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POOpenGL ES 2.0 / MonoTouch: Texture is colorized red
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copied!<p>I'm currently loading a cube-map into my application but it's shown in a red tone. <strong>Edit:</strong> The channel problem is also present when using 2D-Textures, it seems the channels are not in the correct order. Is there any way to change the order of the channels using the iOS methods?</p> <p>That's the code for texture loading:</p> <pre><code>public TextureCube (Generic3DView device, UIImage right, UIImage left, UIImage top, UIImage bottom, UIImage front, UIImage back) : base(device) { _Device = device; GL.GenTextures (1, ref _Handle); GL.BindTexture (TextureType, _Handle); LoadTexture(All.TextureCubeMapPositiveX, right); LoadTexture(All.TextureCubeMapNegativeX, left); LoadTexture(All.TextureCubeMapPositiveY, top); LoadTexture(All.TextureCubeMapNegativeY, bottom); LoadTexture(All.TextureCubeMapPositiveZ, front); LoadTexture(All.TextureCubeMapNegativeZ, back); GL.TexParameter(All.TextureCubeMap, All.TextureMinFilter, (Int32)All.LinearMipmapLinear); GL.TexParameter(All.TextureCubeMap, All.TextureMagFilter, (Int32)All.Linear); GL.GenerateMipmap(All.TextureCubeMap); } private void LoadTexture(All usage, UIImage image) { GL.TexImage2D(usage, 0, (Int32)All.Rgba, (Int32)image.Size.Width, (Int32)image.Size.Height, 0, All.Rgba, All.UnsignedByte, RequestImagePixelData(image)); } protected CGBitmapContext CreateARGBBitmapContext (CGImage inImage) { var pixelsWide = inImage.Width; var pixelsHigh = inImage.Height; var bitmapBytesPerRow = pixelsWide * 4; var bitmapByteCount = bitmapBytesPerRow * pixelsHigh; //Note implicit colorSpace.Dispose() using (var colorSpace = CGColorSpace.CreateDeviceRGB()) { //Allocate the bitmap and create context var bitmapData = Marshal.AllocHGlobal (bitmapByteCount); if (bitmapData == IntPtr.Zero) { throw new Exception ("Memory not allocated."); } var context = new CGBitmapContext (bitmapData, pixelsWide, pixelsHigh, 8, bitmapBytesPerRow, colorSpace, CGImageAlphaInfo.PremultipliedFirst); if (context == null) { throw new Exception ("Context not created"); } return context; } } //Store pixel data as an ARGB Bitmap protected IntPtr RequestImagePixelData (UIImage inImage) { var imageSize = inImage.Size; CGBitmapContext ctxt = CreateARGBBitmapContext (inImage.CGImage); var rect = new RectangleF (0.0f, 0.0f, imageSize.Width, imageSize.Height); ctxt.DrawImage (rect, inImage.CGImage); var data = ctxt.Data; return data; } </code></pre> <p>I think the channels are inverted, but maybe there is a way to invert the bitmap without some custom code.</p> <p>This is the image which is rendered( ignore the fancy model in front of it ):</p> <p><img src="https://i.stack.imgur.com/0gf5F.jpg" alt="Image rendered"></p> <p>And the expected image: <img src="https://i.stack.imgur.com/yOzAZ.jpg" alt="Image expected"></p> <h1>Edit:</h1> <p>The GL_INVALID_OPERATION issue has been fixed, but it does not solve the issue with the red texture.</p> <p>The vertex-shader:</p> <pre><code>attribute vec3 position; uniform mat4 modelViewMatrix; varying mediump vec3 texture; void main() { texture = position.xyz; gl_Position = modelViewMatrix * vec4(position.xyz, 1.0); } </code></pre> <p>The fragment-shader:</p> <pre><code>varying mediump vec3 texture; uniform samplerCube cubeMap; void main() { mediump vec3 cube = vec3(textureCube(cubeMap, texture)); gl_FragColor = vec4(cube.xyz, 1.0); } </code></pre>

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