<@include gpu/Config.slh@>
<$VERSION_HEADER$>
//  <$_SCRIBE_FILENAME$>
//  Generated on <$_SCRIBE_DATE$>
//
//  Created by Zach Pomerantz on 2/16/2016.
//  Copyright 2016 High Fidelity, Inc.
//  Copyright 2024 Overte e.V.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

<@include gpu/ShaderConstants.h@>
<@include gpu/Paint.slh@>

<@if not HIFI_USE_FORWARD@>
    <@include DeferredBufferWrite.slh@>
    INPUT(RENDER_UTILS_ATTR_PREV_POSITION_CS, vec4, _prevPositionCS);
<@else@>
    OUTPUT(0, vec4, _fragColor0);
<@endif@>

struct Grid {
    vec4 period;
    vec4 offset;
    vec4 edge;
};

UNIFORM_BUFFER(0, gridBuffer) {
  Grid grid; 
};

INPUT(GPU_ATTR_TEXCOORD0, vec2, varTexCoord0);
INPUT(GPU_ATTR_TEXCOORD1, vec2, varTexCoord1);
INPUT(GPU_ATTR_COLOR, vec4, varColor);


void main(void) {
    float gridLine = mix(paintGridMajorMinor(varTexCoord0, grid.offset, grid.period, grid.edge),
                      paintGrid(varTexCoord0, grid.offset.xy, grid.period.xy, grid.edge.xy),
                      float(grid.edge.z == 0.0));

    // TODO: this is temporary until Grid can get an
    // entity property for toggling the radius fade
<@if HIFI_USE_TRANSLUCENT@>
    const float SQRT_2 = 1.4142135623730951;

    // multiply by sqrt(2) to hide the chunk pop-in on the corners
    float fade = clamp(1.0 - (length(varTexCoord1) * SQRT_2), 0.0, 1.0);
    float gridWeight = gridLine * fade;
<@else@>
    float gridWeight = gridLine;
<@endif@>

    if (gridWeight <= 0.0) { discard; }

    vec4 color = varColor;
    color.a *= gridWeight;

<@if not HIFI_USE_FORWARD@>
    <@if not HIFI_USE_TRANSLUCENT@>
        vec3 NORMAL = vec3(1.0, 0.0, 0.0);
        packDeferredFragmentUnlit(_prevPositionCS, NORMAL, 1.0, color.rgb);
    <@else@>
        packDeferredFragmentTranslucentUnlit(color.a, color.rgb);
    <@endif@>
<@else@>
    _fragColor0 = color;
<@endif@>
}