OpenGL: Issues Making Icons Rotate [duplicate] - c++

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C : display every x milliseconds (OpenGL)
(1 answer)
Closed 7 years ago.
I have successfully drawn a square with a line through it, a trapezoid with a line through it, and a square on top of a trapezoid with a line through it. At this point I'm just attempting to make all of the icons rotate slowly on the screen, but can't figure out where I'm going wrong.
I've modeled my program after a previous one that I wrote that makes a polygon walk across the screen and jump up and do a flip, but for some reason I can't get any movement out of any of my icons. Is my TimerFunction not behaving as I would expect?
I know it's tedious to read, but I included my whole code because I'm not sure where the issue might be...
void init(void); //function that initializes the window clear color
void DrawsAllIcons(float x[], float y[], int ndraws, int pointsperdraw [], int drawtype[], float colorr[], float colorg[], float colorb[], float rotate, float scalex, float scaley, float transx, float transy); //function to draw the functions in the opened window
void SetupRC(void);
void RenderScene(void);
void settrans2 (float rotate, float scalex, float scaley, float transx, float transy);//function that sets the clear color used to set the state of the OpenGL system
void TimerFunction(int );
//square
float rotate = 00.0;
float xCoords [7] = {1.0, 1.0, -1.0, -1.0, 1.0, 0.0, 0.0};
float yCoords [7] = {1.0,-1.0,-1.0,1.0,1.0,2.0,-2.0};
int numberofDraws = 2;
int pointsPerDraw[2] = {5, 2};
int typeOfDraw[2] = {2,1};
float colorR[3] = {1.0,0.0,0.0};
float colorg[3] = {0.0,1.0,0.0};
float colorb[3] = {0.0,0.0,1.0};
float transx = 5.0;
float transy = 5.0;
float scalex = 2.0;
float scaley = 2.0;
//trapezoid
float rotate2 = 00.0;
float xCoords2 [6] = {1.0, 1.5, -1.5, -1.0, 0.0, 0.0};
float yCoords2 [6] = {1.0,-1.0,-1.0,1.0,2.0,-2.0};
int numberofDraws2 = 2;
int pointsPerDraw2[2] = {4, 2};
int typeOfDraw2[2] = {3,1};
float colorR2[3] = {0.0,0.0,0.0};
float colorg2[3] = {1.0,1.0,0.0};
float colorb2[3] = {0.0,0.0,1.0};
float transx2 = -5.0;
float transy2 = -5.0;
float scalex2 = 2.0;
float scaley2 = 2.0;
//Square on trapezoid
float rotate3 = 00.0;
float xCoords3 [6] = {1.0, 1.0, -1.0, -1.0, 0.0,0.0};
float yCoords3 [6] = {1.0,0.0,0.0,1.0,3.0,-3.0};
int numberofDraws3 = 2;
int pointsPerDraw3[2] = {4, 2};
int typeOfDraw3[2] = {3,1};
float colorR3[3] = {1.0,0.0,0.0};
float colorg3[3] = {0.0,1.0,0.0}; //go down dont overthink
float colorb3[3] = {0.0,0.0,0.0};
float transx3 = 0.0;
float transy3 = 0.0;
float scalex3 = 1.0;
float scaley3 = 1.0;
//trapezoid under square
float rotate4 = 00.0;
float xCoords4 [6] = {1.5, 2.0, -2.0, -1.5, 0.0, 0.0};
float yCoords4 [6] = {0.0,-1.0,-1.0,0.0,3.0,-3.0};
int numberofDraws4 = 2;
int pointsPerDraw4[2] = {4, 2};
int typeOfDraw4[2] = {3,1};
float colorR4[3] = {0.0,0.0,0.0};
float colorg4[3] = {1.0,1.0,0.0};
float colorb4[3] = {0.0,0.0,1.0};
float transx4 = 0.0;
float transy4 = 0.0;
float scalex4 = 1.0;
float scaley4 = 1.0;
int main(int argc, char* *argv)
{
char header[]="This Bad Boy'll Draw any Icon you can think of"; //set up window title
glutInit(&argc, argv); // initialize glopen utility toolkit
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB); // Set up the display mode with a buffer and colors **
glutInitWindowSize(560,440); //window size and position
glutInitWindowPosition(140,20);
SetupRC();
glutCreateWindow(header); // Open and label the window
glutDisplayFunc(RenderScene); //points to the function that will be drawing the item // Set the state of the rendering machine
glutTimerFunc(30, TimerFunction, 1);
glutMainLoop(); // Call and activate the main
return 0;
}
void RenderScene(void)
{
glClear(GL_COLOR_BUFFER_BIT);//note clear color was set in SetupRC
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0,0,540,440); //set viewpoint to dimensions
glOrtho(-20.0,20.0,-20.0,20.0,1.0,-1.0);
glClear(GL_COLOR_BUFFER_BIT);
DrawsAllIcons(xCoords, yCoords, numberofDraws, pointsPerDraw,typeOfDraw,colorR,colorg,colorb, rotate, transx,transy,scalex,scaley); //used GL_LINE_STRIP for the square to show that that case worked
DrawsAllIcons(xCoords2, yCoords2, numberofDraws2, pointsPerDraw2,typeOfDraw2,colorR2,colorg2,colorb2, rotate2, transx2,transy2,scalex2,scaley2); //used GL_POLYGON and GL_LINE for rest
DrawsAllIcons(xCoords3, yCoords3, numberofDraws3, pointsPerDraw3,typeOfDraw3,colorR3,colorg3,colorb3, rotate3, transx3,transy3,scalex3,scaley3);
DrawsAllIcons(xCoords4, yCoords4, numberofDraws4, pointsPerDraw4,typeOfDraw4,colorR4,colorg4,colorb4, rotate4, transx4,transy4,scalex4,scaley4);
glEnd();
glutSwapBuffers(); //
}
void DrawsAllIcons (float x[], float y[], int ndraws, int pointsperdraw [], int drawtype[], float colorr[], float colorg[], float colorb[], float rotateD, float transxD, float transyD, float scalexD, float scaleyD)
{
settrans2(rotateD,scalexD,scaleyD,transxD, transyD);
int k=0; //index for arrays
int drawTooIndex = 0;
ndraws=ndraws-1;
for (int j=0; j<=ndraws; j++) //runs through
{
int whatCase = drawtype[j]; //sees what type of draw
drawTooIndex +=pointsperdraw[j];
switch (whatCase)
{
case 1:
{
glColor3f(colorr[j],colorg[j],colorb[j]);
glBegin(GL_LINES);
glVertex2f(x[k], y[k]); //sets vertex at the first point at k in the point arrays
int i = k+1;
k++;
for (i; i <drawTooIndex; i++)
{
glVertex2f(x[i], y[i]);
k++;
}
glEnd();
glFlush();
}
break;
case 2:
{
glColor3f(colorr[j], colorg[j], colorb[j]);
glBegin(GL_LINE_STRIP);
glVertex2f(x[k], y[k]);
int m = k+1;
k++;
for (m; m <drawTooIndex; m++)
{
glVertex2f(x[m], y[m]);
k++;
}
glEnd();
glFlush();
}
break;
case 3:
{
glColor3f(colorr[j], colorg[j], colorb[j]);
glShadeModel(GL_FLAT);
glBegin(GL_POLYGON);
glVertex2f(x[k], y[k]);
int n = k+1; //gets index of where to start drawing in the x and y arrays
k++;
for (n; n <drawTooIndex; n++)
{
glVertex2f(x[n], y[n]);
k++;
}
glEnd();
glFlush();
}
break;
}
}
}
void SetupRC(void)
{ // function sets the clear color of an open window, and then clears the open window
glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set clear color to pale green
return;
}//end of SetupRC
void settrans2(float rotateDD, float scalexDD, float scaleyDD, float transxDD, float transyDD)
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(transxDD,transyDD,0.0);
glRotatef(rotateDD, 0.0, 0.0, 1.0); // where to put this in the program?
glScalef(scalexDD, scaleyDD, 1.0);
return;
}
void TimerFunction(int value)
{
rotate+=5.0;
rotate2+=5.0;
rotate3+=5.0;
rotate4+=5.0;
}

Answer 1

glutTimerFunc()s only fire once, you need to re-arm them in your callback to get another, as well as poking GLUT for a redraw with the new values:
void TimerFunction(int value)
{
rotate+=5.0;
rotate2+=5.0;
rotate3+=5.0;
rotate4+=5.0;
glutPostRedisplay();
glutTimerFunc( 30, TimerFunction, 1 );
}
All together:
#include <GL/glut.h>
//square
float rotate = 00.0;
float xCoords [7] = {1.0, 1.0, -1.0, -1.0, 1.0, 0.0, 0.0};
float yCoords [7] = {1.0,-1.0,-1.0,1.0,1.0,2.0,-2.0};
int numberofDraws = 2;
int pointsPerDraw[2] = {5, 2};
int typeOfDraw[2] = {2,1};
float colorR[3] = {1.0,0.0,0.0};
float colorg[3] = {0.0,1.0,0.0};
float colorb[3] = {0.0,0.0,1.0};
float transx = 5.0;
float transy = 5.0;
float scalex = 2.0;
float scaley = 2.0;
//trapezoid
float rotate2 = 00.0;
float xCoords2 [6] = {1.0, 1.5, -1.5, -1.0, 0.0, 0.0};
float yCoords2 [6] = {1.0,-1.0,-1.0,1.0,2.0,-2.0};
int numberofDraws2 = 2;
int pointsPerDraw2[2] = {4, 2};
int typeOfDraw2[2] = {3,1};
float colorR2[3] = {0.0,0.0,0.0};
float colorg2[3] = {1.0,1.0,0.0};
float colorb2[3] = {0.0,0.0,1.0};
float transx2 = -5.0;
float transy2 = -5.0;
float scalex2 = 2.0;
float scaley2 = 2.0;
//Square on trapezoid
float rotate3 = 00.0;
float xCoords3 [6] = {1.0, 1.0, -1.0, -1.0, 0.0,0.0};
float yCoords3 [6] = {1.0,0.0,0.0,1.0,3.0,-3.0};
int numberofDraws3 = 2;
int pointsPerDraw3[2] = {4, 2};
int typeOfDraw3[2] = {3,1};
float colorR3[3] = {1.0,0.0,0.0};
float colorg3[3] = {0.0,1.0,0.0}; //go down dont overthink
float colorb3[3] = {0.0,0.0,0.0};
float transx3 = 0.0;
float transy3 = 0.0;
float scalex3 = 1.0;
float scaley3 = 1.0;
//trapezoid under square
float rotate4 = 00.0;
float xCoords4 [6] = {1.5, 2.0, -2.0, -1.5, 0.0, 0.0};
float yCoords4 [6] = {0.0,-1.0,-1.0,0.0,3.0,-3.0};
int numberofDraws4 = 2;
int pointsPerDraw4[2] = {4, 2};
int typeOfDraw4[2] = {3,1};
float colorR4[3] = {0.0,0.0,0.0};
float colorg4[3] = {1.0,1.0,0.0};
float colorb4[3] = {0.0,0.0,1.0};
float transx4 = 0.0;
float transy4 = 0.0;
float scalex4 = 1.0;
float scaley4 = 1.0;
void settrans2(float rotateDD, float scalexDD, float scaleyDD, float transxDD, float transyDD)
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(transxDD,transyDD,0.0);
glRotatef(rotateDD, 0.0, 0.0, 1.0); // where to put this in the program?
glScalef(scalexDD, scaleyDD, 1.0);
return;
}
void DrawsAllIcons( float x[], float y[], int ndraws, int pointsperdraw [], int drawtype[], float colorr[], float colorg[], float colorb[], float rotateD, float transxD, float transyD, float scalexD, float scaleyD)
{
settrans2(rotateD,scalexD,scaleyD,transxD, transyD);
int k=0; //index for arrays
int drawTooIndex = 0;
ndraws=ndraws-1;
for (int j=0; j<=ndraws; j++) //runs through
{
int whatCase = drawtype[j]; //sees what type of draw
drawTooIndex +=pointsperdraw[j];
switch (whatCase)
{
case 1:
{
glColor3f(colorr[j],colorg[j],colorb[j]);
glBegin(GL_LINES);
glVertex2f(x[k], y[k]); //sets vertex at the first point at k in the point arrays
int i = k+1;
k++;
for (i; i <drawTooIndex; i++)
{
glVertex2f(x[i], y[i]);
k++;
}
glEnd();
glFlush();
}
break;
case 2:
{
glColor3f(colorr[j], colorg[j], colorb[j]);
glBegin(GL_LINE_STRIP);
glVertex2f(x[k], y[k]);
int m = k+1;
k++;
for (m; m <drawTooIndex; m++)
{
glVertex2f(x[m], y[m]);
k++;
}
glEnd();
glFlush();
}
break;
case 3:
{
glColor3f(colorr[j], colorg[j], colorb[j]);
glShadeModel(GL_FLAT);
glBegin(GL_POLYGON);
glVertex2f(x[k], y[k]);
int n = k+1; //gets index of where to start drawing in the x and y arrays
k++;
for (n; n <drawTooIndex; n++)
{
glVertex2f(x[n], y[n]);
k++;
}
glEnd();
glFlush();
}
break;
}
}
}
void RenderScene(void)
{
glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set clear color to pale green
glClear(GL_COLOR_BUFFER_BIT);//note clear color was set in SetupRC
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0,0,540,440); //set viewpoint to demensions
glOrtho(-20.0,20.0,-20.0,20.0,1.0,-1.0);
glClear(GL_COLOR_BUFFER_BIT);
DrawsAllIcons(xCoords, yCoords, numberofDraws, pointsPerDraw,typeOfDraw,colorR,colorg,colorb, rotate, transx,transy,scalex,scaley); //used GL_LINE_STRIP for the square to show that that case worked
DrawsAllIcons(xCoords2, yCoords2, numberofDraws2, pointsPerDraw2,typeOfDraw2,colorR2,colorg2,colorb2, rotate2, transx2,transy2,scalex2,scaley2); //used GL_POLYGON and GL_LINE for rest
DrawsAllIcons(xCoords3, yCoords3, numberofDraws3, pointsPerDraw3,typeOfDraw3,colorR3,colorg3,colorb3, rotate3, transx3,transy3,scalex3,scaley3);
DrawsAllIcons(xCoords4, yCoords4, numberofDraws4, pointsPerDraw4,typeOfDraw4,colorR4,colorg4,colorb4, rotate4, transx4,transy4,scalex4,scaley4);
glEnd();
glutSwapBuffers(); //
}
void TimerFunction(int value)
{
rotate+=5.0;
rotate2+=5.0;
rotate3+=5.0;
rotate4+=5.0;
glutPostRedisplay();
glutTimerFunc( 30, TimerFunction, 1 );
}
int main(int argc, char* *argv)
{
char header[]="This Bad Boy'll Draw any Icon you can think of"; //set up window title
glutInit(&argc, argv); // initialize glopen utility toolkit
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB); // Set up the display mode with a buffer and colors **
glutInitWindowSize(560,440); //window size and positoin
glutInitWindowPosition(140,20);
glutCreateWindow(header); // Open and label the window
glutDisplayFunc(RenderScene); //points to the fucntion that will be drawing the item // Set the state of the rendering machine
glutTimerFunc(30, TimerFunction, 1);
glutMainLoop(); // Call and activate the main
return 0;
}