Handle (embedded)textures

asig/asig.go

@@ -32,7 +32,9 @@ type Texel struct {
 	R, G, B, A byte
 }
 
-type Texture struct {
+type EmbeddedTexture struct {
+	cTex *C.struct_aiTexture
+
 	/** Width of the texture, in pixels
 	 *
 	 * If mHeight is zero the texture is compressed in a format
@@ -70,16 +72,12 @@ type Texture struct {
 	FormatHint string
 
 	/** Data of the texture.
-	 *
+	 * Points to an array of mWidth * mHeight aiTexel's (or just len=Width if Height=0, which happens when data is compressed).
-	 * Points to an array of mWidth * mHeight aiTexel's.
+	 * The format of the texture data is always RGBA8888.
-	 * The format of the texture data is always ARGB8888 to
-	 * make the implementation for user of the library as easy
-	 * as possible. If mHeight = 0 this is a pointer to a memory
-	 * buffer of size mWidth containing the compressed texture
-	 * data. Good luck, have fun!
 	 */
-	Texels []Texel
+	Data []byte
 
+	IsCompressed bool
 	Filename     string
 }
 
@@ -99,10 +97,25 @@ type Scene struct {
 	RootNode  *Node
 	Meshes    []*Mesh
 	Materials []*Material
-	Animations []*Animation
+
-	Textures   []*Texture
+	/** Helper structure to describe an embedded texture
-	Lights     []*Light
+	 *
-	Cameras    []*Camera
+	 * Normally textures are contained in external files but some file formats embed
+	 * them directly in the model file. There are two types of embedded textures:
+	 * 1. Uncompressed textures. The color data is given in an uncompressed format.
+	 * 2. Compressed textures stored in a file format like png or jpg. The raw file
+	 * bytes are given so the application must utilize an image decoder (e.g. DevIL) to
+	 * get access to the actual color data.
+	 *
+	 * Embedded textures are referenced from materials using strings like "*0", "*1", etc.
+	 * as the texture paths (a single asterisk character followed by the
+	 * zero-based index of the texture in the aiScene::mTextures array).
+	 */
+	Textures []*EmbeddedTexture
+
+	// Animations []*Animation
+	// Lights     []*Light
+	// Cameras    []*Camera
 }
 
 func (s *Scene) releaseCResources() {
@@ -141,10 +154,64 @@ func parseScene(cs *C.struct_aiScene) *Scene {
 	s.Flags = SceneFlag(cs.mFlags)
 	s.Meshes = parseMeshes(cs.mMeshes, uint(cs.mNumMeshes))
 	s.Materials = parseMaterials(cs.mMaterials, uint(cs.mNumMaterials))
+	s.Textures = parseTextures(cs.mTextures, uint(s.cScene.mNumTextures))
 
 	return s
 }
 
+func parseTextures(cTexIn **C.struct_aiTexture, count uint) []*EmbeddedTexture {
+
+	if cTexIn == nil {
+		return []*EmbeddedTexture{}
+	}
+
+	textures := make([]*EmbeddedTexture, count)
+	cTex := unsafe.Slice(cTexIn, count)
+
+	for i := 0; i < int(count); i++ {
+
+		textures[i] = &EmbeddedTexture{
+			cTex:         cTex[i],
+			Width:        uint(cTex[i].mWidth),
+			Height:       uint(cTex[i].mHeight),
+			FormatHint:   C.GoString(&cTex[i].achFormatHint[0]),
+			Filename:     parseAiString(cTex[i].mFilename),
+			Data:         parseTexels(cTex[i].pcData, uint(cTex[i].mWidth), uint(cTex[i].mHeight)),
+			IsCompressed: cTex[i].mHeight == 0,
+		}
+	}
+
+	return textures
+}
+
+func parseTexels(cTexelsIn *C.struct_aiTexel, width, height uint) []byte {
+
+	//e.g. like a png. Otherwise we have pure color data
+	isCompressed := height == 0
+
+	texelCount := width
+	if !isCompressed {
+		texelCount *= height
+	}
+	texelCount /= 4
+
+	data := make([]byte, texelCount*4)
+	cTexels := unsafe.Slice(cTexelsIn, texelCount)
+
+	for i := 0; i < int(texelCount); i++ {
+
+		//Order here is important as in a compressed format the order will represent arbitrary bytes, not colors.
+		//In aiTexel the struct field order is {b,g,r,a}, which puts A in the high bits and leads to a format of ARGB8888, therefore it must be maintained here
+		index := i * 4
+		data[index] = byte(cTexels[i].b)
+		data[index+1] = byte(cTexels[i].g)
+		data[index+2] = byte(cTexels[i].r)
+		data[index+3] = byte(cTexels[i].a)
+	}
+
+	return data
+}
+
 func parseMeshes(cm **C.struct_aiMesh, count uint) []*Mesh {
 
 	if cm == nil {

asig/enums.go

@@ -1,5 +1,18 @@
 package asig
 
+type aiReturn int32
+
+const (
+	//Indicates that a function was successful
+	aiReturnSuccess = 0x0
+
+	//Indicates that a function failed
+	aiReturnFailure = -0x1
+
+	//Indicates that not enough memory was available to perform the requested operation
+	aiReturnOutofMemory = -0x3
+)
+
 type SceneFlag int32
 
 const (

asig/material.go

@@ -24,6 +24,10 @@ enum aiReturn aiGetMaterialTexture(
     unsigned int* flags);
 */
 import "C"
+import (
+	"errors"
+	"fmt"
+)
 
 type Material struct {
 	cMat *C.struct_aiMaterial
@@ -59,12 +63,35 @@ type MaterialProperty struct {
 	 */
 	TypeInfo MatPropertyTypeInfo
 
-	/** Binary buffer to hold the property's value.
+	//Binary buffer to hold the property's value.
-	 * The size of the buffer is always mDataLength.
-	 */
 	Data []byte
 }
 
 func GetMaterialTextureCount(m *Material, texType TextureType) int {
 	return int(C.aiGetMaterialTextureCount(m.cMat, uint32(texType)))
 }
+
+type GetMatTexInfo struct {
+	Path string
+}
+
+func GetMaterialTexture(m *Material, texType TextureType, texIndex uint) (*GetMatTexInfo, error) {
+
+	outCPath := &C.struct_aiString{}
+	status := aiReturn(C.aiGetMaterialTexture(m.cMat, uint32(texType), C.uint(texIndex), outCPath, nil, nil, nil, nil, nil, nil))
+	if status == aiReturnSuccess {
+		return &GetMatTexInfo{
+			Path: parseAiString(*outCPath),
+		}, nil
+	}
+
+	if status == aiReturnFailure {
+		return nil, errors.New("get texture failed: " + getAiErr().Error())
+	}
+
+	if status == aiReturnOutofMemory {
+		return nil, errors.New("get texture failed: out of memory")
+	}
+
+	return nil, errors.New("get texture failed: unknown error with code " + fmt.Sprintf("%v", status))
+}

go.mod

@@ -2,4 +2,4 @@ module github.com/bloeys/assimp-go
 
 go 1.17
 
-require github.com/bloeys/gglm v0.2.6 // indirect
+require github.com/bloeys/gglm v0.2.6

main.go

@@ -1,14 +1,16 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
+	"image/png"
 
 	"github.com/bloeys/assimp-go/asig"
 )
 
 func main() {
 
-	scene, release, err := asig.ImportFile("tex-cube.fbx", asig.PostProcessTriangulate)
+	scene, release, err := asig.ImportFile("tex-cube.glb", asig.PostProcessTriangulate)
 	defer release()
 
 	if err != nil {
@@ -17,7 +19,7 @@ func main() {
 
 	for i := 0; i < len(scene.Meshes); i++ {
 
-		println("Mesh:", i, "; Verts:", len(scene.Meshes[i].Vertices), "; Normals:", len(scene.Meshes[i].Normals))
+		println("Mesh:", i, "; Verts:", len(scene.Meshes[i].Vertices), "; Normals:", len(scene.Meshes[i].Normals), "; MatIndex:", scene.Meshes[i].MaterialIndex)
 		for j := 0; j < len(scene.Meshes[i].Vertices); j++ {
 			fmt.Printf("V(%v): (%v, %v, %v)\n", j, scene.Meshes[i].Vertices[j].X(), scene.Meshes[i].Vertices[j].Y(), scene.Meshes[i].Vertices[j].Z())
 		}
@@ -25,13 +27,40 @@ func main() {
 
 	for i := 0; i < len(scene.Materials); i++ {
 
+		m := scene.Materials[i]
 		println("Mesh:", i, "; Props:", len(scene.Materials[i].Properties))
-		for j := 0; j < len(scene.Materials[i].Properties); j++ {
+		texCount := asig.GetMaterialTextureCount(m, asig.TextureTypeDiffuse)
+		fmt.Println("Texture count:", texCount)
 
-			p := scene.Materials[i].Properties[j]
+		if texCount > 0 {
-			fmt.Printf("Data Type: %v; Len Bytes: %v; Texture Type: %v\n", p.TypeInfo.String(), len(p.Data), p.Semantic.String())
 
-			fmt.Println("Texture count:", asig.GetMaterialTextureCount(scene.Materials[i], asig.TextureTypeDiffuse))
+			texInfo, err := asig.GetMaterialTexture(m, asig.TextureTypeDiffuse, 0)
+			if err != nil {
+				panic(err)
+			}
+
+			fmt.Printf("%v", texInfo)
+		}
+	}
+
+	ts := scene.Textures
+	for i := 0; i < len(ts); i++ {
+		t := ts[i]
+
+		fmt.Printf("T(%v): Name=%v, Hint=%v, Width=%v, Height=%v, NumTexels=%v", i, t.Filename, t.FormatHint, t.Width, t.Height, len(t.Data))
+
+		if t.FormatHint == "png" {
+			decodePNG(t.Data)
 		}
 	}
 }
+
+func decodePNG(texels []byte) {
+
+	img, err := png.Decode(bytes.NewReader(texels))
+	if err != nil {
+		panic("wow2: " + err.Error())
+	}
+
+	println("C:", img.At(100, 100))
+}