retro palette swap shader specific object

When it comes to creating a retro aesthetic in your game or application, one technique that can be effective is palette swapping using a shader. In this article, we'll explore how you can achieve this effect with a specific object using a custom shader.

The first step is to determine the color codes for your retro palette. This typically involves exporting a texture from software like Photoshop and analyzing its RGB values. If you're not concerned about conserving texture memory, you could create a 256x256x256 3D texture that maps all possible RGB combinations to your selected palette.

Once you have your color palette in hand, the next step is to create a fragment shader that takes an external parameter - a palette mapping those 16 colors to other 16 colors. The `Shader.swap` function can then be used to apply this palette swapping to a specific object.

For example, let's say you want to change the color of an enemy sprite from red to blue. You would create two tables containing the colors you want to replace and the colors you want to swap them with. Then, in your fragment shader, you can use the `Shader.swap` function to apply this palette swapping to the object.

Here's some sample code that demonstrates how this might work:

```

P_COLOR vec4 texColor = texture2D( CoronaSampler0, texCoord );

P_COLOR vec4 FragmentKernel( P_UV vec2 texCoord ) {

Uniform P_COLOR mat4 u_UserData1; // colors

...

}

```

This code looks for a specific color with a red value greater than 0 and swaps it with the corresponding color in the palette.

While this technique can be effective, it's worth noting that it may not always produce the desired results. For example, if your palette has many colors, the shader may need to search through all of them to find a match, which could lead to performance issues. Similarly, if you're upsampling your app surface size to achieve sub-pixel rendering, this could also impact performance.

In conclusion, palette swapping using a custom shader can be a powerful technique for achieving a retro aesthetic in your game or application. By understanding how to create and apply these shaders, you can take control of the color palette and create a unique visual style that sets your project apart from others.

Retro palette swap shader specific object