kraken/standard_assets/shaders/volumetric_fog_osx.vsh

//
//  volumetric_fog_osx.vsh
//  Kraken Engine
//
//  Copyright 2025 Kearwood Gilbert. All rights reserved.
//  
//  Redistribution and use in source and binary forms, with or without modification, are
//  permitted provided that the following conditions are met:
//  
//  1. Redistributions of source code must retain the above copyright notice, this list of
//  conditions and the following disclaimer.
//  
//  2. Redistributions in binary form must reproduce the above copyright notice, this list
//  of conditions and the following disclaimer in the documentation and/or other materials
//  provided with the distribution.
//  
//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
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//


in highp vec4	vertex_position;
uniform highp mat4      inv_mvp_matrix;

uniform highp vec2      slice_depth_scale; // First component is the depth for the nearest plane, in view space.  Second component is the distance between planes, in view space

uniform highp mat4      shadow_mvp1;
out mediump vec4	shadowMapCoord1;

uniform highp mat4  projection_matrix;


void main()
{    
    highp vec4 d = projection_matrix * vec4(0.0, 0.0, slice_depth_scale.x + vertex_position.z * slice_depth_scale.y, 1.0);
    d /= d.w;
    gl_Position = vec4(vertex_position.x, vertex_position.y, d.z, 1.0);

    
    shadowMapCoord1 = inv_mvp_matrix * gl_Position;
    shadowMapCoord1 /= shadowMapCoord1.w;
    shadowMapCoord1.w = 1.0;
    shadowMapCoord1 = shadow_mvp1 * shadowMapCoord1;
    
}