Question

I am loading an object through an obj file in opengl using GLM Library but it comes out on the screen upside down. Also i am providing a capability to user so he can rotate all the objects accordingly by mouse too. e.g. zoom and zoom in and rotate with y axis.

Problem is i dont know how to rotate the object first to make its face according to what i need. After that i want to draw this object and offcourse at that time mouse can play its role to rotate it.

my draw function contain the following code

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glPushMatrix();
glTranslatef(m_fPosX, m_fPosY,-m_fZoom);
glRotatef(m_fRotX, 1.0f, 0.0f, 0.0f);//these two for mouse movement
glRotatef(m_fRotY, 0.0f, 1.0f, 0.0f);
glRotated(180,0.0f, 0.0f, -1.0f);

glDisable(GL_TEXTURE_2D);
glColor3f(0.90f,0.90f,0.90f);
glmDraw(m_p3dModel,GLM_SMOOTH | GLM_MATERIAL); 

glPopMatrix();

here rotate functions are all dependent on mouse movement but if it get load upside down i dont know how to first make my object face right direction and then allow it in this draw function…Which means i need to set its face before calling this draw function.

Answer 1

glRotatef(m_fRotY, 1.0f, 0.0f, 0.0f);

should be

glRotatef(m_fRotY, 0.0f, 1.0f, 0.0f);

copy/paste is the mother of many evils :o)

For transformation / projection / model view tutorial : check link