Normally this would be something like:
glutAddMenuEntry("-", <opid>);
But it doesn't work. After looking it up on Google I couldn't find much information about this, maybe it's not possible using GLUT? I found a couple of examples like:
glutAddMenuEntry("-", 0);
or
glutAddMenuEntry("-", -1);
But neither worked...
#include <math.h>
#include <GL/glut.h>
#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480
void changeSize(int w, int h) {
if(h == 0) h = 1;
float ratio = 1.0 * w / h;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0, 0, w, h);
gluPerspective(45.0f, ratio, 1.0f, 1000.0f);
glMatrixMode(GL_MODELVIEW);
}
void renderScene(void) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(
0.0, 0.0, 5.0,
0.0, 0.0, 0.0,
0.0f, 1.0f, 0.0f
);
glutWireTeapot(1.0);
glutSwapBuffers();
}
void processMenuEvents(int option) {
}
void main(int argc, char **argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowPosition(
(glutGet(GLUT_SCREEN_WIDTH) - WINDOW_WIDTH) / 2,
(glutGet(GLUT_SCREEN_HEIGHT) - WINDOW_HEIGHT) / 2
);
glutInitWindowSize(WINDOW_WIDTH, WINDOW_HEIGHT);
glutCreateWindow("Camera Demo");
glutDisplayFunc(renderScene);
glutReshapeFunc(changeSize);
glutCreateMenu(processMenuEvents);
glutAddMenuEntry("OPTION 1", 1);
glutAddMenuEntry("-", -1);
glutAddMenuEntry("OPTION 2", 2);
glutAttachMenu(GLUT_RIGHT_BUTTON);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glutMainLoop();
}
I don't see separator like Windows does for other items, instead I see the menu item label as a dash.
I just triple checked all my documentation of and about GLUT: GLUT does not support menu separators! The best you can do is use some string "----" or similar as separator and ignore selection of this menu entry.
Related
I tried to draw a simple line in OpenGL:
#include "stdafx.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <freeglut.h>
float startX = -180.0f;
float startZ = -100.0f;
float qtyX = 36;
float qtyZ = 20;
float red = 0.0f, green = 0.0f, blue = 0.0f;
void init(void)
{
glClearColor(0.0, 0.0, 0.0, 0.0);
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glLoadIdentity();
gluLookAt(0.0, 50.0f, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0);
glBegin(GL_LINES);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(50.0f, 50.0f, 50.0f);
glEnd();
//glutWireSphere(20.0f, 20.0f, 20.0f);
glutSwapBuffers();
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei)w, (GLsizei)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-64.0, 64.0, -36.0, 36.0, 10, 10000.0);
glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize(1280, 720);
glutInitWindowPosition(100, 100);
glutCreateWindow(argv[0]);
init();
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}
However, when I run the program, the performance drop significantly then after a few seconds, it stops responding (I have to run task manager and force quit the program). However, when I disable the line and draw the glutWireSphere (or a polygon), the performance is normal.
Is there a problem with my code? Or perhaps GL_LINES is deprecated?
Windows 10, 1070 MaxQ, Visual Studio
I tired implementing a simple zoom in/out using the glutMouseWheelFunc in VC++. I am able to achieve the zooming in/out but while doing so, the axes(GLlines) tend to disappear after zooming more than a certain level.
Am using the glutMouseWheelFunc to increase/decrease z- axis value in glTranslatef.
I have defined 'z' of glTranslatef for as camera distance:
float cDist= 30.0f; // camera distance
Then used it in glTranslatef as,
glTranslatef(0.0f, 0.0f, -cDist);
in display function below.
void display(void) {
glClearColor(0.0, 0.0, 0.0, 1.0); //clear the screen to black
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//clear the color buffer and the depth buffer
enable();
glLoadIdentity();
glTranslatef(0.0f, 0.0f, -cDist);
glRotatef(xrot, 1.0, 0.0, 0.0);
---------------
glBegin(GL_LINES);
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(-500, 0, 0);
glVertex3f(500, 0, 0);
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(0, -500, 0);
glVertex3f(0, 500, 0);
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(0, 0, -500);
glVertex3f(0, 0, 500);
glTranslated(-xpos, 0.0f, -zpos); //translate the screento the position of our camera
glColor3f(1.0f, 1.0f, 1.0f);
glutSwapBuffers();
}
Afterwards, I defined wheelfunc as,
void mouseWheel(int button, int dir, int x, int y)
{
if (dir > 0)
{
cDist = cDist++;
}
else
{
cDist= cDist--;
}
return;
}
and called it in main function with glutMouseWheelFunc(mouseWheel);
int main(int argc, char **argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
glutCreateWindow("Window");
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutMotionFunc(mouseMovement);
glutMouseWheelFunc(mouseWheel);---- here
-----
---
glutMainLoop();
return 0;
}
Is this approach of zooming in proper? if not, what could be the alternative ? Also how can I define axes(lines I drew) to full extent of the screen?
thanks for the help. Seems like I missed up setting up proper depth value for gluPerspective. Once I increased the depth value, zoom out/in was working fine
#include <stdio.h> // this library is for standard input and output
#include "glut.h" // this library is for glut the OpenGL Utility Toolkit
#include <math.h>
float squareX = 0.0f;
float squareY = 200.0f;
static int flag = 1;
void drawShape(void) {
float width = 58.0f;
float height = 40.0f;
glTranslatef(squareX, squareY, 0);
// test
// glScalef(0.0, 0.0, 0.0);
glBegin(GL_POLYGON);
glColor3f(1.0, 0.0, 0.0);
glVertex2f(0, 0);
glVertex2f(width, 0);
glVertex2f(width, height);
glVertex2f(0, height);
glVertex2f(0, 0);
glEnd();
}
void initRendering() {
glEnable(GL_DEPTH_TEST);
}
// called when the window is resized
void handleResize(int w, int h) {
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0f, (float)w, 0.0f, (float)h, -1.0f, 1.0f);
}
int state = 1;
void update(int value) {
if (state == 1) { // 1 : move right
squareX += 1.0f;
if (squareX > 400.0) {
state = 0;
}
}
glutPostRedisplay();
glutTimerFunc(25, update, 0);
}
void display() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
drawShape();
glutSwapBuffers();
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(400, 400);
glutCreateWindow("Moving Square");
initRendering();
glutDisplayFunc(display);
glutReshapeFunc(handleResize);
glutTimerFunc(25, update, 0);
glutMainLoop();
return(0);
}
I want to make the square get bigger while it is moving to the right. See the second GIF below. I know that I need glScalef to make the square bigger but I don't know how to make it bigger while it is moving.
Code preview:
I need it to do something similar to this (sorry about the quality, I created the GIF myself):
Use glScale to scale the rectangle dependent on the X position (squareX):
float rectScale = 1.0f + (squareX / 400.0f);
glScalef(rectScale, rectScale, 1.0f);
Note squareX is in range [0.0, 400.0], so 1.0f + (squareX / 400.0f) is in range [1.0, 2.0].
First the scaling has to be applied to the rectangle. This means it has to be the last operation, which is applied to the model view matrix, before the rectangle is drawn. the final function drawShape may look like this:
void drawShape(void) {
float width = 58.0f;
float height = 40.0f;
glTranslatef(squareX, squareY, 0);
float rectScale = 1.0f + (squareX / 400.0f);
glScalef(rectScale, rectScale, 1.0f);
glBegin(GL_POLYGON);
glColor3f(1.0, 0.0, 0.0);
glVertex2f(0, 0);
glVertex2f(width, 0);
glVertex2f(width, height);
glVertex2f(0, height);
glVertex2f(0, 0);
glEnd();
}
Preview:
My code looks like this Modification in this code will be appreciated. I tried, only rectangle appears not the text.
#include <GL/glut.h>
#include<bits/stdc++.h>
using namespace std;
void init2D(float r, float g, float b)
{
glClearColor(r, g, b, 0.0);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0.0, 600.0, 0.0, 600.0);
}
void RenderToDisplay()
{
int l,lenghOfQuote, i;
char str[80];
strcpy(str,"Have courage and be kind");
cout<<str;
lenghOfQuote = (int)strlen(str);
for (i = 0; i < lenghOfQuote; i++)
{
glColor3f(1.0, 0.0, 0.0);
glutStrokeCharacter(GLUT_STROKE_ROMAN, str[i]);
}
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_POLYGON);
glVertex3f(150.0f, 200.0f, 0.0f);
glColor3f(0.940, 0.37, 0.47);
glVertex3f(450.0f, 200.0f, 0.0f);
glColor3f(0.940, 0.37, 0.47);
glVertex3f(450.0f, 400.0f, 0.0f);
glColor3f(0.69, 0.27, 0.57);
glVertex3f(150.0f, 400.0f, 0.0f);
glColor3f(0.69, 0.27, 0.57);
glEnd();
RenderToDisplay();
glFlush();
}
int main(int argc, char *argv[])
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(600, 600);
glutInitWindowPosition(0,0);
glLineWidth(3);
glutCreateWindow("Assignment Q2");
init2D(0.0, 0.0, 0.0);
glutDisplayFunc(display);
glutMainLoop();
}
You could tell me the comments if you need to ask anything else. I used codeblocks to test this program.
Okay after a day I got it, I'm so dumb :')
#ifdef __APPLE_CC__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
void init2D(float r, float g, float b)
{
glClearColor(r, g, b, 0.0);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0.0, 600.0, 0.0, 600.0);
}
void rectangle()
{
glBegin(GL_POLYGON);
glColor3f(0.4,0,0.8);
glVertex3f(150.0f, 200.0f, 0.0f);
glColor3f(0.4,0,0.8);
glVertex3f(450.0f, 200.0f, 0.0f);
glColor3f(0.6,0,0.6);
glVertex3f(450.0f, 400.0f, 0.0f);
glColor3f(0.6,0,0.6);
glVertex3f(150.0f, 400.0f, 0.0f);
glEnd();
}
void text()
{
char menu[80];
strcpy(menu,"Have courage and be kind");
int len;
len = strlen(menu);
glColor3f(1,1,1);
glMatrixMode( GL_PROJECTION );
glPushMatrix();
glLoadIdentity();
gluOrtho2D( 0, 600, 0, 600 );
glMatrixMode( GL_MODELVIEW );
glPushMatrix();
glLoadIdentity();
glRasterPos2i(190, 300);
for ( int i = 0; i < len; ++i )
{
glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, menu[i]);
}
glPopMatrix();
glMatrixMode( GL_PROJECTION );
glPopMatrix();
glMatrixMode( GL_MODELVIEW );
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT);
rectangle();
text();
glFlush();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition(0, 0);
glutInitWindowSize(600, 600);
glutCreateWindow("Assignment 1 Question 2");
init2D(0.0f, 0.0f, 0.0f);
glutDisplayFunc(display);
glutMainLoop();
}
I am learning OpenGL from book, I did exactly what is in the book, but when I run it (Eclipse C++ IDE) I get just blank screen.
Book is "OpenGL guide for programmers". I think the error is in Reshape(), but code is from book.
#include <iostream>
#include <GL/glew.h>
#include <GL/glut.h>
typedef const char* String;
String TITLE = "OpenGL";
int HEIGHT = 480;
int WIDTH = HEIGHT / 9 * 12;
void Update(int time){
glutPostRedisplay();
glutTimerFunc( 10, Update, 1);
}
void Init(){
glClearColor(1.0, 1.0, 1.0, 0.0);
glShadeModel(GL_FLAT);
}
void Render(){
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 1.0, 0.0);
glLoadIdentity();
gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
glScalef(1.0, 2.0, 1.0); // Modeling transformation
glutWireCube(1.0);
glutSwapBuffers();
}
void Reshape(int w, int h){
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char** argv){
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowSize(WIDTH, HEIGHT);
glutCreateWindow(TITLE);
glewExperimental = true;
GLenum err = glewInit();
if(err!=GLEW_OK){
exit(1);
}
Init();
Update(1);
glutDisplayFunc(Render);
glutReshapeFunc(Reshape);
glutMainLoop();
return 0;
}
Yes reshape function is definitely wrong
use that
void Reshape(GLsizei w,GLsizei h)
{
glViewport(0,0,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (h == 0)
h = 1;
GLfloat aspectRatio;
aspectRatio = static_cast<GLfloat>(w) / static_cast<GLfloat>(h);
gluPerspective(45.0,aspectRatio,1.0,4000.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
instead