gwob

README

gwob

gwob - Pure Go Golang parser for Wavefront .OBJ 3D geometry file format

Install

Install with Go Modules (Go 1.11 or higher)

git clone https://github.com/udhos/gwob
cd gwob
go install

Install without Go Modules (Go before 1.11)

go get github.com/udhos/gwob
cd ~/go/src/github.com/udhos/gwob
go install github.com/udhos/gwob

Usage

Import the package in your Go program:

import "github.com/udhos/gwob"

Example:

// Error handling omitted for simplicity.

import "github.com/udhos/gwob"

options := &gwob.ObjParserOptions{} // parser options

o, errObj := gwob.NewObjFromFile("gopher.obj", options) // parse/load OBJ

// Scan OBJ groups
for _, g := range o.Groups {
    // ...
}

Example

Run the example:

cd example
go run main.go

You can supply a custom input OBJ by setting the env var INPUT:

INPUT=gopher.obj go run main.go

If you specify any command line argument, the OBJ will be dumped to stdout:

go run main.go d

See directory example.

Documentation

See the GoDoc documentation.

Documentation

Overview

Package gwob is a pure Go parser for Wavefront .OBJ 3D geometry file format.

Example:

// Error handling omitted for simplicity.

import "github.com/udhos/gwob"

options := &gwob.ObjParserOptions{} // parser options

o, errObj := gwob.NewObjFromFile("gopher.obj", options) // parse

// Scan OBJ groups
for _, g := range o.Groups {
    // snip
}

See also: https://github.com/udhos/gwob

Index

• Constants
• type Group
• type Material
• type MaterialLib
  • func NewMaterialLib() MaterialLib
  • func ReadMaterialLibFromBuf(buf []byte, options *ObjParserOptions) (MaterialLib, error)
  • func ReadMaterialLibFromFile(filename string, options *ObjParserOptions) (MaterialLib, error)
  • func ReadMaterialLibFromReader(rd io.Reader, options *ObjParserOptions) (MaterialLib, error)
  • func ReadMaterialLibFromStringReader(rd StringReader, options *ObjParserOptions) (MaterialLib, error)
• type Obj
  • func NewObjFromBuf(objName string, buf []byte, options *ObjParserOptions) (*Obj, error)
  • func NewObjFromFile(filename string, options *ObjParserOptions) (*Obj, error)
  • func NewObjFromReader(objName string, rd io.Reader, options *ObjParserOptions) (*Obj, error)
  • func NewObjFromStringReader(objName string, rd StringReader, options *ObjParserOptions) (*Obj, error)
  • func NewObjFromVertex(coord []float32, indices []int) (*Obj, error)
  • func (o *Obj) Coord64(i int) float64
  • func (o *Obj) NumberOfElements() int
  • func (o *Obj) ToFile(filename string) error
  • func (o *Obj) ToWriter(w io.Writer) error
  • func (o *Obj) VertexCoordinates(stride int) (float32, float32, float32)
• type ObjParserOptions
• type StringReader

Constants

const (
	ErrFatal    = true  // ErrFatal means fatal stream error
	ErrNonFatal = false // ErrNonFatal means non-fatal parsing error
)

Internal parsing error

Types

type Group

type Group struct {
	Name       string
	Smooth     int
	Usemtl     string
	IndexBegin int
	IndexCount int
}

Group holds parser result for a group.

type Material

type Material struct {
	Name  string
	MapKd string
	MapKa string
	MapKs string
	MapD  string
	Bump  string
	MapKe string
	Kd    [3]float32
	Ka    [3]float32
	Ks    [3]float32
	Ns    float32
	Ni    float32
	Illum int
	D     float32
	Tr    float32
}

Material holds information for a material. Kd - diffuse color. Ka - ambient color. Ks - specular color. Ns - specular exponent. Ni - optical density aka. index of refraction. Illum - illumination model enum id. D / Tr - trasparency (Tr = 1 - D) MapKa - ambient map MapKd - diffuse map MapKs - specular map MapD - scalar procedural texture map Bump/map_Bump - bump texture map - modify surface normal Ke/MapKe - emissive map - clara.io extension

type MaterialLib

type MaterialLib struct {
	Lib map[string]*Material
}

MaterialLib stores materials.

func NewMaterialLib

func NewMaterialLib() MaterialLib

NewMaterialLib creates a new material lib.

func ReadMaterialLibFromBuf

func ReadMaterialLibFromBuf(buf []byte, options *ObjParserOptions) (MaterialLib, error)

ReadMaterialLibFromBuf parses material lib from a buffer.

func ReadMaterialLibFromFile

func ReadMaterialLibFromFile(filename string, options *ObjParserOptions) (MaterialLib, error)

ReadMaterialLibFromFile parses material lib from a file.

func ReadMaterialLibFromReader

func ReadMaterialLibFromReader(rd io.Reader, options *ObjParserOptions) (MaterialLib, error)

ReadMaterialLibFromReader parses material lib from a reader.

func ReadMaterialLibFromStringReader

func ReadMaterialLibFromStringReader(rd StringReader, options *ObjParserOptions) (MaterialLib, error)

ReadMaterialLibFromStringReader parses material lib from StringReader.

type Obj

type Obj struct {
	Indices []int
	Coord   []float32 // vertex data pos=(x,y,z) tex=(tx,ty) norm=(nx,ny,nz)
	Mtllib  string
	Groups  []*Group

	BigIndexFound  bool // index larger than 65535
	TextCoordFound bool // texture coord
	NormCoordFound bool // normal coord

	StrideSize           int // (px,py,pz),(tu,tv),(nx,ny,nz) = 8 x 4-byte floats = 32 bytes max
	StrideOffsetPosition int // 0
	StrideOffsetTexture  int // 3 x 4-byte floats
	StrideOffsetNormal   int // 5 x 4-byte floats
}

Obj holds parser result for .obj file.

func NewObjFromBuf

func NewObjFromBuf(objName string, buf []byte, options *ObjParserOptions) (*Obj, error)

NewObjFromBuf parses Obj from a buffer.

func NewObjFromFile

func NewObjFromFile(filename string, options *ObjParserOptions) (*Obj, error)

NewObjFromFile parses Obj from a file.

func NewObjFromReader

func NewObjFromReader(objName string, rd io.Reader, options *ObjParserOptions) (*Obj, error)

NewObjFromReader parses Obj from a reader.

func NewObjFromStringReader

func NewObjFromStringReader(objName string, rd StringReader, options *ObjParserOptions) (*Obj, error)

NewObjFromStringReader parses Obj from a StringReader.

func NewObjFromVertex

func NewObjFromVertex(coord []float32, indices []int) (*Obj, error)

NewObjFromVertex creates Obj from vertex data.

func (*Obj) Coord64

func (o *Obj) Coord64(i int) float64

Coord64 gets vertex data as float64.

func (*Obj) NumberOfElements

func (o *Obj) NumberOfElements() int

NumberOfElements gets the number of strides.

func (*Obj) ToFile

func (o *Obj) ToFile(filename string) error

ToFile saves OBJ to file.

func (*Obj) ToWriter

func (o *Obj) ToWriter(w io.Writer) error

ToWriter writes OBJ to writer stream.

func (*Obj) VertexCoordinates

func (o *Obj) VertexCoordinates(stride int) (float32, float32, float32)

VertexCoordinates gets vertex coordinates for a stride index.

type ObjParserOptions

type ObjParserOptions struct {
	LogStats      bool
	Logger        func(string)
	IgnoreNormals bool
}

ObjParserOptions sets options for the parser.

type StringReader

type StringReader interface {
	ReadString(delim byte) (string, error) // Example: bufio.Reader
}

StringReader is input for the parser.