1 //========================================================================
2 // Input lag test
3 // Copyright (c) Camilla Löwy <elmindreda@glfw.org>
4 //
5 // This software is provided 'as-is', without any express or implied
6 // warranty. In no event will the authors be held liable for any damages
7 // arising from the use of this software.
8 //
9 // Permission is granted to anyone to use this software for any purpose,
10 // including commercial applications, and to alter it and redistribute it
11 // freely, subject to the following restrictions:
12 //
13 // 1. The origin of this software must not be misrepresented; you must not
14 // claim that you wrote the original software. If you use this software
15 // in a product, an acknowledgment in the product documentation would
16 // be appreciated but is not required.
17 //
18 // 2. Altered source versions must be plainly marked as such, and must not
19 // be misrepresented as being the original software.
20 //
21 // 3. This notice may not be removed or altered from any source
22 // distribution.
23 //
24 //========================================================================
25 //
26 // This test renders a marker at the cursor position reported by GLFW to
27 // check how much it lags behind the hardware mouse cursor
28 //
29 //========================================================================
30
31 #define GLAD_GL_IMPLEMENTATION
32 #include <glad/gl.h>
33 #define GLFW_INCLUDE_NONE
34 #include <GLFW/glfw3.h>
35
36 #define NK_IMPLEMENTATION
37 #define NK_INCLUDE_FIXED_TYPES
38 #define NK_INCLUDE_FONT_BAKING
39 #define NK_INCLUDE_DEFAULT_FONT
40 #define NK_INCLUDE_DEFAULT_ALLOCATOR
41 #define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
42 #define NK_INCLUDE_STANDARD_VARARGS
43 #include <nuklear.h>
44
45 #define NK_GLFW_GL2_IMPLEMENTATION
46 #include <nuklear_glfw_gl2.h>
47
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51
52 #include "getopt.h"
53
usage(void)54 void usage(void)
55 {
56 printf("Usage: inputlag [-h] [-f]\n");
57 printf("Options:\n");
58 printf(" -f create full screen window\n");
59 printf(" -h show this help\n");
60 }
61
62 struct nk_vec2 cursor_new, cursor_pos, cursor_vel;
63 enum { cursor_sync_query, cursor_input_message } cursor_method = cursor_sync_query;
64
sample_input(GLFWwindow * window)65 void sample_input(GLFWwindow* window)
66 {
67 float a = .25; // exponential smoothing factor
68
69 if (cursor_method == cursor_sync_query) {
70 double x, y;
71 glfwGetCursorPos(window, &x, &y);
72 cursor_new.x = (float) x;
73 cursor_new.y = (float) y;
74 }
75
76 cursor_vel.x = (cursor_new.x - cursor_pos.x) * a + cursor_vel.x * (1 - a);
77 cursor_vel.y = (cursor_new.y - cursor_pos.y) * a + cursor_vel.y * (1 - a);
78 cursor_pos = cursor_new;
79 }
80
cursor_pos_callback(GLFWwindow * window,double xpos,double ypos)81 void cursor_pos_callback(GLFWwindow* window, double xpos, double ypos)
82 {
83 cursor_new.x = (float) xpos;
84 cursor_new.y = (float) ypos;
85 }
86
87 int enable_vsync = nk_true;
88
update_vsync()89 void update_vsync()
90 {
91 glfwSwapInterval(enable_vsync == nk_true ? 1 : 0);
92 }
93
94 int swap_clear = nk_false;
95 int swap_finish = nk_true;
96 int swap_occlusion_query = nk_false;
97 int swap_read_pixels = nk_false;
98 GLuint occlusion_query;
99
swap_buffers(GLFWwindow * window)100 void swap_buffers(GLFWwindow* window)
101 {
102 glfwSwapBuffers(window);
103
104 if (swap_clear)
105 glClear(GL_COLOR_BUFFER_BIT);
106
107 if (swap_finish)
108 glFinish();
109
110 if (swap_occlusion_query) {
111 GLint occlusion_result;
112 if (!occlusion_query)
113 glGenQueries(1, &occlusion_query);
114 glBeginQuery(GL_SAMPLES_PASSED, occlusion_query);
115 glBegin(GL_POINTS);
116 glVertex2f(0, 0);
117 glEnd();
118 glEndQuery(GL_SAMPLES_PASSED);
119 glGetQueryObjectiv(occlusion_query, GL_QUERY_RESULT, &occlusion_result);
120 }
121
122 if (swap_read_pixels) {
123 unsigned char rgba[4];
124 glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, rgba);
125 }
126 }
127
error_callback(int error,const char * description)128 void error_callback(int error, const char* description)
129 {
130 fprintf(stderr, "Error: %s\n", description);
131 }
132
key_callback(GLFWwindow * window,int key,int scancode,int action,int mods)133 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
134 {
135 if (action != GLFW_PRESS)
136 return;
137
138 switch (key)
139 {
140 case GLFW_KEY_ESCAPE:
141 glfwSetWindowShouldClose(window, 1);
142 break;
143 }
144 }
145
draw_marker(struct nk_command_buffer * canvas,int lead,struct nk_vec2 pos)146 void draw_marker(struct nk_command_buffer* canvas, int lead, struct nk_vec2 pos)
147 {
148 struct nk_color colors[4] = { nk_rgb(255,0,0), nk_rgb(255,255,0), nk_rgb(0,255,0), nk_rgb(0,96,255) };
149 struct nk_rect rect = { -5 + pos.x, -5 + pos.y, 10, 10 };
150 nk_fill_circle(canvas, rect, colors[lead]);
151 }
152
main(int argc,char ** argv)153 int main(int argc, char** argv)
154 {
155 int ch, width, height;
156 unsigned long frame_count = 0;
157 double last_time, current_time;
158 double frame_rate = 0;
159 int fullscreen = GLFW_FALSE;
160 GLFWmonitor* monitor = NULL;
161 GLFWwindow* window;
162 struct nk_context* nk;
163 struct nk_font_atlas* atlas;
164
165 int show_forecasts = nk_true;
166
167 while ((ch = getopt(argc, argv, "fh")) != -1)
168 {
169 switch (ch)
170 {
171 case 'h':
172 usage();
173 exit(EXIT_SUCCESS);
174
175 case 'f':
176 fullscreen = GLFW_TRUE;
177 break;
178 }
179 }
180
181 glfwSetErrorCallback(error_callback);
182
183 if (!glfwInit())
184 exit(EXIT_FAILURE);
185
186 if (fullscreen)
187 {
188 const GLFWvidmode* mode;
189
190 monitor = glfwGetPrimaryMonitor();
191 mode = glfwGetVideoMode(monitor);
192
193 width = mode->width;
194 height = mode->height;
195 }
196 else
197 {
198 width = 640;
199 height = 480;
200 }
201
202 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
203 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
204
205 glfwWindowHint(GLFW_SCALE_TO_MONITOR, GLFW_TRUE);
206 glfwWindowHint(GLFW_WIN32_KEYBOARD_MENU, GLFW_TRUE);
207
208 window = glfwCreateWindow(width, height, "Input lag test", monitor, NULL);
209 if (!window)
210 {
211 glfwTerminate();
212 exit(EXIT_FAILURE);
213 }
214
215 glfwMakeContextCurrent(window);
216 gladLoadGL(glfwGetProcAddress);
217 update_vsync();
218
219 last_time = glfwGetTime();
220
221 nk = nk_glfw3_init(window, NK_GLFW3_INSTALL_CALLBACKS);
222 nk_glfw3_font_stash_begin(&atlas);
223 nk_glfw3_font_stash_end();
224
225 glfwSetKeyCallback(window, key_callback);
226 glfwSetCursorPosCallback(window, cursor_pos_callback);
227
228 while (!glfwWindowShouldClose(window))
229 {
230 int width, height;
231 struct nk_rect area;
232
233 glfwPollEvents();
234 sample_input(window);
235
236 glfwGetWindowSize(window, &width, &height);
237 area = nk_rect(0.f, 0.f, (float) width, (float) height);
238
239 glClear(GL_COLOR_BUFFER_BIT);
240 nk_glfw3_new_frame();
241 if (nk_begin(nk, "", area, 0))
242 {
243 nk_flags align_left = NK_TEXT_ALIGN_LEFT | NK_TEXT_ALIGN_MIDDLE;
244 struct nk_command_buffer *canvas = nk_window_get_canvas(nk);
245 int lead;
246
247 for (lead = show_forecasts ? 3 : 0; lead >= 0; lead--)
248 draw_marker(canvas, lead, nk_vec2(cursor_pos.x + cursor_vel.x * lead,
249 cursor_pos.y + cursor_vel.y * lead));
250
251 // print instructions
252 nk_layout_row_dynamic(nk, 20, 1);
253 nk_label(nk, "Move mouse uniformly and check marker under cursor:", align_left);
254 for (lead = 0; lead <= 3; lead++) {
255 nk_layout_row_begin(nk, NK_STATIC, 12, 2);
256 nk_layout_row_push(nk, 25);
257 draw_marker(canvas, lead, nk_layout_space_to_screen(nk, nk_vec2(20, 5)));
258 nk_label(nk, "", 0);
259 nk_layout_row_push(nk, 500);
260 if (lead == 0)
261 nk_label(nk, "- current cursor position (no input lag)", align_left);
262 else
263 nk_labelf(nk, align_left, "- %d-frame forecast (input lag is %d frame)", lead, lead);
264 nk_layout_row_end(nk);
265 }
266
267 nk_layout_row_dynamic(nk, 20, 1);
268
269 nk_checkbox_label(nk, "Show forecasts", &show_forecasts);
270 nk_label(nk, "Input method:", align_left);
271 if (nk_option_label(nk, "glfwGetCursorPos (sync query)", cursor_method == cursor_sync_query))
272 cursor_method = cursor_sync_query;
273 if (nk_option_label(nk, "glfwSetCursorPosCallback (latest input message)", cursor_method == cursor_input_message))
274 cursor_method = cursor_input_message;
275
276 nk_label(nk, "", 0); // separator
277
278 nk_value_float(nk, "FPS", (float) frame_rate);
279 if (nk_checkbox_label(nk, "Enable vsync", &enable_vsync))
280 update_vsync();
281
282 nk_label(nk, "", 0); // separator
283
284 nk_label(nk, "After swap:", align_left);
285 nk_checkbox_label(nk, "glClear", &swap_clear);
286 nk_checkbox_label(nk, "glFinish", &swap_finish);
287 nk_checkbox_label(nk, "draw with occlusion query", &swap_occlusion_query);
288 nk_checkbox_label(nk, "glReadPixels", &swap_read_pixels);
289 }
290
291 nk_end(nk);
292 nk_glfw3_render(NK_ANTI_ALIASING_ON);
293
294 swap_buffers(window);
295
296 frame_count++;
297
298 current_time = glfwGetTime();
299 if (current_time - last_time > 1.0)
300 {
301 frame_rate = frame_count / (current_time - last_time);
302 frame_count = 0;
303 last_time = current_time;
304 }
305 }
306
307 glfwTerminate();
308 exit(EXIT_SUCCESS);
309 }
310
311