159 lines
3.2 KiB
Go
159 lines
3.2 KiB
Go
package main
|
|
|
|
// This reads obj files?
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"io"
|
|
"log"
|
|
"math"
|
|
"strings"
|
|
)
|
|
|
|
type Vec3f struct {
|
|
X, Y, Z float32
|
|
}
|
|
|
|
type Vec2i struct {
|
|
X, Y int
|
|
}
|
|
|
|
type Vec2f struct {
|
|
X, Y float32
|
|
}
|
|
|
|
// A single vertex generally has multiple items associated with it
|
|
// when it's part of a face.
|
|
type Vertex struct {
|
|
Pos Vec3f
|
|
Tex Vec3f
|
|
}
|
|
|
|
type Facef [3]Vertex
|
|
|
|
// struct {
|
|
// Vertices [3]Vec3f
|
|
// TextureCoords [3]Vec2i
|
|
// }
|
|
|
|
type ObjModel struct {
|
|
Vertices []Vec3f
|
|
VTexture []Vec3f
|
|
Faces []Facef
|
|
}
|
|
|
|
func (vi *Vec2i) ToF() Vec2f {
|
|
return Vec2f{float32(vi.X), float32(vi.Y)}
|
|
}
|
|
|
|
func (vi *Vec3f) ToVec2i() Vec2i {
|
|
return Vec2i{int(vi.X), int(vi.Y)}
|
|
}
|
|
|
|
func (v0 *Vec3f) Sub(v1 Vec3f) Vec3f {
|
|
return Vec3f{
|
|
X: v0.X - v1.X,
|
|
Y: v0.Y - v1.Y,
|
|
Z: v0.Z - v1.Z,
|
|
}
|
|
}
|
|
|
|
func (v0 *Vec3f) CrossProduct(v1 Vec3f) Vec3f {
|
|
return Vec3f{
|
|
X: v0.Y*v1.Z - v0.Z*v1.Y,
|
|
Y: v0.Z*v1.X - v0.X*v1.Z,
|
|
Z: v0.X*v1.Y - v0.Y*v1.X,
|
|
}
|
|
}
|
|
|
|
//func (v
|
|
|
|
func (v *Vec3f) Normalize() Vec3f {
|
|
l := float32(math.Sqrt(float64(v.MultSimp(v))))
|
|
return Vec3f{
|
|
X: v.X / l,
|
|
Y: v.Y / l,
|
|
Z: v.Z / l,
|
|
}
|
|
}
|
|
|
|
func (v0 *Vec3f) MultSimp(v1 *Vec3f) float32 {
|
|
return v0.X*v1.X + v0.Y*v1.Y + v0.Z*v1.Z
|
|
}
|
|
|
|
// Parse an obj file at the given reader. Only handles v and f right now
|
|
func ParseObj(reader io.Reader) (*ObjModel, error) {
|
|
result := ObjModel{
|
|
Vertices: make([]Vec3f, 0),
|
|
Faces: make([]Facef, 0),
|
|
}
|
|
breader := bufio.NewReader(reader)
|
|
done := false
|
|
for !done {
|
|
// Scan a line
|
|
line, err := breader.ReadString('\n')
|
|
if err != nil {
|
|
if err == io.EOF {
|
|
done = true
|
|
} else {
|
|
log.Printf("NOT EOF ERR?")
|
|
return nil, err
|
|
}
|
|
}
|
|
line = strings.Trim(line, " \t\n\r")
|
|
if len(line) == 0 {
|
|
continue
|
|
}
|
|
// Find the first "item", whatever that is. This also gets rid of comments
|
|
// since we just don't use lines that start with # (no handler
|
|
var t string
|
|
_, err = fmt.Sscan(line, &t)
|
|
if err != nil {
|
|
log.Printf("SSCANF ERR")
|
|
return nil, err
|
|
}
|
|
line = line[len(t):]
|
|
if t == "v" {
|
|
// Read a vertex, should be just three floats
|
|
var v Vec3f
|
|
_, err := fmt.Sscan(line, &v.X, &v.Y, &v.Z)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
result.Vertices = append(result.Vertices, v)
|
|
} else if t == "vt" {
|
|
// Read a vertex tex coord, should be just three floats too
|
|
var vt Vec3f
|
|
_, err := fmt.Sscan(line, &vt.X, &vt.Y, &vt.Z)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
result.VTexture = append(result.VTexture, vt)
|
|
} else if t == "f" {
|
|
// Read a face; in our example, it's always three sets.
|
|
// For THIS example, we throw away those other values
|
|
var face Facef
|
|
var vi [3]int
|
|
var vti [3]int
|
|
var ti int
|
|
_, err := fmt.Sscanf(line, "%d/%d/%d %d/%d/%d %d/%d/%d",
|
|
&vi[0], &vti[0], &ti, &vi[1], &vti[1], &ti, &vi[2], &vti[2], &ti)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
for i := range 3 {
|
|
if vi[i] > len(result.Vertices) || vi[i] < 1 {
|
|
return nil, fmt.Errorf("Face vertex index out of bounds: %d", vi[i])
|
|
}
|
|
face[i].Pos = result.Vertices[vi[i]-1]
|
|
if vti[i] > len(result.VTexture) || vti[i] < 1 {
|
|
return nil, fmt.Errorf("Face vertex texture index out of bounds: %d", vti[i])
|
|
}
|
|
face[i].Tex = result.VTexture[vti[i]-1]
|
|
}
|
|
result.Faces = append(result.Faces, face)
|
|
}
|
|
}
|
|
return &result, nil
|
|
}
|