How to map sphere texture and not to rotate it?

Posted Wednesday, 16 June, 2010 - 14:26 by loco in

Programming Support

Hi,
I have problems with sphere texturing on rotation and have no idea how to solve it

First, i created a texture

public static int CreateTextureFromBitmap(Bitmap bitmap)
        {
            int textureId = int.MinValue;
            if (bitmap == null)
            {
                return textureId;
            }
 
            GL.GenTextures(1, out textureId);
            GL.BindTexture(TextureTarget.Texture2D, textureId);
 
            BitmapData data =
                bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly,
                                    System.Drawing.Imaging.PixelFormat.Format32bppArgb);
 
            GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, data.Width, data.Height,
                            0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);
 
            bitmap.UnlockBits(data);
 
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
            GL.TexEnv(TextureEnvTarget.TextureEnv, TextureEnvParameter.TextureEnvMode, (int)All.Modulate);
 
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);
 
            return textureId;
        }

Then I created a sphere using the code from OpenTK examples like

public void Draw()
        {
            GL.Enable(EnableCap.Texture2D);
            GL.Enable(EnableCap.TextureGenS);
            GL.Enable(EnableCap.TextureGenT);
 
            VertexPositionNormalTexture[] sphereVertices = CalculateSphereVertices(1, 1, 16, 16);
            IEnumerable<ushort> sphereElements = CalculateSphereElements(1, 1, 16, 16);
 
            GL.Translate(Center.X, Center.Y, Center.Z + 1);
 
            GL.BindTexture(TextureTarget.Texture2D, _textureId);
 
            GL.Begin(BeginMode.Triangles);
            GL.Color4(Color.FloralWhite);
            foreach (var element in sphereElements)
            {
                var vertex = sphereVertices[element];
                GL.TexCoord2(vertex.Texture);
                GL.Normal3(vertex.Normal);
                GL.Vertex3(vertex.Position);
            }
 
            GL.ClearColor(Color.FloralWhite);
 
            GL.End();
            GL.Translate(-Center.X, -Center.Y, -Center.Z - 1);
        }