nil) && (*bv.ByteStride != itemBytes) {
// BufferView data is interleaved, de-interleave