// pathfinder/shaders/tile_vertex.inc.glsl
//
// Copyright © 2020 The Pathfinder Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

vec4 fetchUnscaled(sampler2D srcTexture, vec2 scale, vec2 originCoord, int entry) {
    return texture(srcTexture, (originCoord + vec2(0.5) + vec2(entry, 0)) * scale);
}

void computeTileVaryings(vec2 position,
                         int colorEntry,
                         sampler2D textureMetadata,
                         ivec2 textureMetadataSize,
                         out vec2 outColorTexCoord0,
                         out vec4 outBaseColor,
                         out vec4 outFilterParams0,
                         out vec4 outFilterParams1,
                         out vec4 outFilterParams2,
                         out int outCtrl) {
    vec2 metadataScale = vec2(1.0) / vec2(textureMetadataSize);
    vec2 metadataEntryCoord = vec2(colorEntry % 128 * 8, colorEntry / 128);
    vec4 colorTexMatrix0 = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 0);
    vec4 colorTexOffsets = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 1);
    vec4 baseColor       = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 2);
    vec4 filterParams0   = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 3);
    vec4 filterParams1   = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 4);
    vec4 filterParams2   = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 5);
    vec4 extra           = fetchUnscaled(textureMetadata, metadataScale, metadataEntryCoord, 6);
    outColorTexCoord0 = mat2(colorTexMatrix0) * position + colorTexOffsets.xy;
    outBaseColor = baseColor;
    outFilterParams0 = filterParams0;
    outFilterParams1 = filterParams1;
    outFilterParams2 = filterParams2;
    outCtrl = int(extra.x);
}