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68 lines
2.6 KiB
Markdown
68 lines
2.6 KiB
Markdown
# Mixbox: Practical Pigment Mixing for Digital Painting
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<p align="center">
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<img src="https://scrtwpns.com/mixbox/teaser.jpg"/>
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</p>
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Mixbox is a pigment mixing black-box. You pass RGB colors in and get the mixed RGB out.
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Internally, Mixbox treats the colors as if they were made of actual real-world pigments.
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It uses the Kubelka & Munk theory to predict the color of the resulting mixture.
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This way, Mixbox achieves that blue and yellow mix to green, the same way real pigments do.
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* Paper: https://scrtwpns.com/mixbox.pdf<br>
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* Video: https://youtu.be/ATzVPVNp1qA<br>
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* Talk: https://youtu.be/_qa5iWdfNKg<br>
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* Demo: https://scrtwpns.com/mixbox/painter<br>
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Mixbox is shipping in Rebelle 5 Pro as the [Rebelle Pigments](https://www.escapemotions.com/products/rebelle/about) feature.
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## Usage
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The simplest way to use Mixbox is with the *lerp* interface:
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```c++
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#include <stdio.h>
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#include "mixbox.h"
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int main()
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{
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unsigned char r1=252, g1=211, b1=0; // bright yellow
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unsigned char r2=0, g2=0, b2=96; // deep blue
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float t = 0.5;
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unsigned char r,g,b;
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mixbox_lerp_srgb8(r1,g1,b1, // first color
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r2,g2,b2, // second color
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t, // mixing ratio
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&r,&g,&b); // result
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printf("%d %d %d\n",r,g,b);
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}
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```
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Alternatively, one can use the *latent* interface. This allows mixing multiple RGB colors at once using arbitrary weights:
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```c++
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float latent1[MIXBOX_NUMLATENTS];
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float latent2[MIXBOX_NUMLATENTS];
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float latentMix[MIXBOX_NUMLATENTS];
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mixbox_srgb8_to_latent(r1,g1,b1,latent1);
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mixbox_srgb8_to_latent(r2,g2,b2,latent2);
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for(int i=0;i<MIXBOX_NUMLATENTS;i++)
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{
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latentMix[i] = (1.0f-t)*latent1[i] + t*latent2[i];
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}
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mixbox_latent_to_srgb8(latentMix,&r,&g,&b);
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```
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## Demo
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<p align="center">
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<a href="https://scrtwpns.com/mixbox/painter"><img src="https://scrtwpns.com/mixbox/painter_git.jpg"/></a>
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</p>
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This is a toy painting app with soft round brush and a smudge tool. It runs two color mixing implementations in parallel: one based on Mixbox and the other that performs ordinary RGB mixing. The app allows switching between them on the fly, showing the differences between pigment-based mixing and the normal RGB mixing. To launch the demo in your browser, please <a href="https://scrtwpns.com/mixbox/painter">click here</a>.
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## License
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Copyright (c) 2022, Secret Weapons. All rights reserved.<br>
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This code is for non-commercial use only. It is provided for research and evaluation purposes.<br>
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If you wish to obtain commercial license, please contact: mixbox@scrtwpns.com
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