glfw/tests/timeout.c

//========================================================================
// Event wait timeout test
// Copyright (c) Camilla Löwy <[email protected]>
//
// 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
//
//========================================================================

#define GLAD_GL_IMPLEMENTATION
#include <glad/gl.h>
#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>

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

static bool needs_update;

static void window_close_callback(GLFWwindow* window)
{
    needs_update = true;
}

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);
        needs_update = true;
    }
}

static void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    needs_update = 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);
    glfwSwapInterval(0);
    gladLoadGL(glfwGetProcAddress);
    glfwSetWindowCloseCallback(window, window_close_callback);
    glfwSetKeyCallback(window, key_callback);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_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);
        needs_update = false;

        const double start = glfwGetTime();

        while (!needs_update)
        {
            const double elapsed = glfwGetTime() - start;
            if (elapsed >= 1.0)
                needs_update = true;
            else
                glfwWaitEventsTimeout(1.0 - elapsed);
        }
    }

    glfwDestroyWindow(window);

    glfwTerminate();
    exit(EXIT_SUCCESS);
}