why aren't the opengl shaders compiling? - c++

Question

i have installed OpenGL 4.6 and i'am using visual studio 2019.
i had decided to do a project in C++ with opengl but since i have no previous experience with them i decided to follow this tutorial but now my shaders aren't compiling and i have no idea why.
my main code:
#include <fstream>
#include <string>
#include <glad/glad.h>
#include <GLFW\glfw3.h>
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
float vertex[] = {
0.0f, 0.5f, 0.0f, 0.2f, 0.4f, 0.6f, // top center
0.5f, -0.5f, 0.0f, 0.2f, 0.4f, 0.6f, // bottom right
-0.5f, -0.5f, 0.0f, 0.2f, 0.4f, 0.6f, // bottom left
0.0f, 0.0f, -0.5f, 0.2f, 0.4f, 0.6f // top left
};
unsigned int indices[] = { // note that we start from 0!
0, 1, 2
};
int main() {
glfwInit();
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);
std::cout << glfwGetVersionString();
GLFWwindow* window = glfwCreateWindow(800, 600, "Demo", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
glViewport(0, 0, 800, 600);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
GLuint VBO, VAO, EBO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glGenBuffers(1, &EBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex), vertex, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
unsigned int vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
std::string ContentVert;
std::ifstream infileVert;
infileVert.open("vertex.glsl");
if (infileVert.is_open())
{
while (getline(infileVert, ContentVert))
{
std::cout << ContentVert << '\n';
}
infileVert.close();
}
const GLchar* const vertexShadersrc = { ContentVert.c_str() };
glShaderSource(vertexShader, 1, &vertexShadersrc, NULL);
glCompileShader(vertexShader);
int success;
char infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
unsigned int fragmentShader;
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
std::string ContentFrag;
std::ifstream infileFrag;
infileFrag.open("demo.glsl");
if (infileFrag.is_open())
{
while (getline(infileFrag, ContentFrag))
{
std::cout << ContentFrag << '\n';
}
infileFrag.close();
}
const GLchar* const fragShaderSrc = { ContentFrag.c_str() };
glShaderSource(fragmentShader, 1, &fragShaderSrc, NULL);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
unsigned int shaderProgram;
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
glUseProgram(shaderProgram);
glBindFragDataLocation(shaderProgram, 0, "outColor");
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
while (!glfwWindowShouldClose(window))
{
processInput(window);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glfwTerminate();
return 0;
}
console output:
#version 330
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
out vec3 ourColor;
void main()
{
gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
ourColor = aColor;
}
ERROR::SHADER::VERTEX::COMPILATION_FAILED
WARNING: 0:1: '' : #version directive missing
ERROR: 0:1: '}' : syntax error syntax error
#version 330
out vec4 FragColor;
in vec3 ourColor;
void main() {
FragColor = vec4(ourColor, 1.0);
}
ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
WARNING: 0:1: '' : #version directive missing
ERROR: 0:1: '}' : syntax error syntax error
ERROR::SHADER::PROGRAM::LINKING_FAILED
Attached vertex shader is not compiled
vertex shader:
#version 330
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
out vec3 ourColor;
void main()
{
gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
ourColor = aColor;
}
fragment shader:
#version 330
out vec4 FragColor;
in vec3 ourColor;
void main() {
FragColor = vec4(ourColor, 1.0);
}

Answer 1

The issue is the way how you try to read the file
while (getline(infileVert, ContentVert))
getline reads a single line from the file and stores it to ContentVert. I does not append to ContentVert.
At the end, just the last line of the shader is stored in ContentVert. The content of the last line is "}". That explains the error message:
WARNING: 0:1: '' : #version directive missing
ERROR: 0:1: '}' : syntax error syntax error
I recommend to use std::istreambuf_iterator to read the entire file, from its begin to its end:
std::ifstream infileVert("vertex.glsl", std::fstream::in);
std::string ContentVert;
if ( sourceFile.is_open() )
ContentVert = std::string(std::istreambuf_iterator<char>(infileVert),
std::istreambuf_iterator<char>());