Mandarine.metal

//
//  Mandarine.metal
//  Folium-iOS
//
//  Created by Jarrod Norwell on 1/3/2026.
//

#include <metal_stdlib>
using namespace metal;

struct VertexIn {
    float2 position;
    float2 texcoord;
};

struct VertexOut {
    float4 position [[position]];
    float2 texcoord;
};

vertex VertexOut mandarine_metal_vertex_main(
    const device VertexIn* vertices [[buffer(0)]],
    uint id [[vertex_id]])
{
    VertexOut out;

    float2 pos = vertices[id].position;

    // Convert to NDC
    pos.x = (pos.x / 512.0) * 2.0 - 1.0;
    pos.y = 1.0 - (pos.y / 256.0) * 2.0;

    out.position = float4(pos, 0, 1);
    out.texcoord = vertices[id].texcoord;

    return out;
}

fragment float4 mandarine_metal_fragment_main(
    VertexOut in [[stage_in]],
    texture2d<float> tex [[texture(0)]])
{
    constexpr sampler s(address::clamp_to_edge,
                        filter::nearest);

    return tex.sample(s, in.texcoord);
}