void begin_frame(context& gc) {
//glEnable(GL_CULL_FACE);
//glCullFace(GL_FRONT);
glDisable(GL_CULL_FACE);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
float ofsx = -gc.screen_size().width_/2.0f;
float ofsy = -gc.screen_size().height_/2.0f;
if (rotate_ == -999.0f) {
// first time
rotate_ = gc.rotate();
ofsx_ = ofsx;
ofsy_ = ofsy;
}
if (gc.rotate()- rotate_ > 180.0f) rotate_ += 360.0f;
if (gc.rotate() - rotate_ < -180.0f) rotate_ -= 360.0f;
rotate_ = rotate_ * 0.9f + gc.rotate() * 0.1f;
ofsx_ = ofsx_ * 0.95f + ofsx * 0.05f;
ofsy_ = ofsy_ * 0.95f + ofsy * 0.05f;
//glOrthof(0.0f, (float)gc.screen_size_.width_, (float)gc.screen_size_.height_, 0.0f, -1.0f, 1.0f);
float w = (float)gc.device_screen_size().width_;
float h = (float)gc.device_screen_size().height_;
glOrthof(-1.0f, 1.0f, 1.0f, -1.0f, -1.0f, 1000.0f);
glScalef(2.0f/w, 2.0f/h, 1.0f);
glRotatef(-rotate_, 0.0f,0.0f,1.0f);
glTranslatef(ofsx_, ofsy_, 0.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
#if 0
{
const double t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
const double a = t*90.0;
glDisable(GL_DEPTH_TEST);
glColor4d(1,1,1,1);
glPushMatrix();
glTranslated(400.0,300.0,0.0);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutSolidSphere(100,16,16);
glPopMatrix();
}
#endif
}
