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!! :)
Related
I render the color (GL_COLOR_ATTACHMENT0) and depth (GL_DEPTH_ATTACHMENT) of my scene into a FBO, which works fine on PC with OpenGL 4+.
But on my Smartphone with OpenGL ES 3.1+ I always get for the depth via glCheckFramebufferStatus(GL_FRAMEBUFFER) the status = 36054.
glGenTextures(1, &m_textCol);
glBindTexture(GL_TEXTURE_2D, m_textCol);
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, wth, hgt, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindTexture(GL_TEXTURE_2D, 0);
glGenTextures(1, &m_textDepth);
glBindTexture(GL_TEXTURE_2D, m_textDepth);
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, wth, hgt, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glBindTexture(GL_TEXTURE_2D, 0);
GLuint framebuffer;
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_textCol, 0);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER); always 36053 -> ok
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, m_textDepth, 0);
status = glCheckFramebufferStatus(GL_FRAMEBUFFER); // always 36054 -> not ok
I tried it also with
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, wth, hgt, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL);
but no change.
Has maybe someone an idea what I'm doing wrong? Thanks.
Status 36054 is GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT.
If we look at Section 9.4 of the OpenGL ES3.1 specification, it lists the following valid internalFormat values for depth attachments:
DEPTH_COMPONENT16
DEPTH_COMPONENT24
DEPTH_COMPONENT32F
DEPTH24_STENCIL8
DEPTH32F_STENCIL8
Note that the last two also contain a stencil part. You can use these for the depth component and ignore the stencil attachment if you do not need it. Especially DEPTH24_STENCIL8 has a good chance of being widely supported.
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 trying to use awesomium with opengl (glut and cpp) and I'm having trouble rendering the webpages to textures. The textures are randomly (different every time I run the program) shifted in the x and y axis. Picture:
I thought GL_CLAMP_TO_EDGE would take care of that problem but it did not. What am I doing wrong?
The Awesomiumpart:
web_core = WebCore::Initialize(WebConfig());
view = web_core->CreateWebView(WIDTH, HEIGHT);
WebURL url(WSLit(URL));
view->LoadURL(url);
BindMethods(view);
while (view->IsLoading())
web_core->Update();
Sleep(300);
web_core->Update();
surface = (BitmapSurface*)view->surface();
The part loading the texture:
glBindTexture(GL_TEXTURE_2D, 13);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_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, WIDTH, HEIGHT, 0,
GL_BGRA_EXT, GL_UNSIGNED_BYTE, surface);
This is what I did. I know you solved the problem, but it might help someone in the future.
int w = surface->width();
int h = surface->height();
unsigned char *buffer = new unsigned char[w * h * 4];
surface->CopyTo(buffer, w * 4, 4, false, false);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_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, w, h, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, buffer);
delete[] buffer;
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.
i have managed to load texture
// Load texture
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
pBytes = gltLoadTGA("../earth.tga", &iWidth, &iHeight, &iComponents, &eFormat);
glTexImage2D(GL_TEXTURE_2D, 0, iComponents, iWidth, iHeight, 0, eFormat, GL_UNSIGNED_BYTE, pBytes);
free(pBytes);
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);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
when i texture the sphere like this it does not show (image 256x256 32bit)
glDisable(GL_LIGHTING);
glEnable(GL_TEXTURE_2D);
glutSolidSphere(35.0f, 30, 17);
glDisable(GL_TEXTURE_2D);
glEnable(GL_LIGHTING);
but i have a ship made out of a pyramid shape the same technique works on it
glEnable(GL_TEXTURE_2D);
ship();
glDisable(GL_TEXTURE_2D);
anyone any idea why this is happening please...(please don't mark me down i'm working hard here)
You may have loaded the texture image. But you also need to supply texture coordinates. Your ship may do this. glutSolidSphere however does not, and there's nothing you can do about it. So don't use glutSolidSphere.