Use dep to vendor things

vendor/github.com/faiface/glhf/attr.go

@@ -0,0 +1,80 @@
+package glhf
+
+// AttrFormat defines names and types of OpenGL attributes (vertex format, uniform format, etc.).
+//
+// Example:
+//   AttrFormat{{"position", Vec2}, {"color", Vec4}, {"texCoord": Vec2}}
+type AttrFormat []Attr
+
+// Size returns the total size of all attributes of the AttrFormat.
+func (af AttrFormat) Size() int {
+	total := 0
+	for _, attr := range af {
+		total += attr.Type.Size()
+	}
+	return total
+}
+
+// Attr represents an arbitrary OpenGL attribute, such as a vertex attribute or a shader
+// uniform attribute.
+type Attr struct {
+	Name string
+	Type AttrType
+}
+
+// AttrType represents the type of an OpenGL attribute.
+type AttrType int
+
+// List of all possible attribute types.
+const (
+	Int AttrType = iota
+	Float
+	Vec2
+	Vec3
+	Vec4
+	Mat2
+	Mat23
+	Mat24
+	Mat3
+	Mat32
+	Mat34
+	Mat4
+	Mat42
+	Mat43
+)
+
+// Size returns the size of a type in bytes.
+func (at AttrType) Size() int {
+	switch at {
+	case Int:
+		return 4
+	case Float:
+		return 4
+	case Vec2:
+		return 2 * 4
+	case Vec3:
+		return 3 * 4
+	case Vec4:
+		return 4 * 4
+	case Mat2:
+		return 2 * 2 * 4
+	case Mat23:
+		return 2 * 3 * 4
+	case Mat24:
+		return 2 * 4 * 4
+	case Mat3:
+		return 3 * 3 * 4
+	case Mat32:
+		return 3 * 2 * 4
+	case Mat34:
+		return 3 * 4 * 4
+	case Mat4:
+		return 4 * 4 * 4
+	case Mat42:
+		return 4 * 2 * 4
+	case Mat43:
+		return 4 * 3 * 4
+	default:
+		panic("size of vertex attribute type: invalid type")
+	}
+}