it now uses directx api to set the perspective projection matrix

panda/src/dxgsg8/dxGraphicsStateGuardian8.cxx

@@ -1030,17 +1030,41 @@ prepare_lens() {
     return false;
   }
 
-  const LMatrix4f &projection_mat = _current_lens->get_projection_mat();
-
-  // The projection matrix must always be left-handed Y-up internally,
-  // even if our coordinate system of choice is otherwise.
-  LMatrix4f new_projection_mat =
-    LMatrix4f::convert_mat(CS_yup_left, _current_lens->get_coordinate_system()) *
-    projection_mat;
-
   HRESULT hr;
-  hr = _pD3DDevice->SetTransform(D3DTS_PROJECTION,
-                                     (D3DMATRIX*)new_projection_mat.get_data());
+
+  if (_current_lens->get_type().get_name() == "PerspectiveLens") {
+    // new method, still in test
+    const LMatrix4f mat_temp;
+    float hfov = _current_lens->get_hfov();
+    float vfov = _current_lens->get_vfov();
+    float ar = _current_lens->get_aspect_ratio();
+    float nearf = _current_lens->get_near();
+    float farf = _current_lens->get_far();
+    //dxgsg8_cat.debug() << "hfov " << hfov << " vfov " << vfov << " ar " << ar << " near " << nearf << " far " << farf << endl;
+    
+    double vfov_radian = vfov * 0.0174532925;
+    
+    D3DXMatrixPerspectiveFovLH( (D3DXMATRIX*)mat_temp.get_data(), vfov_radian, ar, nearf, farf );
+    
+    hr = _pD3DDevice->SetTransform(D3DTS_PROJECTION,
+                                   (D3DMATRIX*)mat_temp.get_data());
+    //dxgsg8_cat.debug() << mat_temp << endl;
+    //dxgsg8_cat.debug() << "using perspective projection" << endl;
+  }
+  else {
+    const LMatrix4f &projection_mat = _current_lens->get_projection_mat();
+    
+    // The projection matrix must always be left-handed Y-up internally,
+    // even if our coordinate system of choice is otherwise.
+    LMatrix4f new_projection_mat =
+      LMatrix4f::convert_mat(CS_yup_left, _current_lens->get_coordinate_system()) *
+      projection_mat;
+ 
+    hr = _pD3DDevice->SetTransform(D3DTS_PROJECTION,
+                                   (D3DMATRIX*)new_projection_mat.get_data());
+    //dxgsg8_cat.debug() << new_projection_mat << endl;
+    //dxgsg8_cat.debug() << "using other projection" << endl;
+  }
   return SUCCEEDED(hr);
 }