Axiom.RenderSystems.OpenGL.GLPixelUtil.GetMaxMipmaps C# (CSharp) Метод

		public static int GetMaxMipmaps( int width, int height, int depth, PixelFormat format )
		{
			int count = 0;
			do
			{
				if ( width > 1 )
					width = width / 2;
				if ( height > 1 )
					height = height / 2;
				if ( depth > 1 )
					depth = depth / 2;
				count++;
			} while ( !( width == 1 && height == 1 && depth == 1 ) );

			return count;
		}

        protected override void createInternalResources()
        {
            // Convert to nearest power-of-two size if required
            Width  = GLPixelUtil.OptionalPO2(Width);
            Height = GLPixelUtil.OptionalPO2(Height);
            Depth  = GLPixelUtil.OptionalPO2(Depth);


            // Adjust format if required
            this.format = TextureManager.Instance.GetNativeFormat(TextureType, Format, Usage);

            // Check requested number of mipmaps
            int maxMips = GLPixelUtil.GetMaxMipmaps(Width, Height, Depth, Format);

            MipmapCount = requestedMipmapCount;
            if (MipmapCount > maxMips)
            {
                MipmapCount = maxMips;
            }

            // Generate texture name
            Gl.glGenTextures(1, out this._glTextureID);

            // Set texture type
            Gl.glBindTexture(GLTextureType, this._glTextureID);

            // This needs to be set otherwise the texture doesn't get rendered
            Gl.glTexParameteri(GLTextureType, Gl.GL_TEXTURE_MAX_LEVEL, MipmapCount);

            // Set some misc default parameters so NVidia won't complain, these can of course be changed later
            Gl.glTexParameteri(GLTextureType, Gl.GL_TEXTURE_MIN_FILTER, Gl.GL_NEAREST);
            Gl.glTexParameteri(GLTextureType, Gl.GL_TEXTURE_MAG_FILTER, Gl.GL_NEAREST);
            Gl.glTexParameteri(GLTextureType, Gl.GL_TEXTURE_WRAP_S, Gl.GL_CLAMP_TO_EDGE);
            Gl.glTexParameteri(GLTextureType, Gl.GL_TEXTURE_WRAP_T, Gl.GL_CLAMP_TO_EDGE);

            // If we can do automip generation and the user desires this, do so
            mipmapsHardwareGenerated = Root.Instance.RenderSystem.Capabilities.HasCapability(Capabilities.HardwareMipMaps);
            if (((Usage & TextureUsage.AutoMipMap) == TextureUsage.AutoMipMap) && requestedMipmapCount != 0 &&
                MipmapsHardwareGenerated)
            {
                Gl.glTexParameteri(GLTextureType, Gl.GL_GENERATE_MIPMAP, Gl.GL_TRUE);
            }

            // Allocate internal buffer so that glTexSubImageXD can be used
            // Internal format
            int format = GLPixelUtil.GetClosestGLInternalFormat(Format);
            int width  = Width;
            int height = Height;
            int depth  = Depth;

            {
                // Run through this process to pregenerate mipmap pyramid
                for (int mip = 0; mip <= MipmapCount; mip++)
                {
                    // Normal formats
                    switch (TextureType)
                    {
                    case TextureType.OneD:
                        Gl.glTexImage1D(Gl.GL_TEXTURE_1D, mip, format, width, 0, Gl.GL_RGBA, Gl.GL_UNSIGNED_BYTE, IntPtr.Zero);

                        break;

                    case TextureType.TwoD:
                        Gl.glTexImage2D(Gl.GL_TEXTURE_2D, mip, format, width, height, 0, Gl.GL_RGBA, Gl.GL_UNSIGNED_BYTE, IntPtr.Zero);
                        break;

                    case TextureType.ThreeD:
                        Gl.glTexImage3D(Gl.GL_TEXTURE_3D, mip, format, width, height, depth, 0, Gl.GL_RGBA, Gl.GL_UNSIGNED_BYTE,
                                        IntPtr.Zero);
                        break;

                    case TextureType.CubeMap:
                        for (int face = 0; face < 6; face++)
                        {
                            Gl.glTexImage2D(Gl.GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, mip, format, width, height, 0, Gl.GL_RGBA,
                                            Gl.GL_UNSIGNED_BYTE, IntPtr.Zero);
                        }
                        break;
                    }
                    ;
                    if (width > 1)
                    {
                        width = width / 2;
                    }
                    if (height > 1)
                    {
                        height = height / 2;
                    }
                    if (depth > 1)
                    {
                        depth = depth / 2;
                    }
                }
            }
            _createSurfaceList();
            // Get final internal format
            this.format = GetBuffer(0, 0).Format;
        }