I have written a very basic test setup to render a quad with glfw/glad.
I would expext it to draw a black quad in the middle of the window.
#include <iostream>
#include <array>
#include <cinttypes>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
using uint32 = std::uint32_t;
using gl_shader_id = GLuint;
gl_shader_id get_shader() {
constexpr auto vertex_shader_source = R"(
#version 460 core
layout (location = 0) in vec3 position;
void main() {
gl_Position = vec4(position.x, position.y, position.z, 1.0);
}
)";
constexpr auto fragment_shader_source = R"(
#version 460 core
out vec4 color;
void main() {
color = vec4(0.0, 0.0, 0.0, 1.0f);
}
)";
const auto vertex_shader = glCreateShader(GL_VERTEX_SHADER);
const auto fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
auto success = 0;
glShaderSource(vertex_shader, 1, &vertex_shader_source, nullptr);
glCompileShader(vertex_shader);
glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
if (!success) {
auto info_log = std::string{};
info_log.reserve(512);
glGetShaderInfoLog(vertex_shader, 512, nullptr, info_log.data());
std::cout << info_log << '\n';
assert(false); // Vertex shader compilation failed
}
glShaderSource(fragment_shader, 1, &fragment_shader_source, nullptr);
glCompileShader(fragment_shader);
if (!success) {
auto info_log = std::string{};
info_log.reserve(512);
glGetShaderInfoLog(fragment_shader, 512, nullptr, info_log.data());
std::cout << info_log << '\n';
assert(false); // Vertex shader compilation failed
}
const auto shader_program = glCreateProgram();
glAttachShader(shader_program, vertex_shader);
glAttachShader(shader_program, fragment_shader);
glLinkProgram(shader_program);
glDetachShader(shader_program, vertex_shader);
glDetachShader(shader_program, fragment_shader);
glDeleteShader(vertex_shader);
glDeleteShader(fragment_shader);
return shader_program;
}
int main() {
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
auto handle = glfwCreateWindow(800, 600, "Hello World", nullptr, nullptr);
glfwMakeContextCurrent(handle);
gladLoadGLLoader(reinterpret_cast<GLADloadproc>(glfwGetProcAddress));
const auto shader_id = get_shader();
const auto vertices = std::array<glm::vec3, 4>{
glm::vec3{ -0.5f, -0.5f, 0.0f },
glm::vec3{ -0.5f, 0.5f, 0.0f },
glm::vec3{ 0.5f, -0.5f, 0.0f },
glm::vec3{ 0.5f, 0.5f, 0.0f }
};
const auto indices = std::array<uint32, 6>{
0, 1, 2,
1, 3, 2
};
auto vertex_array = 0u;
auto vertex_buffer = 0u;
auto index_buffer = 0u;
glGenVertexArrays(1, &vertex_array);
glBindVertexArray(vertex_array);
glGenBuffers(1, &vertex_buffer);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), vertices.data(), GL_STATIC_DRAW);
glEnableVertexArrayAttrib(vertex_array, 0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(glm::vec3), nullptr);
glGenBuffers(1, &index_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(uint32), indices.data(), GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);
while (!glfwWindowShouldClose(handle)) {
glfwPollEvents();
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(vertex_array);
glUseProgram(shader_id);
glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, nullptr);
glUseProgram(0);
glBindVertexArray(0);
glfwSwapBuffers(handle);
}
glfwDestroyWindow(handle);
glfwTerminate();
return 0;
}
The program and the shader code compile with no error/warnings.
When i execute the program i get the window which is cleared with the right color.
But the quad that i specified with the vertices and indices is not showing up.
