Ep5: Obj file loading+indexed drawing+uniforms

res/models/loader.go

@@ -0,0 +1,73 @@
+package models
+
+import (
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/bloeys/go-sdl-engine/logging"
+)
+
+type ObjInfo struct {
+	VertPos    []float32
+	TriIndices []uint32
+}
+
+func LoadObj(file string) (objInfo ObjInfo, err error) {
+
+	b, err := os.ReadFile(file)
+	if err != nil {
+		return objInfo, err
+	}
+
+	lines := strings.Split(string(b), "\n")
+	for i := 0; i < len(lines); i++ {
+
+		s := strings.SplitN(lines[i], " ", 2)
+		switch s[0] {
+		case "v":
+
+			vertPosStrings := strings.Split(s[1], " ")
+
+			f, err := strconv.ParseFloat(vertPosStrings[0], 32)
+			if err != nil {
+				return objInfo, err
+			}
+			objInfo.VertPos = append(objInfo.VertPos, float32(f))
+
+			f, err = strconv.ParseFloat(vertPosStrings[1], 32)
+			if err != nil {
+				return objInfo, err
+			}
+			objInfo.VertPos = append(objInfo.VertPos, float32(f))
+
+			f, err = strconv.ParseFloat(vertPosStrings[2], 32)
+			if err != nil {
+				return objInfo, err
+			}
+			objInfo.VertPos = append(objInfo.VertPos, float32(f))
+
+		case "f":
+
+			facesStrings := strings.Split(s[1], " ")
+			objInfo.TriIndices = append(objInfo.TriIndices, getVertIndexFromFace(facesStrings[0]))
+			objInfo.TriIndices = append(objInfo.TriIndices, getVertIndexFromFace(facesStrings[1]))
+			objInfo.TriIndices = append(objInfo.TriIndices, getVertIndexFromFace(facesStrings[2]))
+
+		default:
+		}
+	}
+
+	return objInfo, nil
+}
+
+func getVertIndexFromFace(f string) uint32 {
+
+	indxStr := strings.SplitN(f, "/", 2)[0]
+	index, err := strconv.Atoi(indxStr)
+	if err != nil {
+		logging.ErrLog.Printf("Invalid face index '%v'. Err: %v", indxStr, err)
+		return 0
+	}
+	return uint32(index) - 1
+}

res/models/obj.obj

@@ -0,0 +1,46 @@
+# Blender v2.92.0 OBJ File: ''
+# www.blender.org
+mtllib obj.mtl
+o Cube
+v 2.275618 1.000000 0.349413
+v 3.520138 -1.000000 0.102233
+v 2.275618 1.000000 0.752820
+v 3.520138 -1.000000 1.000000
+v 0.244520 1.000000 0.349413
+v -1.000000 -1.000000 0.102233
+v 0.244520 1.000000 0.752820
+v -1.000000 -1.000000 1.000000
+vt 0.806168 0.568832
+vt 0.693832 0.681168
+vt 0.693832 0.568832
+vt 0.375000 1.000000
+vt 0.375000 0.750000
+vt 0.375000 0.000000
+vt 0.625000 0.250000
+vt 0.375000 0.250000
+vt 0.375000 0.500000
+vt 0.125000 0.750000
+vt 0.125000 0.500000
+vt 0.806168 0.681168
+vt 0.625000 0.931168
+vt 0.625000 0.068832
+vn 0.0000 1.0000 0.0000
+vn 0.0000 0.1227 0.9924
+vn -0.8490 0.5283 0.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.8490 0.5283 0.0000
+vn 0.0000 0.1227 -0.9924
+usemtl Material
+s off
+f 5/1/1 3/2/1 1/3/1
+f 3/2/2 8/4/2 4/5/2
+f 8/6/3 5/7/3 6/8/3
+f 2/9/4 8/10/4 6/11/4
+f 1/3/5 4/5/5 2/9/5
+f 5/7/6 2/9/6 6/8/6
+f 5/1/1 7/12/1 3/2/1
+f 3/2/2 7/13/2 8/4/2
+f 8/6/3 7/14/3 5/7/3
+f 2/9/4 4/5/4 8/10/4
+f 1/3/5 3/2/5 4/5/5
+f 5/7/6 1/3/6 2/9/6