ref: 07e4e3b9719dfa21e92cb22b9ee5f1cb6e293e5a
dir: /external/glfw/tests/timeout.c/
//========================================================================
// Event wait timeout test
// Copyright (c) Camilla Löwy <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would
//    be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
//    be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
//    distribution.
//
//========================================================================
//
// This test is intended to verify that waiting for events with timeout works
//
//========================================================================
#include <glad/gl.h>
#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#include <time.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
static void error_callback(int error, const char* description)
{
    fprintf(stderr, "Error: %s\n", description);
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}
static float nrand(void)
{
    return (float) rand() / (float) RAND_MAX;
}
int main(void)
{
    GLFWwindow* window;
    srand((unsigned int) time(NULL));
    glfwSetErrorCallback(error_callback);
    if (!glfwInit())
        exit(EXIT_FAILURE);
    window = glfwCreateWindow(640, 480, "Event Wait Timeout Test", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }
    glfwMakeContextCurrent(window);
    gladLoadGL(glfwGetProcAddress);
    glfwSetKeyCallback(window, key_callback);
    while (!glfwWindowShouldClose(window))
    {
        int width, height;
        float r = nrand(), g = nrand(), b = nrand();
        float l = (float) sqrt(r * r + g * g + b * b);
        glfwGetFramebufferSize(window, &width, &height);
        glViewport(0, 0, width, height);
        glClearColor(r / l, g / l, b / l, 1.f);
        glClear(GL_COLOR_BUFFER_BIT);
        glfwSwapBuffers(window);
        glfwWaitEventsTimeout(1.0);
    }
    glfwDestroyWindow(window);
    glfwTerminate();
    exit(EXIT_SUCCESS);
}