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