[Tutorial] Fades

[Dahrkael]

Hi :3
I'll explain how to make "fades" in an easy way, ill use a 640x480 resolution.

first you need a scene system like this:
viewtopic.php?f=191&t=67246

then we will make a scene called Transition with this content:

include Gosu

class Transition

    attr_reader :screen_x

    attr_reader :screen_y

 

    def initialize(scene, type)

        @next_scene = scene

        @time = 0

        @fading = type

        @fade_time = 255 if @fading == :in

        @fade_time = 0 if @fading == :out

        @color = Color.new(@fade_time, 0, 0 ,0)

    end

    

    def button_down(id)

    end

    

    def update

        @color = Color.new(@fade_time, 0, 0 ,0)

        case @fading

            

        when :in

            if @fade_time <= 0

                $scene = @next_scene

            else

                @fade_time -= 15 # 15 is cool

            end

        when :out

            if @fade_time >= 255

                $scene = @next_scene

            else

                @fade_time += 15 # 15 is cool

            end

        end

            

        self.draw

    end

    

    def draw

        @next_scene.update

        $window.draw_quad(0, 0, @color, 640, 0, @color, 0, 480, @color, 640, 480, @color, 500)   

    end

    

end

 

If you see the code you will know that the fade is really a black image which is increasing (or decreasing) its opacity.
Fades are normally short, because while the fade is processing, the update is running and can origin problems =)

The correct use is: $scene = Transition.new(next_scene, type_of_fade)
$scene = Transition.new(Porn_Room.new, :in/ut)

 

[Ellie]

Something sortof related but not related, am I right in thinking we don't have to dispose things in Gosu?

draw_quad for example, it draws the quad but then will disappear on the next frame unless it's drawn again, right?

 

[Dahrkael]

Gosu images are not like RGSS Sprites.

If you know, RGSS have two types of images, bitmaps and sprites.

Bitmaps need a rect to be showed. Gosu makes Bitmaps with its own rect to be showed, so dont need to dispose nothing =)

 

[e]

But yes, from experience, if you don't draw it on every tick it WILL disappear. Or maybe I'm doing it wrong? If I don't redraw images, they disappear; now I haven't tried using the Window's draw_quad or draw_line method; do these stay until painted over?

 

[Dahrkael]

Gosu includes at the beginning of all frames something like

"self.contents.clear" so you need to redraw all the things you want in the screen.