ref: 770f3be74eeade974b9c5ccc36b85eaa8f02bf79
dir: /external/glfw/tests/inputlag.c/
//========================================================================
// 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/gl.h>
#define GLFW_INCLUDE_NONE
#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);
gladLoadGL(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);
}