I am having an issue with implementing a frame buffer for post processing. So far I can draw everything to a textured quad and a apply a shader to change the screen, so in that respect it works.
My issue is when I move my models or camera, the model start to render incorrectly and parts of them get "cut off". See the following screen shots as it is hard to explain.
To avoid putting pages and pages of code, all the rendering works fine without the Frame Buffer and every looks fine if I don't move the camera or models.
I set up the frame buffer like this.
//Set up FBO
glGenFramebuffers(1, &m_FrameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, m_FrameBuffer);
glActiveTexture(GL_TEXTURE2);
glGenTextures(1, &m_TexColorBuffer);
glBindTexture(GL_TEXTURE_2D, m_TexColorBuffer);
glTexImage2D(
GL_TEXTURE_2D, 0, GL_RGB, 1280, 720, 0, GL_RGB, GL_UNSIGNED_BYTE, 0
);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glFramebufferTexture2D(
GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_TexColorBuffer, 0
);
glGenRenderbuffers(1, &m_RBODepthStencil);
glBindRenderbuffer(GL_RENDERBUFFER, m_RBODepthStencil);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, 1280, 720);
glFramebufferRenderbuffer(
GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_RBODepthStencil
);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, m_TexColorBuffer, 0);
GLenum DrawBuffers[1] = { GL_COLOR_ATTACHMENT0 };
glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
std::cout << "Frame Buffer: Contructor: Issue completing frame buffer" << std::endl;
//Set Up Shader
m_ScreenShader = new Shader("../Assets/Shaders/screen.vert", "../Assets/Shaders/screen.frag");
//Setup Quad VAO
glGenBuffers(1, &m_QuadVBO);
glBindBuffer(GL_ARRAY_BUFFER, m_QuadVBO);
glBufferData(GL_ARRAY_BUFFER, 24 * sizeof(float), points, GL_STATIC_DRAW);
glGenVertexArrays(1, &m_QuadVAO);
glBindVertexArray(m_QuadVAO);
//glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, m_QuadVBO);
//glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
GLint posAttrib = glGetAttribLocation(m_ScreenShader->getID(), "position");
glEnableVertexAttribArray(posAttrib);
glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), 0);
GLint texAttrib = glGetAttribLocation(m_ScreenShader->getID(), "texcoord");
glEnableVertexAttribArray(texAttrib);
glVertexAttribPointer(texAttrib, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(2 * sizeof(GLfloat)));
I then Bind it prior to drawing the scene (skybox and models) and then draw it like this.
Unbind();
glBindVertexArray(m_QuadVAO);
glDisable(GL_DEPTH_TEST);
m_ScreenShader->enable();
m_ScreenShader->setUniform1f("time", glfwGetTime());
GLint baseImageLoc = glGetUniformLocation(m_ScreenShader->getID(), "texFramebuffer");
glUniform1i(baseImageLoc, 2);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, m_TexColorBuffer);
glDrawArrays(GL_TRIANGLES, 0, 6);
Any help is appreciated!
When rendering into a framebuffer that has a depth buffer and the depth test is enabled, then the depth buffer must be cleared. The depth buffer must be cleared after binding the framebuffer and before drawing to the framebuffer:
gllBindFramebuffer( GL_FRAMEBUFFER, m_FrameBuffer );
glClear( GL_DEPTH_BUFFER_BIT );
Note, if you do not clear the deep buffer, it retains its content. This causes that the depth test may fail at positions, where the geometry has been in the past. It follows that parts are missing in the geometry, as in the image in the question.
Related
So I have an fbo and trying to output a depth texture from the light source perspective. Unfortunately the depth texture is coming out pure white even if I hard code black in the frag shader.
This is my frame buffer initialization
//Render frame to a texture
m_FrameBuffer = 0;
glGenFramebuffers(1, &m_FrameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, m_FrameBuffer); // once frame buffer is bound, must draw to it or black screen
glEnable(GL_TEXTURE_2D);
glGenTextures(1, &m_depthTexture);
glBindTexture(GL_TEXTURE_2D, m_depthTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT16, 1024, 1024, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
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_COMPARE_FUNC, GL_LEQUAL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, m_depthTexture, 0);
glDrawBuffer(GL_NONE);
//Always check that our framebuffer is ok
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
printf("frame buffer binding error");
glBindTexture(GL_TEXTURE_2D, 0);
this is my rendering of frame buffer
glBindFramebuffer(GL_FRAMEBUFFER, m_FrameBuffer);
glViewport(0, 0, 1024, 1024);
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glBindVertexArray(m_VAO);
glBindBuffer(GL_ARRAY_BUFFER, m_VBO);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glDrawArrays(GL_TRIANGLES, 0, vertices.size());
glDisableVertexAttribArray(0);
glBindVertexArray(0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
This is my fragment shader
#version 330 core
// Ouput data
layout(location = 0) out float fragmentdepth;
void main()
{
//fragmentdepth = gl_FragCoord.z;
fragmentdepth = 0;
}
This is my main loop
while (!window.closed())
{
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glDepthFunc(GL_LESS);
window.clear();
CameraControls();
depth.enable();
//depthMVP = depthProjectionMatrix * depthViewMatrix * depthModelMatrix;
depth.setUniformMat4("projection", projection);
depth.setUniformMat4("view", camera);
depth.setUniformMat4("model", shape1->modelMatrix);
shape1->RenderToTexture();
depth.disable();
window.clear();
basic.enable();
basic.setUniformMat4("proj", projection);
//basic.setUniform3f("light_Pos", lightPos);
basic.setUniformMat4("view", camera);
basic.setUniformMat4("model", shape1->modelMatrix);
basic.setUniformMat4("DepthBiasMVP", biasMatrix);
//NEED TO CHANGE THIS TO BIAS MATRIX X DEPTHMVP
//MVP = projection * camera * shape1->modelMatrix;
//basic.setUniformMat4("MVP", MVP);
shape1->Render(basic);
basic.disable();
window.update();
}
I am following this tutorial http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-mapping/
Just answering my own question after looking at my old questions that weren't resolved. If anyone is wondering, my problem was that I had fused two tutorials into one and one of them had different near and far values for the frustum. The framebuffer was black because the object was too far from the camera.
I am making a program with OpenGL that renders frames in the GPU, which I then transfer to memory so I can use them in another program. I have no need for a window or render to screen, so I am using GLFW but with a hidden window and context. Following opengl-tutorial.com I set up a Framebuffer with a texture and a depth renderbuffer so I can render to the texture and then read it's pixels. Just to check things I can make the window visible and I am rendering the texture back on the screen on a quad and using a passthrough shader.
My problem is that when I render to screen directly (with no Framebuffer or texture) the image looks great and smooth. However, when I render to texture and then render the texture to screen, it looks jagged. I don't think the problem is when rendering the texture to screen, because I am also saving the pixels I read into a .jpg and it looks jagged there too.
Both the window and texture are 512x512 pixels in size.
Here is the code where I set up the framebuffer:
FramebufferName = 0;
glGenFramebuffers(1, &FramebufferName);
glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName);
//GLuint renderedTexture;
glGenTextures(1, &renderedTexture);
glBindTexture(GL_TEXTURE_2D, renderedTexture);
glTexImage2D(GL_TEXTURE_2D, 0, textureFormat, textureWidth, textureHeight, 0, textureFormat, GL_UNSIGNED_BYTE, 0);
numBytes = textureWidth * textureHeight * 3; // RGB
pixels = new unsigned char[numBytes]; // allocate image data into RAM
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
//GLuint depthrenderbuffer;
glGenRenderbuffers(1, &depthrenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthrenderbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, textureWidth, textureHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthrenderbuffer);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderedTexture, 0);
DrawBuffers[0] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
std::cout << "Couldn't set up frame buffer" << std::endl;
}
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(-1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(1.0f);
g_quad_vertex_buffer_data.push_back(0.0f);
//GLuint quad_vertexbuffer;
glGenBuffers(1, &quad_vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, quad_vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, g_quad_vertex_buffer_data.size() * sizeof(GLfloat), &g_quad_vertex_buffer_data[0], GL_STATIC_DRAW);
// PBOs
glGenBuffers(cantPBOs, pboIds);
for(int i = 0; i < cantPBOs; ++i) {
glBindBuffer(GL_PIXEL_PACK_BUFFER, pboIds[i]);
glBufferData(GL_PIXEL_PACK_BUFFER, numBytes, 0, GL_DYNAMIC_READ);
}
glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
index = 0;
nextIndex = 0;
Here is the code where I render to the texture:
glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName);
glViewport(0,0,textureWidth,textureHeight); // Render on the whole framebuffer, complete from the lower left corner to the upper right
// Clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
for(int i = 0; i < geometriesToDraw.size(); ++i) {
geometriesToDraw[i]->draw(program);
}
Where draw(ShaderProgram) is the function that calls glDrawArrays. And here is the code where I render the texture to screen:
// Render to the screen
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// Render on the whole framebuffer, complete from the lower left corner to the upper right
glViewport(0,0,textureWidth,textureHeight);
// Clear the screen
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(shaderTexToScreen.getProgramID());
// Bind our texture in Texture Unit 0
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, renderedTexture);
// Set our "renderedTexture" sampler to user Texture Unit 0
glUniform1i(shaderTexToScreen.getUniformLocation("renderedTexture"), 0);
// 1rst attribute buffer : vertices
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, quad_vertexbuffer);
glVertexAttribPointer(
0,
3,
GL_FLOAT,
GL_FALSE,
0,
(void*)0
);
glDrawArrays(GL_TRIANGLES, 0, 6);
glDisableVertexAttribArray(0);
This is what I get when rendering the scene to screen directly:
And this is what I get when rendering the scene to texture:
I can include the code for the vertex and fragment shaders used in rendering the texture to screen, but as I am reading the pixel data straight from the texture and writing it to a file and that still looks jagged, I don't think that is the problem. If there is anything else you want me to include, let me know!
I thought maybe it could be that there is some hidden scaling when doing the rendering to texture and so GL_NEAREST makes it look bad, but if it really is pixel to pixel (both windows and texture are the same size) there shouldn't be a problem there right?
As pointed out by genpfault and Frischer Hering, there is no antialiasing when rendering to a normal texture. However, you can render to a Multisample texture, which will hold information for as many samples as you request. To render this to screen you need to sample the texture to get one color for each pixel, which can be done by calling glBlitFramebuffer. According to the OpenGL reference on glBlitFramebuffer:
If SAMPLE_BUFFERS for the read framebuffer is greater than zero and SAMPLE_BUFFERS for the draw framebuffer is zero, the samples corresponding to each pixel location in the source are converted to a single sample before being written to the destination.
These two links were very helpful too:
http://www.learnopengl.com/#!Advanced-OpenGL/Anti-aliasing
http://ake.in.th/2013/04/02/offscreening-and-multisampling-with-opengl/
Here is my solution, creation of objects:
/// FRAMEBUFFER MULTISAMPLE
framebufferMS = 0;
glGenFramebuffers(1, &framebufferMS);
glBindFramebuffer(GL_FRAMEBUFFER, framebufferMS);
glGenTextures(1, &renderedTextureMS);
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, renderedTextureMS);
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, SAMPLES, textureFormat, textureWidth, textureHeight, GL_TRUE);
glGenRenderbuffers(1, &depthrenderbufferMS);
glBindRenderbuffer(GL_RENDERBUFFER, depthrenderbufferMS);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, SAMPLES, GL_DEPTH24_STENCIL8, textureWidth, textureHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthrenderbufferMS);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderedTextureMS, 0);
DrawBuffersMS[0] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, DrawBuffersMS);
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
std::cout << "Couldn't set up frame buffer" << std::endl;
}
/// FRAMEBUFFER SIMPLE
framebuffer = 0;
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glGenTextures(1, &renderedTexture);
glBindTexture(GL_TEXTURE_2D, renderedTexture);
glTexImage2D(GL_TEXTURE_2D, 0, textureFormat, textureWidth, textureHeight, 0, textureFormat, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_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);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderedTexture, 0);
DrawBuffers[0] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
std::cout << "Couldn't set up frame buffer" << std::endl;
}
And the rendering process:
// Render to framebuffer multisample
glBindFramebuffer(GL_FRAMEBUFFER, framebufferMS);
glViewport(0,0,textureWidth,textureHeight);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
for(int i = 0; i < geometriesToDraw.size(); ++i) {
geometriesToDraw[i]->draw(program);
}
// Sample to normal texture
glBindFramebuffer(GL_READ_FRAMEBUFFER, framebufferMS);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffer);
glBlitFramebuffer(0, 0, textureWidth, textureHeight, 0, 0, textureWidth, textureHeight, GL_COLOR_BUFFER_BIT, GL_NEAREST);
You can also find more questions on the subject here on stackoverflow which I missed because I searches for terms like "jagged" instead of multisampling :P
Thanks a lot for your help!
I ran the framebuffers example in this page -original code- (using glfw3 and glew in xcode 4.6 in osx 10.8), it worked fine, then I wanted to add multisampling (to avoid jagged edges on cube edges and on the floor, glfwWindowHint (GLFW_SAMPLES, 4) was enough when rendering directly to the back-buffer), found some answers directing to opengl.org, tried to use glTexImage2DMultisample but it displayed nothing (black screen). The framebuffer settings and rendering loop is:
// Create frame buffer
GLuint frameBuffer;
glGenFramebuffers(1, &frameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
// Create texture to hold color buffer
GLuint texColorBuffer;
glGenTextures(1, &texColorBuffer);
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, texColorBuffer);
//glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGB, width, height, GL_FALSE);
/*
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
*/
//glFramebufferTexture2DEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texColorBuffer, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, texColorBuffer, 0);
// Create Renderbuffer Object to hold depth and stencil buffers
GLuint rboDepthStencil;
glGenRenderbuffers(1, &rboDepthStencil);
glBindRenderbuffer(GL_RENDERBUFFER, rboDepthStencil);
//glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
glRenderbufferStorageMultisample (GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, width, height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rboDepthStencil);
// ...
while (!window->shouldClose()) {
static int rot = 0;
// Bind our framebuffer and draw 3D scene (spinning cube)
glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
auto err_res = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if(err_res != GL_FRAMEBUFFER_COMPLETE) {
ERR("Incomplete frameBuffer:%X!", err_res);
goto end;
}
glBindVertexArray(vaoCube);
glEnable(GL_DEPTH_TEST);
glUseProgram(sceneShaderProgram);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texKitten);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texPuppy);
// Clear the screen to white
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUniformMatrix4fv(uniModel, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(uniView, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(uniProj, 1, GL_FALSE, glm::value_ptr(proj));
// Draw cube
glEnable(GL_MULTISAMPLE);
glDrawArrays(GL_TRIANGLES, 0, 36);
glEnable(GL_STENCIL_TEST);
// Draw floor
glStencilFunc(GL_ALWAYS, 1, 0xFF);
glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
glStencilMask(0xFF);
glDepthMask(GL_FALSE);
glClear(GL_STENCIL_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 36, 6);
// Draw cube reflection
glStencilFunc(GL_EQUAL, 1, 0xFF);
glStencilMask(0x00);
glDepthMask(GL_TRUE);
model = glm::scale(glm::translate(model, glm::vec3(0, 0, -1)), glm::vec3(1, 1, -1));
glUniformMatrix4fv(uniModel, 1, GL_FALSE, glm::value_ptr(model));
glUniform3f(uniColor, 0.3f, 0.3f, 0.3f);
glDrawArrays(GL_TRIANGLES, 0, 36);
glUniform3f(uniColor, 1.0f, 1.0f, 1.0f);
glDisable(GL_STENCIL_TEST);
/*
// Bind default framebuffer and draw contents of our framebuffer
glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
glBindVertexArray(vaoQuad);
glDisable(GL_DEPTH_TEST);
glUseProgram(screenShaderProgram);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texColorBuffer);
glDrawArrays(GL_TRIANGLES, 0, 6);
*/
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0); // Make sure no FBO is set as the draw framebuffer
glBindFramebuffer(GL_READ_FRAMEBUFFER, frameBuffer); // Make sure your multisampled FBO is the read framebuffer
glDrawBuffer(GL_BACK); // Set the back buffer as the draw buffer
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, GL_COLOR_BUFFER_BIT, GL_LINEAR);
// Swap buffers
glfwSwapBuffers(window->getHandle());
glfwPollEvents();
}
glVersion: 3.2 NVIDIA-8.10.44 304.10.65f03
glRenderer: NVIDIA GeForce 9400M OpenGL Engine
The 'EXT' additions are probably unnecessary but I also tried to run without them before and the result was the same. What am I doing wrong?
EDIT: Now binding GL_TEXTURE_2D_MULTISAMPLE and getting GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE error!
If you checked your framebuffer object for completeness, you would probably have caught this by now... your depth/stencil buffer needs to be multisampled as well.
A framebuffer is considered multisample incomplete by both core and the EXT FBO extension if one attachment has a different number of samples than any other attachment. In your case, you have a color buffer attachment with 4 samples and a depth/stencil attachment with 1 sample.
Name
glCheckFramebufferStatus — check the completeness status of a framebuffer
Description
glCheckFramebufferStatus queries the completeness status of the framebuffer object currently bound to target. target must be GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER or GL_FRAMEBUFFER. GL_FRAMEBUFFER is equivalent to GL_DRAW_FRAMEBUFFER.
The return value is GL_FRAMEBUFFER_COMPLETE if the framebuffer bound to target is complete. Otherwise, the return value is determined as follows:
[...]
GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE is returned if the value of GL_RENDERBUFFER_SAMPLES is not the same for all attached renderbuffers; if the value of GL_TEXTURE_SAMPLES is the not same for all attached textures; or, if the attached images are a mix of renderbuffers and textures, the value of GL_RENDERBUFFER_SAMPLES does not match the value of GL_TEXTURE_SAMPLES.
To fix this, you need to allocate a multisampled depth/stencil attachment with 4 samples:
glRenderbufferStorageMultisample (GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, width, height);
By the way, since your implementation is >= 3.0, you do not need the EXT suffix on anything. All of the constants defined by the EXT extension are identical to ARB / core FBOs, but some of the EXT functions (such as glCheckFramebufferStatusEXT) have more restrictive behavior (requiring each attachment to have the same image dimensions, for instance).
I am currently working on a application with (not yet implemented) post effects. So the 3D scene gets rendered in a buffer and then, another shader renders the buffer on the screen.
My problem is that the program uses my basic shader vor the 3d scene instead of the post effect shader in the second pass. Do you have an idea, what could be doing this?
My approach: I have a class which has two major functions:
- bindBuffer() sets the render Target to a buffer
- renderSSAO() renders the buffer to the screen and hopfuly one day will add an ambient occlusion effect. :)
BIND BUFFER FUNCTION
void SSAOShader::bindBuffer() {
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glViewport(0,0,windowWidth,windowHeight);
}
RENDER FUNCTION
void SSAOShader::renderSSAO(GLuint currentShader) {
// set shader
glUseProgram(shader);
//draw on Screen
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glViewport(0,0,windowWidth,windowHeight);
// clear screen
glClearColor(0.4, 0.4, 0.4, 1.0);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
// bind texture, pass to shader
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, renderTexture);
glUniform1i(textureID, 0);
glBindVertexArray(vertexarray);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glBindVertexArray(0);
glUseProgram(currentShader);
}
Render Loop (the functions are from the ssaoShader-object)
while (!glfwWindowShouldClose(mainWindow)) {
ssaoShader->bindBuffer();
// clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// draw cool stuff
ssaoShader->renderSSAO(programID);
// Swap buffers
glfwSwapBuffers(mainWindow);
glUseProgram(programID);
}
So basically, the render target gets set to my buffer with bindBuffer();, then I draw objects with my basic (phong etc) shader, and the renderSSAO function changes the target to my screen. This function also changes the shader to my post-effects shader and changes it back to whatever it was before. programID is the shader-GLuint.
I know that the problem is the used shader since the result of all is that I only have a black screen with a quad-gon in the world origin. I can also move around like normal.
CONSTRUCTOR
SSAOShader::SSAOShader(float windowWidth, float windowHeight, GLuint currentShader) {
this->windowWidth = windowWidth;
this->windowHeight = windowHeight;
//shader
shader = LoadShaders("Passthrough.vertexshader", "SSAO.fragmentshader");
glUseProgram(shader);
textureID = glGetUniformLocation(shader, "renderTexture");
int status;
glGetProgramiv(shader, GL_COMPILE_STATUS, &status);
std::cout << (status == GL_TRUE) << std::endl;
GLfloat planeVertices[] = {
-1, -1,
1, -1,
-1, 1,
1, 1
};
// create vertex array
glGenVertexArrays(1, &vertexarray);
glBindVertexArray(vertexarray);
// create "uv" (vertex) buffer
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(planeVertices), planeVertices, GL_STATIC_DRAW);
// add vertecies to as attributes
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, (void*)0);
glBindVertexArray(0);
// ---- set up framebuffer ----
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glGenTextures(1, &renderTexture);
glBindTexture(GL_TEXTURE_2D, renderTexture);
glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, windowWidth, windowHeight, 0,GL_RGB, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glGenRenderbuffers(1, &depthrenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthrenderbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, windowWidth, windowHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthrenderbuffer);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderTexture, 0);
DrawBuffers[1] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, DrawBuffers);
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE){
exit(0); // bad luck
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
//glUseProgram(currentShader);
}
VS2012 Project
https://studi.f4.htw-berlin.de/~s0539750/SSAOTest.zip
For who ever is mad enough to look at my code. ;)
I found the problem.
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderTexture, 0);
DrawBuffers[1] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, DrawBuffers);
This part in the constructor changed my GLuint shader;. I don't know why exactly but the reason was that DrawBuffers is a fixed array with size 1. Obviously, accessing DrawBuffers[1] isn't the best idea of the day. ;)
My guess would be that either DarBuffers[1] was used for my "shader" GLuint or the problem was that glDrawBuffers never realy attached GL_COLOR_ATTACHMENT0 to my framebuffer. What is the case?
Thanks for all the help by the way, It helped alot. :)
This is the lovely image I keep seeing gDebugger as I attempt to implement shadow maps. For reference I'm using the tutorial at http://fabiensanglard.net/shadowmapping/index.php. I've tried a couple different things with varying results, mostly either an FBO that has flat depth values(no slight variance indicating weird depth ranges) or this awesome guy. I've tried a huge amount of different things but alas, sans complete FBO failure, I mostly come back to this. For reference, here is what gDebugger spits out as my actual depth buffer:
So, with all that in mind, here's my code. Shader code is withheld because I have yet to get something in my FBO that's worth processing.
Here's how I initialize the FBO/Depth tex:
int shadow_width = 1024;
int shadow_height = 1024;
// Try to use a texture depth component
glGenTextures(1, &depth_tex);
glBindTexture(GL_TEXTURE_2D, depth_tex);
// GL_LINEAR does not make sense for depth texture. However, next tutorial shows usage of GL_LINEAR and PCF
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
// Remove artefact on the edges of the shadowmap
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );
// No need to force GL_DEPTH_COMPONENT24, drivers usually give you the max precision if available
glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24,
shadow_width, shadow_height, 0, GL_DEPTH_COMPONENT,
GL_FLOAT, 0);
// attach the texture to FBO depth attachment point
glBindTexture(GL_TEXTURE_2D, 0);
// create a framebuffer object
glGenFramebuffers(1, &fbo_id);
glBindFramebuffer(GL_FRAMEBUFFER, fbo_id);
// Instruct openGL that we won't bind a color texture with the currently binded FBO
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,GL_TEXTURE_2D, depth_tex, 0);
// switch back to window-system-provided framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, 0);
And here's my render code:
glLoadIdentity();
float lpos[4] = {0,0,0,1};
float lpos3[4] = {5000,-500,5000,1};
glBindTexture(GL_TEXTURE_2D,0);
glBindFramebuffer(GL_FRAMEBUFFER,fbo_id);
glViewport(0, 0, 1024, 1024);
glClear(GL_DEPTH_BUFFER_BIT);
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
setup_mats(lpos[0],lpos[1],lpos[2],lpos3[0],lpos3[1],lpos3[2]);
glCullFace(GL_FRONT);
mdlman.render_models(R_STENCIL);
mdlman.render_model(R_STENCIL,1);
set_tex_mat();
glBindFramebuffer(GL_FRAMEBUFFER,0);
glViewport( 0, 0, (GLsizei)800, (GLsizei)600 );
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
this->r_cam->return_LookAt();
gluPerspective(45,800/600,0.5f,2000.0f);
glMatrixMode(GL_PROJECTION);
glLoadMatrixf(&r_cam->getProjectionMatrix()[0][0]);
glMatrixMode(GL_MODELVIEW);
glLoadMatrixf(&r_cam->getViewMatrix()[0][0]);
glCullFace(GL_BACK);
mdlman.render_models(R_NORM);
And here's how I draw objects for the FBO:
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER,models.at(mdlid).t_buff);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,models.at(mdlid).i_buff);
glNormalPointer(GL_FLOAT,sizeof(vert),BUFFER_OFFSET(sizeof(GLfloat)*2));
glVertexPointer(3, GL_FLOAT,sizeof(vert),BUFFER_OFFSET(sizeof(GLfloat)*5));
glDrawElements(GL_TRIANGLES,(models.at(mdlid).f_index.size())*3,GL_UNSIGNED_INT,0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
Some closing notes: the depth buffer image from gDebugger IS from the lights POV. My camera is quaternion based and uses matrices aligned with OGL for it's lookAt function(which is used to translate to light position/view.) I can provide the code for that if need be. Everything else is pretty much carbon-copied from the tutorial to make sure that I'm not doing or setting up something stupid.