cake.txt

// Instructions
// 1. Download into the folder 'shader' in your MagicaVoxel install folder
// 2. Open the shaders panel on the right
// 3. Cick the cake shader and press play! Your model insides are now cake! (Colors not included)

// Copyright 2020 Aidan (@PossiblyAShrub)

// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
// associated documentation files (the "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
// following conditions: The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
// CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

// xs_begin
// author : '@PossiblyAShrub'
// arg : { id = '0' name = 'Num Layers' value = '8'   range = '1 20'    step = '1' decimal = '0' }
// xs_end

//===== user args =====
// uniform float	i_args[8];

//===== built-in args =====
// uniform vec3		i_volume_size;	// volume size [1-256]
// uniform float	i_color_index;	// color index [0-255]
// uniform vec3		i_mirror;		// mirror mode [0,1]
// uniform vec3		i_axis;			// axis mode [0,1]
// uniform float	i_iter;			// iteration index

//===== built-in functions ===== 
// float voxel( vec3 v );			// get voxel color index at position v

float map(vec3 v) {
	// dump args into named variables
    float numLayers = i_args[0];

    // find all 6 neighbors
    bool up = voxel(v + vec3(0, 1, 0)) != 0;
    bool down = voxel(v + vec3(0, -1, 0)) != 0;
    bool right = voxel(v + vec3(1, 0, 0)) != 0;
    bool left = voxel(v + vec3(-1, 0, 0)) != 0;
    bool front = voxel(v + vec3(0, 0, 1)) != 0;
    bool back = voxel(v + vec3(0, 0, -1)) != 0;

    // if all neighbors are found then we are inside the model
    // so... CAKE
    if (up && down && right && left && front && back) {
        // then do some math to find what layer we're on
        return i_color_index + floor((v.z / i_volume_size.z) * numLayers);
    }

    // otherwise leave things as we found them - they will never notice!
    return voxel(v);
}