I'm looking for a tutorial on how to draw a .PNG using DirectX 10, although I'm having no luck. Anyone know where I can find more information on this? I want to create a 2D game
You can load a png as a texture and render it the same way you render other images. For the transparency you can use Alphablending which you enable with Renderstates. (Tutorial, only googled not tested)
you can use D3DX10CreateShaderResourceViewFromFile to create a shader-resource view from a PNG file. This tutorial explains how it works.
In short:
Create a shader to draw a rectangle
Create vertex layout
Create a vertex buffer which stores the vertices of the rectangle
Create a sampler to sample the texture
Create a texture object
Draw the scene
Related
I can't find on the web how to render 2d text in opengl. I need it for the UI of my program. I dont want to use glutBitmapCharacter, just a simple build in function.
Does anybody know how to do this?
Render everything in an fbo texture then draw your UI in top of it.
I write a program using OpenGL. It implements a simple function: draw a teapot.And in order to make it look nice on the screen, I enable multisample anti-aliasing. And it does. Look at the following bitmap:
But when I save it as a bmp picture, it looks bad. I use FBO and PBO to do it. Now I post part of my code here:
glGenFramebuffers(1,&m_frameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER,m_frameBuffer);
glGenRenderbuffers(1,&m_renderBufferColor);
glBindRenderbuffer(GL_RENDERBUFFER,m_renderBufferColor);
glRenderbufferStorage(GL_RENDERBUFFER,GL_RGB,
m_subImageWidth,m_subImageHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER,GL_COLOR_ATTACHMENT0,
GL_RENDERBUFFER,m_renderBufferColor);
glGenRenderbuffers(1,&m_renderBufferDepth);
glBindRenderbuffer(GL_RENDERBUFFER,m_renderBufferDepth);
glRenderbufferStorage(GL_RENDERBUFFER,GL_DEPTH_COMPONENT,
m_subImageWidth,m_subImageHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER,GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER,m_renderBufferDepth);
glBindFramebuffer(GL_FRAMEBUFFER,0);
glBindFramebuffer(GL_FRAMEBUFFER,m_frameBuffer);
glGenBuffers(1,m_subImageBuffer);
glBindBuffer(GL_PIXEL_PACK_BUFFER,m_subImageBuffer);
glBufferData(GL_PIXEL_PACK_BUFFER,m_bufferSize,
NULL,GL_STREAM_READ);
glBindFramebuffer(GL_FRAMEBUFFER,m_frameBuffer);
glBindBuffer(GL_PIXEL_PACK_BUFFER,m_subImageBuffer);
glPixelStorei(GL_PACK_ALIGNMENT,1);
//注意：以BGR的顺序读取
glReadPixels(0,0,m_subImageWidth,m_subImageHeight,
GL_BGR,GL_UNSIGNED_BYTE,bufferOffset(0));
GLUtils::checkForOpenGLError(__FILE__,__LINE__);
m_subPixels[i] = static_cast<GLubyte*>(glMapBuffer(GL_PIXEL_PACK_BUFFER,GL_READ_ONLY));
gltGenBMP(subImageFile,GLT_BGR,m_subImageWidth,m_subImageHeight,m_subPixels[i]);
glBindBuffer(GL_PIXEL_PACK_BUFFER,0);
glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
glBindBuffer(GL_PIXEL_PACK_BUFFER,0);
I am very curious.Why they are different : render to default famebuffer and save to a bmp picture?
Actually, what I want to do is to get 9 small bitmaps in 9 different adjacent angle and then synthesis one bitmap to display on a stereoscope 3D screen. But the synthesised bitmap looks bad.
Could someone tell me why?
Just because you enable multisample on your frame buffer does not mean your FBO will have it too. You need to use glRenderbufferStorageMultisample when creating the FBO.
See: FBO Blitting is not working
And: http://www.opengl.org/wiki/GL_EXT_framebuffer_multisample
This is also relevant: glReadPixels from FBO fails with multisampling
I'm implementing an algorithm about pencil rendering. First, I should render the model using Phong shading to determine the intensity. Then I should map the texture to the rendered result.
I'm going to do a multipass rendering with opengl and cg shaders. Someone told me that I should try 'render to texture'. But I don't know how to use this method to get the effects that I want. In my opinion, we should first use this method to render the mesh, then we can get a 2D texture about the whole scene. Now that we have draw content to the framebuffer, next we should render to the screen, right? But how to use the rendered texture and do some post-processing on it? Can anybody show me some code or links about it?
I made this tutorial, it might help you : http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-14-render-to-texture/
However, using RTT is overkill for what you're trying to do, I think. If you need the fragment's intensity in the texture, well, you already have it in your shader, so there is no need to render it twice...
Maybe this could be useful ? http://www.ozone3d.net/demos_projects/toon-snow.php
render to a texture with Phong shading
Draw that texture to the screen again in a full screen textured quad, applying a shader that does your desired operation.
I'll assume you need clarification on RTT and using it.
Essentially, your screen is a framebuffer (very similar to a texture); it's a 2D image at the end of the day. The idea of RTT is to capture that 2D image. To do this, the best way is to use a framebuffer object (FBO) (Google "framebuffer object", and click on the first link). From here, you have a 2D picture of your scene (you should check it by saving to an image file that it actually is what you want).
Once you have the image, you'll set up a 2D view and draw that image back onto the screen with an 800x600 quadrilateral or what-have-you. When drawing, you use a fragment program (shader), which transforms the brightness of the image into a greyscale value. You can output this, or you can use it as an offset to another, "pencil" texture.
Two questions -
What is the best way to use a texture in OpenGL to fill the entire window?
I want to use glTexImage2D to take in an array of ints containing colour data, how would I go about doing this? (I've found a couple of pages of reference on glTexImage2D but tutorial on using it would be great)
Clarification:
I have done texturing before. I simply need help on these two specific parts.
glTexImage2D just uploads texture data, nothing more. When you have your texture, draw a texture mapped quad the size of the screen and you will draw your texture pixels to the screen.
A ortographic projection is usually used for this.
NeHe provides tutorials for almost any OpenGL topic.
The first lesson on using textures is #6.
Also you could just upload the pixels with glDrawPixels if you don't need to update to much.
There is a nice example from Nehe on how to use textures here:
I'm trying to convert an openGL [edit: "card that I drew"(?):) thx unwind]containing a lot of textures (nothing moving) into one PNG file that I can use in another part of the framework I'm working with. Is there a C++ library that does that?
thanks!
If you simply mean "take a scene rendered by OpenGL and save it as an image," then it is fairly straightforward. You need to read the scene with glReadPixels(), and then convert that data to an image format such as PNG (http://www.opengl.org/resources/faq/technical/miscellaneous.htm).
There are also more efficient ways of achieving this, such as using FBOs. Instead of rendering the scene directly into the framebuffer, you can render it to a texture via an FBO, then render that texture as a full-screen quad. You can then take this texture and save it to a file (using glGetTexImage, for example).
What is an "OpenGL file"? OpenGL is a graphics API, it doesn't specify any file formats. Do you mean a DDS file, or something?
There are better ways to make a compose texture than drawing them with the graphics card. This is really something you would want to do before hand on the cpu, store and then use as and when you need it with opengl