BlendFunc
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= <span class="f_Header">Example</span> = | = <span class="f_Header">Example</span> = | ||
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| + | <source lang="bascomavr"> | ||
| + | ' Pseudocode | ||
| + | |||
| + | ' The default blend function of (SRC_ALPHA, ONE_MINUS_SRC_ALPHA) causes drawing | ||
| + | ' to overlay the destination using the alpha value | ||
| + | Begin_G BITMAPS | ||
| + | Vertex2II 50, 30, 31, &H47 | ||
| + | Color_A 128 | ||
| + | Vertex2II 60, 40, 31, &H47 | ||
| + | </source> [[File:Clip0096.png|center|Clip0096.png]] <source lang="bascomavr"> | ||
| + | ' A destination factor of zero means that destination pixels are not used | ||
| + | Begin_G BITMAPS | ||
| + | BlendFunc SRC_ALPHA, ZERO | ||
| + | Vertex2II 50, 30, 31, &H47 | ||
| + | Color_A 128 | ||
| + | Vertex2II 60, 40, 31, &H47 | ||
| + | </source> [[File:Clip0097.png|center|Clip0097.png]] <source lang="bascomavr"> | ||
| + | ' Using the source alpha to control how much of the destination to keep | ||
| + | Begin_G BITMAPS | ||
| + | BlendFunc ZERO, SRC_ALPHA | ||
| + | Vertex2II 60, 40, 31, &H47 | ||
| + | </source> [[File:Clip0098.png|center|Clip0098.png]] | ||
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| + | |||
| + | |||
| + | <br/>{{Languages}} | ||
| + | |||
| + | [[Category:FT800 Commands]] | ||
Latest revision as of 22:14, 12 December 2014
Contents |
Action
Specify pixel arithmetic.
Syntax
BlendFunc src, dst
Remarks
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src |
Specifies how the source blending factor is computed. One of ZERO, ONE, SRC_ALPHA,DST_ALPHA,ONE_MINUS_SRC_ALPHA or ONE_MINUS_DST_ALPHA. |
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dst |
Specifies how the destination blending factor is computed, One of ZERO, ONE, SRC_ALPHA,DST_ALPHA,ONE_MINUS_SRC_ALPHA or ONE_MINUS_DST_ALPHA. |
The blend function controls how new color values are combined with the values already in the color buffer.
Given a pixel value source and a previous value in the color buffer destination, the computed color is:
source × src + destination × dst
for each color channel: red, green, blue and alpha.
For more details please refer to the FT800 Series Programmer Guide.PDF from FTDI.
See also
Example
' Pseudocode ' The default blend function of (SRC_ALPHA, ONE_MINUS_SRC_ALPHA) causes drawing ' to overlay the destination using the alpha value Begin_G BITMAPS Vertex2II 50, 30, 31, &H47 Color_A 128 Vertex2II 60, 40, 31, &H47
' A destination factor of zero means that destination pixels are not used Begin_G BITMAPS BlendFunc SRC_ALPHA, ZERO Vertex2II 50, 30, 31, &H47 Color_A 128
Vertex2II 60, 40, 31, &H47
' Using the source alpha to control how much of the destination to keep Begin_G BITMAPS BlendFunc ZERO, SRC_ALPHA
Vertex2II 60, 40, 31, &H47
| Languages | English |
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