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How would you do transparency with bitmaps. They don''t have a value for alpha blending for the level of transparency for each pixel. So how is it done?
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Transparency with bitmaps
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I assume this is for 2D sprites and masks.
You can get the RGB values of each pixel of both source and destination and then combine them using this:
Note: n1 is the source, n2 is the destination, and n is the final pixel colour.
But I find that slow to do with EVERY pixel.
I like to do something like a filter of it. Something that looks like this:
Instead of drawing all pixels like this:
You would only draw some like this... (This is for 50%)
- Rob Loach
OverTech Technologies
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"I don''t know half of you half as well as I should like; And I like less than half of you half as well as you deserve."
- Bilbo Baggins
You can get the RGB values of each pixel of both source and destination and then combine them using this:
r = (((100 - Percentage) * r1) + (Percentage * r2)) / 100
g = (((100 - Percentage) * g1) + (Percentage * g2)) / 100
b = (((100 - Percentage) * b1) + (Percentage * b2)) / 100
Note: n1 is the source, n2 is the destination, and n is the final pixel colour.
But I find that slow to do with EVERY pixel.
I like to do something like a filter of it. Something that looks like this:
Instead of drawing all pixels like this:
11111111111111111111
11111111111111111111
11111111111111111111
11111111111111111111
11111111111111111111
11111111111111111111
You would only draw some like this... (This is for 50%)
10101010101010101010
01010101010101010101
10101010101010101010
01010101010101010101
10101010101010101010
01010101010101010101
- Rob Loach
OverTech Technologies
----------
"I don''t know half of you half as well as I should like; And I like less than half of you half as well as you deserve."
- Bilbo Baggins
Ok, I understand that part.
But where do you get the percentage. In some file types they actually store the information for alpha blending.
But bitmaps don''t do that. I kind of wanted to do partial transparencies. So do I have to store that info in another file?
But where do you get the percentage. In some file types they actually store the information for alpha blending.
But bitmaps don''t do that. I kind of wanted to do partial transparencies. So do I have to store that info in another file?
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