got minimal vertex shader working.

game/renderer_polygon_3d/polygon_model.hpp

@@ -14,19 +14,27 @@ class PolygonModel {
     public:
         PolygonModel(const std::string &filename) : m_filename(filename)
         {
-            if (!import()) {
-                m_loaded = false;
-
-            } else {
-                m_loaded = true;
+            clear();
         }
+
+        void clear()
+        {
+            // TODO: delete buffers if there's data
+
+            m_loaded_from_file = false;
+            m_loaded_to_opengl = false;
+
+            m_data_position.clear();
+            m_data_normal.clear();
+
+            m_vbo_id_position = 0;
+            m_vbo_id_normal   = 0;
+            m_numVertices     = 0;
         }
 
         bool import()
         {
-            m_vbo_id_position = 0;
-            m_vbo_id_normal   = 0;
-            m_numVertices     = 0;
+            clear();
 
             // Create an instance of the Importer class
             Assimp::Importer importer;
@@ -51,12 +59,21 @@ class PolygonModel {
             // Now we can access the file's contents.
             copyVertices(scene);
 
+            m_loaded_from_file = true;
+
             // We're done. Everything will be cleaned up by the importer destructor
             return true;
         }
 
-        bool loadIntoOpenGl()
+        bool uploadToOpenGl()
         {
+            if (!m_loaded_from_file) {
+                std::cerr<<"[polygonmodel] warning: try to upload model data "
+                    << "to OpenGL but no data is loaded!" << std::endl;
+
+                return false;
+            }
+
             glEnableVertexAttribArray(0);
 
             glGenBuffers(1, &m_vbo_id_position);            // Generate buffer
@@ -97,11 +114,21 @@ class PolygonModel {
             model->normals,                     // Buffer data pointer
             GL_STATIC_DRAW);                    // Usage - Data never changes;
 #endif
+            m_loaded_to_opengl = true;
+
             return true;
         }
 
         bool bind()
         {
+            // TODO: check whether this vbo is bound!
+            if (!m_loaded_to_opengl) {
+                std::cout<<"[polygonmodel] warning: try to bind model vbo "
+                    << "which was not uploaded to OpenGL!" << std::endl;
+
+                return false;
+            }
+
             // bind position vbo
             glEnableVertexAttribArray(0);
             glBindBuffer(GL_ARRAY_BUFFER, m_vbo_id_position);
@@ -116,12 +143,20 @@ class PolygonModel {
             glVertexAttribPointer(normalLoc, 3, GL_FLOAT, GL_FALSE, 0, NULL);
 #endif
 
+            m_binding_active = true;
+
             return true;
         }
 
-        void render()
+        bool render()
         {
+            if (!m_binding_active || !m_loaded_to_opengl) {
+                std::cout<<"[polygonmodel] warning: try to render model without bind()" << std::endl;
+                return false;
+            }
+
             glDrawArrays(GL_TRIANGLES, 0, m_numVertices);
+            return true;
         }
 
     private:
@@ -171,11 +206,12 @@ class PolygonModel {
         }
 
         const std::string &filename() const { return m_filename; }
-        bool               ready()    const { return m_loaded; }
 
     private:
         std::string m_filename;
-        bool        m_loaded;
+        bool        m_loaded_from_file;
+        bool        m_loaded_to_opengl;
+        bool        m_binding_active;
 
         // both will hold 3 * numVertices floats
         std::vector<float> m_data_position;

game/renderer_polygon_3d/renderer_polygon_3d.cpp

@@ -9,18 +9,52 @@ namespace endofthejedi {
     {
         std::cout<<"setup 3d" << std::endl;
 
-        m_atomicBomb = new PolygonModel("../data/mesh/small_atomic_bomb.stl");
-        m_atomicBomb->loadIntoOpenGl();
+        //m_atomicBomb = new PolygonModel("../data/mesh/small_atomic_bomb.stl");
+        m_atomicBomb = new PolygonModel("../data/mesh/quad_screen_coords.stl");
+        m_atomicBomb->import();
+        m_atomicBomb->uploadToOpenGl();
 
         m_models.push_back(m_atomicBomb);
+
+        std::string vss =
+            "varying vec3 vertex;\n"
+            "void main()\n"
+            "{\n"
+            "  gl_Position = gl_Vertex;\n"
+            "  vertex = gl_Vertex.xyz;\n"
+            "}\n"
+            ;
+
+        std::string fss =
+            "varying vec3 vertex;\n"
+            "void main()\n"
+            "{\n"
+            //"  gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
+            "  gl_FragColor = vec4(0.5+0.5*vertex.xyz, 1.0);\n"
+            "}\n"
+            ;
+
+        m_shader.init();
+        m_shader.load(vss.c_str(), GL_VERTEX_SHADER);
+        m_shader.load(fss.c_str(), GL_FRAGMENT_SHADER);
     }
 
     void RendererPolygon3d::render(const game::State *state)
     {
+        m_shader.bind();
+
         (void) state;
 
-        m_atomicBomb->bind();
-        m_atomicBomb->render();
+        //m_atomicBomb->bind();
+        //m_atomicBomb->render();
+
+        glColor3f(1.0, 0.0, 0.0);
+        glBegin(GL_QUADS);
+        glVertex2f(-1.0f, -1.0f);
+        glVertex2f(1.0f, -1.0f);
+        glVertex2f(1.0f, 1.0f);
+        glVertex2f(-1.0f, 1.0f);
+        glEnd();
 
         //std::cout<<"render 3d" << std::endl;
     }

game/renderer_polygon_3d/renderer_polygon_3d.hpp

@@ -17,15 +17,18 @@ class PolygonModel;
 namespace endofthejedi {
 
     class RendererPolygon3d : public Renderer {
-        private:
-        protected:
         public:
             void setup();
             void render(const game::State *state) override;
 
         private:
+            // all models are also here (for easy reloading etc.)
             std::vector<PolygonModel*>  m_models;
 
+            // and with a specific variable name here
             PolygonModel               *m_atomicBomb;
+
+            // for rendering everything
+            Shader m_shader;
     };
 }