check shader compilation

src/graphics.cpp

@@ -1,6 +1,6 @@
+#include <boost/algorithm/string.hpp>
 #include <boost/algorithm/string/case_conv.hpp>
 #include <boost/log/trivial.hpp>
-#include <boost/algorithm/string.hpp>
 #include <exception>
 #include <glad/glad.c>
 // glad must be loaded before GLFW
@@ -14,14 +14,15 @@ using namespace std;
 ShaderProgram::Base ShaderProgram::baseFromName(string name) {
   string lname = name;
   boost::algorithm::to_lower(lname); // yes, cpp needs a library to do this.
+                                     // luckily I'm already using boost so I
+                                     // don't need to worry too much about it.
   // can't do a switch over strings in cpp.
   if (lname == "empty") {
     return Empty;
   }
   if (lname == "triangle") {
     return Triangle;
-  }
-  else {
+  } else {
     BOOST_LOG_TRIVIAL(fatal) << "unknown base program \"" << name << "\"";
     exit(EXIT_USAGE);
   }
@@ -63,23 +64,66 @@ ShaderProgram::ShaderProgram(Base base, char **vertexSource,
   glShaderSource(this->frag, 2, fragSource, NULL);
   BOOST_LOG_TRIVIAL(trace) << "compiling fragments shader";
   glCompileShader(this->frag);
+
+  // check if the compilation was successful
+  int success;
+  char infoLog[512];
+  glGetShaderiv(this->vertex, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    glGetShaderInfoLog(this->vertex, 512, NULL, infoLog);
+    BOOST_LOG_TRIVIAL(fatal) << "could not compile vertex shader:\n\n"
+              << infoLog << std::endl;
+    exit(EXIT_SHADER);
+  }
+  glGetShaderiv(this->frag, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    glGetShaderInfoLog(this->frag, 512, NULL, infoLog);
+    BOOST_LOG_TRIVIAL(fatal) << "could not compile fragments shader:\n\n"
+              << infoLog << std::endl;
+    exit(EXIT_SHADER);
+  }
 }
 
-/** runs for every frame
+/** defines the base program behavior.
  *
  * will be called in `mainWindow`.
- *
- * FIXME: dont run the switch case every frame.
  */
-int ShaderProgram::run() {
-  switch (this->base) {
-  case Empty: // same as default
-  default:
-    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+int ShaderProgram::run(GLFWwindow *window) {
+  if (this->base == Triangle) {
+    float vTriangle[] = {
+        -0.5f, -0.5f, 0.0f, // opengl
+        0.5f,  -0.5f, 0.0f, // treats 3d arrays
+        0.0f,  0.5f,  0.0f  // as large 1d arrays
+    };
+    unsigned int oTriangle;
+    glGenBuffers(1, &oTriangle);
+    glBindBuffer(GL_ARRAY_BUFFER, oTriangle);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vTriangle), vTriangle, GL_STATIC_DRAW);
+    while (!glfwWindowShouldClose(window)) {
+      processInput(window);
+
+      glClearColor(0.9f, 0.3f, 0.3f, 1.0f);
       glClear(GL_COLOR_BUFFER_BIT);
-    break;
+
+      glfwSwapBuffers(window);
+      glfwPollEvents();
     }
     return 0;
+  } else // Empty
+  {
+
+    return 0;
+    while (!glfwWindowShouldClose(window)) {
+      processInput(window);
+
+      glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+      glClear(GL_COLOR_BUFFER_BIT);
+
+      glfwSwapBuffers(window);
+      glfwPollEvents();
+    }
+    return 0;
+  }
 }
 
 /* functions that run out graphics stuff */
@@ -117,14 +161,9 @@ int mainWindow(ShaderProgram *shaderProgram, GLFWwindow *window) {
 
   int result = 0;
 
-  BOOST_LOG_TRIVIAL(trace) << "Entering window loop";
-  while (!glfwWindowShouldClose(window)) {
-    processInput(window);
-    shaderProgram->run();
-    glfwSwapBuffers(window);
-    glfwPollEvents();
-  }
-  BOOST_LOG_TRIVIAL(trace) << "Left window loop";
+  BOOST_LOG_TRIVIAL(trace) << "Base program";
+  result = shaderProgram->run(window);
+  BOOST_LOG_TRIVIAL(trace) << "Left base program";
 
   glfwTerminate();
   return result;

src/graphics.hpp

@@ -11,7 +11,7 @@ public:
   std::string baseName();
   static Base baseFromName(std::string name);
   ShaderProgram(Base base, char** vertexSource, char** fragSource);
-  int run();
+  int run(GLFWwindow* window);
 
 protected:
   unsigned int vertex;

src/main.cpp

@@ -116,7 +116,8 @@ void help(char *prog, po::options_description desc) {
        << "1\tGeneric Failure" << endl
        << "2\tBad arguments" << endl
        << "3\tI/O Error" << endl
-       << "3\tOpenGL Error" << endl
+       << "4\tOpenGL Error" << endl
+       << "5\tShader Source Error" << endl
        << endl
        << endl
        << "base programs:" << endl

src/main.hpp

@@ -14,6 +14,7 @@
 const int EXIT_USAGE = 2;
 const int EXIT_IO = 3;
 const int EXIT_GL = 4;
+const int EXIT_SHADER = 5;
 
 namespace po = boost::program_options;
 using namespace std;