rna function:

vecs = Camera.view_frame(scene)

returns 4 points for the camera frame, without this its very hard to know if a point is in the camera view or not, without rewriting blenders internal logic in python.

source/blender/blenkernel/BKE_object.h

@@ -149,7 +149,7 @@ void object_camera_matrix(
 void camera_view_frame_ex(struct Scene *scene, struct Camera *camera, float drawsize, const short do_clip, const float scale[3],
                           float r_asp[2], float r_shift[2], float *r_drawsize, float r_vec[4][3]);
 
-void camera_frame(struct Scene *scene, struct Camera *camera, float r_vec[4][3]);
+void camera_view_frame(struct Scene *scene, struct Camera *camera, float r_vec[4][3]);
 
 void object_relink(struct Object *ob);
 

source/blender/blenkernel/intern/object.c

@@ -3122,7 +3122,7 @@ void camera_view_frame_ex(Scene *scene, Camera *camera, float drawsize, const sh
 	r_vec[3][0]= r_shift[0] - facx; r_vec[3][1]= r_shift[1] + facy; r_vec[3][2]= depth;
 }
 
-void camera_frame(Scene *scene, Camera *camera, float r_vec[4][3])
+void camera_view_frame(Scene *scene, Camera *camera, float r_vec[4][3])
 {
 	float dummy_asp[2];
 	float dummy_shift[2];

source/blender/makesrna/intern/CMakeLists.txt

@@ -95,6 +95,7 @@ set(APISRC
 	rna_actuator_api.c
 	rna_animation_api.c
 	rna_armature_api.c
+	rna_camera_api.c
 	rna_controller_api.c
 	rna_fcurve_api.c
 	rna_image_api.c

source/blender/makesrna/intern/makesrna.c

@@ -2432,7 +2432,7 @@ static RNAProcessItem PROCESS_ITEMS[]= {
 	{"rna_armature.c", "rna_armature_api.c", RNA_def_armature},
 	{"rna_boid.c", NULL, RNA_def_boid},
 	{"rna_brush.c", NULL, RNA_def_brush},
-	{"rna_camera.c", NULL, RNA_def_camera},
+	{"rna_camera.c", "rna_camera_api.c", RNA_def_camera},
 	{"rna_cloth.c", NULL, RNA_def_cloth},
 	{"rna_color.c", NULL, RNA_def_color},
 	{"rna_constraint.c", NULL, RNA_def_constraint},

source/blender/makesrna/intern/rna_camera.c

@@ -209,6 +209,9 @@ void RNA_def_camera(BlenderRNA *brna)
 	RNA_def_property_flag(prop, PROP_EDITABLE);
 	RNA_def_property_ui_text(prop, "DOF Object", "Use this object to define the depth of field focal point");
 	RNA_def_property_update(prop, NC_OBJECT|ND_DRAW, NULL);
+
+	/* Camera API */
+	RNA_api_camera(srna);
 }
 
 #endif

source/blender/makesrna/intern/rna_camera_api.c

@@ -0,0 +1,88 @@
+/*
+ * $Id:
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version. 
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s): Campbell Barton
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/makesrna/intern/rna_camera_api.c
+ *  \ingroup RNA
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+
+#include "RNA_define.h"
+#include "BKE_utildefines.h"
+
+#ifdef RNA_RUNTIME
+
+#include "DNA_scene_types.h"
+#include "BKE_context.h"
+#include "BKE_object.h"
+
+void rna_camera_view_frame(struct Camera *camera, struct Scene *scene,
+                           float vec1_r[3], float vec2_r[3], float vec3_r[3], float vec4_r[3])
+{
+	float vec[4][3];
+
+	camera_view_frame(scene, camera, vec);
+
+	copy_v3_v3(vec1_r, vec[0]);
+	copy_v3_v3(vec2_r, vec[1]);
+	copy_v3_v3(vec3_r, vec[2]);
+	copy_v3_v3(vec4_r, vec[3]);
+}
+
+#else
+
+void RNA_api_camera(StructRNA *srna)
+{
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
+	func= RNA_def_function(srna, "view_frame", "rna_camera_view_frame");
+	RNA_def_function_ui_description(func, "Return 4 points for the cameras frame (before object transformation)");
+
+	RNA_def_pointer(func, "scene", "Scene", "", "Scene to use for aspect calculation, when omitted 1:1 aspect is used");
+
+	/* return location and normal */
+	parm= RNA_def_float_vector(func, "result_1", 3, NULL, -FLT_MAX, FLT_MAX, "Result", NULL, -1e4, 1e4);
+	RNA_def_property_flag(parm, PROP_THICK_WRAP);
+	RNA_def_function_output(func, parm);
+
+	parm= RNA_def_float_vector(func, "result_2", 3, NULL, -FLT_MAX, FLT_MAX, "Result", NULL, -1e4, 1e4);
+	RNA_def_property_flag(parm, PROP_THICK_WRAP);
+	RNA_def_function_output(func, parm);
+
+	parm= RNA_def_float_vector(func, "result_3", 3, NULL, -FLT_MAX, FLT_MAX, "Result", NULL, -1e4, 1e4);
+	RNA_def_property_flag(parm, PROP_THICK_WRAP);
+	RNA_def_function_output(func, parm);
+
+	parm= RNA_def_float_vector(func, "result_4", 3, NULL, -FLT_MAX, FLT_MAX, "Result", NULL, -1e4, 1e4);
+	RNA_def_property_flag(parm, PROP_THICK_WRAP);
+	RNA_def_function_output(func, parm);
+}
+
+#endif
+

source/blender/makesrna/intern/rna_internal.h

@@ -234,6 +234,7 @@ char *rna_TextureSlot_path(struct PointerRNA *ptr);
 void RNA_api_action(StructRNA *srna);
 void RNA_api_armature_edit_bone(StructRNA *srna);
 void RNA_api_bone(StructRNA *srna);
+void RNA_api_camera(StructRNA *srna);
 void RNA_api_drivers(StructRNA *srna);
 void RNA_api_image(struct StructRNA *srna);
 void RNA_api_operator(struct StructRNA *srna);