I am depth only rendering scene to different frame buffer, the problem is a bit hard to explain but as you can see in the image the depth map it is actually suffering from grid like artifacts. Do you have any idea what can be the source of this ?
here is the code for fb creation:
self.shadowTexture = glGenTextures(1);
glBindTexture( GL_TEXTURE_2D, self.shadowTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );
glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, w, h, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, None);
glBindTexture( GL_TEXTURE_2D, 0);
self.fbo = glGenFramebuffers(1)
glBindFramebuffer(GL_FRAMEBUFFER_EXT, self.fbo)
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,GL_TEXTURE_2D, self.shadowTexture, 0);
Your problem most likely comes from the fact that your projection matrix has too much seperation between near and far planes (meaning close together pixels are suffering floating point accuracy issues). Shrink the gap between the 2 planes and that should solve your Z-fighting issues.
Related
When rendering the depth buffer with the iOS simulator Getting the true z value from the depth buffer , all is fine.
But the rendering on real device gives bad result: the depth is rendered with only few values (there is no fade) like when you display an image into a 256 values color range.
Here is the code for the fbo generation:
glGenFramebuffers(1, &sceneFBO);
glGenTextures(2, textures_scene);
glBindTexture(GL_TEXTURE_2D, textures_scene[0]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, widthResolution, heightResolution, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindTexture(GL_TEXTURE_2D, textures_scene[1]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, widthResolution, heightResolution, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);
//TODO: GL_DEPTH_COMPONENT cannot be GL_UNSIGNED_BYTE ?
glBindFramebuffer(GL_FRAMEBUFFER, sceneFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textures_scene[0], 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, textures_scene[1], 0);
It seems that the only working value for GL_DEPTH_ATTACHMENT fbo is GL_UNSIGNED_INT. But it is not enough to render the depth...
PS: I don't want to display again the scene into a GL_COLOR_ATTACHMENT0 with the z-values in order to have a correct depth (for performance reasons) nor use OpenGL ES3.0 or the new metal (iPhone4s support).
Any idea?
There is no depth buffer support in ES 1 or 2. See the answer to this question : glReadPixels doesn't read depth buffer values on iOS
Seems, that it's not possible to use GL_UNSIGNED_BYTE as type parameter together with GL_DEPTH_COMPONENT as internalformat, only GL_UNSIGNED_SHORT and GL_UNSIGNED_INT are allowed according to the GL_OES_depth_texture extension spec: https://www.khronos.org/registry/gles/extensions/OES/OES_depth_texture.txt
I finally put the z value in the alpha part of the scene (I don't use transparency for this fbo).
color.w=(gl_postion.z-near)/(far-near)
A little mcgyver but it does the job.
I'm having trouble with rendering to texture output from this opengl example: http://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Text_Rendering_01
My framebuffer is setup as follows:
glGenTextures(1, &back_text);
glBindTexture(GL_TEXTURE_2D, back_text);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, WINDOW_WIDTH, WINDOW_HEIGHT, 0, GL_BGRA, GL_UNSIGNED_BYTE, 0);
glGenFramebuffersEXT(1, &font_buffer);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, font_buffer);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, back_text, 0);
In best case I can get filled rectangle with color where letter should appear (it appears like alpha is always 1.0).
I've tried original example and it works correctly.
My question is: do I need to enable something to make this work or do I need to take different approach?
Edit:
It turns out that I need to use
glutInitContextVersion(2,0); instead of
glutInitContextVersion(3,2); and world is happy place!! :)
The main steps for depth testing from my understanding:
1) enable depth testing and how we want to depth test
2) create the frame buffer object and make sure it has a depth attached to it
3) bind our frame buffer object ( make sure to clear it before rendering )
4) draw stuff
And that should be it no? our frame buffer depth attachment should have depth data? But I always get straight 1's default depth clear color
step 1:
glEnable(GL_DEPTH_TEST);
glDepthFunc( GL_LEQUAL );
step 2:
//create the frame buffer object
glGenFramebuffers(1, &m_uifboHandle);
// Initialize FBO
glBindFramebuffer(GL_FRAMEBUFFER, m_uifboHandle);
//create 2 texture handles 1 for diffuse, 1 for depth
unsigned int m_uiTextureHandle[2];
glGenTextures( 2, m_uiTextureHandle );
//create the diffuse texture
glBindTexture( GL_TEXTURE_2D, m_uiTextureHandle[0]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, uiWidth, uiHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_uiTextureHandle[0], 0);
.
//create the depth buffer
glBindTexture(GL_TEXTURE_2D, m_uiTextureHandle[1]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, uiWidth, uiHeight, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, m_uiTextureHandle[1], 0);
//go back to default binding
glBindFramebuffer(GL_FRAMEBUFFER, 0);
step 3:
//bind the frame buffer object
glBindFramebuffer( GL_FRAMEBUFFER, m_uifboHandle );
//clear it
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
step 4:
//draw things
Are these not the steps?
Am i missing something?
I've tried a few different tutorials.
I can't get any depth to render to a texture
I keep getting straight 1's over and over.
The framebuffer probably is not complete. Try checking for completeness. Moreover your code was:
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, uiWidth, uiHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
However, it should be (watch the RGB-RGBA):
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, uiWidth, uiHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
I'm trying to make a player in OpenGL. I use ffmpeg to decode the video.
I searched several tutorial (StackOverflow, ....) how to convert my pFrameRGB-> data [0] texture in OpenGL, but it still shows me a white square. I converted my video to 512x256 to comply with 2 ^ n.
I know my pFrameRGB is correct because I can create frameX.ppm with "SaveFrame (...)" function.
I used the following source ( https://github.com/arashafiei/dranger-ffmpeg-tuto/blob/master/tutorial02.c ) code as a model by adapting for my player.
And this is my source code:
http://www.sourcepod.com/uagkel22-19078
Does one of you have a solution to my problem?
Edit 1:
I delete:
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 1 ? GL_REPEAT : GL_CLAMP );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 1 ? GL_REPEAT : GL_CLAMP );
And replaced:
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, pCodecCtx->width, pCodecCtx->height, 0, GL_RGB, GL_UNSIGNED_BYTE, pFrameRGB->data[0]);
by:
if(firstRendering){
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, pCodecCtx->width, pCodecCtx->height, 0, GL_RGB, GL_UNSIGNED_BYTE, pFrameRGB->data[0]);
firstRendering = 0;
}else{
glActiveTexture(texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexSubImage2D( GL_TEXTURE_2D, 0, 0, 0, pCodecCtx->width, pCodecCtx->height, GL_RGB, GL_UNSIGNED_BYTE, pFrameRGB->data[0]);
}
And i try to run but stiil nothing...
In your source code you have these lines:
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 1 ? GL_REPEAT : GL_CLAMP );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 1 ? GL_REPEAT : GL_CLAMP );
First of all, the values you want to set are integers, so you have to use glTexParameteri (note the i at the end).
Second, first you disable mipmapping, then you try to reenable it. If you want to mipmap, you must supply a full image pyramid (within the selected LoD range). For a video player you normally want to disable mipmapping:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
I converted my video to 512x256 to comply with 2 ^ n.
No need to, as of OpenGL-2. Since that version texture images may be of arbitrary dimension.
Also instead of passing the video frames into glTexImage2D, which does a full texture object initialization, I suggest you use glTexSubImage2D which just replaces the image data. You must call glTexImage2D once, before the first call to glTexSubImage2D, with the right format parameters; pass a null pointer to data to initialize the texture without setting the data.
I would like to use the depth buffer to store the depth values of particles in eye space in a 2D texture by using OpenGL 2.1 / GLSL 1.2.
So far I found a way to use the colorbuffer
// create texture
glGenTextures(1, &g_hDepthTexture);
glBindTexture(GL_TEXTURE_2D, g_hDepthTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F_ARB, g_windowWidth, g_windowHeight, 0, GL_RGBA, GL_FLOAT, 0);
// create framebuffer
glGenFramebuffersEXT(1, &g_hFBO);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, g_hFBO);glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, g_hDepthTexture, 0);
However, I don't need the BGA components. Hence, I have tried to use the depth buffer, but the following code clamps each value in the texture to 0...1
// create texture
glGenTextures(1, &g_hDepthTexture);
glBindTexture(GL_TEXTURE_2D, g_hDepthTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, g_windowWidth, g_windowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0); // create framebuffer
glGenFramebuffersEXT(1, &g_hFBO);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, g_hFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, g_hDepthTexture, 0);
I would like to know how to use the depth buffer (probably how to choose the correct internal format / format) so that the texture values are not clamped.
Normalized integer image formats are always clamped. That's why they're normalized integers. If you want an unclamped format, then you need floating point values.
I would suggest using an actual 1-channel floating-point image format, such as GL_R32F. Maybe GL_R16F, depending on how much precision I need. If you don't have GL 3.x hardware, you may be able to use GL_LUMINANCE32F_EXT, depending on what extensions are available.
BTW, if you're doing this for deferred rendering, don't bother. You can actually calculate the eye-space point directly from the regular depth buffer. Yes, really.