tests/inputlag.c - third_party/glfw - Git at Google

 //========================================================================
 // Input lag 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 renders a marker at the cursor position reported by GLFW to
 // check how much it lags behind the hardware mouse cursor
 //
 //========================================================================

 #include <glad/glad.h>
 #include <GLFW/glfw3.h>

 #define NK_IMPLEMENTATION
 #define NK_INCLUDE_FIXED_TYPES
 #define NK_INCLUDE_FONT_BAKING
 #define NK_INCLUDE_DEFAULT_FONT
 #define NK_INCLUDE_DEFAULT_ALLOCATOR
 #define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
 #define NK_INCLUDE_STANDARD_VARARGS
 #include <nuklear.h>

 #define NK_GLFW_GL2_IMPLEMENTATION
 #include <nuklear_glfw_gl2.h>

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "getopt.h"

 void usage(void)
 {
     printf("Usage: inputlag [-h] [-f]\n");
     printf("Options:\n");
     printf("  -f create full screen window\n");
     printf("  -h show this help\n");
 }

 struct nk_vec2 cursor_new, cursor_pos, cursor_vel;
 enum { cursor_sync_query, cursor_input_message } cursor_method = cursor_sync_query;

 void sample_input(GLFWwindow* window)
 {
     float a = .25; // exponential smoothing factor

     if (cursor_method == cursor_sync_query) {
         double x, y;
         glfwGetCursorPos(window, &x, &y);
         cursor_new.x = (float) x;
         cursor_new.y = (float) y;
     }

     cursor_vel.x = (cursor_new.x - cursor_pos.x) * a + cursor_vel.x * (1 - a);
     cursor_vel.y = (cursor_new.y - cursor_pos.y) * a + cursor_vel.y * (1 - a);
     cursor_pos = cursor_new;
 }

 void cursor_pos_callback(GLFWwindow* window, double xpos, double ypos)
 {
     cursor_new.x = (float) xpos;
     cursor_new.y = (float) ypos;
 }

 int enable_vsync = nk_true;

 void update_vsync()
 {
     glfwSwapInterval(enable_vsync == nk_true ? 1 : 0);
 }

 int swap_clear = nk_false;
 int swap_finish = nk_true;
 int swap_occlusion_query = nk_false;
 int swap_read_pixels = nk_false;
 GLuint occlusion_query;

 void swap_buffers(GLFWwindow* window)
 {
     glfwSwapBuffers(window);

     if (swap_clear)
         glClear(GL_COLOR_BUFFER_BIT);

     if (swap_finish)
         glFinish();

     if (swap_occlusion_query) {
         GLint occlusion_result;
         if (!occlusion_query)
             glGenQueries(1, &occlusion_query);
         glBeginQuery(GL_SAMPLES_PASSED, occlusion_query);
         glBegin(GL_POINTS);
         glVertex2f(0, 0);
         glEnd();
         glEndQuery(GL_SAMPLES_PASSED);
         glGetQueryObjectiv(occlusion_query, GL_QUERY_RESULT, &occlusion_result);
     }

     if (swap_read_pixels) {
         unsigned char rgba[4];
         glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, rgba);
     }
 }

 void error_callback(int error, const char* description)
 {
     fprintf(stderr, "Error: %s\n", description);
 }

 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
     if (action != GLFW_PRESS)
         return;

     switch (key)
     {
         case GLFW_KEY_ESCAPE:
             glfwSetWindowShouldClose(window, 1);
             break;
     }
 }

 void draw_marker(struct nk_command_buffer* canvas, int lead, struct nk_vec2 pos)
 {
     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) };
     struct nk_rect rect = { -5 + pos.x, -5 + pos.y, 10, 10 };
     nk_fill_circle(canvas, rect, colors[lead]);
 }

 int main(int argc, char** argv)
 {
     int ch, width, height;
     unsigned long frame_count = 0;
     double last_time, current_time;
     double frame_rate = 0;
     int fullscreen = GLFW_FALSE;
     GLFWmonitor* monitor = NULL;
     GLFWwindow* window;
     struct nk_context* nk;
     struct nk_font_atlas* atlas;

     int show_forecasts = nk_true;

     while ((ch = getopt(argc, argv, "fh")) != -1)
     {
         switch (ch)
         {
             case 'h':
                 usage();
                 exit(EXIT_SUCCESS);

             case 'f':
                 fullscreen = GLFW_TRUE;
                 break;
         }
     }

     glfwSetErrorCallback(error_callback);

     if (!glfwInit())
         exit(EXIT_FAILURE);

     if (fullscreen)
     {
         const GLFWvidmode* mode;

         monitor = glfwGetPrimaryMonitor();
         mode = glfwGetVideoMode(monitor);

         width = mode->width;
         height = mode->height;
     }
     else
     {
         width = 640;
         height = 480;
     }

     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);

     glfwWindowHint(GLFW_SCALE_TO_MONITOR, GLFW_TRUE);

     window = glfwCreateWindow(width, height, "Input lag test", monitor, NULL);
     if (!window)
     {
         glfwTerminate();
         exit(EXIT_FAILURE);
     }

     glfwMakeContextCurrent(window);
     gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
     update_vsync();

     last_time = glfwGetTime();

     nk = nk_glfw3_init(window, NK_GLFW3_INSTALL_CALLBACKS);
     nk_glfw3_font_stash_begin(&atlas);
     nk_glfw3_font_stash_end();

     glfwSetKeyCallback(window, key_callback);
     glfwSetCursorPosCallback(window, cursor_pos_callback);

     while (!glfwWindowShouldClose(window))
     {
         int width, height;
         struct nk_rect area;

         glfwPollEvents();
         sample_input(window);

         glfwGetWindowSize(window, &width, &height);
         area = nk_rect(0.f, 0.f, (float) width, (float) height);

         glClear(GL_COLOR_BUFFER_BIT);
         nk_glfw3_new_frame();
         if (nk_begin(nk, "", area, 0))
         {
             nk_flags align_left = NK_TEXT_ALIGN_LEFT | NK_TEXT_ALIGN_MIDDLE;
             struct nk_command_buffer *canvas = nk_window_get_canvas(nk);
             int lead;

             for (lead = show_forecasts ? 3 : 0; lead >= 0; lead--)
                 draw_marker(canvas, lead, nk_vec2(cursor_pos.x + cursor_vel.x * lead,
                                                   cursor_pos.y + cursor_vel.y * lead));

             // print instructions
             nk_layout_row_dynamic(nk, 20, 1);
             nk_label(nk, "Move mouse uniformly and check marker under cursor:", align_left);
             for (lead = 0; lead <= 3; lead++) {
                 nk_layout_row_begin(nk, NK_STATIC, 12, 2);
                 nk_layout_row_push(nk, 25);
                 draw_marker(canvas, lead, nk_layout_space_to_screen(nk, nk_vec2(20, 5)));
                 nk_label(nk, "", 0);
                 nk_layout_row_push(nk, 500);
                 if (lead == 0)
                     nk_label(nk, "- current cursor position (no input lag)", align_left);
                 else
                     nk_labelf(nk, align_left, "- %d-frame forecast (input lag is %d frame)", lead, lead);
                 nk_layout_row_end(nk);
             }

             nk_layout_row_dynamic(nk, 20, 1);

             nk_checkbox_label(nk, "Show forecasts", &show_forecasts);
             nk_label(nk, "Input method:", align_left);
             if (nk_option_label(nk, "glfwGetCursorPos (sync query)", cursor_method == cursor_sync_query))
                 cursor_method = cursor_sync_query;
             if (nk_option_label(nk, "glfwSetCursorPosCallback (latest input message)", cursor_method == cursor_input_message))
                 cursor_method = cursor_input_message;

             nk_label(nk, "", 0); // separator

             nk_value_float(nk, "FPS", (float) frame_rate);
             if (nk_checkbox_label(nk, "Enable vsync", &enable_vsync))
                 update_vsync();

             nk_label(nk, "", 0); // separator

             nk_label(nk, "After swap:", align_left);
             nk_checkbox_label(nk, "glClear", &swap_clear);
             nk_checkbox_label(nk, "glFinish", &swap_finish);
             nk_checkbox_label(nk, "draw with occlusion query", &swap_occlusion_query);
             nk_checkbox_label(nk, "glReadPixels", &swap_read_pixels);
         }

         nk_end(nk);
         nk_glfw3_render(NK_ANTI_ALIASING_ON);

         swap_buffers(window);

         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;
         }
     }

     glfwTerminate();
     exit(EXIT_SUCCESS);
 }
	//========================================================================
	// Input lag 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 renders a marker at the cursor position reported by GLFW to
	// check how much it lags behind the hardware mouse cursor
	//
	//========================================================================

	#include <glad/glad.h>
	#include <GLFW/glfw3.h>

	#define NK_IMPLEMENTATION
	#define NK_INCLUDE_FIXED_TYPES
	#define NK_INCLUDE_FONT_BAKING
	#define NK_INCLUDE_DEFAULT_FONT
	#define NK_INCLUDE_DEFAULT_ALLOCATOR
	#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
	#define NK_INCLUDE_STANDARD_VARARGS
	#include <nuklear.h>

	#define NK_GLFW_GL2_IMPLEMENTATION
	#include <nuklear_glfw_gl2.h>

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "getopt.h"

	void usage(void)
	{
	printf("Usage: inputlag [-h] [-f]\n");
	printf("Options:\n");
	printf(" -f create full screen window\n");
	printf(" -h show this help\n");
	}

	struct nk_vec2 cursor_new, cursor_pos, cursor_vel;
	enum { cursor_sync_query, cursor_input_message } cursor_method = cursor_sync_query;

	void sample_input(GLFWwindow* window)
	{
	float a = .25; // exponential smoothing factor

	if (cursor_method == cursor_sync_query) {
	double x, y;
	glfwGetCursorPos(window, &x, &y);
	cursor_new.x = (float) x;
	cursor_new.y = (float) y;
	}

	cursor_vel.x = (cursor_new.x - cursor_pos.x) * a + cursor_vel.x * (1 - a);
	cursor_vel.y = (cursor_new.y - cursor_pos.y) * a + cursor_vel.y * (1 - a);
	cursor_pos = cursor_new;
	}

	void cursor_pos_callback(GLFWwindow* window, double xpos, double ypos)
	{
	cursor_new.x = (float) xpos;
	cursor_new.y = (float) ypos;
	}

	int enable_vsync = nk_true;

	void update_vsync()
	{
	glfwSwapInterval(enable_vsync == nk_true ? 1 : 0);
	}

	int swap_clear = nk_false;
	int swap_finish = nk_true;
	int swap_occlusion_query = nk_false;
	int swap_read_pixels = nk_false;
	GLuint occlusion_query;

	void swap_buffers(GLFWwindow* window)
	{
	glfwSwapBuffers(window);

	if (swap_clear)
	glClear(GL_COLOR_BUFFER_BIT);

	if (swap_finish)
	glFinish();

	if (swap_occlusion_query) {
	GLint occlusion_result;
	if (!occlusion_query)
	glGenQueries(1, &occlusion_query);
	glBeginQuery(GL_SAMPLES_PASSED, occlusion_query);
	glBegin(GL_POINTS);
	glVertex2f(0, 0);
	glEnd();
	glEndQuery(GL_SAMPLES_PASSED);
	glGetQueryObjectiv(occlusion_query, GL_QUERY_RESULT, &occlusion_result);
	}

	if (swap_read_pixels) {
	unsigned char rgba[4];
	glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, rgba);
	}
	}

	void error_callback(int error, const char* description)
	{
	fprintf(stderr, "Error: %s\n", description);
	}

	void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
	{
	if (action != GLFW_PRESS)
	return;

	switch (key)
	{
	case GLFW_KEY_ESCAPE:
	glfwSetWindowShouldClose(window, 1);
	break;
	}
	}

	void draw_marker(struct nk_command_buffer* canvas, int lead, struct nk_vec2 pos)
	{
	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) };
	struct nk_rect rect = { -5 + pos.x, -5 + pos.y, 10, 10 };
	nk_fill_circle(canvas, rect, colors[lead]);
	}

	int main(int argc, char** argv)
	{
	int ch, width, height;
	unsigned long frame_count = 0;
	double last_time, current_time;
	double frame_rate = 0;
	int fullscreen = GLFW_FALSE;
	GLFWmonitor* monitor = NULL;
	GLFWwindow* window;
	struct nk_context* nk;
	struct nk_font_atlas* atlas;

	int show_forecasts = nk_true;

	while ((ch = getopt(argc, argv, "fh")) != -1)
	{
	switch (ch)
	{
	case 'h':
	usage();
	exit(EXIT_SUCCESS);

	case 'f':
	fullscreen = GLFW_TRUE;
	break;
	}
	}

	glfwSetErrorCallback(error_callback);

	if (!glfwInit())
	exit(EXIT_FAILURE);

	if (fullscreen)
	{
	const GLFWvidmode* mode;

	monitor = glfwGetPrimaryMonitor();
	mode = glfwGetVideoMode(monitor);

	width = mode->width;
	height = mode->height;
	}
	else
	{
	width = 640;
	height = 480;
	}

	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);

	glfwWindowHint(GLFW_SCALE_TO_MONITOR, GLFW_TRUE);

	window = glfwCreateWindow(width, height, "Input lag test", monitor, NULL);
	if (!window)
	{
	glfwTerminate();
	exit(EXIT_FAILURE);
	}

	glfwMakeContextCurrent(window);
	gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
	update_vsync();

	last_time = glfwGetTime();

	nk = nk_glfw3_init(window, NK_GLFW3_INSTALL_CALLBACKS);
	nk_glfw3_font_stash_begin(&atlas);
	nk_glfw3_font_stash_end();

	glfwSetKeyCallback(window, key_callback);
	glfwSetCursorPosCallback(window, cursor_pos_callback);

	while (!glfwWindowShouldClose(window))
	{
	int width, height;
	struct nk_rect area;

	glfwPollEvents();
	sample_input(window);

	glfwGetWindowSize(window, &width, &height);
	area = nk_rect(0.f, 0.f, (float) width, (float) height);

	glClear(GL_COLOR_BUFFER_BIT);
	nk_glfw3_new_frame();
	if (nk_begin(nk, "", area, 0))
	{
	nk_flags align_left = NK_TEXT_ALIGN_LEFT \| NK_TEXT_ALIGN_MIDDLE;
	struct nk_command_buffer *canvas = nk_window_get_canvas(nk);
	int lead;

	for (lead = show_forecasts ? 3 : 0; lead >= 0; lead--)
	draw_marker(canvas, lead, nk_vec2(cursor_pos.x + cursor_vel.x * lead,
	cursor_pos.y + cursor_vel.y * lead));

	// print instructions
	nk_layout_row_dynamic(nk, 20, 1);
	nk_label(nk, "Move mouse uniformly and check marker under cursor:", align_left);
	for (lead = 0; lead <= 3; lead++) {
	nk_layout_row_begin(nk, NK_STATIC, 12, 2);
	nk_layout_row_push(nk, 25);
	draw_marker(canvas, lead, nk_layout_space_to_screen(nk, nk_vec2(20, 5)));
	nk_label(nk, "", 0);
	nk_layout_row_push(nk, 500);
	if (lead == 0)
	nk_label(nk, "- current cursor position (no input lag)", align_left);
	else
	nk_labelf(nk, align_left, "- %d-frame forecast (input lag is %d frame)", lead, lead);
	nk_layout_row_end(nk);
	}

	nk_layout_row_dynamic(nk, 20, 1);

	nk_checkbox_label(nk, "Show forecasts", &show_forecasts);
	nk_label(nk, "Input method:", align_left);
	if (nk_option_label(nk, "glfwGetCursorPos (sync query)", cursor_method == cursor_sync_query))
	cursor_method = cursor_sync_query;
	if (nk_option_label(nk, "glfwSetCursorPosCallback (latest input message)", cursor_method == cursor_input_message))
	cursor_method = cursor_input_message;

	nk_label(nk, "", 0); // separator

	nk_value_float(nk, "FPS", (float) frame_rate);
	if (nk_checkbox_label(nk, "Enable vsync", &enable_vsync))
	update_vsync();

	nk_label(nk, "", 0); // separator

	nk_label(nk, "After swap:", align_left);
	nk_checkbox_label(nk, "glClear", &swap_clear);
	nk_checkbox_label(nk, "glFinish", &swap_finish);
	nk_checkbox_label(nk, "draw with occlusion query", &swap_occlusion_query);
	nk_checkbox_label(nk, "glReadPixels", &swap_read_pixels);
	}

	nk_end(nk);
	nk_glfw3_render(NK_ANTI_ALIASING_ON);

	swap_buffers(window);

	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;
	}
	}

	glfwTerminate();
	exit(EXIT_SUCCESS);
	}