My main.c file looks like this:
#define GL_SILENCE_DEPRECATION
#define STB_IMAGE_IMPLEMENTATION
#include <stb/stb_image.h>
#include <stdio.h>
#include <stdbool.h>
#include <math.h>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include "gfx/shader.h"
void ErrorCallback(int i,
const char * err_str) {
printf("GLFW Error: %s\n", err_str);
}
void framebuffer_size_callback(GLFWwindow * window, int width, int height) {
glViewport(0, 0, width, height);
}
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
static bool wireframe = false;
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
glfwSetWindowShouldClose(window, GL_TRUE);
}
if (key == GLFW_KEY_TAB && action == GLFW_PRESS) {
if(!wireframe) {
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
}
else {
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}
wireframe = !wireframe;
}
}
int main() {
const int WIDTH = 800;
const int HEIGHT = 600;
glfwSetErrorCallback(ErrorCallback);
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
GLFWwindow * window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", NULL, NULL);
if (window == NULL) {
printf("Failed to create GLFW window!\n");
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc) glfwGetProcAddress)) {
printf("Failed to initialize GLAD!\n");
return -1;
}
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwSetKeyCallback(window, key_callback);
float vertices[] = {
-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f
};
unsigned int indices[] = {
0, 1, 2,
};
shader *s;
char *vertexShaderFile = "../shaders/shader.vs";
char *fragmentShaderFile = "../shaders/shader.fs";
create_shader(s, vertexShaderFile, fragmentShaderFile);
unsigned int VAO, VBO, EBO;
glGenVertexArrays(1, & VAO);
glGenBuffers(1, & VBO);
glGenBuffers(1, &EBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, 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);
while (!glfwWindowShouldClose(window)) {
glClearColor(0.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
useShader(s);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
and this gfx/shader.c file is this:
#include "shader.h"
void detectGLShaderError(char *name, unsigned int shader) {
int success;
char infoLog[512];
glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(shader, 512, NULL, infoLog);
printf("Error with %s shader: %s!\n", name, infoLog);
}
}
void create_shader(shader *s, char *vertexFile, char *fragmentFile) {
char* vertexShaderSource;
char* fragmentShaderSource;
copy_file(&vertexShaderSource, vertexFile);
copy_file(&fragmentShaderSource, fragmentFile);
unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, (const char *const *)&vertexShaderSource, NULL);
glCompileShader(vertexShader);
detectGLShaderError("vertex", vertexShader);
unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, (const char *const *)&fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
detectGLShaderError("fragment", fragmentShader);
unsigned int shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
detectGLShaderError("shader program", shaderProgram);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
s->id = shaderProgram;
}
void useShader(shader *s) {
glUseProgram(s->id);
}
void setBool(shader *s, char *name, bool value) {
glUniform1i(glGetUniformLocation(s->id, name), value);
}
void setInt(shader *s, char *name, int value) {
glUniform1i(glGetUniformLocation(s->id, name), value);
}
void setFloat(shader *s, char *name, float value) {
glUniform1f(glGetUniformLocation(s->id, name), value);
}
void copy_file(char **c, const char* filename) {
FILE* f = fopen(filename, "rb");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
fseek(f, 0, SEEK_SET);
char *string = malloc(fsize + 1);
fread(string, fsize, 1, f);
fclose(f);
string[fsize] = 0;
*c = malloc(strlen(string) + 1);
memcpy(*c, string, strlen(string) + 1);
}
Now I wanted to create a new array right after the int indices[] in main.c one so I added this code:
// ... other code ...
float vertices[] = {
-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f
};
float texCoords[] = {
0.0f, 0.0f,
1.0f, 0.0f,
0.5f, 1.0f
};
unsigned int indices[] = { // note that we start from 0!
0, 1, 2, // first triangle
};
// ... other code ...
However, I got a segmentation fault in gfx/shader.c:
Process 8356 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x0000000100025e14 game`create_shader(s=0x0000000000000000, vertexFile="../shaders/shader.vs", fragmentFile="../shaders/shader.fs") at shader.c:36:11
33
34 glDeleteShader(vertexShader);
35 glDeleteShader(fragmentShader);
-> 36 s->id = shaderProgram;
37 }
38
39 void useShader(shader *s) {
which seemed pretty random to me. If I deleted the texCoords[] variable everything worked just fine. For further testing I just add a int c; right after I created indices:
unsigned int indices[] = {
0, 1, 2,
};
int c;
shader *s;
And I again got a segmentation fault in the exact same place which doesn't really make sense as these things look unrelated. I could declare int c in other places in the files before the window creation and write after the line shader *s; however I get a segmentation fault no matter where I try to define texCoords[]. What is going on and how can I fix it?