Refactor 'fit in camera view' code, and expose it to RNA.

This changes BKE's fitting code to use `BKE_camera_params_compute_viewplane` instead of
`BKE_camera_view_frame`. This allows that code to work with orthographic projection too.

Also, two funcs were added to rna's Object, to resp. get the projection matrix of that
object (mostly useful for cameras and lamps objects), and return position this object
should be to see all (to fit) a given set of points.

Reviewers: campbellbarton

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D961

1 files changed, 51 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_object_api.c b/source/blender/makesrna/intern/rna_object_api.c
index 831e5486236..3dc75ef83f6 100644
--- a/source/blender/makesrna/intern/rna_object_api.c
+++ b/source/blender/makesrna/intern/rna_object_api.c
@@ -112,6 +112,28 @@ static void rna_Scene_mat_convert_space(Object *ob, ReportList *reports, bPoseCh
 	BKE_constraint_mat_convertspace(ob, pchan, (float (*)[4])mat_ret, from, to);
 }
 
+static void rna_Object_calc_matrix_camera(
+        Object *ob, float mat_ret[16], int width, int height, float scalex, float scaley)
+{
+	CameraParams params;
+
+	/* setup parameters */
+	BKE_camera_params_init(&params);
+	BKE_camera_params_from_object(&params, ob);
+
+	/* compute matrix, viewplane, .. */
+	BKE_camera_params_compute_viewplane(&params, width, height, scalex, scaley);
+	BKE_camera_params_compute_matrix(&params);
+
+	copy_m4_m4((float (*)[4])mat_ret, params.winmat);
+}
+
+static void rna_Object_camera_fit_coords(
+        Object *ob, Scene *scene, int num_cos, float *cos, float co_ret[3], float *scale_ret)
+{
+	BKE_camera_view_frame_fit_to_coords(scene, (float (*)[3])cos, num_cos / 3, ob, co_ret, scale_ret);
+}
+
 /* copied from Mesh_getFromObject and adapted to RNA interface */
 /* settings: 0 - preview, 1 - render */
 static Mesh *rna_Object_to_mesh(
@@ -468,6 +490,35 @@ void RNA_api_object(StructRNA *srna)
 	parm = RNA_def_enum(func, "to_space", space_items, CONSTRAINT_SPACE_WORLD, "",
 	                    "The space to which you want to transform 'matrix'");
 
+	/* Camera-related operations */
+	func = RNA_def_function(srna, "calc_matrix_camera", "rna_Object_calc_matrix_camera");
+	RNA_def_function_ui_description(func, "Generate the camera projection matrix of this object "
+	                                      "(mostly useful for Camera and Lamp types)");
+	parm = RNA_def_property(func, "result", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_multi_array(parm, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(parm, "", "The camera projection matrix");
+	RNA_def_function_output(func, parm);
+	parm = RNA_def_int(func, "x", 1, 0, INT_MAX, "", "Width of the render area", 0, 10000);
+	parm = RNA_def_int(func, "y", 1, 0, INT_MAX, "", "Height of the render area", 0, 10000);
+	parm = RNA_def_float(func, "scale_x", 1.0f, 1.0e-6f, FLT_MAX, "", "Width scaling factor", 1.0e-2f, 100.0f);
+	parm = RNA_def_float(func, "scale_y", 1.0f, 1.0e-6f, FLT_MAX, "", "height scaling factor", 1.0e-2f, 100.0f);
+
+	func = RNA_def_function(srna, "camera_fit_coords", "rna_Object_camera_fit_coords");
+	RNA_def_function_ui_description(func, "Compute the coordinate (and scale for ortho cameras) "
+	                                      "given object should be to 'see' all given coordinates");
+	parm = RNA_def_pointer(func, "scene", "Scene", "", "Scene to get render size information from, if available");
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	parm = RNA_def_float_array(func, "coordinates", 1, NULL, -FLT_MAX, FLT_MAX, "", "Coordinates to fit in",
+	                           -FLT_MAX, FLT_MAX);
+	RNA_def_property_flag(parm, PROP_REQUIRED | PROP_NEVER_NULL | PROP_DYNAMIC);
+	parm = RNA_def_property(func, "co_return", PROP_FLOAT, PROP_XYZ);
+	RNA_def_property_array(parm, 3);
+	RNA_def_property_ui_text(parm, "", "The location to aim to be able to see all given points");
+	RNA_def_property_flag(parm, PROP_OUTPUT);
+	parm = RNA_def_property(func, "scale_return", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_ui_text(parm, "", "The ortho scale to aim to be able to see all given points (if relevant)");
+	RNA_def_property_flag(parm, PROP_OUTPUT);
+
 	/* mesh */
 	func = RNA_def_function(srna, "to_mesh", "rna_Object_to_mesh");
 	RNA_def_function_ui_description(func, "Create a Mesh datablock with modifiers applied");