mirror of
https://github.com/QB64-Phoenix-Edition/QB64pe.git
synced 2024-07-26 19:05:54 +00:00
6e01fc8dce
Added new _STRCMP and _STRICMP commands for quick string comparisons. Cleaned up QB64 to finish removing the QUI (quick user insert) code and folders. Altered UCASE and LCASE routines to be faster in some situations for us.
99 lines
3.3 KiB
Plaintext
99 lines
3.3 KiB
Plaintext
The _DONTBLEND statement turns off 32 bit alpha blending for the current image or screen mode where [[_BLEND]] is default.
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{{PageSyntax}}
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: '''_DONTBLEND''' [{{Parameter|imageHandle&}}]
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{{Parameters}}
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* If {{Parameter|imageHandle&}} is omitted, it is assumed to be the current [[_DEST]]ination write page.
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''Usage:''
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* If {{Parameter|imageHandle&}} is not valid, an [[ERROR Codes|Invalid handle]] error will occur.
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* [[_DONTBLEND]] is faster than the default [[_BLEND]] unless you really need to use it in 32 bit!
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* '''32 bit screen surface backgrounds(black) have zero [[_ALPHA]] so that they are transparent when placed over other surfaces.'''
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: Use [[CLS]] or [[_DONTBLEND]] to make a new surface background [[_ALPHA]] 255 or opague.
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''Example 1:'' Use _DONTBLEND when you want the 32 bit screen surface to be opaque so that it covers up other backgrounds. [[CLS]] works too.
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{{CodeStart}} '' ''
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{{Cl|SCREEN}} {{Cl|_NEWIMAGE}}(1280, 720, 32)
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'{{Cl|CLS}}
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{{Cl|_DONTBLEND}} '<<< comment out to see the difference
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{{Cl|LINE}} (100, 100)-(500, 500), {{Cl|_RGB32}}(255, 255, 0), BF
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b& = SaveBackground&
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{{Cl|PRINT}} "This is just test junk"
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{{Cl|PRINT}}
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{{Cl|PRINT}} "Hit any key and the text should disappear, leaving us our pretty yellow box."
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{{Cl|SLEEP}}
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RestoreBackground b&
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{{Cl|END}}
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{{Cl|FUNCTION}} SaveBackground&
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SaveBackground& = {{Cl|_COPYIMAGE}}(0)
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{{Cl|END FUNCTION}}
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{{Cl|SUB}} RestoreBackground (Image {{Cl|AS}} {{Cl|LONG}})
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{{Cl|_PUTIMAGE}} (200, 200), Image, 0
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{{Cl|END SUB}} '' ''
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{{CodeEnd}}
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''Example 2:'' Turning off blending to create transparency.
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{{CodeStart}}
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{{Cl|SCREEN (statement)|SCREEN}} {{Cl|_NEWIMAGE}}(640, 480, 32)
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alphaSprite& = {{Cl|_NEWIMAGE}}(64, 64, 32)
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{{Cl|_DONTBLEND}} alphaSprite& ' turn off alpha-blending
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'Create a simple sprite with transparency
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{{Cl|_DEST}} alphaSprite&
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{{Cl|FOR}} y = 0 {{Cl|TO}} 63
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{{Cl|FOR}} x = 0 {{Cl|TO}} 63
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alpha = {{Cl|SQR}}((x - 32) ^ 2 + (y - 32) ^ 2) / 32
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{{Cl|IF}} alpha < 0 {{Cl|THEN}} alpha = 0
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alpha = (1 - alpha * alpha) 'parabolic curve
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{{Cl|PSET}} (x, y), {{Cl|_RGBA32}}(255, 255, 255, alpha * 255)
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{{Cl|NEXT}}
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{{Cl|NEXT}}
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'Make a simple background texture
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{{Cl|_DEST}} 0
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{{Cl|FOR}} y = 1 {{Cl|TO}} 479
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{{Cl|FOR}} x = 0 {{Cl|TO}} 639
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{{Cl|PSET}} (x, y), {{Cl|_RGB32}}(x {{Cl|AND (boolean)|AND}} 255, y {{Cl|AND (boolean)|AND}} 255, (x {{Cl|XOR (boolean)|XOR}} y) {{Cl|AND (boolean)|AND}} 255)
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{{Cl|NEXT}}
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{{Cl|NEXT}}
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'Store background so we can show moveable objects on it
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background& = {{Cl|_COPYIMAGE}}
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'Treat my alpha values as transparency
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{{Cl|_BLEND}} alphaSprite&
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ph = 0
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{{Cl|DO}}: {{Cl|_LIMIT}} 60
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x = 320 - 250 * {{Cl|COS}}(ph) - ({{Cl|_WIDTH (function)|_WIDTH}}(alphaSprite&) \ 2)
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y = 240 - 150 * {{Cl|COS}}(ph * 1.3) - ({{Cl|_HEIGHT}}(alphaSprite&) \ 2)
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ph = ph + 0.03
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{{Cl|_PUTIMAGE}} , background&, 0
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{{Cl|_PUTIMAGE}} (x, y), alphaSprite&, 0
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{{Cl|_DISPLAY}}
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{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|LEN}}({{Cl|INKEY$}}) '' ''
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{{CodeEnd}}{{small|Code by Zom-B}}
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''Explanation:'''To make the alpha image, turn alpha blending off. Otherwise PSET blends the pixel to instead of making the sprite transparent.
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{{PageSeeAlso}}
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* {{KW|_BLEND}}
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* {{KW|_BLEND (function)}}
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* [[Images]]
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{{PageNavigation}} |