#pragma once

#define __STRINGIFY(x) #x
#define _STRINGIFY(x) __STRINGIFY(x)

constexpr const char* utilityShaderSource = R"V0G0N(
#include <metal_stdlib>
using namespace metal;

#define GET_BUFFER_BINDING(index) (28 + index)
#define GET_TEXTURE_BINDING(index) (29 + index)
#define GET_SAMPLER_BINDING(index) (14 + index)\n

constant float2 positions[] = {float2(-1.0, -3.0), float2(-1.0, 1.0), float2(3.0, 1.0)};

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

vertex VertexOut vertexFullscreen(ushort vid [[vertex_id]]) {
    VertexOut out;
    out.position = float4(positions[vid], 0.0, 1.0);
    out.texCoord = positions[vid] * 0.5 + 0.5;
    out.texCoord.y = 1.0 - out.texCoord.y;

    return out;
}

fragment float4 fragmentPresent(VertexOut in [[stage_in]], texture2d<float> tex [[texture(0)]], sampler samplr [[sampler(0)]]) {
    return tex.sample(samplr, in.texCoord);
}

/*
vertex void vertexCopyTextureToTexture(uint vid [[vertex_id]], texture2d<float, access::read> src [[texture(GET_TEXTURE_BINDING(0))]], texture2d<float, access::write> dst [[texture(GET_TEXTURE_BINDING(1))]], constant uint32_t& width [[buffer(GET_BUFFER_BINDING(0))]]) {
    uint2 coord = uint2(vid % width, vid / width);
    return dst.write(float4(src.read(coord).r, 0.0, 0.0, 0.0), coord);
}
*/

struct RestrideParams {
    uint oldStride;
    uint newStride;
};

// TODO: use uint32? Since that would require less iterations
vertex void vertexRestrideBuffer(uint vid [[vertex_id]], device uint8_t* src [[buffer(GET_BUFFER_BINDING(0))]], device uint8_t* dst [[buffer(GET_BUFFER_BINDING(1))]], constant RestrideParams& params [[buffer(GET_BUFFER_BINDING(2))]]) {
    for (uint32_t i = 0; i < params.oldStride; i++) {
        dst[vid * params.newStride + i] = src[vid * params.oldStride + i];
    }
}
)V0G0N";