How to use MOAIColor to draw circle

[tingnapianhai]

Hi, I want to use MOAIColor to set the color for circle drawing, not just MOAIGfxDevice.setPenColor.

This is the way by using MOAIGfxDevice which already works.

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1. local function onDraw()


2.         MOAIGfxDevice.setPenColor(1,0,1,1)


3.         MOAIDraw.fillCircle(0, 0, self.radius, self.steps)


4. end

But I want to use MOAIColor to do this. Like:

Code: Select all

1. local function onDraw()


2.         color = MOAIColor.new()


3.         color:setColor(1,0,1,1)


4.         MOAIGfxDevice.setPenColor(color)


5.         MOAIDraw.fillCircle(0, 0, self.radius, self.steps)


6. end

But this doesnot work, anyone knows how to implement it ? Thanks

[pygy79]

I think that it is possible but more complex than that. I didn't test the method, but I believe it should work.

You must first render your polygons to a script Deck (there's an example in the deck section of the samples). Make them white.
Then, when you instantiate a prop, you can make it inherit its color from your color object.

Schematically:

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1. prop:setDeck(yourScriptableDeck)


2. prop:setAttrLink(MOAIColor.INHERIT_COLOR, color, MOAIColor.INHERIT_COLOR)

If this doesn't work, linking each channel individually should definitely work. See here for the constants: http://getmoai.com/docs/class_m_o_a_i_color.html

From there on, updates to the color objects will propagate to your props.

You should also have a look at these articles:

http://getmoai.com/wiki/index.php?title ... s_Part_One, http://getmoai.com/wiki/index.php?title ... s_Part_Two

The second gives more details about the attributes.

[derickdong]

Is there some requirement that makes it necessary for you to draw a circle this way? If you want to render a circle and use MOAIColor to set its color, I'd recommend just using a MOAIDeck/MOAIProp combo with a texture of a circle. If you make the circle in the texture white, you can set it using MOAIColor.

[pygy79]

derickdong's method has the advantage that you can have anti-aliased borders if your texture does. MOAIDraw does not support anti-aliasing.

[zandegran]

If this doesn't work, linking each channel individually should definitely work. See here for the constants: http://getmoai.com/docs/class_m_o_a_i_color.html

I tried using the attributes as parameters to setpencolor and it is not working..

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1. color=MOAIColor.new()


2. color:setColor(1,1,1)


3. print("Col",color.ATTR_R_COL)

This code prints nil.
As you said it should work...

is there some requirement that makes it necessary for you to draw a circle this way?

yes there is. I need to seek color for a specific time..It also gives me the flexibility of choosing EaseTypes


I'm a colleague of "tingnapianhai"

[derickdong]

I tried using the attributes as parameters to setpencolor and it is not working..

Code: Select all

1. color=MOAIColor.new()


2. color:setColor(1,1,1)

I just tried the method pygy79 suggested, and it works. However, using setPenColor in the draw function overrides the color value (as it probably should).

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1. MOAISim.openWindow ( "test", 320, 480 )


2.  


3. viewport = MOAIViewport.new ()


4. viewport:setSize ( 320, 480 )


5. viewport:setScale ( 320, 480 )


6.  


7. layer = MOAILayer2D.new ()


8. layer:setViewport ( viewport )


9. MOAISim.pushRenderPass ( layer )


10.  


11. function onDraw ( index, xOff, yOff, xFlip, yFlip )


12.         MOAIDraw.fillCircle ( 0, 0, 64, 32 )


13. end


14.  


15. scriptDeck = MOAIScriptDeck.new ()


16. scriptDeck:setRect ( -64, -64, 64, 64 )


17. scriptDeck:setDrawCallback ( onDraw )


18.  


19. color = MOAIColor.new()


20. color:setColor(1, 0, 0, 1)


21.  


22. prop = MOAIProp2D.new ()


23. prop:setDeck ( scriptDeck )


24. layer:insertProp ( prop )


25.  


26. prop:setAttrLink(MOAIColor.INHERIT_COLOR, color, MOAIColor.COLOR_TRAIT)


27.  

print("Col",color.ATTR_R_COL)[/code] This code prints nil.
As you said it should work...

An instance of MOAIColor doesn't have this attribute. If you want the current red value of color, it would be:

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1. print(color:getAttr(MOAIColor.ATTR_R_COL))

is there some requirement that makes it necessary for you to draw a circle this way?

yes there is. I need to seek color for a specific time..It also gives me the flexibility of choosing EaseTypes

I was referring to why you were using a MOAIScriptDeck and the MOAIDraw methods for drawing the circle. Rendering a texture of a circle, via a MOAIProp and MOAIGfxQuad2D, is a far superior method in nearly every way. It also allows the use of MOAIColor, and is somewhat easier to boot.