| //======================================================================== |
| // Vsync enabling test |
| // Copyright (c) Camilla Berglund <elmindreda@elmindreda.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 renders a high contrast, horizontally moving bar, allowing for |
| // visual verification of whether the set swap interval is indeed obeyed |
| // |
| //======================================================================== |
| |
| #include <GL/glfw3.h> |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <math.h> |
| |
| static int swap_interval; |
| static double frame_rate; |
| |
| static void update_window_title(GLFWwindow* window) |
| { |
| char title[256]; |
| |
| sprintf(title, "Tearing detector (interval %i, %0.1f Hz)", |
| swap_interval, frame_rate); |
| |
| glfwSetWindowTitle(window, title); |
| } |
| |
| static void set_swap_interval(GLFWwindow* window, int interval) |
| { |
| swap_interval = interval; |
| glfwSwapInterval(swap_interval); |
| update_window_title(window); |
| } |
| |
| static void error_callback(int error, const char* description) |
| { |
| fprintf(stderr, "Error: %s\n", description); |
| } |
| |
| static void window_size_callback(GLFWwindow* window, int width, int height) |
| { |
| glViewport(0, 0, width, height); |
| } |
| |
| static void key_callback(GLFWwindow* window, int key, int action, int mods) |
| { |
| if (key == GLFW_KEY_SPACE && action == GLFW_PRESS) |
| set_swap_interval(window, 1 - swap_interval); |
| } |
| |
| int main(void) |
| { |
| float position; |
| unsigned long frame_count = 0; |
| double last_time, current_time; |
| GLFWwindow* window; |
| |
| glfwSetErrorCallback(error_callback); |
| |
| if (!glfwInit()) |
| exit(EXIT_FAILURE); |
| |
| window = glfwCreateWindow(640, 480, "", NULL, NULL); |
| if (!window) |
| { |
| glfwTerminate(); |
| exit(EXIT_FAILURE); |
| } |
| |
| glfwMakeContextCurrent(window); |
| set_swap_interval(window, 0); |
| |
| last_time = glfwGetTime(); |
| frame_rate = 0.0; |
| |
| glfwSetWindowSizeCallback(window, window_size_callback); |
| glfwSetKeyCallback(window, key_callback); |
| |
| glMatrixMode(GL_PROJECTION); |
| glOrtho(-1.f, 1.f, -1.f, 1.f, 1.f, -1.f); |
| glMatrixMode(GL_MODELVIEW); |
| |
| while (!glfwWindowShouldClose(window)) |
| { |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| position = cosf((float) glfwGetTime() * 4.f) * 0.75f; |
| glRectf(position - 0.25f, -1.f, position + 0.25f, 1.f); |
| |
| glfwSwapBuffers(window); |
| glfwPollEvents(); |
| |
| frame_count++; |
| |
| current_time = glfwGetTime(); |
| if (current_time - last_time > 1.0) |
| { |
| frame_rate = frame_count / (current_time - last_time); |
| frame_count = 0; |
| last_time = current_time; |
| update_window_title(window); |
| } |
| } |
| |
| glfwTerminate(); |
| exit(EXIT_SUCCESS); |
| } |
| |