add NodeImageTexture for dynamic images, test image thumbnail opening and rendering

engine/canvas.cpp

@@ -212,7 +212,7 @@ void ui::Canvas::stroke_draw()
 }
 void ui::Canvas::stroke_commit()
 {
-    if (!m_dirty)
+    if (!m_dirty || m_layers.empty())
         return;
     m_dirty = false;
 
@@ -503,7 +503,7 @@ void ui::Canvas::save(std::string data_path)
     glActiveTexture(GL_TEXTURE0);
 }
 
-void ui::Canvas::save_project(std::string data_path)
+void ui::Canvas::project_save(std::string data_path)
 {
     static char name[128];
     sprintf(name, "%s/latlong.pano", data_path.c_str());
@@ -513,6 +513,14 @@ void ui::Canvas::save_project(std::string data_path)
         LOG("cannot write project to %s", name);
         return;
     }
+
+    // load thumbnail
+    Image thumb = thumbnail_generate(64, 64);
+    fwrite(&thumb.width, sizeof(int), 1, fp);
+    fwrite(&thumb.height, sizeof(int), 1, fp);
+    fwrite(&thumb.comp, sizeof(int), 1, fp);
+    fwrite(thumb.data(), thumb.size(), 1, fp);
+
     fwrite(&m_width, sizeof(int), 1, fp);
     fwrite(&m_height, sizeof(int), 1, fp);
     
@@ -538,7 +546,7 @@ void ui::Canvas::save_project(std::string data_path)
     LOG("project saved to %s", name);
 }
 
-void ui::Canvas::open_project(std::string data_path)
+void ui::Canvas::project_open(std::string data_path)
 {
     static char name[128];
     sprintf(name, "%s/latlong.pano", data_path.c_str());
@@ -548,6 +556,14 @@ void ui::Canvas::open_project(std::string data_path)
         LOG("cannot write project to %s", name);
         return;
     }
+
+    // skip thumbnail
+    Image thumb;
+    fread(&thumb.width, sizeof(int), 1, fp);
+    fread(&thumb.height, sizeof(int), 1, fp);
+    fread(&thumb.comp, sizeof(int), 1, fp);
+    fseek(fp, thumb.size(), SEEK_CUR);
+
     fread(&m_width, sizeof(int), 1, fp);
     fread(&m_height, sizeof(int), 1, fp);
     
@@ -581,8 +597,86 @@ void ui::Canvas::open_project(std::string data_path)
     fclose(fp);
     LOG("project restore from %s", name);
 }
+ui::Image ui::Canvas::thumbnail_generate(int w, int h)
+{
+    // save viewport and clear color states
+    GLint vp[4];
+    GLfloat cc[4];
+    glGetIntegerv(GL_VIEWPORT, vp);
+    glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
+    GLboolean blend = glIsEnabled(GL_BLEND);
 
+    // prepare common states
+    glViewport(0, 0, w, h);
 
+    RTT fb;
+    fb.create(w, h);
+    fb.bindFramebuffer();
+    fb.clear({ 1, 1, 1, 1 });
+    ui::Plane m_face_plane;
+    m_face_plane.create<1>(2, 2);
+
+    // recalculate because of different aspect ratio than the m_proj matrix
+    glm::mat4 proj = glm::perspective(glm::radians(m_cam_fov), (float)w / (float)h, 0.1f, 1000.f);
+
+    glEnable(GL_BLEND);
+    for (int plane_index = 0; plane_index < 6; plane_index++)
+    {
+        auto plane_mvp = proj * m_mv * m_plane_transform[plane_index] * glm::translate(glm::vec3(0, 0, -1));
+
+        ui::ShaderManager::use(kShader::Checkerboard);
+        ui::ShaderManager::u_mat4(kShaderUniform::MVP, plane_mvp);
+        m_face_plane.draw_fill();
+
+        ui::ShaderManager::use(kShader::TextureAlpha);
+        ui::ShaderManager::u_int(kShaderUniform::Tex, 0);
+        ui::ShaderManager::u_mat4(kShaderUniform::MVP, plane_mvp);
+        for (auto layer_index : m_order)
+        {
+            ui::ShaderManager::u_float(kShaderUniform::Alpha, m_layers[layer_index].m_opacity);
+            m_layers[layer_index].m_rtt[plane_index].bindTexture();
+            m_face_plane.draw_fill();
+            m_layers[layer_index].m_rtt[plane_index].unbindTexture();
+        }
+    }
+
+    fb.unbindFramebuffer();
+
+    // read the rendered image
+    ui::Image image;
+    image.create(w, h);
+    fb.readTextureData((uint8_t*)image.data());
+
+    fb.destroy();
+
+    // restore viewport and clear color states
+    blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
+    glViewport(vp[0], vp[1], vp[2], vp[3]);
+    glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    glActiveTexture(GL_TEXTURE0);
+
+    return std::move(image);
+}
+ui::Image ui::Canvas::thumbnail_read(std::string data_path)
+{
+    static char name[128];
+    sprintf(name, "%s/latlong.pano", data_path.c_str());
+    FILE* fp = fopen(name, "rb");
+    if (!fp)
+    {
+        LOG("cannot read project %s", name);
+        return {}; // return empty image
+    }
+    Image thumb;
+    fread(&thumb.width, sizeof(int), 1, fp);
+    fread(&thumb.height, sizeof(int), 1, fp);
+    fread(&thumb.comp, sizeof(int), 1, fp);
+    thumb.create();
+    fread((uint8_t*)thumb.data(), thumb.size(), 1, fp);
+    fclose(fp);
+    LOG("project thumbnail read from %s", name);
+    return std::move(thumb);
+}
 ///////////////////////////////////////////////////////////////////////////////////////////
 
 void ui::Layer::destroy()