enhance offscreen

easy3d/util/version.h

@@ -59,7 +59,7 @@ namespace easy3d {
 #define EASY3D_VERSION_NR 1020503
 
 /// Easy3D release date, in the format YYYYMMDD.
-#define EASY3D_RELEASE_DATE 20240611
+#define EASY3D_RELEASE_DATE 20240613
 
 
 #endif  // EASY3D_UTIL_VERSION_H

easy3d/viewer/offscreen.cpp

@@ -47,8 +47,8 @@ namespace easy3d {
     }
 
 
-    bool OffScreen::render(const std::string &image_file) const {
-        return snapshot(image_file);
+    bool OffScreen::render(const std::string &file_name, float scaling, int samples, int back_ground, bool expand) const {
+        return snapshot(file_name, scaling, samples, back_ground, expand);
     }
 
 

easy3d/viewer/offscreen.h

@@ -42,6 +42,7 @@ namespace easy3d {
      *              LOG(ERROR) << "failed to load model";
      *              return EXIT_FAILURE;
      *          }
+     *          ... when necessary, access the camera and modify the view here.
      *          bool success = os.render("image.png");
      *      \endcode
      */
@@ -64,11 +65,22 @@ namespace easy3d {
         //@}
 
         /**
-         * @brief Render the current scene into an image file.
-         * @param image_file The file name of the image to which the scene will be saved.
+         * @brief  Render the current scene into an image file. Supported image format: png, jpg, bmp, and tga.
+         * @details This function renders the scene into a framebuffer and takes a snapshot of the framebuffer.
+         *      It allows the snapshot image to have a dimension different from the offscreen renderer, and it
+         *      has no limit on the image size (if memory allows).
+         * @param file_name The image file name.
+         * @param scaling The scaling factor that determines the size of the image (default to 1.0, same size as
+         *      the offscreen renderer), i.e.,
+         *      image_width = width() * scaling;
+         *      image_height = height() * scaling;
+         * @param samples The required number of samples for antialiased rendering (which can be different from
+         *      that of the default framebuffer). The default value is 4.
+         * @param back_ground Determines the background color. 0: current color; 1: white; 2: transparent.
+         * @param expand Expand the frustum to ensure the image aspect ratio.
          * @return true on success and false otherwise.
          */
-        bool render(const std::string& image_file) const;
+        bool render(const std::string& file_name, float scaling = 1.0f, int samples = 4, int back_ground = 1, bool expand = true) const;
 
 
         /// @name Other properties

easy3d/viewer/viewer.h

@@ -336,19 +336,19 @@ namespace easy3d {
         /**
          * @brief  Take a snapshot of the screen and save it to an image file. Supported image format: png, jpg, bmp, and tga.
          * @details This function renders the scene into a framebuffer and takes a snapshot of the framebuffer.
-         *      It allow the snapshot image to have a dimension different from the viewer and it has no limit on the
+         *      It allows the snapshot image to have a dimension different from the viewer, and it has no limit on the
          *      image size (if memory allows).
          * @param file_name The image file name.
          * @param scaling The scaling factor that determines the size of the image (default to 1.0, using the viewer size), i.e., 
          *      image_width = viewer_width * scaling;
          *      image_height = viewer_height * scaling;
-         * @param samples The required number of samples for antialiased rendering (can be different from the default framebuffer).
-         *      The default value is 0 (no antialiasing).
+         * @param samples The required number of samples for antialiased rendering (which can be different from
+         *      that of the default framebuffer). The default value is 4.
          * @param back_ground Determines the background color. 0: current color; 1: white; 2: transparent.
          * @param expand Expand the frustum to ensure the image aspect ratio.
          * @return true on success and false otherwise.
          */
-        bool snapshot(const std::string& file_name, float scaling = 1.0f, int samples = 0, int back_ground = 1, bool expand = true) const;
+        bool snapshot(const std::string& file_name, float scaling = 1.0f, int samples = 4, int back_ground = 1, bool expand = true) const;
 
         /**
          * @brief Query the XYZ coordinates of the surface point under the cursor.

tests/CMakeLists.txt

@@ -18,6 +18,7 @@ add_executable(Tests
         visualization_viewer_imgui/viewer.h
         visualization_viewer_imgui/viewer.cpp
         visualization_multi_view/main.cpp
+        visualization_offscreen/offscreen.cpp
         visualization_camera_interpolation/main.cpp
         visualization_camera_interpolation/viewer.h
         visualization_camera_interpolation/viewer.cpp

tests/main.cpp

@@ -46,6 +46,7 @@ int test_kdtree();
 int test_point_cloud_algorithms();
 int test_surface_mesh_algorithms();
 
+int offscreen();
 int test_viewer_imgui(int duration);
 int test_composite_view(int duration);
 int test_real_camera();
@@ -103,6 +104,8 @@ int main(int argc, char* argv[]) {
     result += test_point_cloud_algorithms();
     result += test_surface_mesh_algorithms();
 
+    result += offscreen();
+
     const int duration = 1500; // in millisecond
     result += test_viewer_imgui(duration);
     result += test_composite_view(duration);

tests/visualization_offscreen/offscreen.cpp

@@ -0,0 +1,56 @@
+/********************************************************************
+ * Copyright (C) 2015 Liangliang Nan <[email protected]>
+ * https://3d.bk.tudelft.nl/liangliang/
+ *
+ * This file is part of Easy3D. If it is useful in your research/work,
+ * I would be grateful if you show your appreciation by citing it:
+ * ------------------------------------------------------------------
+ *      Liangliang Nan.
+ *      Easy3D: a lightweight, easy-to-use, and efficient C++ library
+ *      for processing and rendering 3D data.
+ *      Journal of Open Source Software, 6(64), 3255, 2021.
+ * ------------------------------------------------------------------
+ *
+ * Easy3D is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License Version 3
+ * as published by the Free Software Foundation.
+ *
+ * Easy3D 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, see <http://www.gnu.org/licenses/>.
+ ********************************************************************/
+
+#include <easy3d/viewer/offscreen.h>
+#include <easy3d/util/resource.h>
+
+
+using namespace easy3d;
+
+
+int offscreen() {
+    const std::string file_name = resource::directory() + "/data/bunny.ply";
+    OffScreen os;
+    if (!os.add_model(file_name)) {
+        LOG(ERROR) << "failed to load model. Please make sure the file exists and format is correct.";
+        return EXIT_FAILURE;
+    }
+
+    bool failed(false);
+    if (!os.render("bunny-0.png"))
+        failed = true;
+    if (!os.render("bunny-1.png", 2.0f, 0))
+        failed = true;
+    if (!os.render("bunny-2.png", 2.0f, 4, 0))
+        failed = true;
+    if (!os.render("bunny-3.png", 2.0f, 4, 1))
+        failed = true;
+    if (!os.render("bunny-4.png", 2.0f, 4, 2))
+        failed = true;
+
+    LOG_IF(failed, ERROR) << "offscreen renderer failed to render the scene";
+    return failed ? EXIT_FAILURE : EXIT_SUCCESS;
+}