indexing

	description: "[

		Example component to show implementation of a 3D scene component.
		
		Drawing:
		Implement 'draw' and put your OpenGL code there.
		
		Events:
		See EM_COMPONENT

	]"
	date: "$Date$"
	revision: "$Revision$"

class SIERPINSKI_DISPLAY

inherit

	EM_3D_COMPONENT

	SINGLE_MATH
		export {NONE} all end

create

	make

feature {NONE} -- Initialisation

	make is
			-- Initialise default values.
		local
			point1, color1: GL_VECTOR_3D [REAL]
			point2, color2: GL_VECTOR_3D [REAL]
			point3, color3: GL_VECTOR_3D [REAL]
			point4, color4: GL_VECTOR_3D [REAL]
			fog_color: GL_VECTOR_4D [REAL]
		do
			make_3d_component
			set_tooltip ("drag to rotate / left click to increase detail / right click to decrease detail")

			subdivisions := 0
			longitude := 10
			latitude := 20
			distance := 2.5

			create point1.make_xyz (1, -0.4, 0)
			create point2.make_xyz (-cosine (Pi/3), -0.4, sine (Pi/3))
			create point3.make_xyz (-cosine (Pi/3), -0.4, -sine (Pi/3))
			create point4.make_xyz (0, 1, 0)
			create color1.make_xyz (1, 0, 0)
			create color2.make_xyz (0, 1, 0)
			create color3.make_xyz (0, 0, 1)
			create color4.make_xyz (1, 1, 1)

			create pyramid.make (point1, point2, point3, point4, color1, color2, color3, color4)
			pyramid.subdivide (subdivisions)

			-- Light
			create light.make (Em_gl_light0)
			light.ambient.set_xyzt (0, 0, 0, 1)
			light.specular.set_xyzt (1, 1, 1, 1)
			light.diffuse.set_xyzt (1, 1, 1, 1)
			light.position.set_xyz (0.5, 0.5, 0.5)
			light.apply_values

			-- Fog
			create fog_color.make_xyzt (0, 0, 0, 1.0)
			gl_fogi (Em_gl_fog_mode, Em_gl_exp2)
			gl_fogfv (Em_gl_fog_color, fog_color.pointer)
			gl_fogf (Em_gl_fog_density, 0.35)
			gl_hint (Em_gl_fog_hint, Em_gl_nicest)
			gl_fogf (Em_gl_fog_start, 1)
			gl_fogf (Em_gl_fog_end, 4)

			-- Event registration
			mouse_clicked_event.subscribe (agent handle_mouse_clicked)
			mouse_dragged_event.subscribe (agent handle_mouse_dragged)
			mouse_wheel_up_event.subscribe (agent handle_mouse_wheel_up)
			mouse_wheel_down_event.subscribe (agent handle_mouse_wheel_down)
		end

feature -- Access

	subdivisions: INTEGER
			-- Level of subdivision

	longitude: REAL
			-- Longitude of the eye (in degree) around center (0,0,0)

	latitude: REAL
			-- Latitude of the eye (in degree) around center (0,0,0)

	distance: REAL
			-- Distance of the eye to center (0,0,0)

	pyramid: SIERPINSKI_PYRAMID
			-- Subdivided pyramid

	pyramid_display_list: INTEGER
			-- Display list id of pyramid

	light: GL_LIGHT
			-- OpenGL light

feature -- Status report

	is_lighting_enabled: BOOLEAN
			-- Is lighting enabled?

	is_fog_enabled: BOOLEAN
			-- Is fog enabled?

feature -- Status setting

	enable_lighting is
			-- Enable lighting.
		do
			is_lighting_enabled := True
		ensure
			lighting_enabled: is_lighting_enabled
		end

	disable_lighting is
			-- Disable lighting
		do
			is_lighting_enabled := False
		ensure
			lighting_disabled: not is_lighting_enabled
		end

	enable_fog is
			-- Enable fog.
		do
			is_fog_enabled := True
		ensure
			fog_enabled: is_fog_enabled
		end

	disable_fog is
			-- Disable fog
		do
			is_fog_enabled := False
		ensure
			fog_disabled: not is_fog_enabled
		end

feature -- Basic operations

	increase_distance is
			-- Increase distance.
		do
			distance := distance + 0.5
			if distance > 6 then
				distance := 6
			end
		end

	decrease_distance is
			-- Decrease distance.
		do
			distance := distance - 0.5
			if distance < 0 then
				distance := 0
			end
		end

	increase_subdivisions is
			-- Increase subdivisions.
		do
			subdivisions := subdivisions + 1
			pyramid.subdivide (subdivisions)
			-- Free display list to trigger generation of a new one
			gl_delete_lists (pyramid_display_list, 1)
			pyramid_display_list := 0
		ensure
			subdivisions_increased: subdivisions = old subdivisions + 1
		end

	decrease_subdivisions is
			-- Decrease subdivisions.
		do
			if subdivisions > 0 then
				subdivisions := subdivisions - 1
				pyramid.subdivide (subdivisions)
				-- Free display list to trigger generation of a new one
				gl_delete_lists (pyramid_display_list, 1)
				pyramid_display_list := 0
			end
		ensure
			subdivisions_decreased: old subdivisions > 0 implies subdivisions = old subdivisions - 1
		end

feature -- Drawing

	draw is
			-- Draw pyramid.
		do
			-- Set up eye position
			gl_translatef (0, 0, -distance)
			gl_rotatef (-longitude, 0, 1, 0)
			gl_rotatef (latitude, cosine (-longitude / 180 * pi),0,sine (-longitude / 180 * pi))
			-- Generate a display list if necessary and call it
			if pyramid_display_list = 0 then
				pyramid_display_list := gl_gen_lists (1)
				gl_new_list (pyramid_display_list, Em_gl_compile)
					pyramid.draw
				gl_end_list
			end

			if is_lighting_enabled then
				gl_enable (Em_gl_lighting)
				gl_enable (Em_gl_color_material)
				gl_color_material (Em_gl_front_and_back, Em_gl_ambient_and_diffuse)
				light.enable
			end
			if is_fog_enabled then
				gl_enable (Em_gl_fog)
			end
			gl_call_list (pyramid_display_list)
			if is_lighting_enabled then
				gl_disable (Em_gl_color_material)
				gl_disable (Em_gl_lighting)
			end
			if is_fog_enabled then
				gl_disable (Em_gl_fog)
			end
		end

feature {NONE} -- Mouse management

	handle_mouse_clicked (event: EM_MOUSEBUTTON_EVENT) is
			-- Handle mouse clicked event.
		local
			model_matrix, projection_matrix: ARRAY [DOUBLE]
			model_c, projection_c: ANY
			viewport: GL_VECTOR_4D [INTEGER]
			y_new: INTEGER
			result_x, result_y, result_z: DOUBLE
			temp: ANY
			click_1, click_2: GL_VECTOR_3D [DOUBLE]
			window_z: REAL
		do
			if event.is_left_button then
				increase_subdivisions
			elseif event.is_right_button and subdivisions > 0 then
				decrease_subdivisions
			end

			-- glu_un_project test:
			----------------------------------

			-- Vorbereitung fuer beide Varianten
			if video_subsystem.video_surface.is_opengl_blitting_enabled then
				video_subsystem.video_surface.disable_opengl_blitting
			end

			create model_matrix.make (0, 15)
			create projection_matrix.make (0, 15)
			create viewport.make_xyzt (0, 0, 0, 0)
			model_c := model_matrix.to_c
			projection_c := projection_matrix.to_c

			gl_get_doublev_external (Em_gl_modelview_matrix, $model_c)
			gl_get_doublev_external (Em_gl_projection_matrix, $projection_c)
			gl_get_integerv_external (Em_gl_viewport, viewport.pointer)
			y_new := video_subsystem.video_surface.height - event.screen_y -- OpenGL renders with (0,0) on bottom, mouse reports with (0,0) on top

			-- 1. Variante: Erzeuge Strahl durch Maus und teste anschliessend Schnittpunkte mit Objekten
			-- http://www.3dkingdoms.com/selection.html#point

			temp := glu_un_project_external (event.x.to_double, y_new.to_double, 0, $model_c, $projection_c, viewport.pointer, $result_x, $result_y, $result_z)
			create click_1.make_xyz (result_x, result_y, result_z)
			temp := glu_un_project_external (event.x.to_double, y_new.to_double, 1, $model_c, $projection_c, viewport.pointer, $result_x, $result_y, $result_z)
			create click_2.make_xyz (result_x, result_y, result_z)

--			io.put_string ("Click ray: "+click_1.out+" to "+click_2.out+"%N")
			-- Jetzt testen, was Strahl von click1 bis click2 trifft, und was am naechsten ist.

			-- 2. Variante: Erzeuge Raumpunkt, der richtigen "Depth"-Wert erzeugt
			-- http://wiki.delphigl.com/index.php/GluUnProject

			gl_read_pixels (event.screen_x, y_new, 1, 1, Em_gl_depth_component, Em_gl_float, $window_z)
			temp := glu_un_project (event.screen_x, y_new, window_z, $model_c, $projection_c, viewport.pointer, $result_x, $result_y, $result_z)
			create click_1.make_xyz (result_x, result_y, result_z)

--			io.put_string ("Click point: "+click_1.out+"%N")
			-- Jetzt testen, was am naechsten bei click1 ist.
		end

	handle_mouse_dragged (event: EM_MOUSEMOTION_EVENT) is
			-- Handle mouse dragged event.
		do
			longitude := longitude - event.motion.x
			latitude := latitude + event.motion.y
			if latitude > 90 then
				latitude := 90
			elseif latitude < -90 then
				latitude := -90
			end
		end

	handle_mouse_wheel_up is
			-- Handle mouse wheel up event.
		do
			distance := distance - 0.1
			if distance < 0 then
				distance := 0
			end
		end

	handle_mouse_wheel_down is
			-- Handle mouse wheel down event.
		do
			distance := distance + 0.1
			if distance > 6 then
				distance := 6
			end
		end
end