ISSUE: When launched, GLWindow displays only a white screen and the cursor displays a loading circle, signifying that something is still being loaded. The window displays “Not Responding” shortly after that.
I have tried downgrading to openGL 3.3 and have used glad to help with that, but the problem persists.
Hello all,
I’ve been working to create a sphere with alternating colors using a vertex shader.
The code that I’ve shared below was slightly altered from code that was used to shade a quad, which worked fine. I expect that there will be issues with similar logic being used to shade a circle, or to build a sphere and shade that. I am NOT at that point yet however. Something is keeping my GL Window from displaying properly and I am hoping that someone can help me with my GLFW and glew logic to share why the window is failing to load.
Primary Class
#include <iostream>
#include <sstream>
#define GLEW_STATIC
//always GLEW before GLFW
#include "GL/glew.h"
#include "GLFW/glfw3.h"
#include "glm/glm.hpp"
#include "ShaderProgram.h"
#ifndef M_PI
# define M_PI 3.141592653
#endif
/////gLOBAL
GLFWwindow* w = NULL;
const int wWidth = 800;
const int wHeight = 600;
void key_callback(GLFWwindow *w, int key, int scancode, int action, int mode);
//update colors based on average framerate
void averageFPS(GLFWwindow* window);
//screen resizing
void glfw_onFramebufferSize(GLFWwindow* window, int width, int height);
bool initOpenGL();
static void error(int error, const char *desc)
{
fputs(desc, stderr);
}
//setting up values for keys
int main() {
if (!initOpenGL()) ///5IMPR
{
// An error occured
std::cerr << "GLFW not initialized" << std::endl;
return -1;
}
glfwSetErrorCallback(error);
GLfloat vertices[] = {
-0.5f, 0.5f, 0.0f,
0.5f, 0.5f, 0.0f,
-0.5f, 1.0f, 0.0f
};
GLuint indices[] = {
0, 1, 2,
0, 2, 3
};
// 2. Set up buffers on the GPU
GLuint vbo, ibo, vao;
glGenBuffers(1, &vbo); // Generate an empty vertex buffer on the GPU
glBindBuffer(GL_ARRAY_BUFFER, vbo); // "bind" or set as the current buffer we are working with
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); // copy the data from CPU to GPU
glGenVertexArrays(1, &vao); // Tell OpenGL to create new Vertex Array Object
glBindVertexArray(vao); // Make it the current one
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL); // Define a layout for the first vertex buffer "0"
glEnableVertexAttribArray(0); // Enable the first attribute or attribute "0"
// Set up index buffer
glGenBuffers(1, &ibo); // Create buffer space on the GPU for the index buffer
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glBindVertexArray(0); // unbind to make sure other code doesn't change it
ShaderProgram shaderProgram;
shaderProgram.assignShaders("shaders/ColorShader.vert", "shaders/ColorShader.frag");
////////SETUP RENDERING
while (!glfwWindowShouldClose(w))
{
averageFPS(w);
//process events
glfwPollEvents();
// Clear the screen
glClear(GL_COLOR_BUFFER_BIT);
shaderProgram.use();
GLfloat time = (GLfloat)glfwGetTime();
GLfloat blueSetting = (sin(time) / 2) + 0.5f;
glm::vec2 pos;
pos.x = sin(time) / 2;
pos.y = cos(time) / 2;
shaderProgram.setUniform("vertColor", glm::vec4(0.0f, 0.0f, blueSetting, 1.0f));
shaderProgram.setUniform("posOffset", pos);
/////COLOR OF CIRCLE OUTLINE
//glColor4f(0.0, 0.0, 1.0, 1.0); //RGBA
//PRIMARY BODY
// Draw our line
glBegin(GL_LINE_LOOP);
//glColor3f(0,0,1);
static double iteration = 0;
// The x, y offset onto the screen -- this should later be centered
static const int offset = 150;
static const float radius = 50;
// Calculate our x, y cooredinates
double x1 = offset + radius + 100 * cos(1);
double y1 = offset + radius + 100 * sin(1);
static double wobble = 0.0;
// A = (π * r²)
double a = M_PI * (100 * 2); //area
// C = (2 * π * r)
double c = 2 * M_PI * 100; //circumference
static double b = 128;
for (double i = 0; i < 2 * M_PI; i = i + ((2 * M_PI) / b))
{
double x = x1 + radius * cos(i);
double y = y1 + radius * sin(i);
glVertex2f(x, y);
glVertex2f(x, y);
}
iteration += 0.01;
////PRIMARY BODY End
glBindVertexArray(vao);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
//glDrawElements(GL_LINE_LOOP, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
// Swap buffers and look for events
glfwSwapBuffers(w);
}
//clean up
glDeleteVertexArrays(1, &vao);
glDeleteBuffers(1, &vbo);
glDeleteBuffers(1, &ibo);
//glfwDestroyWindow(w);
glfwTerminate();
return 0;
}
///////START Initializing glfw glew etc
bool initOpenGL(){
//this method will exit on these conditions
GLuint error = glfwInit();
if (!error)
return false;
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
w = glfwCreateWindow(wWidth, wHeight, "Exercise", NULL, NULL);
//Filling Window
if (w== NULL)
{
std::cerr << "glfw window not created" << std::endl;
glfwTerminate();
return false;
}
//update context
glfwMakeContextCurrent(w);
// Initialize GLEWunifor
glewExperimental = GL_TRUE;
GLuint err = glewInit();
if (err != GLEW_OK)
{
std::cerr << "initialize GLEW Failed" << std::endl;
return false;
}
//setup key callbacks
glfwSetKeyCallback(w, key_callback);
glfwSetFramebufferSizeCallback(w, glfw_onFramebufferSize);
while (!glfwWindowShouldClose(w))
{
//int width, height;
// glfwGetFramebufferSize(w, &width, &height); //move out of while??
// glViewport(0, 0, width, height); //remove??
}
glClearColor(0.23f, 0.38f, 0.47f, 1.0f); ///5ADD
// Define the viewport dimensions
glViewport(0, 0, wWidth, wHeight); //necessary?
return true;
}
void key_callback(GLFWwindow *w, int key, int scancode, int action, int mode)
{
// See http://www.glfw.org/docs/latest/group__keys.html
if ((key == GLFW_KEY_ESCAPE || key == GLFW_KEY_Q) && action == GLFW_PRESS)
glfwSetWindowShouldClose(w, GL_TRUE);
if (key == GLFW_KEY_W && action == GLFW_PRESS)
{
bool showWires = false;
if (showWires)
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}
}
//whever window resizes, do this
void glfw_onFramebufferSize(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
void averageFPS(GLFWwindow* window) ///5ADDdown
{
static double previousSeconds = 0.0;
static int frameCount = 0;
double passedSeconds;
double currentSeconds = glfwGetTime(); //seconds since GLFW started
passedSeconds = currentSeconds - previousSeconds;
// Limit time updates to 4 times per second
if (passedSeconds > 0.25)
{
previousSeconds = currentSeconds;
double fps = (double)frameCount / passedSeconds;
// double frameInMilSecs = 1000.0 / fps;
frameCount = 0;}
frameCount++;
}
Shader Manager/Handler Class
#include "ShaderProgram.h"
#include <fstream>
#include <iostream>
#include <sstream>
ShaderProgram::ShaderProgram()
: mProgram(0){
}
ShaderProgram::~ShaderProgram()
{
glDeleteProgram(mProgram);
}
bool ShaderProgram::assignShaders(const char* vertFileName, const char* fragFileName)
{
//Shaders output objects called programs that define their relationship and lead to .exe functionality
//assigning pointer to the shader
string vsString = readFile(vertFileName);
string fsString = readFile(fragFileName);
const GLchar* fsSourcePtr = fsString.c_str();
const GLchar* vsSourcePtr = vsString.c_str();
//creating vertex shader(vs) shader object
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
//assigning shader source using address. Replaces the source code in a shader object //@arg (shader, count Strings, pointer to const File ,size)
glShaderSource(vs, 1, &vsSourcePtr, NULL);
glShaderSource(fs, 1, &fsSourcePtr, NULL);
glCompileShader(vs);
glCompileShader(fs);
testProgramCompile();
testShaderCompile(vs);
testShaderCompile(fs);
//createProgram returns GLUint which is basically an unsigned int... we will use This Handler to create a program object
mProgram = glCreateProgram();
if (mProgram == 0)
{
std::cerr << "Shader cannot be created" << std::endl;
return false;
}
//assign the program object(mProgram) to the Shader
glAttachShader(mProgram, vs);
glAttachShader(mProgram, fs);
//this method accepts a GLuint "program" . If its an object of type GL_VERTEX_SHADER,
//itll create a .exe that runs on the programmable vertex processor. same goes for geometric and fragment shaders if they were included
//it will also bind all user defined uniform variables and attributes to the program
//The program can then be made part of a defined state by calling useProgram
glLinkProgram(mProgram);
testProgramCompile();
testShaderCompile(vs);
testShaderCompile(vs);
//cleaning up the elements we already used
glDeleteShader(vs);
glDeleteShader(fs);
//clear the identifier lookup map(in this case, there's only one)
mUniformIdentifiers.clear();
return true;
}//end main
//Read the shaderFile. strngstream for reading multiple lines
string ShaderProgram:: readFile(const string& filename) {
std::stringstream strgstream;
std::ifstream file;
try
{
file.open(filename, std::ios::in);
if (!file.fail())
{
strgstream << file.rdbuf();
}
file.close();
}
catch (std::exception e)
{
std::cerr << "Error: File or File Name Issues" << std::endl;
}
return strgstream.str();
}
//use the Program Object we created in this current state(color)
void ShaderProgram::use()
{
if (mProgram != 0)
glUseProgram(mProgram);
}
void ShaderProgram::testProgramCompile() {
int status = 0;
GLuint program = mProgram;
// ///CHECKING GL_LINK_STATUS to see if Program Link was successul. Link Status will return GL_TRUE if it was
glGetProgramiv( mProgram, GL_LINK_STATUS, &status); //requesting the status
if (status == GL_FALSE)
{
std::cerr << "Linking Error with Program " << std::endl;
}
}
void ShaderProgram :: testShaderCompile(GLuint shader) {
int status = 0;
// ///CHECKING GL_LINK_STATUS to see if Program Link was successul. Link Status will return GL_TRUE if it was
glGetProgramiv(shader, GL_LINK_STATUS, &status); //requesting the status
if (status == GL_FALSE)
{
std::cerr << "Linking Error with Shader " << std::endl;
}
}
////GETTERS AND SETTERS
GLuint ShaderProgram::getProgram() const
{
return mProgram;
}
void ShaderProgram::setUniform(const GLchar* name, const glm::vec2& v)
{
GLint address = getUniformIdentifier(name);
glUniform2f(address, v.x, v.y);
}
void ShaderProgram::setUniform(const GLchar* name, const glm::vec3& v)
{
GLint address = getUniformIdentifier(name);
glUniform3f(address, v.x, v.y, v.z);
}
void ShaderProgram:: setUniform(const GLchar* name, const glm::vec4& v) {
GLint address = getUniformIdentifier(name);
glUniform4f(address, v.x, v.y, v.z, v.w);
}
//Maybe need to switch places with setUniform
GLint ShaderProgram :: getUniformIdentifier(const GLchar* name) {
std::map<std::string, GLint>::iterator it;
it = mUniformIdentifiers.find(name);
//std::map<std::string, GLint>
// Only need to query the shader program IF it doesn't already exist.
if (it == mUniformIdentifiers.end())
{
// Find it and add it to the map
mUniformIdentifiers[name] = glGetUniformLocation(mProgram, name);
}
// Return it
return mUniformIdentifiers[name];
}