Opengl GL_QUADS produces error 0x506

Question

I have some code in OpenGL to render a YUV image onto an OpenGL viewport. The program works without a problem when running on nvidia cards, but it generates an error when running over the Intel HD 3000, which sadly is the target machine. The point where the error is generated is marked in the code.

The shader programs are

// Vertex Shader
#version 120
void main() {
  gl_TexCoord[0] = gl_MultiTexCoord0;
  gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}

// fragment shader
#version 120
uniform sampler2D texY;
uniform sampler2D texU;
uniform sampler2D texV;
void main() {
  vec4 color;
  float y = texture2D(texY, gl_TexCoord[0].st).r;
  float u = texture2D(texU, gl_TexCoord[0].st).r;
  float v = texture2D(texV, gl_TexCoord[0].st).r;
  color.r = (1.164 * (y - 0.0625)) + (1.596 * (v - 0.5));
  color.g = (1.164 * (y - 0.0625)) - (0.391 * (u - 0.5)) - (0.813 * (v - 0.5));
  color.b = (1.164 * (y - 0.0625)) + (2.018 * (u - 0.5));
  color.a = 1.0;
  gl_FragColor = color;
};

Then I run the program like this:

GLuint textures[3];
glGenTextures(3, textures);

glBindTexture(GL_TEXTURE_2D, textures[YTEX]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glBindTexture(GL_TEXTURE_2D, textures[UTEX]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glBindTexture(GL_TEXTURE_2D, textures[VTEX]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glBindTexture(GL_TEXTURE_2D, 0);

GLsizei size = width * height;

GLvoid *y = yuv_buffer;
GLvoid *u = (GLubyte *)y + size;
GLvoid *v = (GLubyte *)u + (size >> 2);

glUseProgram(program_id);

glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textures[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE,
            GL_UNSIGNED_BYTE, y);
glUniform1i(glGetUniformLocation(program_id, "texY"), 0);

glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, textures[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width >> 1, height >> 1, 0,
            GL_LUMINANCE, GL_UNSIGNED_BYTE, u);
glUniform1i(glGetUniformLocation(program_id, "texU"), 1);

glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, textures[2]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width >> 1, height >> 1, 0,
            GL_LUMINANCE, GL_UNSIGNED_BYTE, u);
glUniform1i(glGetUniformLocation(program_id, "texV"), 2);

glBegin(GL_QUADS);
glTexCoord2f(texLeft, texTop);
glVertex2i(left, top);
glTexCoord2f(texLeft, texBottom);
glVertex2i(left, bottom);
glTexCoord2f(texRight, texBottom);
glVertex2i(right, bottom);
glTexCoord2f(texRight, texTop);
glVertex2i(right, top);
glEnd();

// glError() returns 0x506 here

glBindTexture(GL_TEXTURE_2D, 0);
glActiveTexture(GL_TEXTURE0);

glUseProgram(0);

update since the error happens with frame buffers, I discover they are used like this: when the program is instantiated, a frame buffer is created like this:

glViewport(0, 0, (GLint)width, (GLint)height);

glGenFramebuffers(1, &fbo_id);
glGenTextures(1, &fbo_texture);
glGenRenderbuffers(1, &rbo_id);

glBindTexture(GL_TEXTURE_2D, fbo_texture);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0,
            GL_RGBA, GL_UNSIGNED_BYTE, 0);
glBindTexture(GL_TEXTURE_2D, 0);

glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rbo_id);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, width, height);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_id);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                          GL_TEXTURE_2D, fbo_texture, 0);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
                            GL_RENDERBUFFER_EXT, rbo_id);

GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);

glPushAttrib(GL_TEXTURE_BIT);

glBindTexture(GL_TEXTURE_2D, m_frameTexture->texture());
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glPopAttrib();

The YUV image comes spliced in tiles, which are assembled by rendering in this fbo. Whenever a frame starts, this is performed:

glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
glDrawBuffer(GL_BACK);

glViewport(0, 0, (GLint)width, (GLint)height);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, (double)width, 0.0, (double)height, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

glBindFramebuffer(GL_FRAMEBUFFER_EXT, fbo_id);

Then the code above is executed, and after all the tiles had been assembled together

glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
glPushAttrib(GL_VIEWPORT_BIT | GL_TEXTURE_BIT | GL_ENABLE_BIT);
glViewport(0, 0, width, height);

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);

glMatrixMode(GL_PROJECTION);
glPushMatrix();

glLoadIdentity();
glOrtho(0.0, (double)width, 0.0, (double)height, -1.0, 1.0);

glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();

glEnable(GL_TEXTURE_2D);
glDisable(GL_DEPTH_TEST);

glBindTexture(GL_TEXTURE_2D, fbo_texture);

glBegin(GL_QUADS);
glTexCoord2i(0, 0);
glVertex2f(renderLeft, renderTop);
glTexCoord2i(0, 1);
glVertex2f(renderLeft, renderTop + renderHeight);
glTexCoord2i(1, 1);
glVertex2f(renderLeft + renderWidth, renderTop + renderHeight);
glTexCoord2i(1, 0);
glVertex2f(renderLeft + renderWidth, renderTop);
glEnd();

glPopMatrix();

glMatrixMode(GL_PROJECTION);
glPopMatrix();
glPopAttrib();

Answer 1

What's the value of status after:

GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

If the value is anything other than GL_FRAMEBUFFER_COMPLETE, OpenGL will probably choke when it tries to read from the FBO.

The glCheckFramebufferStatus docs describes other (error) values it can return, and what causes them.

Of particular interest might be:

If the currently bound framebuffer is not framebuffer complete, then it is an error to attempt to use the framebuffer for writing or reading. This means that rendering commands (glDrawArrays and glDrawElements) as well as commands that read the framebuffer (glReadPixels, glCopyTexImage2D, and glCopyTexSubImage2D) will generate the error GL_INVALID_FRAMEBUFFER_OPERATION if called while the framebuffer is not framebuffer complete.

(emphasis mine)

edit based on your comments:

To paraphrase the docs wrt GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:

Not all framebuffer attachment points are framebuffer attachment complete. This means that one of the following is happening:

• At least one attachment point with a renderbuffer or texture attached has its attached object no longer in existence or has an attached image with a width or height of zero,
• The color attachment point has a non-color-renderable image attached. Color-renderable formats include GL_RGBA4, GL_RGB5_A1, and GL_RGB565.
• The depth attachment point has a non-depth-renderable image attached. GL_DEPTH_COMPONENT16 is the only depth-renderable format.
• The stencil attachment point has a non-stencil-renderable image attached. GL_STENCIL_INDEX8 is the only stencil-renderable format.

We can rule out the last 2 bullets, because it doesn't appear that you're using depth or stencil attachements. That leaves two calls to examine:

glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, fbo_texture, 0);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, rbo_id);

From the opengl.org wiki on FBOs:

You get GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT when any of the attachments are 'incomplete'. Criteria for completeness are:

• The source object for the image still exists and has the same type it was attached with.
• The image has a non-zero width and height.
• The layer for 3D or array textures attachments is less than the depth of the texture.
• The image's format must match the attachment point's requirements, as defined above. Color-renderable formats for color attachments, etc.

The wiki says of GL_COLOR_ATTACHMENTi​:

These attachment points can only have images bound to them with color-renderable formats. All compressed image formats are not color-renderable, and thus cannot be attached to an FBO.

Double check that the fbo_texture and rbo_id are still valid, and that their height/width aren't 0. Finally, it could be fbo_texture's format. You've got it set to GL_RGBA8, but the docs say valid options include GL_RGBA4, GL_RGB5_A1, and GL_RGB565. I'm not sure whether or not that excludes all other formats (like your GL_RGBA8). The wiki seems to suggest that any non-compressed format should work. Try switching it to GL_RGBA4, and see if that works out.

Answer 2

glGetError error codes "stick" and are not automatically cleared. If something at the beginning your program generates OpenGL error AND you check for error code 1000 opengl calls later, error will be still here.

So if you want to understand what's REALLY going on, check for errors after every OpenGL call, or call glGetError in a loop, until all error codes are returned (as OpenGL documentation suggests).