Call to glDrawElements breaks display on some GPUs? - c++

Question

I'm working on a 3D PBR engine along with some colleagues (OpenGL 3.3 + GLFW3 and ImGui), and we have a peculiar error : the application enters its drawing loop normally and gives no OpenGL error whatsoever (as shown by extensive use of glCheckError()), but the screen is completely blank. The peculiar part is that this only happens on my colleagues' computer that uses an Nvidia GeForce GTX 1060 as its graphic cards (2 of my friends have the same exact computer).
After some investigation, it turns out that this error is triggered by a function that is called a single time before the main loop. Long story short, it renders a quad to a texture bound via a framebuffer using a couple shaders. I narrowed down the problem to the glDrawElements call ; on those computers, not changing anything except commenting out this line fixes the display (at the cost of the texture displaying garbage instead of the expected result of the draw call), whereas all of the other computers run the app fine even with the line uncommented.
The culprit function is as follows :
/**
* Returns a texture identifier filled with a precomputed irradiance map calculated
* from a provided, already set up-environment map
*/
GLuint precomputeIrradianceMap(GLuint envMapId)
{
std::cerr << "Precomputing irradiance map ... " << std::endl;
GLuint irradianceVAO, irradianceVBO, irradianceMap,
irradianceVertShader, irradianceFragShader, irradianceProgram, captureFBO,
captureRBO;
GLint aPos_location, env_map;
glGenVertexArrays(1, &irradianceVAO);
glBindVertexArray(irradianceVAO);
glGenBuffers(1, &irradianceVBO);
glBindBuffer(GL_ARRAY_BUFFER, irradianceVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(quad_vertices), quad_vertices, GL_STATIC_DRAW);
glGenFramebuffers(1, &captureFBO);
glGenRenderbuffers(1, &captureRBO);
glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 320, 320);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, captureRBO);
checkGLerror();
glGenTextures(1, &irradianceMap);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, irradianceMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, 320, 320, 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_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glBindTexture(GL_TEXTURE_2D, envMapId);
checkGLerror();
irradianceVertShader = createShaderFromSource(GL_VERTEX_SHADER, "shaders/irradiance_vert.glsl");
irradianceFragShader = createShaderFromSource(GL_FRAGMENT_SHADER, "shaders/irradiance_frag.glsl");
irradianceProgram = glCreateProgram();
glAttachShader(irradianceProgram, irradianceVertShader);
glAttachShader(irradianceProgram, irradianceFragShader);
printShaderLog(irradianceVertShader);
printShaderLog(irradianceFragShader);
glLinkProgram(irradianceProgram);
glUseProgram(irradianceProgram);
checkGLerror();
env_map = glGetUniformLocation(irradianceProgram, "environmentMap");
aPos_location = glGetAttribLocation(irradianceProgram, "aPos");
glEnableVertexAttribArray(aPos_location);
checkGLerror();
glVertexAttribPointer(aPos_location, 3, GL_FLOAT, GL_FALSE, 0, (void *) 0);
glUniform1i(env_map, 0);
checkGLerror();
glViewport(0, 0, 320, 320);
glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, irradianceMap, 0);
checkGLerror();
glClearDepth(1.f);
glClearColor(0.f, 0.f, 0.f, 1.f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
checkGLerror();
// This is the culprit
// glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, quad_indices);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
checkGLerror();
// glDisableVertexAttribArray(aPos_location);
glDeleteShader(irradianceVertShader);
glDeleteShader(irradianceFragShader);
glDeleteProgram(irradianceProgram);
glDeleteFramebuffers(1, &captureFBO);
glDeleteRenderbuffers(1, &captureRBO);
glDeleteBuffers(1, &irradianceVBO);
glDeleteVertexArrays(1, &irradianceVAO);
checkGLerror();
std::cerr << "... done " << std::endl;
return irradianceMap;
}
You can safely replace checkGLerror() by std::cerr << glCheckError() << std::endl. As I said before, there is no OpenGL error whatsoever, all the shaders compile fine, and this only breaks on computers equipped with an Nvidia GeForce GTX 1060.
The rest of the code is mostly setting up VAOs, VBOs and the like, and the render loop is as follows :
while (!glfwWindowShouldClose(window))
{
glfwGetFramebufferSize(window, &display_w, &display_h);
float newRatio = (float)display_w / display_h;
if(ratio != newRatio)
{
ratio = newRatio;
setAspectRatio(p, ratio);
invP = p.inverse();
glViewport(0, 0, display_w, display_h);
}
ImGui_ImplGlfwGL3_NewFrame();
// Rendering + OpenGL rendering
// Draw the skybox, then the model
ImGui::Begin("Physical parameters", NULL, ImGuiWindowFlags_AlwaysAutoResize);
ImGui::SliderFloat("Dielectric specularity", &ds, 0.f, 1.f, "%.3f");
ImGui::SliderFloat("Light intensity", &l0, 0.f, 10.f, "%.2f");
ImGui::Checkbox("Use irradiance map as skybox", &skyOrIrradiance);
ImGui::Checkbox("Debug draw irradiance map", &debugDraw);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, skyOrIrradiance ? irradianceTexture : skybox_texture);
ImGui::End();
Matrix4f v = camera->getMatrix(), invV = v.inverse();
// glClearColor(0.45f, 0.55f, 0.60f, 1.00f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindVertexArray(vertex_array_objs[0]);
glUseProgram(skybox_program);
glUniformMatrix4fv(skybox_v_location, 1, GL_FALSE, (const GLfloat *) invV.data());
glUniformMatrix4fv(skybox_p_location, 1, GL_FALSE, (const GLfloat *) invP.data());
glDisable(GL_DEPTH_TEST);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, quad_indices);
glBindVertexArray(vertex_array_objs[1]);
glUseProgram(program);
glUniformMatrix4fv(mv_location, 1, GL_FALSE, (const GLfloat *) v.data());
glUniformMatrix4fv(p_location, 1, GL_FALSE, (const GLfloat *)p.data());
glUniform1f(uDS_location, ds);
glUniform1f(L0_location, l0);
glActiveTexture(GL_TEXTURE0 + model.activeTexturesCount());
glBindTexture(GL_TEXTURE_2D, irradianceTexture);
glUniform1i(irradiance_location, model.activeTexturesCount());
glEnable(GL_DEPTH_TEST);
model.render();
if(debugDraw)
{
displayTexture(irradianceTexture);
displayTexture(skybox_texture, 0.f, -1.f);
}
camera->drawControls();
// Draw basic interface
basicInterface();
ImGui::Render();
ImGui_ImplGlfwGL3_RenderDrawData(ImGui::GetDrawData());
glfwSwapBuffers(window);
glfwPollEvents();
camera->update(window);
}
model.render() is as follows :
void GltfModel::render() const
{
for(unsigned int i = 0; i < _activeTextures.size(); i++)
{
if(_textureLocations[i] > -1)
{
int j = _activeTextures[i];
glActiveTexture(GL_TEXTURE0 + i);
glBindTexture(GL_TEXTURE_2D, _textureIds[j]);
glUniform1i(_textureLocations[i], i);
}
}
glBindBuffer(GL_ARRAY_BUFFER, _buffers[ARRAY_BUFFER]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _buffers[ELEMENT_ARRAY_BUFFER]);
glDrawElements(_drawingMode, _indicesCount, _indicesType, NULL);
}
Thanks by advance for your time !
EDIT : putting a glClear(GL_COLOR_BUFFER_BIT) call right before glfwSwapBuffers(window) still displays a white screen with the culprit line uncommented even though the clear color has been set to light blue. Commenting the culprit line indeed displays a light blue screen, so this makes me think it's a framebuffer issue, but I can't say for sure.