551455-graphics-programming-2526-the-repo-Zyb3rWolfi/TheRepo/TheLabs/Shapes/_TexturedCube.cs

using LearnOpenTK.Common;
using OpenTK.Graphics.OpenGL4;
using OpenTK.Mathematics;
using OpenTK.Windowing.Desktop;
using StbImageSharp;

namespace TheLabs.Shapes;

public class TexturedCube
{
    // Vertex Array Object, Vertex Buffer Object, Element Buffer Object
    private int _vao;
    private int _vbo;
    private int _ebo;
    private int _tb;
    private int _vertexCount;
    public Vector3 Position = Vector3.Zero;
    
    private readonly float[] _cubevertices =
    {
        // Position           // Color (RGBA)
        // Front face (z = +0.5)
        -0.5f, -0.5f,  0.5f,  0f, 0f, // Bottom-left
        0.5f, -0.5f,  0.5f,  1f, 0f, // Bottom-right
        0.5f,  0.5f,  0.5f,  1f, 1f, // Top-right
        -0.5f,  0.5f,  0.5f,  0f, 1f, // Top-left
        
        // Back face (z = -0.5)
        -0.5f, -0.5f, -0.5f,  1f, 0f, // Bottom-left
        0.5f, -0.5f, -0.5f,  0f, 0f, // Bottom-right
        0.5f,  0.5f, -0.5f,  0f, 1f, // Top-right
        -0.5f,  0.5f, -0.5f,  1f, 1f, // Top-left
        
        // Left face (x = -0.5)
        -0.5f, -0.5f, -0.5f,  0f, 0f, // Bottom-left
        -0.5f, -0.5f,  0.5f,  1f, 0f, // Bottom-right
        -0.5f,  0.5f,  0.5f,  1f, 1f, // Top-right
        -0.5f,  0.5f, -0.5f,  0f, 1f, // Top-left   
        // Right face (x = +0.5)
        0.5f, -0.5f, -0.5f,  1f, 0f, // Bottom-left
        0.5f, -0.5f,  0.5f,  0f, 0f, // Bottom-right
        0.5f,  0.5f,  0.5f,  0f, 1f, // Top-right
        0.5f,  0.5f, -0.5f,  1f, 1f, // Top-left
        
        // Top face (y = +0.5)
        -0.5f,  0.5f, -0.5f,  0f, 1f, // Bottom-left
        0.5f,  0.5f, -0.5f,  1f, 1f, // Bottom-right
        0.5f,  0.5f,  0.5f,  1f, 0f, // Top-right
        -0.5f,  0.5f,  0.5f,  0f, 0f, // Top-left
        
        // Bottom face (y = -0.5)
        -0.5f, -0.5f, -0.5f,  1f, 1f, // Bottom-left
        0.5f, -0.5f, -0.5f,  0f, 1f, // Bottom-right
        0.5f, -0.5f,  0.5f,  0f, 0f, // Top-right
        -0.5f, -0.5f,  0.5f,  1f, 0f, // Top-left
        
        
        
    };
    private readonly uint[] _cubeIndices =
    {
        // Front face
        0, 2, 1,
        0, 2, 3,
        // Back face
        4, 5, 6,
        4, 6, 7,
        // Left face
        8, 9, 10,
        8, 10, 11,
        // Right face
        12, 14, 13,
        12, 14, 15,
        // Top face
        16, 17, 18,
        16, 18, 19,
        // Bottom face
        20, 22, 21,
        20, 22, 23
        
    };

    public TexturedCube()
    {
        _tb = GL.GenTexture();
        GL.BindTexture(TextureTarget.Texture2D, _tb);
        StbImage.stbi_set_flip_vertically_on_load(1);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.Repeat);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.Repeat);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.LinearMipmapLinear);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
        // Load the image
        ImageResult image = ImageResult.FromStream(File.OpenRead("Textures/placeholder.png"), ColorComponents.RedGreenBlueAlpha);
        GL.TexImage2D(TextureTarget.Texture2D,0, PixelInternalFormat.Rgba, image.Width, image.Height, 0, PixelFormat.Rgba, PixelType.UnsignedByte, image.Data);
        GL.GenerateMipmap(GenerateMipmapTarget.Texture2D);
        // The number of vertices to draw
        _vertexCount = _cubeIndices.Length;
        // The Vertex Array Object
        // This stores the confifuration of vertex atributes
        _vao = GL.GenVertexArray(); 
        // The Vertex Buffer Object
        // This stores the actual vertex data e.g. positions, colors, normals, texture coordinates
        _vbo = GL.GenBuffer();
        // The Element Buffer Object, stores the indices for indexed drawing
        _ebo = GL.GenBuffer(); 
        
        // We bind the VAO
        GL.BindVertexArray(_vao);
        GL.BindBuffer(BufferTarget.ArrayBuffer, _vbo); // Specifying the type of buffer
        // Uploading the vertex data to the GPU
        GL.BufferData(BufferTarget.ArrayBuffer, _cubevertices.Length * sizeof(float), _cubevertices, BufferUsageHint.StaticDraw);
        
        // Now we set up the EBO
        GL.BindBuffer(BufferTarget.ElementArrayBuffer, _ebo);
        // Uploading the index data to the GPU
        GL.BufferData(BufferTarget.ElementArrayBuffer, _cubeIndices.Length * sizeof(uint), _cubeIndices, BufferUsageHint.StaticDraw);
        
        // We tell opengl how to interpret the vertex data.
        // The Location 0 corresponds to the layout(location = 0) in the vertex shader
        // How many components (x, y, z) -> 3
        // Data type -> float
        // Not normalized
        // The Stride -> The total size of a vertex (in bytes)
        // The offset -> The position data starts at the beginning of the vertex data so 0
        var stride = 5 * sizeof(float);
        GL.VertexAttribPointer(0, 3, VertexAttribPointerType.Float, false, stride, 0);
        GL.EnableVertexAttribArray(0);
        
        GL.VertexAttribPointer(1, 2, VertexAttribPointerType.Float, false, 5 * sizeof(float), 3 * sizeof(float));
        GL.EnableVertexAttribArray(1);
        GL.BindVertexArray(0);

    }
    

    public void Draw(Shader shader, Matrix4 view, Matrix4 projection, float rotation)
    {
        // Create the model matrix with rotation and translation
        Matrix4 model = Matrix4.CreateRotationY(rotation) * Matrix4.CreateRotationX(rotation * 0.5f) * Matrix4.CreateTranslation(Position);

        shader.Use();
        GL.Uniform1(GL.GetUniformLocation(shader.Handle, "uTexture"), 0);
        GL.UniformMatrix4(GL.GetUniformLocation(shader.Handle, "model"), false, ref model);
        GL.UniformMatrix4(GL.GetUniformLocation(shader.Handle, "view"), false, ref view);
        GL.UniformMatrix4(GL.GetUniformLocation(shader.Handle, "projection"), false, ref projection);
        int texLoc = GL.GetUniformLocation(shader.Handle, "uTexture");
        GL.Uniform1(texLoc, 0);
        
        GL.ActiveTexture(TextureUnit.Texture0);
        GL.BindTexture(TextureTarget.Texture2D, _tb);
        
        GL.BindVertexArray(_vao);
        GL.DrawElements(PrimitiveType.Triangles, _vertexCount, DrawElementsType.UnsignedInt, 0);
        
    }
    
    public void Dispose()
    {
        GL.DeleteBuffer(_vbo);
        GL.DeleteBuffer(_ebo);
        GL.DeleteVertexArray(_vao);
    }
}