Using gluLookAt to move camera in 2D iPhone game ?
- by Mr.Gando
Hey guys,
I'm trying to use gluLookAt to move the camera in my iPhone game, but every time I've tried to use gluLookAt my screen just goes "blank" ( grey in this case )
I'm trying to render a simple triangle and to move the camera, this is my code:
to setup my scene I do:
glViewport(0, 0, backingWidth, backingHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glRotatef(-90.0, 0.0, 0.0, 1.0); //using iPhone in horizontal mode
glOrthof(-240, 240, -160, 160, -1, 1);
glMatrixMode(GL_MODELVIEW);
then my "triangle rendering" code looks like:
GLfloat triangle[] = {0, 100, 100, 0, -100, 0,};
glClearColor(0.7, 0.7, 0.7, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnableClientState(GL_VERTEX_ARRAY);
glColor4f(1.0, 0.0, 0.0, 1.0);
glVertexPointer(2, GL_FLOAT, 0, &triangle);
glDrawArrays(GL_TRIANGLES, 0, 6);
glDisableClientState(GL_VERTEX_ARRAY);
This draws a red triangle in the middle of the screen, when I try to apply gluLookAt ( I got the implementation of the function from Cocos2D so I asume it's correct ), i do:
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0,0,1,0,0,0,0,0,1); // try to move the camera a bit ?
GLfloat triangle[] = {0, 100, 100, 0, -100, 0,};
glClearColor(0.7, 0.7, 0.7, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnableClientState(GL_VERTEX_ARRAY);
glColor4f(1.0, 0.0, 0.0, 1.0);
glVertexPointer(2, GL_FLOAT, 0, &triangle);
glDrawArrays(GL_TRIANGLES, 0, 6);
glDisableClientState(GL_VERTEX_ARRAY);
This leads me to grey screen (glClearColor is grey), I've tried all sort of things and read what I've found about gluLookAt on the net, but no luck :(, if someone could explain me or show me how to move to move the camera in a top-down fashion ( zelda, etc ), I would really appreciate it.
Thanks!
