Add C compatible API to access the adaptiveEvaluator class from non-C++.

This is the case with blender.

opensubdiv/osdutil/CMakeLists.txt

@@ -35,6 +35,7 @@ set(PUBLIC_HEADER_FILES
     batch.h
     drawItem.h
     drawController.h
+    evaluator_capi.h    
     mesh.h
     refiner.h
     topology.h
@@ -43,7 +44,9 @@ set(PUBLIC_HEADER_FILES
 
 add_library(osdutil
     adaptiveEvaluator.h
-    adaptiveEvaluator.cpp    
+    adaptiveEvaluator.cpp
+    evaluator_capi.h
+    evaluator_capi.cpp            
     mesh.h
     mesh.cpp
     refiner.h

opensubdiv/osdutil/evaluator_capi.cpp

@@ -0,0 +1,147 @@
+/*
+ * ***** 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.
+ *
+ * The Original Code is Copyright (C) 2013 Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Sergey Sharybin.
+ *                 Brecht van Lommel
+ *                 Dirk Van Gelder
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include "evaluator_capi.h"
+
+#include <iostream>
+
+#include "adaptiveEvaluator.h"
+#include "topology.h"
+
+#if !defined(WITH_ASSERT_ABORT)
+#  define OSD_abort()
+#else
+#  include <stdlib.h>
+#  define OSD_abort() abort()
+#endif
+
+#if defined(_MSC_VER)
+#  define __func__ __FUNCTION__
+#endif
+
+/* Define this when you want to have additional verbosity
+ * about what's being passed to OpenSubdiv.
+ */
+#undef DEBUG_PRINT
+
+using namespace OpenSubdiv;
+
+/* **************** Types declaration **************** */
+
+typedef struct OpenSubdiv_EvaluatorDescr {
+    PxOsdUtilSubdivTopology topology;
+    PxOsdUtilAdaptiveEvaluator evaluator;
+    std::vector<float> coarsePositions;
+} OpenSubdiv_EvaluatorDescr;
+
+
+/* **************** Mesh descriptor functions **************** */
+
+OpenSubdiv_EvaluatorDescr *openSubdiv_createEvaluatorDescr(int numVertices)
+{
+    OpenSubdiv_EvaluatorDescr *evaluator_descr =
+	new OpenSubdiv_EvaluatorDescr();
+    
+    evaluator_descr->topology.numVertices = numVertices;
+    
+    return evaluator_descr;
+}
+
+void openSubdiv_deleteEvaluatorDescr(
+    OpenSubdiv_EvaluatorDescr *evaluator_descr)
+{
+    delete(evaluator_descr);
+}
+
+void openSubdiv_createEvaluatorDescrFace(OpenSubdiv_EvaluatorDescr *evaluator_descr, int num_vertices, int *indices)
+{
+#ifdef DEBUG_PRINT
+        printf("Adding face index:%d vertices:", (int)evaluator_descr->topology.nverts.size());
+	for (int i = 0; i < num_vertices; i++) {
+		printf("%d ", indices[i]);
+	}
+	printf("\n");
+#endif
+
+        evaluator_descr->topology.nverts.push_back(num_vertices);
+	for (int i = 0; i < num_vertices; i++) {
+            evaluator_descr->topology.indices.push_back(indices[i]);
+        }
+}
+
+void openSubdiv_finishEvaluatorDescr(OpenSubdiv_EvaluatorDescr *evaluator_descr,
+                                int refinementLevel)
+{
+    std::string errorMessage;
+    evaluator_descr->topology.refinementLevel = refinementLevel;
+    
+    if (not evaluator_descr->topology.IsValid(&errorMessage)) {
+        std::cout <<"OpenSubdiv topology is not valid due to " << errorMessage << std::endl;
+    } else {
+        if (not evaluator_descr->evaluator.Initialize(
+                evaluator_descr->topology, &errorMessage)) {
+            std::cout <<"OpenSubdiv uniform evaluator initialization failed due to " << errorMessage << std::endl;
+        }
+    }
+}
+
+
+int openSubdiv_setEvaluatorCoarsePositions(
+    struct OpenSubdiv_EvaluatorDescr *evaluator_descr,
+    const float *positions, int numVertices)
+{
+    std::string errorMessage;
+
+    // TODO: returns void, need error check on length of positions?
+    evaluator_descr->evaluator.SetCoarsePositions(
+        &evaluator_descr->coarsePositions[0],
+        (int)evaluator_descr->coarsePositions.size(),
+	&errorMessage);
+    
+    // Refine with 1 thread for now
+    if (not evaluator_descr->evaluator.Refine(1, &errorMessage)) {
+        std::cout << "OpenSubdiv refinement failed due to " << errorMessage << std::endl;
+        return 0;
+    }
+
+    return 1;
+}
+
+
+void openSubdiv_evaluateLimit(
+    struct OpenSubdiv_EvaluatorDescr *evaluation_descr,
+    int face_id, float u, float v,
+    float P[3], float dPdu[3], float dPdv[3])
+{
+    OsdEvalCoords coords;
+    coords.u = u;
+    coords.v = v;
+    coords.face = face_id;
+
+    evaluation_descr->evaluator.EvaluateLimit(coords, P, dPdu, dPdv);
+}
+   

opensubdiv/osdutil/evaluator_capi.h

@@ -0,0 +1,39 @@
+#ifndef __OPENSUBDIV_OSDUTIL_EVALUATOR_CAPI_H__
+#define __OPENSUBDIV_OSDUTIL_EVALUATOR_CAPI_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Types declaration. */
+struct OpenSubdiv_EvaluationDescr;
+
+/* Methods to create and delete evaluators. */
+struct OpenSubdiv_EvaluatorDescr *openSubdiv_createEvaluatorDescr(int numVertices);
+void openSubdiv_deleteEvaluatorDescr(struct OpenSubdiv_EvaluatorDescr *evaluator_descr);
+void openSubdiv_createEvaluatorDescrFace(struct OpenSubdiv_EvaluatorDescr *evaluator_descr, int num_vertices, int *indices);
+void openSubdiv_finishEvaluatorDescr(struct OpenSubdiv_EvaluatorDescr *evaluator_descr, int refinementLevel);
+
+/* Set the positions of points on the coarse mesh and refine. This method    */
+/* will perform catmull/clark refinement on the CVs to be ready to call      */
+/* openSubdiv_evaluateDescr.  Points here are 3 floats/point.                */
+int openSubdiv_setEvaluatorCoarsePositions(
+    struct OpenSubdiv_EvaluatorDescr *evaluator_descr,
+    const float *positions, int numVertices);
+    
+/* Evaluate the subdivision limit surface at the given ptex face and u/v,    */
+/* return position and derivative information.  Derivative pointers can be   */
+/* NULL.  Note that face index here is the ptex index, or the index into     */
+/* faces after turning all the faces on the original mesh into quads.        */
+void openSubdiv_evaluateLimit(
+    struct OpenSubdiv_EvaluatorDescr *evaluation_descr,
+    int face_id, float u, float v,
+    float P[3], float dPdu[3], float dPdv[3]);
+    
+    
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __OPENSUBDIV_CAPI_H__ */