// Adapted from https://github.com/Twinklebear/webgl-volume-raycaster
//
// The MIT License (MIT)
// Copyright (c) 2018 Will Usher
// 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.

VARYING vec3 vray_dir;
VARYING vec3 transformed_eye;

void MAIN()
{
    POSITION = MODELVIEWPROJECTION_MATRIX * vec4(VERTEX, 1.0);
    transformed_eye = (inverse(MODEL_MATRIX) * vec4(CAMERA_POSITION, 1.0)).xyz / 100 + vec3(0.5);
    vray_dir = (MODEL_MATRIX * vec4(VERTEX, 1.0)).xyz - CAMERA_POSITION;
}