Starting work on Engine+Mesh+Material systems/packages

meshes/mesh.go

@@ -0,0 +1,81 @@
+package meshes
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/bloeys/assimp-go/asig"
+	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/asserts"
+	"github.com/bloeys/nmage/buffers"
+)
+
+type Mesh struct {
+	Name   string
+	BufObj *buffers.BufferObject
+}
+
+func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh, error) {
+
+	scene, release, err := asig.ImportFile(modelPath, asig.PostProcessTriangulate|postProcessFlags)
+	if err != nil {
+		return nil, errors.New("Failed to load model. Err: " + err.Error())
+	}
+	defer release()
+
+	if len(scene.Meshes) == 0 {
+		return nil, errors.New("No meshes found in file: " + modelPath)
+	}
+
+	mesh := &Mesh{Name: name, BufObj: buffers.NewBufferObject()}
+
+	sceneMesh := scene.Meshes[0]
+	mesh.BufObj.GenBuffer(flattenVec3(sceneMesh.Normals), buffers.BufUsageStatic, buffers.BufTypeNormal, buffers.DataTypeVec3)
+	mesh.BufObj.GenBuffer(flattenVec3(sceneMesh.Vertices), buffers.BufUsageStatic, buffers.BufTypeVertPos, buffers.DataTypeVec3)
+	mesh.BufObj.GenBufferUint32(flattenFaces(sceneMesh.Faces), buffers.BufUsageStatic, buffers.BufTypeIndex, buffers.DataTypeUint32)
+
+	if len(sceneMesh.ColorSets) > 0 {
+		mesh.BufObj.GenBuffer(flattenVec4(sceneMesh.ColorSets[0]), buffers.BufUsageStatic, buffers.BufTypeColor, buffers.DataTypeVec4)
+	}
+
+	return mesh, nil
+}
+
+func flattenVec3(vec3s []gglm.Vec3) []float32 {
+
+	floats := make([]float32, len(vec3s)*3)
+	for i := 0; i < len(vec3s); i++ {
+		floats[i*3+0] = vec3s[i].X()
+		floats[i*3+1] = vec3s[i].Y()
+		floats[i*3+2] = vec3s[i].Z()
+	}
+
+	return floats
+}
+
+func flattenVec4(vec4s []gglm.Vec4) []float32 {
+
+	floats := make([]float32, len(vec4s)*4)
+	for i := 0; i < len(vec4s); i++ {
+		floats[i*4+0] = vec4s[i].X()
+		floats[i*4+1] = vec4s[i].Y()
+		floats[i*4+2] = vec4s[i].Z()
+		floats[i*4+3] = vec4s[i].W()
+	}
+
+	return floats
+}
+
+func flattenFaces(faces []asig.Face) []uint32 {
+
+	asserts.True(len(faces[0].Indices) == 3, fmt.Sprintf("Face doesn't have 3 indices. Index count: %v\n", len(faces[0].Indices)))
+
+	uints := make([]uint32, len(faces)*3)
+	for i := 0; i < len(faces); i++ {
+		uints[i*3+0] = uint32(faces[i].Indices[0])
+		uints[i*3+1] = uint32(faces[i].Indices[1])
+		uints[i*3+2] = uint32(faces[i].Indices[2])
+	}
+
+	return uints
+}