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https://github.com/glfw/glfw.git
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131 lines
3.6 KiB
C
131 lines
3.6 KiB
C
//========================================================================
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// Vsync enabling test
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// Copyright (c) Camilla Berglund <elmindreda@elmindreda.org>
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would
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// be appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such, and must not
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// be misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source
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// distribution.
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//
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//========================================================================
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//
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// This test renders a high contrast, horizontally moving bar, allowing for
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// visual verification of whether the set swap interval is indeed obeyed
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//
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//========================================================================
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#include <GLFW/glfw3.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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static int swap_interval;
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static double frame_rate;
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static void update_window_title(GLFWwindow* window)
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{
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char title[256];
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sprintf(title, "Tearing detector (interval %i, %0.1f Hz)",
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swap_interval, frame_rate);
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glfwSetWindowTitle(window, title);
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}
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static void set_swap_interval(GLFWwindow* window, int interval)
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{
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swap_interval = interval;
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glfwSwapInterval(swap_interval);
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update_window_title(window);
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}
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static void error_callback(int error, const char* description)
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{
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fprintf(stderr, "Error: %s\n", description);
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}
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static void window_size_callback(GLFWwindow* window, int width, int height)
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{
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glViewport(0, 0, width, height);
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}
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static void key_callback(GLFWwindow* window, int key, int action, int mods)
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{
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if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
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set_swap_interval(window, 1 - swap_interval);
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}
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int main(void)
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{
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float position;
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unsigned long frame_count = 0;
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double last_time, current_time;
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GLFWwindow* window;
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glfwSetErrorCallback(error_callback);
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if (!glfwInit())
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exit(EXIT_FAILURE);
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window = glfwCreateWindow(640, 480, "", NULL, NULL);
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if (!window)
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{
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glfwTerminate();
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exit(EXIT_FAILURE);
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}
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glfwMakeContextCurrent(window);
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set_swap_interval(window, 0);
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last_time = glfwGetTime();
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frame_rate = 0.0;
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glfwSetWindowSizeCallback(window, window_size_callback);
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glfwSetKeyCallback(window, key_callback);
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glMatrixMode(GL_PROJECTION);
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glOrtho(-1.f, 1.f, -1.f, 1.f, 1.f, -1.f);
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glMatrixMode(GL_MODELVIEW);
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while (!glfwWindowShouldClose(window))
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{
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glClear(GL_COLOR_BUFFER_BIT);
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position = cosf((float) glfwGetTime() * 4.f) * 0.75f;
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glRectf(position - 0.25f, -1.f, position + 0.25f, 1.f);
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glfwSwapBuffers(window);
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glfwPollEvents();
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frame_count++;
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current_time = glfwGetTime();
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if (current_time - last_time > 1.0)
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{
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frame_rate = frame_count / (current_time - last_time);
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frame_count = 0;
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last_time = current_time;
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update_window_title(window);
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}
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}
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glfwTerminate();
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exit(EXIT_SUCCESS);
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}
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