Hi, thanks.
I got it all figured out actually. I was getting confused with glFrustrum because in OpenGL I used the function name, glFrustrum. In OpenGL-ES it seems that only glFrustumf is available. I found some replacements for gluPerspective and gluLookat.
I'm porting my game engine I coded in c++ over the last 2 years to the iPhone. So I just need to fill in the gaps between OpenGL/SDL/GLu and iPhoneOS/OpenGL-ES.
void perspective(double fovy, double aspect, double zNear, double zFar)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
double xmin, xmax, ymin, ymax;
ymax = zNear * tan(fovy * M_PI / 360.0);
ymin = -ymax;
xmin = ymin * aspect;
xmax = ymax * aspect;
glFrustumf(xmin, xmax, ymin, ymax, zNear, zFar);
glMatrixMode(GL_MODELVIEW);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glDepthMask(GL_TRUE);
}void orthographic()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrthof( 0, 320, 480, 0, 1, 0 );
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glDepthMask(GL_FALSE);
} perspective(85, 480/320, 0.01,10); void gluLookAt(GLfloat eyex, GLfloat eyey, GLfloat eyez,
GLfloat centerx, GLfloat centery, GLfloat centerz,
GLfloat upx, GLfloat upy, GLfloat upz)
{
GLfloat m[16];
GLfloat x[3], y[3], z[3];
GLfloat mag;
/* Make rotation matrix */
/* Z vector */
z[0] = eyex - centerx;
z[1] = eyey - centery;
z[2] = eyez - centerz;
mag = sqrt(z[0] * z[0] + z[1] * z[1] + z[2] * z[2]);
if (mag) { /* mpichler, 19950515 */
z[0] /= mag;
z[1] /= mag;
z[2] /= mag;
}
/* Y vector */
y[0] = upx;
y[1] = upy;
y[2] = upz;
/* X vector = Y cross Z */
x[0] = y[1] * z[2] - y[2] * z[1];
x[1] = -y[0] * z[2] + y[2] * z[0];
x[2] = y[0] * z[1] - y[1] * z[0];
/* Recompute Y = Z cross X */
y[0] = z[1] * x[2] - z[2] * x[1];
y[1] = -z[0] * x[2] + z[2] * x[0];
y[2] = z[0] * x[1] - z[1] * x[0];
/* mpichler, 19950515 */
/* cross product gives area of parallelogram, which is < 1.0 for
* non-perpendicular unit-length vectors; so normalize x, y here
*/
mag = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
if (mag) {
x[0] /= mag;
x[1] /= mag;
x[2] /= mag;
}
mag = sqrt(y[0] * y[0] + y[1] * y[1] + y[2] * y[2]);
if (mag) {
y[0] /= mag;
y[1] /= mag;
y[2] /= mag;
}
#define M(row,col) m[col*4+row]
M(0, 0) = x[0];
M(0, 1) = x[1];
M(0, 2) = x[2];
M(0, 3) = 0.0;
M(1, 0) = y[0];
M(1, 1) = y[1];
M(1, 2) = y[2];
M(1, 3) = 0.0;
M(2, 0) = z[0];
M(2, 1) = z[1];
M(2, 2) = z[2];
M(2, 3) = 0.0;
M(3, 0) = 0.0;
M(3, 1) = 0.0;
M(3, 2) = 0.0;
M(3, 3) = 1.0;
#undef M
glMultMatrixf(m);
/* Translate Eye to Origin */
glTranslatef(-eyex, -eyey, -eyez);
}