OpenGL not displaying rectangle

OpenGL
1

I have checked the entire codebase and have not been able to recognize the problem.

Here’s the main part where I hypothesize it lies:

unsigned int vertexShader;

if(compileVertexShader(&vertexShader, vertexShaderSource) == FAIL)
{
    return FAIL;
}

unsigned int fragmentShader;

if(compileFragmentShader(&fragmentShader, fragmentShaderSource) == FAIL)
{
    return FAIL;
}

unsigned int shaderProgram;
shaderProgram = glCreateProgram();

glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);

if(checkShaderProgramSuccess(shaderProgram) == FAIL)
{
    return FAIL;
}

glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);

unsigned int VBO;
unsigned int VAO;
unsigned int EBO;

glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);

glBindVertexArray(VAO);

glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(rectangle.vertices), rectangle.vertices, GL_STATIC_DRAW);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(rectangle.indices), rectangle.indices, GL_STATIC_DRAW);

glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);

glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);

while(!glfwWindowShouldClose(window))
{
    windowRender(window, shaderProgram, VBO, EBO);

    glfwPollEvents();
}

printf("Program closing due to user input. The program ran successfully without error.\n");

cleanup();

return SUCCESS;

And here’s the entire codebase

main.c

#include "main.h"

#include "window.h"
#include "display.h"
#include "shaders.h"

// gcc Assets/Code/main.c Assets/Code/window.c Assets/Code/display.c Assets/Code/shaders.c -lGLEW -lGL -lglfw -o "Game" -Wall

const char* vertexShaderSource = "#version 330 core\n"
    "layout (location = 0) in vec3 aPos;\n"
    "void main()\n"
    "{\n"
    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
    "}\0";

const char* fragmentShaderSource = "#version 330 core\n"
    "out vec4 FragColor;\n"
    "void main()\n"
    "{\n"
    "FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
    "}\0";

GLFWwindow* window;

float test_rectangle_vertices[] = {
        0.5f,  0.5f, 0.0f,  // top right
        0.5f, -0.5f, 0.0f,  // bottom right
        -0.5f, -0.5f, 0.0f,  // bottom left
        -0.5f,  0.5f, 0.0f   // top left
    };

unsigned int test_rectangle_indices[] = {
    0, 1, 3,
    1, 2, 3
};

void cleanup()
{
    if(window)
    {
        glfwDestroyWindow(window);
    }

    glfwTerminate();
}

void print_glfw_error()
{
    const char* error_ptr;
    glfwGetError(&error_ptr);

    printf("%s\n", error_ptr);
}

void print_glew_error(GLenum error)
{
    printf("%s\n", glewGetErrorString(error));
}

bool initialize_glew()
{
    // GLAD is not very glad, GLEW is what makes me glad

    GLenum glewinit_return_value = glewInit();

    if(glewinit_return_value != GLEW_OK)
    {
        print_glew_error(glewinit_return_value);
        handle_error(true, true); // clean up, and the error was fatal

        return FAIL;
    }

    return SUCCESS;
}

void handle_error(bool is_cleanup, bool is_fatal)
{
    if(is_fatal)
    {
        printf("Fatal error. Program aborted.\n");
    }

    if(is_cleanup)
    {
        cleanup();
    }
}

void createShape(Shape* rectangle, float* shape_vertices, unsigned int*  shape_indices)
{
    printf("Creating shape...\n");

    rectangle->vertices = shape_vertices;
    rectangle->indices = shape_indices;

    printf("Shape created.\n");
}

int main()
{
    if(!glfwInit())
    {
        print_glfw_error();
        handle_error(false, true); // do not clean up, and the error was fatal
        return FAIL;
    }

    window = createWindow();

    if(window == NULL)
    {
        return FAIL;
    }

    if(initialize_glew() == FAIL)
    {
        return FAIL;
    }

    glViewport(0, 0, 1920, 1080);

    Shape rectangle;

    createShape(&rectangle, test_rectangle_vertices, test_rectangle_indices);

    unsigned int vertexShader;

    if(compileVertexShader(&vertexShader, vertexShaderSource) == FAIL)
    {
        return FAIL;
    }

    unsigned int fragmentShader;

    if(compileFragmentShader(&fragmentShader, fragmentShaderSource) == FAIL)
    {
        return FAIL;
    }

    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();

    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    if(checkShaderProgramSuccess(shaderProgram) == FAIL)
    {
        return FAIL;
    }

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    unsigned int VBO;
    unsigned int VAO;
    unsigned int EBO;

    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(rectangle.vertices), rectangle.vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(rectangle.indices), rectangle.indices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    while(!glfwWindowShouldClose(window))
    {
        windowRender(window, shaderProgram, VBO, EBO);

        glfwPollEvents();
    }

    printf("Program closing due to user input. The program ran successfully without error.\n");

    cleanup();

    return SUCCESS;
}

display.c

#include "main.h"

// Rectangle's gone. This is depressing.

void windowRender(GLFWwindow* window, unsigned int shaderProgram, unsigned int VAO, unsigned int EBO)
{
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glUseProgram(shaderProgram);
    glBindVertexArray(VAO);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    glfwSwapBuffers(window);
}

#include "main.h"

// Please stop

bool compileVertexShader(unsigned int* vertexShaderInput, const char* vertexShaderSourceInput)
{
    *vertexShaderInput = glCreateShader(GL_VERTEX_SHADER);

    glShaderSource(*vertexShaderInput, 1, &vertexShaderSourceInput, NULL);
    glCompileShader(*vertexShaderInput);

    int is_successful;
    char infoLog[512];

    glGetShaderiv(*vertexShaderInput, GL_COMPILE_STATUS, &is_successful);

    if(!is_successful)
    {
        glGetShaderInfoLog(*vertexShaderInput, 512, NULL, infoLog);
        printf("Vertex shader compilation failed. Error log is as follows:\n%s", infoLog);

        handle_error(true, true); // clean up, and the error was fatal

        return FAIL;
    }

    return SUCCESS;
}

bool compileFragmentShader(unsigned int* fragmentShaderInput, const char* fragmentShaderSourceInput)
{
    *fragmentShaderInput = glCreateShader(GL_FRAGMENT_SHADER);

    glShaderSource(*fragmentShaderInput, 1, &fragmentShaderSourceInput, NULL);
    glCompileShader(*fragmentShaderInput);

    int is_successful;
    char infoLog[512];

    glGetShaderiv(*fragmentShaderInput, GL_COMPILE_STATUS, &is_successful);

    if(!is_successful)
    {
        glGetShaderInfoLog(*fragmentShaderInput, 512, NULL, infoLog);
        printf("Fragment shader compilation failed. Error log is as follows:\n%s", infoLog);

        handle_error(true, true); // clean up, and the error was fatal

        return FAIL;
    }

    return SUCCESS;
}

bool checkShaderProgramSuccess(unsigned int shaderProgram)
{
    int is_successful;
    char infoLog[512];

    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &is_successful);

    if(!is_successful)
    {
        glGetShaderInfoLog(shaderProgram, 512, NULL, infoLog);
        printf("Shader program compilation failed. Error log is as follows:\n%s", infoLog);

        handle_error(true, true); // clean up, and the error was fatal

        return FAIL;
    }

    return SUCCESS;
}

window.c

#include "main.h"

// Hours that the rectangle has been gone. It's just black. Darkness.

GLFWwindow* createWindow()
{
    GLFWwindow* window = glfwCreateWindow(1920, 1080, "Badpa", NULL, NULL);

    if(!window)
    {
        print_glfw_error();
        handle_error(true, true); // clean up, and the error was fatal

        return NULL;
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    glfwMakeContextCurrent(window);

    return window;
}

main.h

#pragma once

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>

#include <GL/glew.h>
#include <GLFW/glfw3.h>

#define SUCCESS 0
#define FAIL 1

void cleanup();
void handle_error(bool is_cleanup, bool is_fatal);
void print_glfw_error();
void print_glew_error(GLenum error);
bool initialize_glew();

typedef struct{
    float* vertices;
    unsigned int* indices;
} Shape;

window.h

#pragma once

GLFWwindow* createWindow();

shaders.h

#pragma once

bool compileVertexShader(unsigned int* vertexShaderInput, const char* vertexShaderSourceInput);
bool compileFragmentShader(unsigned int* fragmentShaderInput, const char* fragmentShaderSourceInput);
bool checkShaderProgramSuccess(unsigned int shaderProgram);

display.h

#pragma once

bool windowRender(GLFWwindow* window, unsigned int shaderProgram, unsigned int VAO, unsigned int EBO);
2

Alright, I fixed it. I made the rookie mistake of forgetting that the sizeof of a pointer will NOT return the size of the array. Stored the size separately, and now the bug is fixed.