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POUnable to load most image formats as textures in OpenGL
 

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  1. POUnable to load most image formats as textures in OpenGL
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    <p>I'm attempting to load a variety of image formats to display with alpha blending in OpenGL for our company's software, but I seem to have no luck on this. I'm trying to load Bitmaps like this:</p> <pre><code>private Bitmap LoadBitmap(string filename) { Bitmap original = new Bitmap(filename); Bitmap toReturn = new Bitmap(original.Width, original.Height, PixelFormat.Format24bppRgb); using (Graphics gr = Graphics.FromImage(toReturn)) { gr.DrawImage(original, new Rectangle(0, 0, toReturn.Width, toReturn.Height)); } original.Dispose(); return toReturn; } </code></pre> <p>Loading it into a texture like this:</p> <pre><code>private uint[] GetTexture(Bitmap convertToTexture) { // Setup return value uint[] toReturn = null; // Make sure the device and the bitmap exists if (convertToTexture != null) { // Dispose the imagery first DisposeTexture(); mImageryTexture = new uint[1]; // Setup the bitmap Rectangle rect = new Rectangle(Point.Empty, convertToTexture.Size); BitmapData bitmapdata = convertToTexture.LockBits(rect, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); // Bind the texture glGenTextures(1, mImageryTexture); glBindTexture(GL_TEXTURE_2D, mImageryTexture[0]); glTexImage2D(GL_TEXTURE_2D, 0, (int)GL_RGB8, convertToTexture.Width, convertToTexture.Height, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, bitmapdata.Scan0); // Linear Filtering glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Clamp glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); // Release the bitmap convertToTexture.UnlockBits(bitmapdata); // Set the return value to this imagery toReturn = mImageryTexture; } return toReturn; } </code></pre> <p>And using the texture like this:</p> <pre><code>public bool DrawGLScene() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); // Test bitmap Rectangle rect = new Rectangle(); rect.Size = testBitmap.Size; RenderQuad(testBitmap, rect); RenderLines(rect); rect.X += rect.Width; // Test JPEG rect.Size = testJpeg.Size; RenderQuad(testJpeg, rect); RenderLines(rect); rect.X += rect.Width; // Test PNG rect.Size = testPng.Size; RenderQuad(testPng, rect); RenderLines(rect); rect.X += rect.Width; // Test GIF rect.Size = testGif.Size; RenderQuad(testGif, rect); RenderLines(rect); return true; } private void RenderQuad(Bitmap image, Rectangle rect) { uint[] imageryTexture = GetTexture(image); // Color all the vertices white with transparency glEnable(GL_TEXTURE_2D); glColor4ub(255, 255, 255, 255); /////////////////////////////////////////////////// // Draw the image of the area. /////////////////////////////////////////////////// // Fill the path with the background transparent color. glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glBindTexture(GL_TEXTURE_2D, imageryTexture[0]); // Building a quad of the image glBegin(GL_QUADS); // top left of texture glTexCoord2f(0, 1); glVertex2i(rect.Left, rect.Top); // top right of texture glTexCoord2f(1, 1); glVertex2i(rect.Right, rect.Top); // bottom right of texture glTexCoord2f(1, 0); glVertex2i(rect.Right, rect.Bottom); // bottom left of texture glTexCoord2f(0, 0); glVertex2i(rect.Left, rect.Bottom); glEnd(); } private void RenderLines(Rectangle rect) { // Fill the path with the background transparent color. // Color all the vertices transparent gray Color LineColor = Color.Tomato; glColor4ub(LineColor.R, LineColor.G, LineColor.B, 255); glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); // Building a quad of the image glBegin(GL_QUADS); // top left of texture glVertex2i(rect.Left, rect.Top); // top right of texture glVertex2i(rect.Right, rect.Top); // bottom right of texture glVertex2i(rect.Right, rect.Bottom); // bottom left of texture glVertex2i(rect.Left, rect.Bottom); glEnd(); } </code></pre> <p>What am I doing wrong? I can load some bitmap files, but not others. PNGs, JPEGs, and GIFs don't work at all. All I get are white squares (from the vertex colors).</p> <p>Here's the full code below. I'm using NeHe's lesson 2 code as basis for this code (since I can't post the company software code in its entirety):</p> <pre><code>public class OpenGLForm : Form { #region Member Variables private const string AbsolutePath = @"C:\&lt;path-to-images&gt;\"; /// &lt;summary&gt; /// Required designer variable. /// &lt;/summary&gt; private System.ComponentModel.Container components = null; private Bitmap testBitmap = null; private Bitmap testJpeg = null; private Bitmap testPng = null; private Bitmap testGif = null; private uint[] mImageryTexture = null; private static uint _hwnd = 0; private static uint _hDC = 0; private static uint _hRC = 0; private bool _appActive = true; private bool _done = true; public bool Done { get { return _done; } set { _done = value; } } #endregion // Lots of OpenGL function and constant declaration here #region Win32 Interop // Constant values were found in the "WinUser.h" header file. public const int WM_ACTIVATEAPP = 0x001C; public const int WA_ACTIVE = 1; public const int WA_CLICKACTIVE = 2; public const int CDS_FULLSCREEN = 0x00000004; // Flag for ChangeDisplaySettings public const int DISP_CHANGE_SUCCESSFUL = 0; // Return value for ChangeDisplaySettings // Constant values were found in the "WinGDI.h" header file. public const int CCHDEVICENAME = 32; // size of a device name string public const int CCHFORMNAME = 32; // size of a form name string public const int DM_BITSPERPEL = 0x40000; public const int DM_PELSWIDTH = 0x80000; public const int DM_PELSHEIGHT = 0x100000; public const int BITSPIXEL = 12; // number of bits per pixel public const uint PFD_DOUBLEBUFFER = 0x00000001; // PIXELFORMATDESCRIPTOR flag public const uint PFD_DRAW_TO_WINDOW = 0x00000004; // PIXELFORMATDESCRIPTOR flag public const uint PFD_SUPPORT_OPENGL = 0x00000020; // PIXELFORMATDESCRIPTOR flag public const uint PFD_TYPE_RGBA = 0; // pixel type public const uint PFD_MAIN_PLANE = 0; // layer type [StructLayout(LayoutKind.Sequential)] public struct PIXELFORMATDESCRIPTOR { public ushort nSize; public ushort nVersion; public uint dwFlags; public byte iPixelType; public byte cColorBits; public byte cRedBits; public byte cRedShift; public byte cGreenBits; public byte cGreenShift; public byte cBlueBits; public byte cBlueShift; public byte cAlphaBits; public byte cAlphaShift; public byte cAccumBits; public byte cAccumRedBits; public byte cAccumGreenBits; public byte cAccumBlueBits; public byte cAccumAlphaBits; public byte cDepthBits; public byte cStencilBits; public byte cAuxBuffers; public byte iLayerType; public byte bReserved; public uint dwLayerMask; public uint dwVisibleMask; public uint dwDamageMask; } // by marking the structure with CharSet.Auto, the structure will get marshaled as Unicode characters // on Unicode platforms, if not the name fields would always get marshaled as arrays of ANSI characters [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)] public class DEVMODE { [MarshalAs(UnmanagedType.ByValArray, SizeConst = CCHDEVICENAME)] public char[] dmDeviceName; public short dmSpecVersion; public short dmDriverVersion; public short dmSize; public short dmDriverExtra; public int dmFields; public DEVMODE_UNION u; public short dmColor; public short dmDuplex; public short dmYResolution; public short dmTTOption; public short dmCollate; [MarshalAs(UnmanagedType.ByValArray, SizeConst = CCHFORMNAME)] public char[] dmFormName; public short dmLogPixels; public int dmBitsPerPel; public int dmPelsWidth; public int dmPelsHeight; public int dmDisplayFlagsOrdmNup; // union of dmDisplayFlags and dmNup public int dmDisplayFrequency; public int dmICMMethod; public int dmICMIntent; public int dmMediaType; public int dmDitherType; public int dmReserved1; public int dmReserved2; public int dmPanningWidth; public int dmPanningHeight; } // modeling a union in C#, each possible struct data type starts at FieldOffset 0 [StructLayout(LayoutKind.Explicit)] public struct DEVMODE_UNION { [FieldOffset(0)] public short dmOrientation; [FieldOffset(2)] public short dmPaperSize; [FieldOffset(4)] public short dmPaperLength; [FieldOffset(6)] public short dmPaperWidth; [FieldOffset(8)] public short dmScale; [FieldOffset(10)] public short dmCopies; [FieldOffset(12)] public short dmDefaultSource; [FieldOffset(14)] public short dmPrintQuality; [FieldOffset(0)] public int dmPosition_x; [FieldOffset(4)] public int dmPosition_y; [FieldOffset(0)] public int dmDisplayOrientation; [FieldOffset(0)] public int dmDisplayFixedOutput; } #endregion #region OpenGLSetup private bool SetupPixelFormat(ref uint hdc) { PIXELFORMATDESCRIPTOR pfd = new PIXELFORMATDESCRIPTOR(); ushort pfdSize = (ushort)Marshal.SizeOf(typeof(PIXELFORMATDESCRIPTOR)); // sizeof(PIXELFORMATDESCRIPTOR) pfd.nSize = pfdSize; // size of pfd pfd.nVersion = 1; // version number pfd.dwFlags = (PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW | PFD_DOUBLEBUFFER); // flags pfd.iPixelType = (byte)PFD_TYPE_RGBA; // RGBA type pfd.cColorBits = (byte)GetDeviceCaps(hdc, BITSPIXEL); // color depth pfd.cRedBits = 0; // color bits ignored pfd.cRedShift = 0; pfd.cGreenBits = 0; pfd.cGreenShift = 0; pfd.cBlueBits = 0; pfd.cBlueShift = 0; pfd.cAlphaBits = 0; // no alpha buffer pfd.cAlphaShift = 0; // shift bit ignored pfd.cAccumBits = 0; // no accumulation buffer pfd.cAccumRedBits = 0; // accum bits ignored pfd.cAccumGreenBits = 0; pfd.cAccumBlueBits = 0; pfd.cAccumAlphaBits = 0; pfd.cDepthBits = 32; // 32-bit z-buffer pfd.cStencilBits = 0; // no stencil buffer pfd.cAuxBuffers = 0; // no auxiliary buffer pfd.iLayerType = (byte)PFD_MAIN_PLANE; // main layer pfd.bReserved = 0; // reserved pfd.dwLayerMask = 0; // layer masks ignored pfd.dwVisibleMask = 0; pfd.dwDamageMask = 0; int pixelformat = ChoosePixelFormat(hdc, ref pfd); if (pixelformat == 0) // Did Windows Find A Matching Pixel Format? { MessageBox.Show("Can't Find A Suitable PixelFormat.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); return false; } if (SetPixelFormat(hdc, pixelformat, ref pfd) == 0) // Are We Able To Set The Pixel Format? { MessageBox.Show("Can't Set The PixelFormat.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); return false; } return true; } private bool InitGL() // All Setup For OpenGL Goes Here { glShadeModel(GL_SMOOTH); // Enable Smooth Shading glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background glClearDepth(1.0f); // Depth Buffer Setup // Add alpha blending support glDepthFunc(GL_LEQUAL); glDisable(GL_DEPTH_TEST); glEnable(GL_TEXTURE_2D); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE); return true; // Initialization Went OK } public bool SetupRenderingContext() { if (!CreateGLWindow()) { return false; // initialization failed, quit } _hwnd = (uint)((this.Handle).ToInt32()); _hDC = GetDC(_hwnd); if (_hDC == 0) { MessageBox.Show("Can't Create A GL Device Context", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); return false; } // not doing the following wglSwapBuffers() on the DC will result in a failure to subsequently create the RC wglSwapBuffers(_hDC); if (!SetupPixelFormat(ref _hDC)) { return false; } // create the rendering context and make it current _hRC = wglCreateContext(_hDC); if (_hRC == 0) // Are We Able To Get A Rendering Context? { MessageBox.Show("Can't Create A GL Rendering Context.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); return false; } if (!wglMakeCurrent(_hDC, _hRC)) // Try To Activate The Rendering Context { MessageBox.Show("Can't Activate The GL Rendering Context.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); return false; } OpenGLForm_Resize(this, new EventArgs()); // Set up the perspective GL screen return InitGL(); // Initialize Our Newly Created GL Window } #endregion #region FormSetup private bool CreateGLWindow() { Resize += new EventHandler(OpenGLForm_Resize); TopMost = false; WindowState = System.Windows.Forms.FormWindowState.Normal; FormBorderStyle = System.Windows.Forms.FormBorderStyle.Sizable; // The cursor is displayed only if the display count is greater than or equal to 0 do { }while (ShowCursor(true) &lt; 0); return true; } #endregion #region Constructor/Destructor public OpenGLForm() { // // Required for Windows Form Designer support // InitializeComponent(); testBitmap = LoadBitmap(AbsolutePath + "bitmap.bmp"); testJpeg = LoadBitmap(AbsolutePath + "jpeg.jpg"); testPng = LoadBitmap(AbsolutePath + "png.png"); testGif = LoadBitmap(AbsolutePath + "gif.gif"); } /// &lt;summary&gt; /// Clean up any resources being used. /// &lt;/summary&gt; protected override void Dispose(bool disposing) { if (disposing) { if (components != null) { components.Dispose(); } if (_hRC != 0) // Do We Have A Rendering Context? { if (!wglMakeCurrent(0, 0)) // Are We Able To Release The DC And RC Contexts? { MessageBox.Show("Release Of DC And RC Failed.", "Shutdown Error", MessageBoxButtons.OK, MessageBoxIcon.Information); } if (!wglDeleteContext(_hRC)) // Are We Able To Delete The RC? { MessageBox.Show("Release Rendering Context Failed.", "Shutdown Error", MessageBoxButtons.OK, MessageBoxIcon.Information); } } if (_hDC != 0 &amp;&amp; ReleaseDC(_hwnd, _hDC) == 0) // Are We Able To Release The DC { MessageBox.Show("Release Device Context Failed.", "Shutdown Error", MessageBoxButtons.OK, MessageBoxIcon.Information); } } base.Dispose(disposing); } private Bitmap LoadBitmap(string filename) { Bitmap original = new Bitmap(filename); Bitmap toReturn = new Bitmap(original.Width, original.Height, PixelFormat.Format24bppRgb); using (Graphics gr = Graphics.FromImage(toReturn)) { gr.DrawImage(original, new Rectangle(0, 0, toReturn.Width, toReturn.Height)); } original.Dispose(); return toReturn; } #endregion #region Windows Form Designer generated code /// &lt;summary&gt; /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// &lt;/summary&gt; private void InitializeComponent() { // // OpenGLForm // this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(632, 453); this.KeyPreview = true; this.Name = "OpenGLForm"; this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen; this.Text = "\"NeHe\'s First Polygon Tutorial\""; this.KeyUp += new System.Windows.Forms.KeyEventHandler(this.OpenGLForm_KeyUp); } #endregion #region Events protected override void WndProc(ref System.Windows.Forms.Message m) { // Listen for operating system messages. switch (m.Msg) { // The WM_ACTIVATEAPP message occurs when the application // becomes the active application or becomes inactive. case WM_ACTIVATEAPP: { // The WParam value identifies what is occurring. _appActive = ((int)m.WParam == WA_ACTIVE || (int)m.WParam == WA_CLICKACTIVE); // Invalidate to get new scene painted. Invalidate(); break; } default: { break; } } base.WndProc(ref m); } /*! This will stop the display from flickering on Paint event */ protected override void OnPaintBackground(PaintEventArgs e) { } protected override void OnPaint(PaintEventArgs e) { // make sure the app is active if (_appActive) { DrawGLScene(); wglSwapBuffers(_hDC); Invalidate(); } } private void OpenGLForm_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e) { switch (e.KeyCode) { case Keys.Escape: { Close(); break; } default: { break; } } } private void OpenGLForm_Resize(object sender, EventArgs e) // Resize And Initialize The GL Window { int width = ClientRectangle.Width; int height = ClientRectangle.Height; if (height == 0) // Prevent A Divide By Zero By { height = 1; // Making Height Equal One } // Switch to projection mode glMatrixMode(GL_PROJECTION); glLoadIdentity(); // Change to ortho-graphic camera, with top left as (0, 0) coordinate, // and bottom right as the control size gluOrtho2D(0, ClientRectangle.Width, ClientRectangle.Height, 0); glViewport(0, 0, ClientRectangle.Width, ClientRectangle.Height); // Switch back to model view glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // Reset The Modelview Matrix } #endregion /// &lt;summary&gt; /// The main entry point for the application. /// &lt;/summary&gt; [STAThread] static void Main() { while (true) { OpenGLForm form = new OpenGLForm(); // create the form if (!form.SetupRenderingContext()) // setup form and OpenGL { break; // initialization failed, quit } Application.Run(form); if (form.Done) // Was There A Quit Received? { form.DisposeTexture(); break; } } } public bool DrawGLScene() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); // Test bitmap Rectangle rect = new Rectangle(); rect.Size = testBitmap.Size; RenderQuad(testBitmap, rect); RenderLines(rect); rect.X += rect.Width; // Test JPEG rect.Size = testJpeg.Size; RenderQuad(testJpeg, rect); RenderLines(rect); rect.X += rect.Width; // Test PNG rect.Size = testPng.Size; RenderQuad(testPng, rect); RenderLines(rect); rect.X += rect.Width; // Test GIF rect.Size = testGif.Size; RenderQuad(testGif, rect); RenderLines(rect); return true; } private void RenderQuad(Bitmap image, Rectangle rect) { uint[] imageryTexture = GetTexture(image); // Color all the vertices white with transparency glEnable(GL_TEXTURE_2D); glColor4ub(255, 255, 255, 255); /////////////////////////////////////////////////// // Draw the image of the area. /////////////////////////////////////////////////// // Fill the path with the background transparent color. glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glBindTexture(GL_TEXTURE_2D, imageryTexture[0]); // Building a quad of the image glBegin(GL_QUADS); // top left of texture glTexCoord2f(0, 1); glVertex2i(rect.Left, rect.Top); // top right of texture glTexCoord2f(1, 1); glVertex2i(rect.Right, rect.Top); // bottom right of texture glTexCoord2f(1, 0); glVertex2i(rect.Right, rect.Bottom); // bottom left of texture glTexCoord2f(0, 0); glVertex2i(rect.Left, rect.Bottom); glEnd(); } private void RenderLines(Rectangle rect) { // Fill the path with the background transparent color. // Color all the vertices transparent gray Color LineColor = Color.Tomato; glColor4ub(LineColor.R, LineColor.G, LineColor.B, 255); glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); // Building a quad of the image glBegin(GL_QUADS); // top left of texture glVertex2i(rect.Left, rect.Top); // top right of texture glVertex2i(rect.Right, rect.Top); // bottom right of texture glVertex2i(rect.Right, rect.Bottom); // bottom left of texture glVertex2i(rect.Left, rect.Bottom); glEnd(); } // Creates a texture from a given bitmap. private uint[] GetTexture(Bitmap convertToTexture) { // Setup return value uint[] toReturn = null; // Make sure the device and the bitmap exists if (convertToTexture != null) { // Dispose the imagery first DisposeTexture(); mImageryTexture = new uint[1]; // Setup the bitmap Rectangle rect = new Rectangle(Point.Empty, convertToTexture.Size); BitmapData bitmapdata = convertToTexture.LockBits(rect, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); // Bind the texture glGenTextures(1, mImageryTexture); glBindTexture(GL_TEXTURE_2D, mImageryTexture[0]); glTexImage2D(GL_TEXTURE_2D, 0, (int)GL_RGB8, convertToTexture.Width, convertToTexture.Height, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, bitmapdata.Scan0); // Linear Filtering glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Clamp glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); // Release the bitmap convertToTexture.UnlockBits(bitmapdata); // Set the return value to this imagery toReturn = mImageryTexture; } return toReturn; } // Disposes the currently held texture. public void DisposeTexture() { if (mImageryTexture != null) { glDeleteTextures(1, mImageryTexture); mImageryTexture = null; } } } </code></pre>
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      1. POUnable to load most image formats as textures in OpenGL
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      1. POUnable to load most image formats as textures in OpenGL
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    1. COHave you considered debugging your code. At all.
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    2. COYou can debug OpenGL? I can otherwise get certain image files to work, yet not others. I'll try to clarify above.
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      1. POUnable to load most image formats as textures in OpenGL
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