#version 450

/*
 * Kiyo data
 * - WORKGROUP_SIZE and NUM_IMAGES are provided by the engine
 */

layout ( local_size_x = WORKGROUP_SIZE, local_size_y = WORKGROUP_SIZE, local_size_z = 1 ) in;
layout( binding = 0, rgba8 ) uniform image2D images[NUM_IMAGES];
layout( push_constant ) uniform PushConstants
{
    float time;
    int in_image;
    int out_image;
} constants;

/*
 * User data
 */

vec3 palette( in float t, in vec3 a, in vec3 b, in vec3 c, in vec3 d )
{
    return a + b*cos( 6.28318*(c*t+d) );
}

void main()
{
    ivec2 p = ivec2( gl_GlobalInvocationID.xy );
    ivec2 screenSize = imageSize( images[ constants.out_image ] );
    if( p.x > screenSize.x || p.y > screenSize.y )
    {
        return;
    }

    vec2 pos = vec2( float( p.x ) / float( screenSize.x ), float( p.y ) / float( screenSize.y ) ) - 0.5f;

    float t = constants.time * .1f + 0.5f * length( pos );
    vec3 color = palette( t, vec3( 0.5, 0.5, 0.5 ), vec3( 0.5, 0.5, 0.5 ), vec3( 2.0, 1.0, 0.0 ), vec3( 0.5, 0.20, 0.25 ) );
    imageStore( images[ constants.out_image ], p, vec4( color, 1 ) );
}