sss

.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${fileDirname}"
+        }
+    ]
+}

cmd/stl2gltf.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"git.dengqn.com/dqn/stl2gltf"
+)
+
+func main() {
+	stl := stl2gltf.Load("D:\\src\\go\\stl2gltf\\example\\0c448109-7ac9-4f6d-aaf6-ce6bb744032f.stl")
+	// log.Println(stl)
+
+	stl2gltf.Convert(stl, "C:\\Users\\13040\\Downloads\\0c448109-7ac9-4f6d-aaf6-ce6bb744032f.gltf")
+
+}

convert.go

@@ -0,0 +1,134 @@
+package stl2gltf
+
+import (
+	"encoding/base64"
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+)
+
+func Convert(stl STL, outFile string) {
+	// buf
+	indexBuf := make([]byte, 0)
+	normalBuf := make([]byte, 0)
+	positionBuf := make([]byte, 0)
+
+	padding := func(buf []byte) []byte {
+		log.Println("padding: ", len(buf)%4)
+		for len(buf)%4 != 0 {
+			log.Println("padding")
+			buf = append(buf, 0x00)
+		}
+		return buf
+	}
+
+	// 写入顶点
+	for i := range stl.TriangleNum {
+		t := stl.Triangles[i]
+		positionBuf = append(positionBuf, t.Position...)
+	}
+	positionBuf = padding(positionBuf)
+
+	// 写入法向量
+	for i := range stl.TriangleNum {
+		t := stl.Triangles[i]
+		normalBuf = append(normalBuf, t.Normal...)
+		normalBuf = append(normalBuf, t.Normal...)
+		normalBuf = append(normalBuf, t.Normal...)
+	}
+	normalBuf = padding(normalBuf)
+	// 写入索引
+	for i := range stl.TriangleNum * 3 {
+		buf := make([]byte, 2)
+		binary.LittleEndian.PutUint16(buf, uint16(i))
+		indexBuf = append(indexBuf, buf...)
+	}
+	indexBuf = padding(indexBuf)
+
+	log.Println(len(positionBuf), len(normalBuf), len(indexBuf))
+
+	allData := make([]byte, 0)
+	allData = append(allData, positionBuf...)
+	allData = append(allData, normalBuf...)
+	allData = append(allData, indexBuf...)
+
+	base := base64.StdEncoding.EncodeToString(allData)
+
+	attributes := make(map[string]int, 0)
+	attributes["POSITION"] = 0
+	attributes["NORMAL"] = 1
+
+	gltf := GLTF{
+		Asset:   Asset{Version: "2.0"},
+		Scenes:  []Scene{{Nodes: []int{0}}},
+		Nodes:   []Node{{Mesh: 0}},
+		Meshes:  []Mesh{{Primitives: []Primitive{{Attributes: attributes, Indices: 2, Mode: 4}}}},
+		Buffers: []Buffer{{Uri: fmt.Sprintf("data:application/gltf-buffer;base64,%s", base), ByteLength: len(allData)}},
+		BufferViews: []BufferView{
+			// position
+			{
+				Buffer:     0,
+				ByteOffset: 0,
+				ByteLength: len(positionBuf),
+				Target:     34962,
+			},
+			// normal
+			{
+				Buffer:     0,
+				ByteOffset: len(positionBuf),
+				ByteLength: len(normalBuf),
+				Target:     34962,
+			},
+			// index
+			{
+				Buffer:     0,
+				ByteOffset: len(positionBuf) + len(normalBuf),
+				ByteLength: len(indexBuf),
+				Target:     34963,
+			},
+		},
+		Accessors: []Accessor{
+			{
+				BufferView:    0,
+				ByteOffset:    0,
+				ComponentType: 5126,
+				Type:          "VEC3",
+				Count:         len(positionBuf) / 12,
+				Max:           stl.Max,
+				Min:           stl.Min,
+			},
+			{
+				BufferView:    1,
+				ByteOffset:    0,
+				ComponentType: 5126,
+				Type:          "VEC3",
+				Count:         int(stl.TriangleNum),
+				// Max:           []float32{1, 1, 1},
+				// Min:           []float32{-1, -1, -1},
+			},
+			{
+				BufferView:    2,
+				ByteOffset:    0,
+				ComponentType: 5123,
+				Type:          "SCALAR",
+				Count:         stl.TriangleNum,
+			},
+		},
+	}
+
+	data, err := json.MarshalIndent(gltf, " ", " ")
+	if err != nil {
+		log.Println("marshal error: ", err.Error())
+		return
+	}
+	os.Remove(outFile)
+	f, err := os.OpenFile(outFile, os.O_CREATE, os.ModePerm)
+	if err != nil {
+		log.Println("write file error: ", err.Error())
+		return
+	}
+	defer f.Close()
+	f.Write(data)
+}

data.go

@@ -0,0 +1,77 @@
+package stl2gltf
+
+// Triangle 50B
+type Triangle struct {
+	Normal    []byte // 4 * 3     12
+	Position  []byte // 4 * 3 * 3 36
+	Attribute []byte // 2         02
+}
+
+type STL struct {
+	Header      string
+	TriangleNum int
+	Triangles   []Triangle
+
+	Max []float32
+	Min []float32
+}
+
+type Asset struct {
+	Version string `json:"version"`
+}
+
+type Scene struct {
+	Nodes []int `json:"nodes"`
+}
+
+type Node struct {
+	Mesh int `json:"mesh"`
+}
+
+type Primitive struct {
+	Attributes map[string]int `json:"attributes"`
+	Indices    int            `json:"indices"`
+	Mode       int            `json:"mode"`
+}
+
+type Mesh struct {
+	Primitives []Primitive `json:"primitives"`
+}
+
+type Buffer struct {
+	Uri        string `json:"uri"`
+	ByteLength int    `json:"byteLength"`
+}
+
+type BufferView struct {
+	Buffer     int `json:"buffer"`
+	ByteOffset int `json:"byteOffset"`
+	ByteLength int `json:"byteLength"`
+	Target     int `json:"target"`
+}
+
+type Accessor struct {
+	BufferView    int       `json:"bufferView"`
+	ByteOffset    int       `json:"byteOffset"`
+	ComponentType int       `json:"componentType"`
+	Count         int       `json:"count"`
+	Type          string    `json:"type"`
+	Max           []float32 `json:"max,omitempty"`
+	Min           []float32 `json:"min,omitempty"`
+}
+
+type GLTF struct {
+	Asset Asset `json:"asset"`
+
+	Scenes []Scene `json:"scenes"`
+
+	Nodes []Node `json:"nodes"`
+
+	Meshes []Mesh `json:"meshes"`
+
+	Buffers []Buffer `json:"buffers"`
+
+	BufferViews []BufferView `json:"bufferViews"`
+
+	Accessors []Accessor `json:"accessors"`
+}

go.mod

@@ -0,0 +1,3 @@
+module git.dengqn.com/dqn/stl2gltf
+
+go 1.22.0

load.go

@@ -0,0 +1,72 @@
+package stl2gltf
+
+import (
+	"encoding/binary"
+	"log"
+	"math"
+	"os"
+)
+
+func Load(filePath string) (stl STL) {
+	file, err := os.OpenFile(filePath, os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		log.Panic("open file " + filePath + " error: " + err.Error())
+	}
+	headerBuf := make([]byte, 80)
+	file.Read(headerBuf)
+	triangleNumBuf := make([]byte, 4)
+	file.Read(triangleNumBuf)
+
+	stl.Header = string(headerBuf)
+	stl.TriangleNum = int(binary.LittleEndian.Uint32(triangleNumBuf))
+
+	stl.Triangles = make([]Triangle, 0)
+
+	max := []float32{0, 0, 0}
+	min := []float32{0, 0, 0}
+	for range stl.TriangleNum {
+		normalBuf := make([]byte, 4*3)
+		file.Read(normalBuf)
+
+		positionBuf := make([]byte, 4*3*3)
+		file.Read(positionBuf)
+
+		for r := range 3 {
+			x := math.Float32frombits(binary.LittleEndian.Uint32(positionBuf[:4+(r*4)]))
+			y := math.Float32frombits(binary.LittleEndian.Uint32(positionBuf[(r * 4) : (r*4)+4]))
+			z := math.Float32frombits(binary.LittleEndian.Uint32(positionBuf[(r*4)+4 : (r*4)+8]))
+			if max[0] < x {
+				max[0] = x
+			}
+			if max[1] < y {
+				max[1] = y
+			}
+			if max[2] < z {
+				max[2] = z
+			}
+			if min[0] > x {
+				min[0] = x
+			}
+			if min[1] > y {
+				min[1] = y
+			}
+			if min[2] > z {
+				min[2] = z
+			}
+		}
+
+		attributeBuf := make([]byte, 2)
+		file.Read(attributeBuf)
+
+		stl.Triangles = append(stl.Triangles, Triangle{
+			Normal:    normalBuf,
+			Position:  positionBuf,
+			Attribute: attributeBuf,
+		})
+	}
+
+	stl.Max = max
+	stl.Min = min
+
+	return stl
+}