void DrawGLScene(void)
{
double stretch,height,position,rotation;
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
glLoadIdentity();
gluLookAt(5.0, 5.0, 20.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
position=cos((double)frame*speed)*2;
height=fabs(sin((double)frame*speed)*10)+1;
rotation=cos((double)frame*speed)*90;
stretch=1+0.3*sin((double)frame*speed/2);
if(useMyTransformations) {
if(doTranslate) myTranslatef(position,height-5,0.0);
if(doRotate) myRotatef(rotation,0.2,0.6,0.77);
if(doScale) myScalef(1/sqrt(stretch),stretch,1/sqrt(stretch));
} else {
if(doTranslate) glTranslatef(position,height-5,0.0);
if(doRotate) glRotatef(rotation,0.2,0.6,0.77);
if(doScale) glScalef(1/sqrt(stretch),stretch,1/sqrt(stretch));
}
//drawCube();
drawTeapot();
frame++;
glutSwapBuffers();
}
void rotateCameraLeft(float degrees, float *eyePosition, float *centerPosition, float *upVector){
// Please implement this function.
GLdouble gaze[3] = { centerPosition[0] - eyePosition[0], centerPosition[1] - eyePosition[1], centerPosition[2] - eyePosition[2] };
GLdouble normGaze[3];
double gazeLength;
GLdouble normUp[3];
double upLength;
GLdouble right[3];
GLdouble normRight[3];
double rightLength;
GLfloat rotate[16];
GLfloat rotEye[3];
GLfloat rotUp[3];
gazeLength = sqrt(SQR(gaze[0]) + SQR(gaze[1]) + SQR(gaze[2]));
for (int i = 0; i < 3; i++)
{
normGaze[i] = gaze[i] / gazeLength;
}
upLength = sqrt(SQR(upVector[0]) + SQR(upVector[1]) + SQR(upVector[2]));
for (int i = 0; i < 3; i++)
{
normUp[i] = upVector[i] / upLength;
}
right[0] = normGaze[1] * normUp[2] - normGaze[2] * normUp[1];
right[1] = normGaze[2] * normUp[0] - normGaze[0] * normUp[2];
right[2] = normGaze[0] * normUp[1] - normGaze[1] * normUp[0];
rightLength = sqrt(SQR(right[0]) + SQR(right[1]) + SQR(right[2]));
for (int i = 0; i < 3; i++)
{
normRight[i] = right[i] / rightLength;
}
myRotatef(rotate, degrees, normUp[0], normUp[1], normUp[2]);
rotEye[0] = rotate[0] * eyePosition[0] + rotate[4] * eyePosition[1] + rotate[8] * eyePosition[2];
rotEye[1] = rotate[1] * eyePosition[0] + rotate[5] * eyePosition[1] + rotate[9] * eyePosition[2];
rotEye[2] = rotate[2] * eyePosition[0] + rotate[6] * eyePosition[1] + rotate[10] * eyePosition[2];
rotUp[0] = rotate[0] * normUp[0] + rotate[4] * normUp[1] + rotate[8] * normUp[2];
rotUp[1] = rotate[1] * normUp[0] + rotate[5] * normUp[1] + rotate[9] * normUp[2];
rotUp[2] = rotate[2] * normUp[0] + rotate[6] * normUp[1] + rotate[10] * normUp[2];
eyePosition[0] = rotEye[0];
eyePosition[1] = rotEye[1];
eyePosition[2] = rotEye[2];
upVector[0] = rotUp[0];
upVector[1] = rotUp[1];
upVector[2] = rotUp[2];
}
void display( void ) {
/*
* Set clear color to gray
*/
myClearColor ( 0.8, 0.8, 0.8, 0.0 );
/*
* Clear screen window
*/
myClear( GL_COLOR_BUFFER_BIT );
myLoadIdentity();
myPushMatrix();
/*
* plain old polygon test
*/
if ( (displayNumber % 4) == 1) {
/* default clipping */
myOrtho2D( -100.0, 100.0, -100.0, 100.0 );
/* default viewport */
myViewport( 0, 0, screenWidth, screenHeight );
myPushMatrix();
/* draw the polys */
drawPolys();
}
else if ( (displayNumber % 4) == 2) {
/* clipping test */
myOrtho2D( -65.0, 75.0, -80.0, 65.0 );
/* default viewport */
myViewport( 0, 0, screenWidth, screenHeight );
/* flip screen around! */
myScalef(-1.0,1.0);
myPushMatrix();
/* draw the polys */
drawPolys();
}
else if ( (displayNumber % 4) == 3) {
/* default clipping */
myOrtho2D( -100.0, 100.0, -100.0, 100.0 );
/* default viewport */
myViewport( 0, 0, screenWidth, screenHeight );
/* rotate screen */
myRotatef(15.0);
myPushMatrix();
/* draw the tranformed polys */
drawPolys();
}
else /* displayNumber == 0 */ {
/* default clipping */
myOrtho2D( -100.0, 100.0, -100.0, 100.0 );
/* default viewport */
myViewport( 0, 0, screenWidth, screenHeight );
myRotatef(-15.0);
myScalef(.5,.5);
myPushMatrix();
myRotatef(15.0);
myPushMatrix();
/* draw the tranformed polys */
drawPolys();
}
/*
* Flush GL buffers to the display
*/
glFlush( );
}
void rotateCameraLeft(float degrees, float *eyePosition, float *centerPosition, float *upVector){
GLfloat identity[16]; // will hold the identity matrix
GLfloat rMatrix[16]; // will hold the rotation matrix found by myRotatef()
GLfloat gaze[] = { centerPosition[0] - eyePosition[0], centerPosition[1] - eyePosition[1], centerPosition[2] - eyePosition[2] }; // z-axis vector
GLfloat normGaze[3]; // normalized z-axis vector
GLfloat rotEye[3]; // rotated eye position
GLfloat normUp[3]; // normalized up vector
GLfloat rotUp[3]; // rotated up vector
GLfloat right[3]; // right vector
GLfloat normRight[3]; // normalized right vector
float gazeLength;
float upLength;
float rightLength;
gazeLength = sqrtf(SQR(gaze[0]) + SQR(gaze[1]) + SQR(gaze[2])); // find the length of the gaze vector
for (int i = 0; i < 3; i++) // normalize the gaze vector
{
normGaze[i] = gaze[i] / gazeLength;
}
upLength = sqrtf(SQR(upVector[0]) + SQR(upVector[1]) + SQR(upVector[2])); // find the length of the up vector
for (int i = 0; i < 3; i++) // normlaize the up vector
{
normUp[i] = upVector[i] / upLength;
}
// cross product of the normalized gaze and up vectors to get the right vector
right[0] = normUp[2] * normGaze[1] - normUp[1] * normGaze[2];
right[1] = normUp[0] * normGaze[2] - normUp[2] * normGaze[0];
right[2] = normUp[1] * normGaze[0] - normUp[0] * normGaze[1];
rightLength = sqrtf(SQR(right[0]) + SQR(right[1]) + SQR(right[2])); // find the length of the right vector
for (int i = 0; i < 3; i++) // normalize the right vector (even though it already should be normalized)
{
normRight[i] = right[i] / rightLength;
}
// fill out the identity matrix to pull the rotation matrix into this function
identity[0] = 1; identity[4] = 0; identity[8] = 0; identity[12] = 0;
identity[1] = 0; identity[5] = 1; identity[9] = 0; identity[13] = 0;
identity[2] = 0; identity[6] = 0; identity[10] = 1; identity[14] = 0;
identity[3] = 0; identity[7] = 0; identity[11] = 0; identity[15] = 1;
for (int i = 0; i < 16; i++) // set matrix to the identity matrix
{
rMatrix[i] = identity[i];
}
myRotatef(rMatrix, -degrees, normUp[0], normUp[1], normUp[2]); // get the rotation matrix for a rotation of degrees around the up vector
// get the rotated eye position
rotEye[0] = rMatrix[0] * eyePosition[0] + rMatrix[4] * eyePosition[1] + rMatrix[8] * eyePosition[2];
rotEye[1] = rMatrix[1] * eyePosition[0] + rMatrix[5] * eyePosition[1] + rMatrix[9] * eyePosition[2];
rotEye[2] = rMatrix[2] * eyePosition[0] + rMatrix[6] * eyePosition[1] + rMatrix[10] * eyePosition[2];
// get the rotated up vector
rotUp[0] = rMatrix[0] * normUp[0] + rMatrix[4] * normUp[1] + rMatrix[8] * normUp[2];
rotUp[1] = rMatrix[1] * normUp[0] + rMatrix[5] * normUp[1] + rMatrix[9] * normUp[2];
rotUp[2] = rMatrix[2] * normUp[0] + rMatrix[6] * normUp[1] + rMatrix[10] * normUp[2];
// set the eye position to be equal to the rotated eye position
eyePosition[0] = rotEye[0];
eyePosition[1] = rotEye[1];
eyePosition[2] = rotEye[2];
// set the up vector to be equal to the rotated up vector
upVector[0] = rotUp[0];
upVector[1] = rotUp[1];
upVector[2] = rotUp[2];
}
