OpenGL Deferred rendering static? - c++

I'm trying to implement deferred rendering in my engine but I'm having some problems.
It seems that there is some static in the triangles being drawn.
Here is the drawing code:
// GEOMETRY PASS
gbuffer->BindForWriting(); // glBind(GL_DRAW_FRAMEBUFFER, fbo);
window->Clear(); // glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST); // Before it was glDisable(GL_DEPTH_TEST); (I was testing)
... // Render all objects (they are rendering well when not using deferred rendering)
// LIGHTING PASS
glBindFramebuffer(GL_FRAMEBUFFER, 0);
window->Clear(); // Clear buffer again (same thing above)
gbuffer->BindForReading(); // glBind(GL_READ_FRAMEBUFFER, fbo);
GLsizei HalfWidth = (GLsizei)(window->GetSize().x / 2.0f);
GLsizei HalfHeight = (GLsizei)(window->GetSize().y / 2.0f); // Get half the size of the window
gbuffer->SetReadBuffer(GBUFFER_POSITION); // glReadBuffer(GL_COLOR_ATTACHMENT0);
glBlitFramebuffer(0, 0, window->GetSize().x, window->GetSize().y, 0, 0, HalfWidth, HalfHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
gbuffer->SetReadBuffer(GBUFFER_DIFFUSE); // glReadBuffer(GL_COLOR_ATTACHMENT1);
glBlitFramebuffer(0, 0, window->GetSize().x, window->GetSize().y, 0, HalfHeight, HalfWidth, window->GetSize().y, GL_COLOR_BUFFER_BIT, GL_LINEAR);
gbuffer->SetReadBuffer(GBUFFER_NORMAL); // glReadBuffer(GL_COLOR_ATTACHMENT2);
glBlitFramebuffer(0, 0, window->GetSize().x, window->GetSize().y, HalfWidth, HalfHeight, window->GetSize().x, window->GetSize().y, GL_COLOR_BUFFER_BIT, GL_LINEAR);
gbuffer->SetReadBuffer(GBUFFER_TEXCOORD); // glReadBuffer(GL_COLOR_ATTACHMENT3);
glBlitFramebuffer(0, 0, window->GetSize().x, window->GetSize().y, HalfWidth, 0, window->GetSize().x, HalfHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
(upleft is diffuse, upright is normals, downleft is position and downright is texture coords)
EDIT:
New screenshot after i enabled GL_DEPTH_TEST:
EDIT 2
Here is the GBuffer setup:
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);
glGenTextures(4, textures);
glGenTextures(1, &depthTexture);
for (int i = 0; i < 4; i++) {
glBindTexture(GL_TEXTURE_2D, textures[i]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, windowSize.x, windowSize.y, 0, GL_RGB, GL_FLOAT, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, textures[i], 0);
}
glBindTexture(GL_TEXTURE_2D, depthTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, windowSize.x, windowSize.y, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTexture, 0);
GLenum drawBuffers[] = {
GL_COLOR_ATTACHMENT0,
GL_COLOR_ATTACHMENT1,
GL_COLOR_ATTACHMENT2,
GL_COLOR_ATTACHMENT3
};
glDrawBuffers(4, drawBuffers);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if (status != GL_FRAMEBUFFER_COMPLETE) {
// PRINT ERROR TO LOG ( No errors here i've already checked)
return;
}
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
EDIT 3 I'm following this tutorial if it helps in anything

I forgot to disable GL_BLEND before drawing the objects in the buffer.
Now it's working fine.
glDisable(GL_BLEND);
(Deferred rendering...)
glEnable(GL_BLEND);

Related

How to render anti-aliased image to a texture (and then write to PNG)?

I'd like to use the "render to texture" paradigm to write a .png screenshot of my OpenGL 3D rendering. I have it working without multi-sampling, but I'm struggling to get an anti-aliased image.
First of all, is this possible?
Second, what is the right combination of API calls?
(meta third question, how can I better debug this? glCheckFramebufferStatus is clearly not enough).
Here's what I'm working with:
// https://stackoverflow.com/questions/7402504/multisampled-render-to-texture-in-ios
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA4, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
GLuint resolved_framebuffer, resolvedColorRenderbuffer;
glGenFramebuffers(1, &resolved_framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, resolved_framebuffer);
glGenRenderbuffers(1, &resolvedColorRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, resolvedColorRenderbuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
GLuint framebuffer;
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
GLuint colorRenderbuffer, depthRenderbuffer;
glGenRenderbuffers(1, &colorRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_RGBA8, width, height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer);
glGenRenderbuffers(1, &depthRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, width, height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer);
assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
glBindFramebuffer( GL_FRAMEBUFFER, framebuffer );
glClearColor(background_color(0), background_color(1), background_color(2), 0.f);
glClear(GL_COLOR_BUFFER_BIT);// | GL_DEPTH_BUFFER_BIT);
draw_scene();
glBindFramebuffer( GL_READ_FRAMEBUFFER, framebuffer );
glBindFramebuffer( GL_DRAW_FRAMEBUFFER, resolved_framebuffer );
// https://forum.juce.com/t/ios-8-getting-the-demo-building/13570/20
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
// ^--- this is throwing `GL_INVALID_OPERATION`
GLubyte* pixels = (GLubyte*)calloc(width*height*4,sizeof(GLubyte));
glReadPixels(0, 0,width, height,GL_RGBA, GL_UNSIGNED_BYTE, pixels);
writePNG(pixels);
Currently I'm getting a blank image and glBlitFramebuffer is throwing GL_INVALID_OPERATION. Apparently this error can correspond to many things, and I'm not sure which is applying. My buffers seem "good" according to glCheckFramebufferStatus.
This question has been asked in similar forms before:
Cannot render to texture with multisampling
Multisampled render to texture in ios
But none of the answers have lead to a complete working example. I would love to find/create a minimal example of this.
The tutorial at https://learnopengl.com/Advanced-OpenGL/Anti-Aliasing basically had what I needed. The working solution is:
unsigned int framebuffer;
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
// create a multisampled color attachment texture
unsigned int textureColorBufferMultiSampled;
glGenTextures(1, &textureColorBufferMultiSampled);
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, textureColorBufferMultiSampled);
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGBA, width, height, GL_TRUE);
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, textureColorBufferMultiSampled, 0);
// create a (also multisampled) renderbuffer object for depth and stencil attachments
unsigned int rbo;
glGenRenderbuffers(1, &rbo);
glBindRenderbuffer(GL_RENDERBUFFER, rbo);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, width, height);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// configure second post-processing framebuffer
unsigned int intermediateFBO;
glGenFramebuffers(1, &intermediateFBO);
glBindFramebuffer(GL_FRAMEBUFFER, intermediateFBO);
// create a color attachment texture
unsigned int screenTexture;
glGenTextures(1, &screenTexture);
glBindTexture(GL_TEXTURE_2D, screenTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, screenTexture, 0); // we only need a color buffer
assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
draw_scene();
glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, intermediateFBO);
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
glBindFramebuffer(GL_FRAMEBUFFER, intermediateFBO);
GLubyte* pixels = (GLubyte*)calloc(width*height*4,sizeof(GLubyte));
glReadPixels(0, 0,width, height,GL_RGBA, GL_UNSIGNED_BYTE, pixels);
writePNG(pixels);
It seems there're at least two errors in the code in the original question:
The framebuffer should have a multisample texture attached, not a renderbuffer (glFramebufferTexture2D(... GL_TEXTURE_2D_MULTISAMPLE instead of glRenderbufferStorageMultisample)
Must call glBindFramebuffer(GL_FRAMEBUFFER, intermediateFBO); after blitting and before glReadPixels

Framebuffer Texture rendered to screen is stretched at certain points

I'm currently trying to test out rendering to a framebuffer for various uses, but whenever I have an object(say a square) at a certain y-value, it appears "stretched", and then past a certain y-value or a certain x-value it seems to "thin out" and disappears. I have determined the x and y-values that it disappears at, but the coordinates seem to not have any rhyme or reason.
When I remove the framebuffer binding and render directly to the screen it draws the square perfectly fine, no matter the x or y-value.
Drawing a basic square(using immediate mode to remove possible errors) with a wide x-value looks like this:
Code here:
Window window("Framebuffer Testing", 1600, 900); //1600x900 right now
int fbowidth = 800, fboheight = 600;
mat4 ortho = mat4::orthographic(0, width, 0, height, -1.0f, 1.0f);
//trimmed out some code from shader creation that is bugless and unneccessary to include
Shader shader("basic"); shader.setUniform("pr_matrix", ortho);
Shader drawFromFBO("fbotest"); shader.setUniform("pr_matrix", ortho);
GLfloat screenVertices[] = {
0, 0, 0, 0, height, 0,
width, height, 0, width, 0, 0};
GLushort indices[] = {
0, 1, 2,
2, 3, 0 };
GLfloat texcoords[] = { //texcoords sent to the drawFromFBO shader
0, 0, 0, 1, 1, 1,
1, 1, 1, 0, 0, 0 };
IndexBuffer ibo(indices, 6);
VertexArray vao;
vao.addBuffer(new Buffer(screenVertices, 4 * 3, 3), 0);
vao.addBuffer(new Buffer(texcoords, 2 * 6, 2), 1);
GLuint fbo;
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fbowidth, fboheight, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glBindTexture(GL_TEXTURE_2D, 0);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, texture, 0);
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
std::cout << "false" << std::endl;
glEnable(GL_TEXTURE_2D);
//the x-values mess up at ~783 thru 800 and the y-values at 0 thru ~313
while(!window.closed()) {
glClearColor(0.2f, 0.2f, 0.2f, 1.0f); //grey
window.clear(); //calls glclear for depth and color buffer
//bind framebuffer and shader
shader.enable(); //literally just calls glUseProgram(id) with the compiled shader id
glViewport(0, 0, fbowidth, fboheight);
glBindFramebuffer(GL_FRAMEBUFFER, fbo); //bind the fbo
glClearColor(1.0f, 0.0f, 1.0f, 1.0f); //set clear color to pink
glClear(GL_COLOR_BUFFER_BIT);
//render a red square to the framebuffer texture
glBegin(GL_QUADS); {
glColor3f(1.0f, 0.0f, 0.0f); //set the color to red
glVertex3f(700, 400, 0);
glVertex3f(700, 450, 0);
glVertex3f(750, 450, 0);
glVertex3f(750, 400, 0);
} glEnd();
shader.disable();
glBindFramebuffer(GL_FRAMEBUFFER, 0); //set framebuffer to the default
//render from framebuffer to screen
glViewport(0, 0, width, height);
drawFromFBO.enable();
glActiveTexture(GL_TEXTURE0);
drawFromFBO.setUniform1i("texfbo0", 0);
glBindTexture(GL_TEXTURE_2D, texture);
vao.bind();
ibo.bind();
glDrawElements(GL_TRIANGLES, ibo.getCount(), GL_UNSIGNED_SHORT, NULL);
ibo.unbind();
vao.unbind();
drawFromFBO.disable();
window.update();
}
If you want to see any thing extra, the file is located at my Github: here

OpenGL Mutlisampling Multiple Render Target FBO's

I am trying Deferred Shading and I am having troubles trying to MultiSample a Multiple Render Target. It Seems as if I am only copying over one anti-Aliased Texture instead of 3 (Diffuse,Position,Normals). Only the Diffuse are copied.
This is the Anti Alias FBO creation for my Geometry Pass:
IntBuffer drawBuffs = BufferUtils.createIntBuffer(3);
private void CreateFBOAntiAlias() {
AntiAliasFrameBuffer = glGenFramebuffers();
GL30.glBindFramebuffer(GL_FRAMEBUFFER, AntiAliasFrameBuffer);
textureColorMultiSampled = generateMultiSampleTexture(4);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL32.GL_TEXTURE_2D_MULTISAMPLE, textureColorMultiSampled,
0);
texturePositionMultiSampled = generateMultiSampleTexture(4);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1,
GL32.GL_TEXTURE_2D_MULTISAMPLE, texturePositionMultiSampled ,
0);
textureNormalMultiSampled = generateMultiSampleTexture(4);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2,
GL32.GL_TEXTURE_2D_MULTISAMPLE, textureNormalMultiSampled ,
0);
drawBuffs.put(0, GL30.GL_COLOR_ATTACHMENT0);
drawBuffs.put(1, GL30.GL_COLOR_ATTACHMENT1);
drawBuffs.put(2, GL30.GL_COLOR_ATTACHMENT2);
GL20.glDrawBuffers(drawBuffs);
AntiAliasRenderBufferObject = glGenRenderbuffers();
glBindRenderbuffer(GL_RENDERBUFFER, AntiAliasRenderBufferObject);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4,
GL_DEPTH24_STENCIL8, width, height);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
GL_RENDERBUFFER, AntiAliasRenderBufferObject);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
System.err
.println("ERROR::FRAMEBUFFER:: Framebuffer is not complete!");
} else {
System.err.println("FrameBuffer AntiAliasFBO success");
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
private int generateMultiSampleTexture(int samples) {
int texture;
texture = GL11.glGenTextures();
GL11.glBindTexture(GL32.GL_TEXTURE_2D_MULTISAMPLE, texture);
GL32.glTexImage2DMultisample(GL32.GL_TEXTURE_2D_MULTISAMPLE, samples,
GL11.GL_RGBA8, width, height, true);
GL11.glBindTexture(GL32.GL_TEXTURE_2D_MULTISAMPLE, 0);
return texture;
}
This is the creation for my Target FBO:
public void CreateFBO() {
fbo_handle = glGenFramebuffers();
diffuse_handle = GL11.glGenTextures();
position_handle = GL11.glGenTextures();
normal_handle = GL11.glGenTextures();
glBindFramebuffer(GL_FRAMEBUFFER, fbo_handle);
//////////////////DIFFUSE////////////////////////////////////
GL11.glBindTexture(GL11.GL_TEXTURE_2D, diffuse_handle);
GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA, width, height,0,
GL11.GL_RGBA, GL11.GL_INT, (ByteBuffer) null);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL11.GL_TEXTURE_2D, diffuse_handle, 0);
/////////////////POSITION////////////////////////////////////
GL11.glBindTexture(GL11.GL_TEXTURE_2D, position_handle);
GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0,
GL11.GL_RGBA, GL11.GL_INT, (ByteBuffer) null);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1,
GL11.GL_TEXTURE_2D, position_handle, 0);
///////////////NORMALS/////////////////////////////////////////
GL11.glBindTexture(GL11.GL_TEXTURE_2D, normal_handle);
GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL_RGBA16F, width, height, 0,
GL11.GL_RGBA, GL11.GL_INT, (ByteBuffer) null);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2,
GL11.GL_TEXTURE_2D, normal_handle, 0);
//////////////////////////////////////////////////////////////////
drawBuffs.put(0, GL30.GL_COLOR_ATTACHMENT0);
drawBuffs.put(1, GL30.GL_COLOR_ATTACHMENT1);
drawBuffs.put(2, GL30.GL_COLOR_ATTACHMENT2);
GL20.glDrawBuffers(drawBuffs);
rbo_depth_buffer_handle = glGenRenderbuffers();
glBindRenderbuffer(GL_RENDERBUFFER, rbo_depth_buffer_handle);
glRenderbufferStorage(GL_RENDERBUFFER, GL14.GL_DEPTH_COMPONENT32,
width, height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, rbo_depth_buffer_handle);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
System.err.println("Framebuffer configuration error");
} else {
System.err.println("Deferred configuration Success");
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
I bind my AA FBO during the Geometry pass, unbind it and perform a Blit from the AA FBO to my Target FBO and Render the Fullscreen Quad with undesire results.
public void blit() {
GL11.glEnable(GL13.GL_MULTISAMPLE);
glBindFramebuffer(GL_READ_FRAMEBUFFER, AntiAliasFrameBuffer);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo_handle);
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height,
GL11.GL_COLOR_BUFFER_BIT, GL11.GL_NEAREST);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
Edit: I've tried blitting from a normal MRT fbo to another normal MRT FBO without the Multi-Sampling calls and again it seems i'm copying over just ONE texture. Rhe root of my problem is incorrectly blitting an MRT to another MRT.
Whew, ok My main problem was my blitting was incorrect. The blitting Method should be
public void blit() {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindFramebuffer(GL_READ_FRAMEBUFFER, AntiAliasFrameBuffer);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo_handle);
GL11.glReadBuffer(GL_COLOR_ATTACHMENT0);
GL11.glDrawBuffer(GL_COLOR_ATTACHMENT0);
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height,
GL11.GL_COLOR_BUFFER_BIT, GL11.GL_NEAREST);
GL11.glReadBuffer(GL_COLOR_ATTACHMENT1);
GL11.glDrawBuffer(GL_COLOR_ATTACHMENT1);
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height,
GL11.GL_COLOR_BUFFER_BIT, GL11.GL_NEAREST);
GL11.glReadBuffer(GL_COLOR_ATTACHMENT2);
GL11.glDrawBuffer(GL_COLOR_ATTACHMENT2);
glBlitFramebuffer(0, 0, width, height, 0, 0, width, height,
GL11.GL_COLOR_BUFFER_BIT, GL11.GL_NEAREST);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
the general setup for my AA FBO/FBO is correct, and all textures are copied over successfully and with major improvement over Aliasing.

Deferred shader textures from FBO display as black

I am trying to use deferred shading to implement SSAO and I have problems to access my textures in the deferred fragment shader. The code is in C++/Qt5 and makes use of Coin3D to generate the rest of the UI (but this shouldn't really matter here).
The fragment shader of the deferred pass is:
#version 150 compatibility
uniform sampler2D color;
uniform sampler2D position;
uniform sampler2D normal;
uniform vec3 dim;
uniform vec3 camPos;
uniform vec3 camDir;
void main()
{
// screen position
vec2 t = gl_TexCoord[0].st;
// the color
vec4 c = texture2D(color, t);
gl_FragColor = c + vec4(1.0, t.x, t.y, 1.0);
}
The code for running the deferred pass is
_geometryBuffer.Unbind();
// push state
{
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glPushAttrib(GL_DEPTH_BUFFER_BIT |
GL_COLOR_BUFFER_BIT |
GL_LIGHTING_BIT |
GL_SCISSOR_BIT |
GL_POLYGON_BIT |
GL_CURRENT_BIT);
glDisable(GL_DEPTH_TEST);
glDisable(GL_ALPHA_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_CULL_FACE);
}
// bind shader
// /!\ IMPORTANT to do before specifying locations
_deferredShader->bind();
_CheckGLErrors("deferred");
// specify positions
_deferredShader->setUniformValue("camPos", ...);
_deferredShader->setUniformValue("camDir", ...);
_geometryBuffer.Bind(GBuffer::TEXTURE_TYPE_NORMAL, 2);
_deferredShader->setUniformValue("normal", GLint(2));
_geometryBuffer.Bind(GBuffer::TEXTURE_TYPE_POSITION, 1);
_deferredShader->setUniformValue("position", GLint(1));
_geometryBuffer.Bind(GBuffer::TEXTURE_TYPE_DIFFUSE, 0);
_deferredShader->setUniformValue("color", GLint(0));
_CheckGLErrors("bind");
// draw screen quad
{
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glColor3f(0, 0, 0);
glVertex2f(-1, -1);
glTexCoord2f(1, 0);
glColor3f(0, 0, 0);
glVertex2f( 1, -1);
glTexCoord2f(1, 1);
glColor3f(0, 0, 0);
glVertex2f( 1, 1);
glTexCoord2f(0, 1);
glColor3f(0, 0, 0);
glVertex2f(-1, 1);
glEnd();
}
_deferredShader->release();
// for debug
_geometryBuffer.Unbind(2);
_geometryBuffer.Unbind(1);
_geometryBuffer.Unbind(0);
_geometryBuffer.DeferredPassBegin();
_geometryBuffer.DeferredPassDebug();
// pop state
{
glPopAttrib();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
}
I know that the textures have been correctly processed in the geometry buffer creation because I can dump them into files and get the expected result.
The deferred pass doesn't work. The shader compiled correctly and I get the following result on screen:
And the last part of my code (DeferredPassBegin/Debug) is to draw the FBO to the screen (as shown in screenshot) as a proof that the GBuffer is correct.
The current result seems to mean that the textures are not correctly bound to their respective uniform, but I know that the content is valid as I dumped the textures to files and got the same results as shown above.
My binding functions in GBuffer are:
void GBuffer::Unbind()
{
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
}
void GBuffer::Bind(TextureType type, uint32_t idx)
{
glActiveTexture(GL_TEXTURE0 + idx);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, _textures[static_cast<uint32_t>(type)]);
}
void GBuffer::Unbind(uint32_t idx)
{
glActiveTexture(GL_TEXTURE0 + idx);
glDisable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, 0);
}
Finally, the textures are 512/512, and I created them in my GBuffer with:
WindowWidth = WindowHeight = 512;
// Create the FBO
glGenFramebuffers(1, &_fbo);
glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
const uint32_t NUM = static_cast<uint32_t>(NUM_TEXTURES);
// Create the gbuffer textures
glGenTextures(NUM, _textures);
glGenTextures(1, &_depthTexture);
for (unsigned int i = 0 ; i < NUM; i++) {
glBindTexture(GL_TEXTURE_2D, _textures[i]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, WindowWidth, WindowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i + _firstIndex, GL_TEXTURE_2D, _textures[i], 0);
}
// depth
glBindTexture(GL_TEXTURE_2D, _depthTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, WindowWidth, WindowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, _depthTexture, 0);
GLenum buffers[NUM];
for(uint32_t i = 0; i < NUM; ++i){
buffers[i] = GLenum(GL_COLOR_ATTACHMENT0 + i + _firstIndex);
}
glDrawBuffers(NUM, buffers);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if (status != GL_FRAMEBUFFER_COMPLETE) {
printf("FB error, status: 0x%x\n", status);
return _valid = false;
}
// unbind textures
glBindTexture(GL_TEXTURE_2D, 0);
// restore default FBO
glBindFramebuffer(GL_FRAMEBUFFER, 0);
How can I debug farther at this stage?
I know that the texture data is valid, but I can't seem to bind it to the shader correctly (but I have other shaders that use textures loaded from files and which work fine).
--- Edit 1 ---
As asked, the code for DeferredPassBegin/Debug (mostly coming from this tutorial )
void GBuffer::DeferredPassBegin() {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindFramebuffer(GL_READ_FRAMEBUFFER, _fbo);
}
void GBuffer::DeferredPassDebug() {
GLsizei HalfWidth = GLsizei(_texWidth / 2.0f);
GLsizei HalfHeight = GLsizei(_texHeight / 2.0f);
SetReadBuffer(TEXTURE_TYPE_POSITION);
glBlitFramebuffer(0, 0, _texWidth, _texHeight,
0, 0, HalfWidth, HalfHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
SetReadBuffer(TEXTURE_TYPE_DIFFUSE);
glBlitFramebuffer(0, 0, _texWidth, _texHeight,
0, HalfHeight, HalfWidth, _texHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
SetReadBuffer(TEXTURE_TYPE_NORMAL);
glBlitFramebuffer(0, 0, _texWidth, _texHeight,
HalfWidth, HalfHeight, _texWidth, _texHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
}
Arghk!!!
So I expected that texture parameters were not mandatory, but as I looked at some code, I just tried to specify my texture parameters. When generating the FBO textures, I use now
for (unsigned int i = 0 ; i < NUM; i++) {
glBindTexture(GL_TEXTURE_2D, _textures[i]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, WindowWidth, WindowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
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);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i + _firstIndex, GL_TEXTURE_2D, _textures[i], 0);
}
And with this change, I get the expected result (with only c in the fragment shader, and similar correct results if I switch to visualizing the normal / position).
Conclusion: one must specify the texture parameters for deferred shading to work (at least with the graphics setup of my application / machine).

OpenGL FBO does not render to texture (C++)

I have been trying to render a teapot to a FBO and then use the subsequent texture as a texture map. nothing seems to come up, so I was wondering what I was doing wrong. Below is the main loop:
//switch to fbo
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(0.0,0.0,5.0,
0.0,0.0,-1.0,
0.0f,1.0f,0.0f);
glLightfv(GL_LIGHT0, GL_POSITION, lpos);
glRotatef(a,0,1,1);
glutSolidTeapot(1);
//switch to main
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glLoadIdentity();
gluLookAt(0.0,0.0,5.0,
0.0,0.0,-1.0,
0.0f,1.0f,0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindTexture(GL_TEXTURE_2D, img);
//draw cube
glColor4f(1, 1, 1, 1);
glBegin(GL_TRIANGLES);
// front faces
glNormal3f(0,0,1);
// face v0-v1-v2
glTexCoord2f(1,1); glVertex3f(1,1,1);
glTexCoord2f(0,1); glVertex3f(-1,1,1);
glTexCoord2f(0,0); glVertex3f(-1,-1,1);
...draws cube
I have tried using the glFramebufferStatus and it has returned "success"
glGenTextures(1, &img);
glBindTexture(GL_TEXTURE_2D, img);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glGenFramebuffers(1,&fbo);
glBindFramebuffer(GL_FRAMEBUFFER,fbo);
glGenRenderbuffers(1, &depthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, 512, 512);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthbuffer);
glGenTextures(1, &img);
glBindTexture(GL_TEXTURE_2D, img);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, img, 0);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if (status==GL_FRAMEBUFFER_COMPLETE) {
printf("success\n");
}
However, all I get is the cube with no texture mapping.
There are two possible errors here:
Rendering into the FBO fails. To check if this is the case, clear the FBO with a distinct background color (e.g. pink) and see if the texture is affected (by reading it back to the CPU, for example). You should also make sure that your transformation matrices and the viewport (glViewport) are correct.
Texture mapping fails. Make sure that you've got everything set up for texture mapping and test texture mapping with a static texture first.
What about glEnable ( GL_TEXTURE_2D ) ?