<html> <head> <style></style></head> <body class='hmmessage'><div dir='ltr'> Hello Henry Thank you for your quick answer. It seems that cairo-gl is not currently available on Ubuntu and I would like to stick with tools that are available from the repositories since some users prefer that way to work. I will keep the suggestion for later anyway. Do you have an idea how I could solve my "problem"? Do you think it could be related to the last argument passed to the the glTexImage2D function? Thank you again Victor <div><div id="SkyDrivePlaceholder"></div><hr id="stopSpelling">From: hsong@sisa.samsung.com To: nadaeck@hotmail.com; cairo@cairographics.org Subject: RE: [cairo] trouble with Cairo text in OpenGL Date: Wed, 4 Jan 2012 17:10:34 +0000 <meta http-equiv="Content-Type" content="text/html; charset=unicode"> <meta name="Generator" content="Microsoft SafeHTML"> <style> .ExternalClass p.ecxMsoNormal, .ExternalClass li.ecxMsoNormal, .ExternalClass div.ecxMsoNormal {margin-bottom:.0001pt;font-size:12.0pt;font-family:"Times New Roman","serif";} .ExternalClass a:link, .ExternalClass span.ecxMsoHyperlink {color:blue;text-decoration:underline;} .ExternalClass a:visited, .ExternalClass span.ecxMsoHyperlinkFollowed {color:purple;text-decoration:underline;} .ExternalClass p {margin-right:0in;margin-left:0in;font-size:12.0pt;font-family:"Times New Roman","serif";} .ExternalClass span.ecxEmailStyle18 {font-family:"Calibri","sans-serif";color:#1F497D;} .ExternalClass .ecxMsoChpDefault {font-size:10.0pt;} @page WordSection1 {size:8.5in 11.0in;} .ExternalClass div.ecxWordSection1 {page:WordSection1;} </style> <div class="ecxWordSection1"> Hi, Vector,   If you use cairo/gl backend, there is no need to make GL calls directly.    For example   /* create a gl surface */ cairo_surface_t *surface = cairo_gl_surface_create_for_window (….);   cairo_t *cr = cairo_create (surface);   /* draw text on gl surface */ cairo_select_font_face (cr, "serif", CAIRO_FONT_SLANT_NORMAL,  CAIRO_FONT_WEIGHT_BOLD);  cairo_set_font_size (cr, 32.0);  cairo_set_source_rgb (cr, 1.0, 1.0, 0.0);  cairo_show_text (cr, "HELLO");   /* stroke a rectangle on gl surface */ cairo_rectangle (cr, 10, 10, 100, 100); cairo_set_source_rgba (cr, 1.0, 0.0, 0.0, 1.0); cairo_stroke (cr);   /* display gl surface on screen */ cairo_gl_surface_swapbuffers (surface);   /* clean up */ cairo_surface_destroy (surface); cairo_destroy (cr);     Hope this helps   Henry   <div> <div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in"> From: cairo-bounces+hsong=sisa.samsung.com@cairographics.org [mailto:cairo-bounces+hsong=sisa.samsung.com@cairographics.org] On Behalf Of Victor henri Sent: Wednesday, January 04, 2012 6:38 AM To: cairo@cairographics.org Subject: [cairo] trouble with Cairo text in OpenGL </div> </div>   <div> <div> Hello I have trouble drawing text in an OpenGL texture with Cairo It works with SDL and SDL_ttf with :     GLuint textureId;               SDL_Color Color = {150, 0, 240};         SDL_Surface *Message = TTF_RenderText_Blended(font, "Hello!", Color);         unsigned Texture = 0;         glGenTextures(1, &Texture);         glBindTexture(GL_TEXTURE_2D, Texture);         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);         glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Message->w, Message->h, 0, GL_BGRA, GL_UNSIGNED_BYTE, Message->pixels);                 glBegin(GL_QUADS);         glColor4f(1, 0, 0, 1);         glTexCoord2d(0, 0); glVertex3d(0, 0, 0);         glTexCoord2d(1, 0); glVertex3d(0.2, 0, 0);         glTexCoord2d(1, 1); glVertex3d(0.2, -0.2, 0);         glTexCoord2d(0, 1); glVertex3d(0,  -0.2, 0);         glEnd();                 glDeleteTextures(1, &Texture);                 SDL_FreeSurface(Message); Clearly, the Message->pixels argument in "glTexImage2D" seems important; if I replace it with NULL, I get random lines and points. If I do this with Cairo :         cairo_surface_t *surface;         cairo_t *cr;         GLuint textureId;         unsigned char* surfaceData;         surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 64, 64);         cr = cairo_create (surface);         cairo_select_font_face (cr, "serif", CAIRO_FONT_SLANT_NORMAL,  CAIRO_FONT_WEIGHT_BOLD);         cairo_set_font_size (cr, 32.0);         cairo_set_source_rgb (cr, 1.0, 1.0, 0.0);         cairo_show_text (cr, "HELLO");                 surfaceData = cairo_image_surface_get_data (surface);                 unsigned Texture = 0;         glGenTextures(1, &Texture);         glBindTexture(GL_TEXTURE_2D, Texture);         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);         glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, cairo_image_surface_get_width (surface), cairo_image_surface_get_height (surface), 0, GL_BGRA, GL_UNSIGNED_BYTE, surfaceData);                        glBegin(GL_QUADS);         glColor4f(1, 0, 0, 1);        glTexCoord2d(0, 0); glVertex3d(0, 0, 0);         glTexCoord2d(1, 0); glVertex3d(0.2, 0, 0);         glTexCoord2d(1, 1); glVertex3d(0.2, -0.2, 0);         glTexCoord2d(0, 1); glVertex3d(0,  -0.2, 0);         glEnd();                 glDeleteTextures(1, &Texture);         cairo_destroy (cr);         cairo_surface_destroy (surface); If I do that I get a few red points but not the text I want. I use the " cairo_image_surface_get_data (surface)" function to get the appropriate data and to give it to glTextImage2D but I suppose this is where it won't work. In some examples I have come across the "create_cairo_context" through which surfaceData can be taken. But this function seems completely unknown on my system... I am using Ubuntu Linux 11.10 (lateste version) Please could give me some help about this? Victor </div> </div> </div></div> </div></body> </html>