Working on object parser

tinyrender1/go.mod

@@ -1,3 +1,5 @@
 module tinyrender1
 
 go 1.22.5
+
+require github.com/udhos/gwob v1.0.0

tinyrender1/go.sum

@@ -0,0 +1,2 @@
+github.com/udhos/gwob v1.0.0 h1:P9br9SLca7H5Hr/WuEcO9+ViUm+wlQnr4vxpPU6c6ww=
+github.com/udhos/gwob v1.0.0/go.mod h1:xj4qGbkwL1sTPm1V17NfcIhkgG2rjfb8cUv9YIqE6DE=

tinyrender1/main.go

@@ -6,6 +6,8 @@ import (
 	"log"
 	"os"
 	"runtime/pprof" // For performance whatever
+
+	"github.com/udhos/gwob"
 )
 
 const (

tinyrender1/obj.go

@@ -0,0 +1,66 @@
+package main
+
+// This reads obj files?
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type Vec3f struct {
+	X, Y, Z float32
+}
+
+type Facef [3]Vec3f
+
+type ObjModel struct {
+	Vertices []Vec3f
+	Faces    []Facef
+}
+
+func ParseObj(reader io.Reader) (*ObjModel, error) {
+	result := ObjModel{
+		Vertices: make([]Vec3f, 0),
+		Faces:    make([]Facef, 0),
+	}
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		// Scan a line
+		line := strings.Trim(scanner.Text(), " \t")
+		// 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 {
+			return nil, err
+		}
+		line = line[len(t):]
+		if t == "v" {
+			// Read a vertex, should be just three floats
+			var vertex Vec3f
+			_, err := fmt.Sscan(line, vertex.X, vertex.Y, vertex.Z)
+			if err != nil {
+				return nil, err
+			}
+			result.Vertices = append(result.Vertices, vertex)
+		} 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
+			for i := range 3 {
+				var vi, ti0, ti1 int
+				_, err := fmt.Sscanf(line, "%d/%d/%d", vi, ti0, ti1)
+				if err != nil {
+					return nil, err
+				}
+				if vi > len(result.Vertices) || vi < 1 {
+					return nil, fmt.Errorf("Face vertex index out of bounds: %d", vi)
+				}
+				face[i] = result.Vertices[vi-1]
+			}
+			result.Faces = append(result.Faces, face)
+		}
+	}
+	return &result, nil
+}