Geometry Nodes: Color mix nodes don't effect the alpha #104401

New Issue

Shmuel Israel · 2023-02-07T08:11:25+01:00

Shmuel Israel commented

2023-02-07 08:11:25 +01:00

System Information
Operating system:
Graphics card:

Blender Version
Broken: 3.4.1

Short description of error
whenever I try doing any math with colors, the alpha isn't affected when I use the color mix node in any blend mode.

Exact steps for others to reproduce the error

Open blender geometry nodes.
Add 2 combine color, color or whatever node with different different values for the alpha's.
Use a mix color node with any operation like add, subtract etc.
See that the alpha didn't change (use the spreadsheet or the hover over).

**System Information** Operating system: Graphics card: **Blender Version** Broken: 3.4.1 **Short description of error** whenever I try doing any math with colors, the alpha isn't affected when I use the color mix node in any blend mode. **Exact steps for others to reproduce the error** 1. Open blender geometry nodes. 2. Add 2 combine color, color or whatever node with different different values for the alpha's. 3. Use a mix color node with any operation like add, subtract etc. 4. See that the alpha didn't change (use the spreadsheet or the hover over).

Shmuel Israel commented

2023-02-07 08:11:25 +01:00

Added subscriber: @shmuel

Scurest commented

2023-02-07 19:08:18 +01:00

Geometry nodes are like shader nodes I think: color sockets don't carry alpha. That's why eg. the Image Texture node has a separate Color and Alpha socket.

That makes the alpha appearing in the color picker misleading of course.

Geometry nodes are like shader nodes I think: color sockets don't carry alpha. That's why eg. the Image Texture node has a separate Color and Alpha socket. That makes the alpha appearing in the color picker misleading of course.

Shmuel Israel commented

2023-02-07 21:56:10 +01:00

Geometry nodes are like shader nodes I think: color sockets don't carry alpha. That's why eg. the Image Texture node has a separate Color and Alpha socket.

That makes the alpha appearing in the color picker misleading of course.

This isn't true. Geometry nodes are different than shaders, seeing as thay have a separate answer combine color nodes that have an alpha socket. I didn't make this bug report because I was bored; I ran into an issue where I'm trying to do math with quaternions - a 4 dimension number and am using the color sockets for it - and when I do math operation I don't want to separate the color into its components do the math and then recombine it. That's just inconvenient.

> Geometry nodes are like shader nodes I think: color sockets don't carry alpha. That's why eg. the Image Texture node has a separate Color and Alpha socket. > > That makes the alpha appearing in the color picker misleading of course. This isn't true. Geometry nodes are different than shaders, seeing as thay have a separate answer combine color nodes that have an alpha socket. I didn't make this bug report because I was bored; I ran into an issue where I'm trying to do math with quaternions - a 4 dimension number and am using the color sockets for it - and when I do math operation I don't want to separate the color into its components do the math and then recombine it. That's just inconvenient.

Scurest commented

2023-02-07 22:09:43 +01:00

You're right, my bad. (I wonder why they're separate on some nodes and not others though.)

edit: I think the problem is the geo node code ends up going through the same ramp_blend function that the shader node code uses, so just like for shader nodes, it operates only on the first three components (the alpha of the A operand goes through unchanged).

You're right, my bad. (I wonder why they're separate on some nodes and not others though.) edit: I think the problem is the geo node code ends up going through the same `ramp_blend` function that the shader node code uses, so just like for shader nodes, it operates only on the first three components (the alpha of the A operand goes through unchanged).

Iliya Katushenock commented

2023-02-07 23:10:24 +01:00

will check