I am working with sdl ttf for rendering text to opengl, actually everything it's fine, but like you know, when you open a ttf sdl file you specify it on pixels, and you can't change the font size. Actually you can change the font size but you need to close and re-open the font, and that will be a little slow, so, is there any way to change the font size or something like that?
I need to do the following: Font size that can get resized and adjusted to the window screen (like the opengl -1.0f - 1.0f range that works with something similar to percent), multiline rendering support with no background.
You could put it on a surface and scale the surface. That will probably deform the text, which might be an issue.
Or you could have an array of text sizes. Load the same font with a range of text sizes. As you scale your image, use the different fonts instead of changing the size of one font.
Related
I've inherited a project which renders a 3D scene directly to the window using OpenGL. The code works fine, but we're now drawing an icon onto the 3D view to "Exit 3D view mode". This also works fine, but results in a lot of flickering as the view is rapidly rotated.
I'd like to be able to draw to an off-screen bitmap (ie. without a HWND), then draw my icon to the bitmap, then finally StretchBlt the bitmap to the window using double-buffering. We do this in other contexts (such as zooming into an image which does not need OpenGL) and it works great. My problem is that I am an OpenGL novice and all attempts at starting with the DC of the off-screen bitmap and creating a HWND from this DC fail, usually because of selecting a pixel format for the DC.
There are a few questions asking similar things here on StackOverflow (eg. this question without an accepted answer. Is this possible ? If so is there a relatively straightforward tutorial describing the procedure? If the process is extremely complex requiring detailed OpenGL knowledge, then I may just have to leave it and live with the flickering because it is a rarely used mode in our software.
Just draw the Icon using OpenGL using a textured quad.
All this draw to a bitmap copy to DC StretchBlt involves several roundtrips from and to graphics memory (wastes bandwidth) and StretchBlt will likely not be GPU accelerated. All in all what you want to do is inefficient and may even reduce quality.
I presume you have the icon stored in your executable as a resource. The most simple way to go about it is to create a memory DC (CreateCompatibleDC) with a DIBSECTION (CreateDIBSection), draw the icon to that and load the DIBSECTION data into a OpenGL texture. Then to draw the icon use glViewport to select the destination rectangle in window coordinates, use an identity transform to draw a rectangle covering the whole viewport (position values (-1,1)→(1,1), texture coordinate values (0,0)→(1,1) gives you the right outcome).
Important side fix: In case your program does silly things like setting viewport and the fixed function pipeline GL_PROJECTION matrix in a window resize handler you should clean up that anti pattern and move this to where it belongs: In the drawing code.
I use this link to draw text with a specific Font using freeType Library:
http://nehe.gamedev.net/tutorial/freetype_fonts_in_opengl/24001/
How can I underline or strikeout text?
A "font effect" is nothing more than drawing text and then drawing something on top of it. An underline font is exactly what it looks like: drawing text, then drawing a line under it. In the case of OpenGL, you would use line rendering. Strikethrough is simply a matter of drawing that light higher.
The only real question is where to draw the line. For underlines, you draw it at the baseline. For strikethrough, you draw it maybe 2/5ths of the way from the baseline to the top. Or whatever looks good.
I'm using SFML 1.6 to make a small game, and I need to display some text, so I use the sf::String class. The problem is, when I increase the size to 96pt, the edges appear a little blurry. When I increase the size of text in Microsoft Word though, it appears very clean and has crisp edges. Is there a way to do that with SFML?
Looking at the SFML sources, it appears that it is using the embedded Arial font. Yes, it can also load the .ttf font file, but I guess you didn't load it yet.
So the problem is tht SFML tries to scale the fixed-size bitmap when you are rendering the text.
To get rid of the aliasing try following this sample http://www.sfml-dev.org/tutorials/1.4/graphics-fonts.php and load the .ttf manually.
I am building an OpenGL application. I read through the GLUI tutorial on Code Project to create windows form controls on an OpenGL Application. But my requirement is to develop a color choser/picker, like an RGB chart or RGB cube to select a color. The tutorial on Code project shows the list of colors as a drop down box. However that wont really help me, as I require it to be present as a windows color picker. I know that color picker as a dialog box is a part of the windows application. Can anyone suggest me a way to use it with my OpenGL Application?
You can try fox-toolkit. It is a C++ based Toolkit for developing Graphical User Interfaces. It provides Color Picker and OpenGL widgets for 3D graphical manipulations.
On windows, you can call directly ChooseColor() from the windows API. It will open the native color color chooser.If you need a cross-platform solution, tiny file dialogs on sourceforge also has a color picker and no main loop.
You could render a Quad/Triangle/Cirle with different color on each vertex and activate smooth shading for interpolation between these points. Then just read back the color value from OpenGL at the mouse position.
edit: or like that where you calculate the color on the mouse position by yourself (reading values slows down OpenGL a lot!): http://sharathpatali.wordpress.com/2009/07/07/a-color-picker-for-pymt/
I did this with simple gradient image which i kept in memory. Then i just tracked my mouse position on the image, and simply read the data from the image (that was kept in RAM) and get the 32bit RGBA color value for it. This is easier than reading the pixels from screen (also faster and more reliable).
This also allows a lot more flexible way of presenting the palette, only your imagination is the limit on the looks of your palette. Note: you must use 32bit colors on the image, because if you want smooth edges, you simply just fade the alpha but keep the colors the same, so the colors wont get distorted at edges. Don't forget to enable blending when rendering the image.
I've encountered a problem drawing SFML Text. In my application, I use views as a sort of coordinate system for my application. Thus, a typical view would be 10 x 10 or 20 x 20. All my normal drawing functions work fine, when drawing primitives and lines, etc., and the relevant code doesn't have to know about the coordinate system.
However, when I tried to draw text to the screen, I found that it appeared gigantic. When I reduced the font size drastically, it appeared extremely blurry and pixellated, as if it were trying to render to GIANT pixels that are 1x1 in my view.
Is there a way to draw text with a standard font size, in a way that it won't be affected by the view? Ideally, my text would width/size-wise on any view? How can I accomplish this?
Thanks for any input!
(P.S., I'm using SFML 2.0, for reference)
You can set another view (i.e. apply OpenGL transformation) and render text after it. Here is an example from sfml tutorial:
sf::View View(sf::FloatRect(600, 700, 1400, 1300));
App.SetView(View);
// Draw the game...
App.SetView(App.GetDefaultView());
// Draw the interface...