Added timer_callback sample for user callbacks

freeglut/freeglut/CMakeLists.txt

@@ -535,6 +535,7 @@ IF(UNIX)
 ENDIF()
 ADD_DEMO(subwin          progs/demos/subwin/subwin.c)
 ADD_DEMO(timer           progs/demos/timer/timer.c)
+ADD_DEMO(timer_callback  progs/demos/timer_callback/timer.c)
 
 
 

freeglut/freeglut/progs/demos/timer_callback/timer.c

@@ -0,0 +1,174 @@
+/* Timer (callback) demo
+ *
+ * Written by John Tsiombikas <nuclear@member.fsf.org>
+ * Modified by Vincent Simonetti
+ *
+ * A modification of the timer sample, but with this
+ * offering a use of the user-data callback.
+ */
+#include <stdio.h>
+#include <GL/freeglut.h>
+
+struct display_index_s
+{
+	/* color index will be advanced every time the timer expires */
+	int surround_color_index;
+	int center_color_index;
+};
+typedef struct display_index_s display_index_t;
+
+struct timer_state_s
+{
+	int* color_index_ptr;
+	int* timer_time_ptr;
+};
+typedef struct timer_state_s timer_state_t;
+
+struct menu_state_s
+{
+	int* timer_time_ptr;
+	int menu_id;
+};
+typedef struct menu_state_s menu_state_t;
+
+void disp(void* uptr);
+void timer_func(int which, void* uptr);
+
+const float color[][3] = {
+	{1, 0, 0},
+	{0, 1, 0},
+	{0, 0, 1},
+	{1, 1, 0},
+	{0, 1, 1},
+	{1, 0, 1}
+};
+const int timerInts[] = {
+    250,
+    500,
+    1000
+};
+
+void createMenuEntries(menu_state_t* menuState)
+{
+	int i;
+    for (i = 0; i < sizeof(timerInts) / sizeof(*timerInts); i++)
+    {
+        char temp[10] = {'\0'};
+        /* flag current value */
+        if ((*menuState->timer_time_ptr) == timerInts[i])
+            temp[0] = '+';
+        else
+            temp[0] = '-';
+
+        sprintf(temp + 1, " %4d ms", timerInts[i]);
+
+        glutAddMenuEntry(temp, timerInts[i]);
+    }
+}
+
+void updateMenuEntries(menu_state_t* menuState)
+{
+	int i;
+    for (i = 0; i < sizeof(timerInts) / sizeof(*timerInts); i++)
+    {
+        char temp[10] = { '\0' };
+        /* flag current value */
+        if ((*menuState->timer_time_ptr) == timerInts[i])
+            temp[0] = '+';
+        else
+            temp[0] = '-';
+
+        sprintf(temp + 1, " %4d ms", timerInts[i]);
+
+        glutChangeToMenuEntry(i+1, temp, timerInts[i]);
+    }
+}
+
+void MenuHandler(int timerInt, void* user_ptr)
+{
+	menu_state_t* menuState;
+	
+	if (!user_ptr)
+	{
+		/* In case main menu is selected somehow */
+		return;
+	}
+
+	menuState = (menu_state_t*)user_ptr;
+
+	*menuState->timer_time_ptr = timerInt;
+	glutSetMenu(menuState->menu_id);
+	updateMenuEntries(menuState);
+}
+
+int main(int argc, char **argv)
+{
+	int timerSurroundInt = 1000, timerCenterInt = 500;
+	display_index_t displayIndex = { 0, 2 };
+	timer_state_t surroundTimerState = { &displayIndex.surround_color_index, &timerSurroundInt };
+	timer_state_t centerTimerState = { &displayIndex.center_color_index, &timerCenterInt };
+	menu_state_t surroundMenuState = { &timerSurroundInt, 0 };
+	menu_state_t centerMenuState = { &timerCenterInt, 0 };
+
+	glutInit(&argc, argv);
+	glutInitWindowSize(128, 128);
+	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+	glutCreateWindow("timer test");
+
+	glutDisplayFuncUcall(disp, &displayIndex);
+
+    /* get timer started, its reset in the timer function itself */
+    glutTimerFuncUcall(timerSurroundInt, timer_func, 1, &surroundTimerState);
+	glutTimerFuncUcall(timerCenterInt, timer_func, 2, &centerTimerState);
+
+    /* menus for setting timing */
+	surroundMenuState.menu_id = glutCreateMenuUcall(MenuHandler, &surroundMenuState);
+    createMenuEntries(&surroundMenuState);
+
+	centerMenuState.menu_id = glutCreateMenuUcall(MenuHandler, &centerMenuState);
+    createMenuEntries(&centerMenuState);
+
+    glutCreateMenuUcall(MenuHandler, NULL); /* doesn't matter, no clickable entries in this menu */
+    glutAddSubMenu("Center", centerMenuState.menu_id);
+    glutAddSubMenu("Surround", surroundMenuState.menu_id);
+    glutAttachMenu(GLUT_RIGHT_BUTTON);
+
+	glutMainLoop();
+	return 0;
+}
+
+void disp(void* user_ptr)
+{
+	const display_index_t* displayIndex;
+	int cidx, pcidx;
+
+	displayIndex = (display_index_t*)user_ptr;
+	
+	cidx = displayIndex->surround_color_index;
+	glClearColor(color[cidx][0], color[cidx][1], color[cidx][2], 1);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	pcidx = displayIndex->center_color_index;
+    glPointSize(10.f);
+    glColor3f(color[pcidx][0], color[pcidx][1], color[pcidx][2]);
+    glBegin(GL_POINTS);
+        glVertex2i(0,0);
+    glEnd();
+
+	glutSwapBuffers();
+}
+
+void timer_func(int which, void* user_ptr)
+{
+	const timer_state_t* timerState;
+	
+	timerState = (timer_state_t*)user_ptr;
+
+	/* advance the color index and trigger a redisplay */
+	*timerState->color_index_ptr = (*timerState->color_index_ptr + 1) % (sizeof color / sizeof *color);
+    
+	glutPostRedisplay();
+
+	/* (re)set the timer callback and ask glut to call it in x ms */
+    glutTimerFuncUcall(*timerState->timer_time_ptr, timer_func, which, user_ptr);
+}