use checkboard as default texture if model has texture coordinates

easy3d/renderer/state.cpp

@@ -25,7 +25,10 @@
  ********************************************************************/
 
 #include <easy3d/renderer/state.h>
+#include <easy3d/renderer/texture_manager.h>
+#include <easy3d/renderer/opengl_error.h>
 #include <easy3d/util/logging.h>
+#include <easy3d/util/resource.h>
 
 
 namespace easy3d {
@@ -106,9 +109,16 @@ namespace easy3d {
         coloring_method_ = TEXTURED;
         property_location_ = texcoord_location;
         property_name_ = texcoord_name;
-        texture_ = texture;
-        texture_repeat_ = repeat;
-        texture_fractional_repeat_ = repeat_fraction;
+        if (texture) {
+            texture_ = texture;
+            texture_repeat_ = repeat;
+            texture_fractional_repeat_ = repeat_fraction;
+        }
+        else { // create a default color texture
+            texture_ = create_color_texture();
+            texture_repeat_ = 5.0f;
+            texture_fractional_repeat_ = 0.0f;
+        }
     }
 
 
@@ -117,7 +127,10 @@ namespace easy3d {
         coloring_method_ = SCALAR_FIELD;
         property_location_ = scalar_location;
         property_name_ = scalar_name;
-        texture_ = texture;
+        if (texture)
+            texture_ = texture;
+        else // create a default scalar texture
+            texture_ = create_scalar_texture();
         texture_repeat_ = 1.0f;
         texture_fractional_repeat_ = 0.0f;
         clamp_lower_ = clamp_lower;
@@ -129,6 +142,28 @@ namespace easy3d {
         coloring_method_ = method;
         property_location_ = location;
         property_name_ = name;
+
+        if (method == TEXTURED)
+            texture_ = create_color_texture();
+        else if (method == SCALAR_FIELD)
+            texture_ = create_scalar_texture();
+    }
+
+
+    Texture* State::create_color_texture() {
+        const std::string texture_file = resource::directory() + "/textures/checkerboard.png";
+        auto tex = TextureManager::request(texture_file, Texture::REPEAT);
+        LOG_IF_FIRST_N(3, !tex, ERROR) << "failed to create texture from " << texture_file << ". " << COUNTER;
+        return tex;
+    }
+
+
+    Texture* State::create_scalar_texture() {
+        const std::string texture_file = resource::directory() + "/colormaps/default.png";
+        auto tex = TextureManager::request(texture_file);
+        LOG_IF_FIRST_N(3, !tex, ERROR) << "failed to create texture from " << texture_file << ". " << COUNTER;
+        easy3d_debug_log_gl_error
+        return tex;
     }
 
 }

easy3d/renderer/state.h

@@ -119,9 +119,11 @@ namespace easy3d {
          * Constructs a scheme for textured rendering.
          * @param texcoord_location The location of texture coordinate.
          * @param texcoord_name The name of the texture coordinate property.
-         * @param texture The pointer to the texture.
+         * @param texture The pointer to the texture. If nullptr, a default texture will be created from
+         *      "textures/checkerboard.png". Client code is expected to provide a meaningful texture at a later stage.
          * @param repeat The repeat factor of the texture. Default value is 1.0.
          * @param repeat_fraction The fractional repeat factor of the texture. Default value is 0.0.
+         * @note
          */
         void set_texture_coloring(Location texcoord_location, const std::string &texcoord_name,
                                   const Texture *texture = nullptr, float repeat = 1.0f,
@@ -131,7 +133,8 @@ namespace easy3d {
          * Constructs a scheme for rendering scalar fields.
          * @param scalar_location The location of the scalar field.
          * @param scalar_name The name of the scalar field.
-         * @param texture The pointer to the texture.
+         * @param texture The pointer to the texture. Default is nullptr, a scalar default texture will be created
+         *      from "/colormaps/default.png". Client code can provide a more suitable texture at a later stage.
          * @param clamp_lower The percentage of values to be clamped at the lower side of the range. Default is 5%.
          * @param clamp_upper The percentage of values to be clamped at the upper side of the range. Default is 5%.
          */
@@ -256,6 +259,15 @@ namespace easy3d {
         void set_highlight_range(const std::pair<int, int> &range) { highlight_range_ = range; }
         const std::pair<int, int> &highlight_range() const { return highlight_range_; }
 
+    protected:
+        // Create a default texture.
+        // Default texture file: "/textures/checkerboard.png";
+        Texture* create_color_texture();
+
+        // Create a default texture for rendering scalar fields.
+        // Default texture file: "/colormaps/default.png";
+        Texture* create_scalar_texture();
+
     protected:
         bool visible_;
         bool selected_;
@@ -275,7 +287,7 @@ namespace easy3d {
         const Texture *texture_;
         // How many times do you want to repeat the texture?
         float texture_repeat_;
-        // Control at a finer level: 100 fractional repeat == repeat.
+        // Control at a finer level: 100 fractional repeat == 1 repeat.
         float texture_fractional_repeat_;
 
         bool ssao_enabled_;

tests/visualization_scalar_field/main.cpp

@@ -60,17 +60,6 @@ int test_scalar_field(int duration) {
 
     drawable->set_scalar_coloring(State::VERTEX, "v:elevation", nullptr, 0.0f, 0.0f);
 
-    // Create texture for coloring the scalar field.
-    const std::string texture_file = resource::directory() + "/colormaps/rainbow.png";
-    Texture *texture = TextureManager::request(texture_file);
-    if (!texture) {
-        LOG(ERROR) << "failed to create texture.";
-        return EXIT_FAILURE;
-    }
-
-    // Use the texture
-    drawable->set_texture(texture);
-
     viewer.set_usage("testing scalar field...");
 
     Timer<>::single_shot(duration, (Viewer*)&viewer, &Viewer::exit);

tutorials/Tutorial_303_ScalarField/main.cpp

@@ -70,16 +70,15 @@ int main(int argc, char **argv) {
 
     drawable->set_scalar_coloring(State::VERTEX, "v:elevation", nullptr, 0.0f, 0.0f);
 
-    // Create texture for coloring the scalar field.
-    const std::string texture_file = resource::directory() + "/colormaps/rainbow.png";
-    Texture *texture = TextureManager::request(texture_file);
-    if (!texture) {
-        LOG(ERROR) << "failed to create texture.";
-        return EXIT_FAILURE;
-    }
-
-    // Use the texture
-    drawable->set_texture(texture);
+    // A default scalar texture is automatically created.
+    // However, you can choose a more suitable one using the code below:
+//    const std::string texture_file = resource::directory() + "/colormaps/rainbow.png";
+//    Texture *texture = TextureManager::request(texture_file);
+//    if (!texture) {
+//        LOG(ERROR) << "failed to create texture.";
+//        return EXIT_FAILURE;
+//    }
+//    drawable->set_texture(texture); // Use the texture
 
     // run the viewer
     return viewer.run();