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I have a very basic program, I built a box from quads and now i want to rotate the box on the
x-axis using my timer which increases the angle.
My problem is that when i use the glRotatef() function it is rotating the camera and not the
box object.
My code:
/* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above notice and this permission notice shall be included in all copies
* or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/* File for "Basic Shapes" lesson of the OpenGL tutorial on
* www.videotutorialsrock.com
*/
#include <iostream>
#include <stdlib.h> //Needed for "exit" function
//Include OpenGL header files, so that we can use OpenGL
#ifdef __APPLE__
#include <OpenGL/OpenGL.h>
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
using namespace std;
//Global variables
GLfloat _cameraAngle = 0.0f;
GLfloat _angle = 30.0f;
GLfloat size = 1.0f;
GLfloat f = -5.0f;
GLfloat b = -6.0f;
//Called when a key is pressed
void handleKeypress(unsigned char key, //The key that was pressed
int x, int y) { //The current mouse coordinates
switch (key) {
case 27: //Escape key
exit(0); //Exit the program
}
}
//Initializes 3D rendering
void initRendering() {
//Makes 3D drawing work when something is in front of something else
glEnable(GL_DEPTH_TEST);
}
//Called when the window is resized
void handleResize(int w, int h) {
//Tell OpenGL how to convert from coordinates to pixel values
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION); //Switch to setting the camera perspective
//Set the camera perspective
glLoadIdentity(); //Reset the camera
gluPerspective(45.0, //The camera angle
(double)w / (double)h, //The width-to-height ratio
1.0, //The near z clipping coordinate
200.0); //The far z clipping coordinate
}
//Draws the 3D scene
void drawScene() {
//Clear information from last draw
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW); //Switch to the drawing perspective
glLoadIdentity(); //Reset the drawing perspective
glRotatef(_angle,1.0f,0.0f,0.0f);
//========== BOX ===========//
glBegin(GL_QUADS); //Begin quadrilateral coordinates
//front
glColor3f(1.0f,0.0f,0.0f);
glVertex3f(size,size,f);//top-right
glVertex3f(-size,size,f);//top-left
glVertex3f(-size,-size,f);//bottom-left
glVertex3f(size,-size,f);//bottom-right
//back
glColor3f(0.0f,1.0f,0.0f);
glVertex3f(size,size,B)/>;//top(back)-right
glVertex3f(-size,size,B)/>;//top(back)-left
glVertex3f(-size,-size,B)/>;//bottom(back)-left
glVertex3f(size,-size,B)/>;//bottom(back)-right
//left
glColor3f(0.0f,0.0f,1.0f);
glVertex3f(-size,size,B)/>;//top(back)-left
glVertex3f(-size,size,f);//top-left
glVertex3f(-size,-size,f);//bottom-left
glVertex3f(-size,-size,B)/>;//bottom(back)-left
//right
glColor3f(0.5f,0.5f,0.0f);
glVertex3f(size,size,B)/>;//top(back)-right
glVertex3f(size,size,f);//top-right
glVertex3f(size,-size,f);//bottom-right
glVertex3f(size,-size,B)/>;//bottom(back)-right
//top
glColor3f(0.2f,0.4f,0.6f);
glVertex3f(-size,size,B)/>;//top(back)-left
glVertex3f(-size,size,f);//top-left
glVertex3f(size,size,f);//top-right
glVertex3f(size,size,B)/>;//top(back)-right
//bottom
glColor3f(0.2f,0.1f,0.7f);
glVertex3f(-size,-size,B)/>;//bottom(back)-left
glVertex3f(-size,-size,f);//bottom-left
glVertex3f(size,-size,f);//bottom-right
glVertex3f(size,-size,B)/>;//bottom(back)-right
glEnd(); //End quadrilateral coordinates
glutSwapBuffers(); //Send the 3D scene to the screen
}
void update(int value) {
_angle += 2.0f;
if (_angle > 360) {
_angle -= 360;
}
glutPostRedisplay(); //Tell GLUT that the display has changed
//Tell GLUT to call update again in 25 milliseconds
glutTimerFunc(25, update, 0);
}
int main(int argc, char** argv) {
//Initialize GLUT
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(400, 400); //Set the window size
//Create the window
glutCreateWindow("Box");
initRendering(); //Initialize rendering
//Set handler functions for drawing, keypresses, and window resizes
glutDisplayFunc(drawScene);
glutKeyboardFunc(handleKeypress);
glutReshapeFunc(handleResize);
glutTimerFunc(25, update, 0); //Add a timer
glutMainLoop(); //Start the main loop. glutMainLoop doesn't return.
return 0; //This line is never reached
}
Thanks
This post has been edited by Java Student: 26 March 2011 - 11:17 PM
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