Differential D3675
WeightPainting: Drawing Authored by Alexander Gavrilov (angavrilov) on Sep 4 2018, 3:46 PM.
Details This is a first patch of two. The first patch will do the weight painting. When that is committed we will do the edit lattice in a second patch. Moved the weightpaint drawing to the fragment shader. The shader uses a texture that uses the U.cobo custom color band, or internal color band. New weight paint shader 
Diff Detail
Event TimelineComment Actions Implementation looks fine but i'm not sure doing the color ramp sampling in the fragment shader is better, because it adds too many color change and can make the user think there is more vertices weighted differently. I would sample the weight in the vertex shader, convert to linear (for interpolation), then convert back to sRGB in the fragment shader.
Comment Actions Checked, +1 to @Clément Foucault (fclem)'s comments. Interpolating the color band looks nice, perhaps we can get feedback from a rigger here if they think it's useful. Since it adds color detail where there is no geometry. Otherwise patch LGTM.
Comment Actions To elaborate: alert color is a feature to show points that have weight of exactly 0 (either for the group, or for all groups) in a different color, normally black. Most of the time this is useful for easily detecting mistakes in painting, like an unintended light touch with a brush to a different part of the object, or unclean boundary. However, for multipaint this is absolutely essential, because it cannot paint at all on vertices where the collective weight is exactly zero. Plus, of course, for multipaint you have to display the collective weight of all selected groups, because that is what it operates on. Comment Actions I think @Alexander Gavrilov (angavrilov) have a point. We should support these corner cases because they are important to the workflow. Maybe use a special weight value in the VBO and a special case color in the vertex shader. Comment Actions If I recall, there is a setting somewhere to set the alert color, so it probably should use that. There definitely is an option in the Options menu that selects the operation mode for the alert. Regarding alert color implementation, a special value like -1 can indeed be used in VBO (provided true weights are clamped to the correct 0-1 range), but the vertex shader should split it into two values: true weight, and alpha-like alert status, and interpolate those. Otherwise you would risk either weird interpolation between a non-zero and alert weight, or being unable to see the alert color if a null vertex is completely surrounded by weighted ones. I.e. alert color is one case where the approach of computing color in the vertex shader and then interpolating seems to be obviously better, and it should be emulated even by the weight in the fragment shader approach. Regarding multipaint, if something is not clear about how it works, I may be able to help, since rewriting it into something that is actually usable was my first major patch for blender. Comment Actions Since I introduced changes conflicting with this patch, I decided to update it myself.
Comment Actions Comparison of color ramps. New colors are more dull because of the prior change to multiply and the fact that a truly white material seems to be impossible.
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And an example of a more complex mesh and weight arrangement than a cube:  | |||||||||||||||||||||||||||||||||||||||||||||||||||||
