using System.Numerics;
using static Raylib_cs.Raylib;

namespace Examples.Models;

public class MeshDemo
{
    public unsafe static int Main()
    {
        // Initialization
        //--------------------------------------------------------------------------------------
        const int screenWidth = 800;
        const int screenHeight = 450;

        InitWindow(screenWidth, screenHeight, "raylib [models] example - mesh demo");

        // Define the camera to look into our 3d world
        Camera3D camera = new();
        camera.Position = Vector3.One * 1.5f;
        camera.Target = Vector3.Zero;
        camera.Up = Vector3.UnitY;
        camera.FovY = 60.0f;
        camera.Projection = CameraProjection.Perspective;

        // Generate a mesh using utils to allocate/access mesh attribute data
        Mesh tetrahedron = new(4, 4);
        tetrahedron.AllocVertices();
        tetrahedron.AllocTexCoords();
        tetrahedron.AllocColors();
        tetrahedron.AllocIndices();
        Span<Vector3> vertices = tetrahedron.VerticesAs<Vector3>();
        Span<Vector2> texcoords = tetrahedron.TexCoordsAs<Vector2>();
        Span<Color> colors = tetrahedron.ColorsAs<Color>();
        Span<ushort> indices = tetrahedron.IndicesAs<ushort>();

        // Coordinates for a regular tetrahedron
        vertices[0] = new(MathF.Sqrt(8f / 9f), 0f, -1f / 3f);
        vertices[1] = new(-MathF.Sqrt(2f / 9f), MathF.Sqrt(2f / 3f), -1f / 3f);
        vertices[2] = new(-MathF.Sqrt(2f / 9f), -MathF.Sqrt(2f / 3f), -1f / 3f);
        vertices[3] = Vector3.UnitZ;

        texcoords[0] = Vector2.Zero;
        texcoords[1] = Vector2.UnitX;
        texcoords[2] = Vector2.UnitY;
        texcoords[3] = Vector2.One;

        colors[0] = Color.Pink;
        colors[1] = Color.Lime;
        colors[2] = Color.SkyBlue;
        colors[3] = Color.Violet;

        indices[0] = 2;
        indices[1] = 1;
        indices[2] = 0;

        indices[3] = 1;
        indices[4] = 3;
        indices[5] = 0;

        indices[6] = 2;
        indices[7] = 3;
        indices[8] = 1;

        indices[9] = 0;
        indices[10] = 3;
        indices[11] = 2;

        float rotationAngle = 0f;
        Raylib.UploadMesh(ref tetrahedron, false);
        Model model = Raylib.LoadModelFromMesh(tetrahedron);

        Image image = Raylib.GenImagePerlinNoise(16, 16, 0, 0, 1000f);
        Raylib.ImageBlurGaussian(ref image, 2);
        Raylib.ImageColorBrightness(ref image, 100);
        Raylib.ImageDither(ref image, 4, 4, 4, 4);
        Texture2D texture = Raylib.LoadTextureFromImage(image);
        Raylib.UnloadImage(image);

        Raylib.SetMaterialTexture(ref model, 0, MaterialMapIndex.Diffuse, ref texture);

        SetTargetFPS(60);
        //--------------------------------------------------------------------------------------

        // Main game loop
        while (!WindowShouldClose())
        {
            // Update
            //----------------------------------------------------------------------------------
            UpdateCamera(ref camera, CameraMode.Free);
            rotationAngle = Raymath.Wrap(rotationAngle += 1f, 0f, 360f);
            //----------------------------------------------------------------------------------

            // Draw
            //----------------------------------------------------------------------------------
            BeginDrawing();
            ClearBackground(Color.RayWhite);

            BeginMode3D(camera);
            Raylib.DrawModelEx(model, Vector3.Zero, Vector3.UnitX, rotationAngle, Vector3.One, Color.White);
            EndMode3D();

            EndDrawing();
            //----------------------------------------------------------------------------------
        }

        // De-Initialization
        //--------------------------------------------------------------------------------------
        UnloadTexture(texture);
        UnloadModel(model);

        CloseWindow();
        //--------------------------------------------------------------------------------------

        return 0;
    }
}