wireframe

src/graphics.cpp

@@ -22,6 +22,9 @@ ShaderProgram::Base ShaderProgram::baseFromName(string name) {
   }
   if (lname == "triangle") {
     return Triangle;
+  }
+  if (lname == "polygons") {
+    return Polygons;
   } else {
     BOOST_LOG_TRIVIAL(fatal) << "unknown base program \"" << name << "\"";
     exit(EXIT_USAGE);
@@ -40,6 +43,8 @@ string ShaderProgram::baseName() {
     return "Empty";
   case ShaderProgram::Base::Triangle:
     return "Triangle";
+  case ShaderProgram::Base::Polygons:
+    return "Polygons";
   default:
     // this should never occur, as the switch case should cover all variants.
     throw std::runtime_error("Undefined base Program");
@@ -50,13 +55,14 @@ string ShaderProgram::baseName() {
  * @param vertexSource C style string with NULL termination
  * @param fragSource C style string with NULL termination
  */
-ShaderProgram::ShaderProgram(Base base, string vertexSource,
-                             string fragSource) {
+ShaderProgram::ShaderProgram(Base base, string vertexSource, string fragSource,
+                             bool wireframe /* = false */) {
   int success;
   char infoLog[512];
   const char *vertexSource_c = vertexSource.c_str();
   const char *fragSource_c = fragSource.c_str();
   this->base = base;
+  this->wireframe = wireframe;
   BOOST_LOG_TRIVIAL(info) << "With base program \"" << this->baseName() << "\"";
   // NOTE: char arrays and char pointers are not actually the same.
   // glShaderSource requires a char[] as it appears. We pass the
@@ -149,8 +155,9 @@ int ShaderProgram::run(GLFWwindow *window) {
     // VBOs) when it's not directly necessary.
     glBindVertexArray(0);
 
-    // uncomment this call to draw in wireframe polygons.
-    // glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    if (this->wireframe) {
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    }
     while (!glfwWindowShouldClose(window)) {
       // input
       // -----
@@ -163,7 +170,8 @@ int ShaderProgram::run(GLFWwindow *window) {
 
       // draw our first triangle
       glUseProgram(this->program);
-      glBindVertexArray(VAOTriangle); // seeing as we only have a single VAO there's no
+      glBindVertexArray(
+          VAOTriangle); // seeing as we only have a single VAO there's no
                         // need to bind it every time, but we'll do so to
                         // keep things a bit more organized
       glDrawArrays(GL_TRIANGLES, 0, 3);
@@ -181,6 +189,90 @@ int ShaderProgram::run(GLFWwindow *window) {
     glDeleteBuffers(1, &VBOTriangle);
     glDeleteProgram(this->program);
 
+    // glfw: terminate, clearing all previously allocated GLFW resources.
+    // ------------------------------------------------------------------
+    glfwTerminate();
+    return 0;
+  } else if (this->base == Polygons) {
+    // set up vertex data (and buffer(s)) and configure vertex attributes
+    // ------------------------------------------------------------------
+    float vertices[] = {
+        0.5f,  0.8f,  0.0f, // top right
+        0.5f,  -0.5f, 0.0f, // bottom right
+        -0.5f, -0.5f, 0.0f, // bottom left
+        -0.5f, 0.5f,  0.0f  // top left
+    };
+    unsigned int indices[] = {
+        // note that we start from 0!
+        0, 1, 3, // first triangle
+        1, 2, 3  // second triangle
+    };
+
+    unsigned int VBOTriangle, VAOTriangle, EBOindicies;
+    glGenBuffers(1, &EBOindicies);
+    glGenVertexArrays(1, &VAOTriangle);
+    glGenBuffers(1, &VBOTriangle);
+    // bind the Vertex Array Object first, then bind and set vertex buffer(s),
+    // and then configure vertex attributes(s).
+    glBindVertexArray(VAOTriangle);
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBOTriangle);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBOindicies);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
+                 GL_STATIC_DRAW);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float),
+                          (void *)0);
+    glEnableVertexAttribArray(0);
+
+    // note that this is allowed, the call to glVertexAttribPointer registered
+    // VBO as the vertex attribute's bound vertex buffer object so afterwards we
+    // can safely unbind
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBOindicies);
+
+    // You can unbind the VAO afterwards so other VAO calls won't accidentally
+    // modify this VAO, but this rarely happens. Modifying other VAOs requires a
+    // call to glBindVertexArray anyways so we generally don't unbind VAOs (nor
+    // VBOs) when it's not directly necessary.
+    glBindVertexArray(0);
+
+    if (this->wireframe) {
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    }
+    while (!glfwWindowShouldClose(window)) {
+      // input
+      // -----
+      processInput(window);
+
+      // render
+      // ------
+      glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+      glClear(GL_COLOR_BUFFER_BIT);
+
+      // draw our first triangle
+      glUseProgram(this->program);
+      glBindVertexArray(
+          VAOTriangle); // seeing as we only have a single VAO there's no
+                        // need to bind it every time, but we'll do so to
+                        // keep things a bit more organized
+      /* glDrawArrays(GL_TRIANGLES, 0, 3); */
+      glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+      // glBindVertexArray(0); // no need to unbind it every time
+
+      // glfw: swap buffers and poll IO events (keys pressed/released, mouse
+      // moved etc.)
+      // -------------------------------------------------------------------------------
+      glfwSwapBuffers(window);
+      glfwPollEvents();
+    }
+    // optional: de-allocate all resources once they've outlived their purpose:
+    // ------------------------------------------------------------------------
+    glDeleteVertexArrays(1, &VAOTriangle);
+    glDeleteBuffers(1, &VBOTriangle);
+    glDeleteProgram(this->program);
+
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------
     glfwTerminate();
@@ -189,6 +281,9 @@ int ShaderProgram::run(GLFWwindow *window) {
   {
     // use the compiled shader
     glUseProgram(this->program);
+    if (this->wireframe) {
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    }
     while (!glfwWindowShouldClose(window)) {
       processInput(window);
 

src/graphics.hpp

@@ -7,14 +7,16 @@
 
 class ShaderProgram {
 public:
-  enum Base { Empty, Triangle };
+  enum Base { Empty, Triangle, Polygons };
   std::string baseName();
   static Base baseFromName(std::string name);
-  ShaderProgram(Base base, std::string vertexSource, std::string fragSource);
+  ShaderProgram(Base base, std::string vertexSource, std::string fragSource,
+                bool wireframe = false);
   int run(GLFWwindow *window);
 
 protected:
   unsigned int vertex;
+  bool wireframe;
   unsigned int frag;
   Base base;
   unsigned int program;

src/main.cpp

@@ -18,7 +18,8 @@ int main(int argc, char **argv) {
   po::options_description desc("Available options");
   desc.add_options()("help,h", "show help")("verbose,v", "more verbose output")(
       "vert", po::value<string>()->required(), "vertex shader file")(
-      "frag", po::value<string>()->required(), "fragment shader file")(
+      "frag", po::value<string>()->required(),
+      "fragment shader file")("wire,w", "activate wireframe mode")(
       "base,b", po::value<string>()->required(), "base program");
 
   /* unused for now */
@@ -104,7 +105,7 @@ int main(int argc, char **argv) {
   BOOST_LOG_TRIVIAL(trace) << "Creating ShaderProgram";
 
   // TODO: determinde ShaderProgram::Base with a CLI arg
-  ShaderProgram shaderProgram(base, vert, frag);
+  ShaderProgram shaderProgram(base, vert, frag, !vm["wire"].empty());
 
   /* Run our main program */
   BOOST_LOG_TRIVIAL(trace) << "Starting mainWindow";
@@ -117,7 +118,8 @@ int main(int argc, char **argv) {
 void help(char *prog, po::options_description desc) {
   cout << "Usage:" << endl
        << prog
-       << " [-vh] [--vert] shaders/vertex.glsl [--frag] shaders/fragment.glsl"
+       << " [-vwh] \\\n\t--vert shaders/vertex.glsl \\\n\t--frag "
+          "shaders/fragment.glsl \\\n\t--base BASE_PROGRAM"
        << endl
        << endl
        << "return values:" << endl
@@ -132,6 +134,7 @@ void help(char *prog, po::options_description desc) {
        << "base programs:" << endl
        << "Empty\t\t-\tEmpty window with colored background" << endl
        << "Triangle\t-\tA static Triangle" << endl
+       << "Polygons\t-\tA small amount of polygons" << endl
        << endl
        << endl
        << desc << endl;