diff options
author | Sven Gothel <[email protected]> | 2013-07-17 00:04:47 +0200 |
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committer | Sven Gothel <[email protected]> | 2013-07-17 00:04:47 +0200 |
commit | 55e480cd487e3089fae9b836eb213cd7c6b3d79a (patch) | |
tree | dc8f17c921f727d88f435687d0638b71d9c4c9a0 | |
parent | 87ebce459700e602d596302825d3ee6ac7145d40 (diff) |
Texture: Fix 'premultiply alpha' semantics in API doc description. Texture class does _nor_ premultiply RGBA image data by default!
-rw-r--r-- | src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java b/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java index 2be2f6575..f2ef3ac25 100644 --- a/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java +++ b/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java @@ -109,15 +109,20 @@ import com.jogamp.opengl.util.texture.spi.*; * see <a href="#textureCallOrder"> order of texture commands above</a>. * * <p><a name="premult"><b>Alpha premultiplication and blending</b></a> - * <br/><i>Disclaimer: Consider performing alpha premultiplication in shader code, if really desired! Otherwise use RGBA.</i> - * <br/> The mathematically correct way to perform blending in OpenGL - * (with the SrcOver "source over destination" mode, or any other - * Porter-Duff rule) is to use "premultiplied color components", which - * means the R/G/ B color components have already been multiplied by - * the alpha value. To make things easier for developers, the Texture - * class will automatically convert non-premultiplied image data into - * premultiplied data when storing it into an OpenGL texture. As a - * result, it is important to use the correct blending function; for + * <p> + * <i>Disclaimer: Consider performing alpha premultiplication in shader code, if really desired! Otherwise use RGBA.</i><br/> + * </p> + * <p> + * The Texture class does not convert RGBA image data into + * premultiplied data when storing it into an OpenGL texture. + * </p> + * <p> + * The mathematically correct way to perform blending in OpenGL + * with the SrcOver "source over destination" mode, or any other + * Porter-Duff rule, is to use <i>premultiplied color components</i>, + * which means the R/G/ B color components must have been multiplied by + * the alpha value. If using <i>premultiplied color components</i> + * it is important to use the correct blending function; for * example, the SrcOver rule is expressed as: <pre> gl.glBlendFunc(GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA); |