# Simple material using the normals of the surface as color
#
# Each axis composing the normals are translated to color values.
# This material is useful for debugging normals or display models in a colorful way.
class NormalsMaterial
	super Material

	redef fun draw(actor, model, camera)
	do
		var program = app.normals_program
		program.use
		program.mvp.uniform camera.mvp_matrix

		var mesh = model.mesh

		# TODO apply normal map

		program.translation.uniform(actor.center.x, actor.center.y, actor.center.z, 0.0)
		program.scale.uniform actor.scale

		program.tex_coord.array_enabled = true
		program.tex_coord.array(mesh.texture_coords, 2)

		program.coord.array_enabled = true
		program.coord.array(mesh.vertices, 3)

		program.rotation = new Matrix.gamnit_euler_rotation(actor.pitch, actor.yaw, actor.roll)

		program.normal.array_enabled = true
		program.normal.array(mesh.normals, 3)

		if mesh.indices.is_empty then
			glDrawArrays(mesh.draw_mode, 0, mesh.vertices.length/3)
		else
			glDrawElements(mesh.draw_mode, mesh.indices.length, gl_UNSIGNED_SHORT, mesh.indices_c.native_array)
		end
	end
end