Added ply loader and camera.

camera.go

@@ -0,0 +1,78 @@
+package goga
+
+const (
+	default_camera_pos_x = 5
+	default_camera_pos_y = 5
+	default_camera_pos_z = 5
+	default_camera_up_x  = 0
+	default_camera_up_y  = 0
+	default_camera_up_z  = 1
+	default_camera_fov   = 60
+	default_camera_znear = 1
+	default_camera_zfar  = 20
+)
+
+type Camera struct {
+	Viewport                  Vec4
+	Position, LookAt, Up      Vec3
+	Fov, Ratio, Znear, Zfar   float64
+	Projection, Ortho3D, View Mat4
+	Ortho                     Mat3
+}
+
+// Creates a new 2D/3D camera.
+// Pass the viewport as arguments.
+func NewCamera(x, y, width, height int) *Camera {
+	camera := &Camera{}
+	camera.Position = Vec3{default_camera_pos_x, default_camera_pos_y, default_camera_pos_z}
+	camera.Up = Vec3{default_camera_up_x, default_camera_up_y, default_camera_up_z}
+	camera.Fov = default_camera_fov
+	camera.Znear = default_camera_znear
+	camera.Zfar = default_camera_zfar
+	camera.SetViewport(x, y, width, height)
+	camera.CalcRatio()
+
+	return camera
+}
+
+// Updates viewport.
+func (c *Camera) SetViewport(x, y, width, height int) {
+	c.Viewport = Vec4{float64(x), float64(y), float64(width), float64(height)}
+}
+
+// Calculates viewport ratio (width/height).
+func (c *Camera) CalcRatio() {
+	c.Ratio = (c.Viewport.Z - c.Viewport.X) / (c.Viewport.W - c.Viewport.Y)
+}
+
+// Calculates projection matrix and returns it.
+func (c *Camera) CalcProjection() *Mat4 {
+	c.Projection.Identity()
+	c.Projection.Perspective(c.Fov, c.Ratio, c.Znear, c.Zfar)
+
+	return &c.Projection
+}
+
+// Calculates orthogonal projection matrix and returns it.
+func (c *Camera) CalcOrtho() *Mat3 {
+	c.Ortho.Identity()
+	c.Ortho.Ortho(c.Viewport)
+
+	return &c.Ortho
+}
+
+// Calculates 3D orthogonal projection matrix and returns it.
+func (c *Camera) CalcOrtho3D() *Mat4 {
+	c.Ortho3D.Identity()
+	c.Ortho3D.Ortho(c.Viewport, c.Znear, c.Zfar)
+
+	return &c.Ortho3D
+}
+
+// Calculates view matrix and returns it.
+func (c *Camera) CalcView() *Mat4 {
+	c.View.Identity()
+	c.View.LookAt(c.Position, c.LookAt, c.Up)
+
+	return &c.View
+}