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Questions tagged [alpha]

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Why is it so important to minimize alpha in textures for rendering

When modeling something like a hair or foliage using textures with alpha value for offline or real-time rendering, it seems to be common practice among computer modelers to try to minimize the amount ...
Lenny White's user avatar
0 votes
3 answers

How do I add two color values containing alpha?

I started out writing my Color class as just containing R, G, B triplets. Adding colors in this situation turns out to be fairly simple. ...
Hakanai's user avatar
  • 111
0 votes
1 answer

In alpha premultiplied sRGB a color component can't be greater than the alpha, right?

Afaik, in alpha premultiplied color the components stored so: [r * a, g * a, b * a, a] So the fully opaque white color is: ...
nikitablack's user avatar
0 votes
1 answer

OpenGL blending with the screen

I don't understand how OpenGL performs the blending of a texture on the screen. By default, the clear color is set to (0, 0, 0, 0). If we use the default blending equation GL_SRC_ALPHA and ...
Jojolatino's user avatar
1 vote
1 answer

Given a background image B and a composie image of A OVER B, can we somehow recover image A?

I often find myself in the situation where I have some old image where I composed a translucent overlay on top of a background, but then lost (or more likely discarded) the overlay. I still have pre-...
swestrup's user avatar
  • 113
3 votes
1 answer

Repeating alpha over/under operation multiple times

I have two RGBA colors in linear [0..1] space, src and dst and I want to alpha blender src ...
piegames's user avatar
  • 297
1 vote
0 answers

Sorting my geometry for alpha testing

Here is my predicament. I am trying to draw a multitude of dots that leave trails behind them real time. Heres the difficulty, that line fades. Each dot line has a defined z position and the goal ...
J.Doe's user avatar
  • 1,445
2 votes
2 answers

How to perform additive blending in Metal. What do these terms mean?

Forgive me, I dont really understand the basis of alpha blending. Like I know the formula but when it comes to the terms blending operation, source blend factor, and destination blend factor I am ...
J.Doe's user avatar
  • 1,445
1 vote
1 answer

Are docs correct?

I'm referring to this section: Considering the formula co = Cs x αs + Cb x αb x (1 - αs) the docs state ...
uglycode's user avatar
  • 113
4 votes
1 answer

Avoid having an opaque and transparent variant of each pixel shader

Transparency can be achieved (or actually approximated) by using alpha-to-coverage (in case of MSAA) or basic alpha/transparency blending using the following approach: Bind a rasterizer state with a ...
Matthias's user avatar
  • 1,044
0 votes
1 answer

Make Object created in a list blend in/dissolve out of a scene

I have a number of (opaque) objects created using the glGenLists() glNewList() utilities. As generated, the Alpha values are all set to 1 Is there a way to make these objects when summoned blend into ...
Sharat V Chandrasekhar's user avatar