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jakes
04-26-2009, 03:53 AM
Please help me this is the second time i have posted this post
as i am a beginner my coding is not to good i am using the code below which i used from a great site called (lighthouse 3d.com)
in the code their are functions that use the gluLookAt command to move the camera around it moves and rotates left and right and moves forwards and backwards the problem is i need the camera to move up and down in the y axis but as i said before my coding is not good could someone please help me i think the functions have to be changed....... CODE BELOW

#include <math.h>
#include <GL/glut.h>




float angle=0.0,deltaAngle = 0.0,ratio;
float x=0.0f,y=1.75f,z=5.0f;
float lx=0.0f,ly=0.0f,lz=-1.0f;
GLint snowman_display_list;
int deltaMove = 0;


void changeSize(int w, int h)
{

// Prevent a divide by zero, when window is too short
// (you cant make a window of zero width).
if(h == 0)
h = 1;

ratio = 1.0f * w / h;
// Reset the coordinate system before modifying
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Set the viewport to be the entire window
glViewport(0, 0, w, h);

// Set the clipping volume
gluPerspective(45,ratio,1,1000);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(x, y, z,
x + lx,y + ly,z + lz,
0.0f,1.0f,0.0f);


}


void drawSnowMan() {


glColor3f(1.0f, 1.0f, 1.0f);

// Draw Body
glTranslatef(0.0f ,0.75f, 0.0f);
glutSolidSphere(0.75f,20,20);


// Draw Head
glTranslatef(0.0f, 1.0f, 0.0f);
glutSolidSphere(0.25f,20,20);

// Draw Eyes
glPushMatrix();
glColor3f(0.0f,0.0f,0.0f);
glTranslatef(0.05f, 0.10f, 0.18f);
glutSolidSphere(0.05f,10,10);
glTranslatef(-0.1f, 0.0f, 0.0f);
glutSolidSphere(0.05f,10,10);
glPopMatrix();

// Draw Nose
glColor3f(1.0f, 0.5f , 0.5f);
glRotatef(0.0f,1.0f, 0.0f, 0.0f);
glutSolidCone(0.08f,0.5f,10,2);
}



GLuint createDL() {
GLuint snowManDL;

// Create the id for the list
snowManDL = glGenLists(1);

// start list
glNewList(snowManDL,GL_COMPILE);

// call the function that contains
// the rendering commands
drawSnowMan();

// endList
glEndList();

return(snowManDL);
}

void initScene() {

glEnable(GL_DEPTH_TEST);
snowman_display_list = createDL();

}

void orientMe(float ang) {


lx = sin(ang);
lz = -cos(ang);
glLoadIdentity();
gluLookAt(x, y, z,
x + lx,y + ly,z + lz,
0.0f,1.0f,0.0f);
}


void moveMeFlat(int i) {
x = x + i*(lx)*0.1;
z = z + i*(lz)*0.1;
glLoadIdentity();
gluLookAt(x, y, z,
x + lx,y + ly,z + lz,
0.0f,1.0f,0.0f);
}




--------------------------------------------------------------------------------

Here are some of the new bits. The function bellow starts by checking if any of the variables which define camera action are different from zero, and if so it will call the appropriate function to perform the required movement.


--------------------------------------------------------------------------------



void renderScene(void) {

if (deltaMove)
moveMeFlat(deltaMove);
if (deltaAngle) {
angle += deltaAngle;
orientMe(angle);
}
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Draw ground

glColor3f(0.9f, 0.9f, 0.9f);
glBegin(GL_QUADS);
glVertex3f(-100.0f, 0.0f, -100.0f);
glVertex3f(-100.0f, 0.0f, 100.0f);
glVertex3f( 100.0f, 0.0f, 100.0f);
glVertex3f( 100.0f, 0.0f, -100.0f);
glEnd();

// Draw 36 SnowMen

for(int i = -3; i < 3; i++)
for(int j=-3; j < 3; j++) {
glPushMatrix();
glTranslatef(i*10.0,0,j * 10.0);
glCallList(snowman_display_list);;
glPopMatrix();
}
glutSwapBuffers();
}



--------------------------------------------------------------------------------

The functions that follow are the ones which we've registered as callbacks for the special keys, and normal keys release, respectively.


--------------------------------------------------------------------------------


void pressKey(int key, int x, int y) {

switch (key) {
case GLUT_KEY_LEFT :
deltaAngle = -0.01f;break;
case GLUT_KEY_RIGHT :
deltaAngle = 0.01f;break;
case GLUT_KEY_UP :
deltaMove = 1;break;
case GLUT_KEY_DOWN :
deltaMove = -1;break;
}
}

void releaseKey(int key, int x, int y) {

switch (key) {
case GLUT_KEY_LEFT :
case GLUT_KEY_RIGHT :
deltaAngle = 0.0f;break;
case GLUT_KEY_UP :
case GLUT_KEY_DOWN :
deltaMove = 0;break;
}
}



--------------------------------------------------------------------------------

In the main function there are three new lines:

glutIgnoreKeyRepeat is called with a non-zero parameter to ask GLUT to stop reporting key repeats. Afterwards, both glutSpecialUpFunc and glutKeyboardUpFunc are called to register the callbacks.


--------------------------------------------------------------------------------


int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowPosition(100,100);
glutInitWindowSize(640,360);
glutCreateWindow("SnowMen from 3D-Tech");

initScene();

glutIgnoreKeyRepeat(1);
glutSpecialFunc(pressKey);
glutSpecialUpFunc(releaseKey);

glutDisplayFunc(renderScene);
glutIdleFunc(renderScene);

glutReshapeFunc(changeSize);

glutMainLoop();

return(0);
}

please help

jakes