indexing

	description: "[

		A simple GLSL scene

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

class MAIN_SCENE

inherit

	EM_GL_SCENE

	EMGL_VIEW
		export {NONE} all end

	EMGL_BASIC_RENDERER
		export {NONE} all end

	GLEW_FUNCTIONS
		export {NONE} all end

	CG_FUNCTIONS_EXTERNAL
		export {NONE} all end

	CGENUM_ENUM_EXTERNAL
		rename
			is_valid_enum as cg_is_valid_enum
		export
			{NONE} all
		end

	CGGL_FUNCTIONS_EXTERNAL
		export {NONE} all end

	CGGLENUM_ENUM_EXTERNAL
		rename
			is_valid_enum as cg_gl_is_valid_enum
		export
			{NONE} all
		end

create

	make

feature {NONE} -- Initialisation

	CgContext: POINTER
	CgVertexProfile: INTEGER
	CgProgram: POINTER

	make is
			-- Initialise default values.
		local
			filename: STRING
			file: PLAIN_TEXT_FILE
			file_string: ANY

			main: ANY
			args: ANY

			error: INTEGER
			error_string: STRING
				-- Handle to the vertex and fragment shader
		do

			make_scene

			-- Initialise normalized speed for rotation of pyramid

			cgcontext := cg_create_context_external

			if cgcontext = 0x0 then
				io.put_string ("Failed to create cg context")
			end

			CgVertexProfile := cg_glget_latest_profile_external (cg_gl_vertex)
			if cgvertexprofile = cg_unknown then
				io.put_string("Invalid profile type")
			end

			cg_glset_optimal_options_external (cgvertexprofile)

			filename := "Cg/Wave.cg"
			main := (create {STRING}.make_from_string ("main")).to_c
			args := (create {STRING}.make_from_string ("")).to_c

			create file.make (filename)
			file.open_read
			file.read_stream (file.count)
			file_string := (create {STRING}.make_from_string (file.last_string)).to_c

			CgProgram := cg_create_program_external (cgcontext, cg_source, $file_string, cgvertexprofile, $main, $args)

			if CgProgram = 0x0 then
				error := cg_get_error_external
				create error_string.make_from_c (cg_get_error_string_external (error))
				io.put_string ("Cg Error: " + error_string + "%N")
			end

			cg_glload_program_external (CgProgram)
		ensure
			speed_not_void: speed /= Void
		end

feature -- Access

	program: EMGL_SHADER_PROGRAM
		-- Handle to the program object

	angle: DOUBLE
		-- Rotation angle in degrees

	speed: EM_NORMALIZED_SPEED
		-- Rotation speed for pyramid

feature -- Drawing

	quadric_renderer: EMGLU_QUADRIC is
			-- Quadric renderer
		do
			create result
		end

	draw is
			-- Draw scene.
		do
			if program/=void then
				program.use
				program.uniform1f ( "time", time.ticks )
			end

			-- Move the pyramid into the screen and rotate it
			emgl_translatef (0, 0, -9)
			emgl_rotatef (angle, 0, 1, 0)

			emgl_begin (Em_gl_triangles)
				-- Front
				emgl_color3f(1, 0, 0) -- Red
				emgl_vertex3d (0, 1, 0)
				emgl_vertex3d (-1, -1, 1)
				emgl_vertex3d (1, -1, 1)

				-- Right
				emgl_color3f(0, 1, 0) -- Green
				emgl_vertex3d (0, 1, 0)
				emgl_vertex3d (1, -1, 1)
				emgl_vertex3d (1, -1, -1)

				-- Back
				emgl_color3f (0, 0, 1) -- Blue
				emgl_vertex3d (0, 1, 0)
				emgl_vertex3d (1, -1, -1)
				emgl_vertex3d (-1, -1, -1)

				-- Left
				emgl_color3f (1, 1, 0) -- Yellow
				emgl_vertex3d (0, 1, 0)
				emgl_vertex3d (-1, -1, -1)
				emgl_vertex3d (-1, -1, 1)
			emgl_end

			emgl_color3f (1, 0, 1)
			emgl_translatef (0, 3, 0)
			quadric_renderer.sphere (2, 20, 10)

			if program/=void then
				program.unuse
			end

			-- Increment the angle
			if angle < 360 then
				angle := angle + speed.get_delta
			else
				angle := 0
			end
		end

invariant
	speed_not_void: speed /= Void

end