image question
BlitzMax Forums/BlitzMax Beginners Area/image question
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| hey, I have ships which are drawn on a black back ground. 2d ships of course. top down view. if i had one on a blue background, is there someway i can mask the blue, that it doesn't show up when in game, and hence the ship image isn't read as being from the border of this blue? also does magic pink still work? |
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| Function SetMaskColor( red,green,blue ) Description Set current mask color. Information The current mask color is used to build an alpha mask when images are loaded or modified. The red, green and blue parameters should be in the range of 0 to 255. Just make sure you have alpha mask set, and that you set the mask colour before you load the image. (well the before load thing isnt compulsory (ish), but it makes things a hell of a lot easyer) |
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| before I load it? or before I draw it? so for this one image of the background is blue, i can setmaskcolor(code to blue) then draw it? or load it with it masked already. Just wondering if you meant draw instead of load. |
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| errrr.. which of those two options have you tried? The current mask color is used to build an alpha mask when images are loaded or modified I would guess 'before' you load but don't take my word for it. |
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| Did I not post "...set the mask colour before you load the image..." |
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| could be a typo :) |
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| so then I cant have more than one mask color, its either black blue pink yellow or green or whatever |
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| No, you can then change it for the next image you load. What it is doing is building an alpha mask, so you tell it that its green, load the image it builds the mask with green as the mask colour, then you tell it the mask colour is cyan, and it loads the next image and builds the mask with the colour cyan etc What I tend to do is load the image as a pixmap, find the colour of the top left pixel, kill the pixmap, set the mask colour to the colour I just found, then load the image back in as an image. (I dont really do this, but that explains it easyer) |
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| so if i set the mask before i load one drawing, it doesn't set it for the rest, that are way after? reason i ask is all my images are globals in globals.bmx which is included in my main. when i want to add graphics or sound, i just add a global newsound = loadsound blah blah |
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| Anything you set within BM holds until it is set to something different, so its fully up to you to decide when you need to have it a different value for the next operation you are doing :-) |
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| P1) How do I do this R1) You set this before you load an image P2) Before I Draw the Image or before I load the Image R2) Before you load the Image P3) So I can only Set it once R3) No you can set it before you load any image, and reset it before you load another image P3) So I have to set it before I load every image R3) Ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh In case you didnt realise this is just cut from the docs Function SetMaskColor( red,green,blue ) Description Set current mask color. Information The current mask color is used to build an alpha mask when images are loaded or modified. The red, green and blue parameters should be in the range of 0 to 255. So, when you load (or modify) an image, Bmax builds an Alpha mask for that image, with the current mask color. If you want the Mask colour to be a different mask colour you change it. If you dont want the mask colour to be a different colour you dont change it |
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| lol, are you sure about this? Can't I just set the alpha after I turn my computer off? |
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| Before you _load_ an image, which means: as you are creating it in your painting software, you should add a socalled Alphachannel to your picture in order to "paint with transparency". So you specify the (half-)transparent parts of your picture already in your image programme. I would recommend GIMP or Photoshop. Save it as a png file and be happy with it. |
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| Or use Pixia. Small easy app that supports this kind of stuff extremely well. |
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| To echo Justus: if you save images as PNG with proper alpha channels, you won't need to worry about this at all... |
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| so if I save a ship with a blue alpha channel, and one with a black one, when they loadimage in blitzmax, they are fine. true? thanks alot guys! im not artist after all... |
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| no. Unless you tell the program to change the alpha channal to blue for the blue one, then load it in, then change it to black for the black one then load it in. THEN they are ok. If you save them with an alpha channel (which isnt a colour so dont go saying what colour it used to be) they will be ok, otherwise you have to change the alpha mask colour to the colour you wnat masked each time you load the image. But once the images are loaded the have an alpha channel SO IT DOESNT MATTER what colour it used to be, cos NOW its an alpha layer |
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| save all with one channel. |
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| What? Look if you have made the images, just change the mask colour to the colour you ued for the background, and load them in. Then change the mask colour if you have some that you made with a different colour |
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SetMaskColor 0,0,0 'Set Mask to Black
ImageWithBlackMask:TImage = LoadImage("MyImageWithABlackMask.png")
SetMaskColor 0,0,255 'Set Mask To Blue
ImageWithBlueMask:TImage = LoadImage("MyImageWithABlueMask.png")
Repeat
DrawImage ImageWithBlackMask,10,10 'Both Images will be drawn correctly.
DrawImage ImageWithBlueMask,100,100
Flip
Until GameDone
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