PCK-Studio/PCK-Studio/Rendering/Texture/CubeTexture.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OpenTK.Graphics.OpenGL;
using PckStudio.Extensions;

namespace PckStudio.Rendering.Texture
{
    internal class CubeTexture : Texture
    {
        public CubeTexture(Image cubeTexture, int slot = 0)
            : base(TextureTarget.TextureCubeMap)
        {
            Bind(slot);

            GL.GenerateMipmap(GenerateMipmapTarget.TextureCubeMap);

            SetTexParameter(TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
            SetTexParameter(TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);

            SetTexParameter(TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
            SetTexParameter(TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);
            SetTexParameter(TextureParameterName.TextureWrapR, (int)TextureWrapMode.ClampToEdge);

            int heightPerFace = cubeTexture.Height / 3;
            int widthPerFace  = cubeTexture.Width / 4;

            Size faceSize = new Size(widthPerFace, heightPerFace);

            Image[] faces = new Image[6];

            Point rightFace = new Point(widthPerFace * 2, heightPerFace * 1);
            faces[0] = cubeTexture.GetArea(new Rectangle(rightFace, faceSize));

            Point lefttFace = new Point(widthPerFace * 0, heightPerFace * 1);
            faces[1] = cubeTexture.GetArea(new Rectangle(lefttFace, faceSize));
            
            Point topFace = new Point(widthPerFace * 1, heightPerFace * 0);
            faces[2] = cubeTexture.GetArea(new Rectangle(topFace, faceSize));
            
            Point bottomFace = new Point(widthPerFace * 1, heightPerFace * 2);
            faces[3] = cubeTexture.GetArea(new Rectangle(bottomFace, faceSize));
            
            Point frontFace = new Point(widthPerFace * 1, heightPerFace * 1);
            faces[4] = cubeTexture.GetArea(new Rectangle(frontFace, faceSize));
            
            Point backFace = new Point(widthPerFace * 3, heightPerFace * 1);
            faces[5] = cubeTexture.GetArea(new Rectangle(backFace, faceSize));

            for(int i = 0; i < 6; i++)
            {
                var texture = new Bitmap(faces[i]);
                BitmapData data = texture.LockBits(new Rectangle(Point.Empty, texture.Size), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                GL.TexImage2D(TextureTarget.TextureCubeMapPositiveX + i, 0, PixelInternalFormat.Rgb8, widthPerFace, heightPerFace, 0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);
            }
        }
    }
}