reading glsl files

data/shader/frag/basic.glsl

@@ -0,0 +1 @@
+# empty

src/graphics.cpp

@@ -1,3 +1,4 @@
+#include <exception>
 #include <glad/glad.c>
 // glad must be loaded before GLFW
 #include "graphics.hpp"
@@ -14,21 +15,26 @@ string ShaderProgram::baseName() {
     return "Empty";
   case Triangle:
     return "Triangle";
+  default:
+    throw exception();
   }
 }
 
-ShaderProgram::ShaderProgram(Base base, string vertexSource,
-                             string fragSource) {
+ShaderProgram::ShaderProgram(Base base, char** vertexSource,
+                             char** fragSource) {
+  // NOTE: char arrays and char pointers are not actually the same.
+  // glShaderSource requires a char[] as it appears. We pass the
+  // variable by reference to avoid duplication in memory.
   BOOST_LOG_TRIVIAL(trace) << "creating empty shaders";
   this->vertex = glCreateShader(GL_VERTEX_SHADER);
   this->frag = glCreateShader(GL_FRAGMENT_SHADER);
   BOOST_LOG_TRIVIAL(trace) << "loading vertex shader";
-  glShaderSource(this->vertex, 1, vertexSource.c_str(),
+  glShaderSource(this->vertex, 1, vertexSource,
                  NULL);
   BOOST_LOG_TRIVIAL(trace) << "compiling vertex shader";
   glCompileShader(this->vertex);
   BOOST_LOG_TRIVIAL(trace) << "loading fragments shader";
-  glShaderSource(this->frag, 2, fragSource.c_str(), NULL);
+  glShaderSource(this->frag, 2, fragSource, NULL);
   BOOST_LOG_TRIVIAL(trace) << "compiling fragments shader";
   glCompileShader(this->frag);
 }

src/graphics.hpp

@@ -9,7 +9,7 @@ class ShaderProgram {
 public:
   enum Base { Empty, Triangle };
   std::string baseName();
-  ShaderProgram(Base base, std::string vertexSource, std::string fragSource);
+  ShaderProgram(Base base, char** vertexSource, char** fragSource);
   int run();
 
 protected:

src/main.cpp

@@ -1,3 +1,6 @@
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
 #include <fstream>
 #include <iostream>
 
@@ -46,40 +49,47 @@ int main(int argc, char **argv) {
   if (vm.count("verbose")) {
     boost::log::core::get()->set_filter(boost::log::trivial::severity >=
                                         boost::log::trivial::trace);
-    BOOST_LOG_TRIVIAL(trace) << "verbose flag found, setting log level to trace";
+    BOOST_LOG_TRIVIAL(trace)
+        << "verbose flag found, setting log level to trace";
   }
 
   /* init graphics stuff */
   result = initGl();
-  if (result != 0) { return EXIT_GL;}
+  if (result != 0) {
+    return EXIT_GL;
+  }
 
   /* setup the shader program */
   BOOST_LOG_TRIVIAL(trace) << "Reading shader files";
-  ifstream vertexFileStream(vm["vert"].as<string>());
-  ifstream fragFileStream(vm["frag"].as<string>());
-  std::stringstream vertexSource;
-  std::stringstream fragSource;
-  vertexSource << vertexFileStream.rdbuf();
-  fragSource << fragFileStream.rdbuf();
-
-  if (vertexFileStream.fail()) {
-    BOOST_LOG_TRIVIAL(fatal)
-        << "Error while reading the vertex shader file.";
-    return EXIT_IO;
-  }
-  if (fragFileStream.fail()) {
-    BOOST_LOG_TRIVIAL(fatal)
-        << "Error while reading the frag shader file.";
-    return EXIT_IO;
-  }
-  vertexFileStream.close();
-  fragFileStream.close();
+  auto fvert = fopen(vm["vert"].as<string>().c_str(), "r");
+  auto ffrag = fopen(vm["frag"].as<string>().c_str(), "r");
+  // get file sizes
+  BOOST_LOG_TRIVIAL(trace) << "Reading shader file sizes";
+  fseek(fvert, 0L, SEEK_END);
+  fseek(ffrag, 0L, SEEK_END);
+  size_t svert = ftell(fvert);
+  size_t sfrag = ftell(ffrag);
+  fseek(fvert, 0L, SEEK_SET);
+  fseek(ffrag, 0L, SEEK_SET);
+  BOOST_LOG_TRIVIAL(trace) << "allocating " << svert
+                           << " B for vert source file";
+  BOOST_LOG_TRIVIAL(trace) << "allocating " << sfrag
+                           << " B for frag source file";
+  char *vert = (char *)malloc(svert + 1);
+  char *frag = (char *)malloc(sfrag + 1);
+  fread(vert, sizeof(char), svert, fvert);
+  fread(frag, sizeof(char), sfrag, ffrag);
+  BOOST_LOG_TRIVIAL(debug) << "vert file:\n```glsl\n" << vert << "```\n"
+                           << svert << "B";
+  BOOST_LOG_TRIVIAL(debug) << "frag file:\n```glsl\n" << frag << "```\n"
+                           << sfrag << "B";
+  fclose(fvert);
+  fclose(ffrag);
 
   BOOST_LOG_TRIVIAL(trace) << "Creating ShaderProgram";
 
   // TODO: determinde ShaderProgram::Base with a CLI arg
-  ShaderProgram shaderProgram(ShaderProgram::Base::Empty, vertexSource.str(),
-                              fragSource.str());
+  ShaderProgram shaderProgram(ShaderProgram::Base::Empty, &vert, &frag);
 
   /* Run our main program */
   BOOST_LOG_TRIVIAL(trace) << "Starting mainWindow";