can now render a trianglegit add .

include/env-vars.h.in

@@ -1,3 +1,4 @@
 #pragma once
 
 #define GALAXY_SHADER_BIN_DIR "@GALAXY_SHADER_BIN_DIR@"
+#define WIREFRAME_RENDERING 1

include/grenderer.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "gwindow.h"
+#include "gshader.h"
 #include "logger.h"
 
 class GRenderer {
@@ -13,4 +14,8 @@ public:
 private:
   Logger *logger;
   GWindow *window;
+  GShader *shader;
+
+  unsigned int VAO;
+  unsigned int VBO;
 };

include/gshader.h

@@ -4,10 +4,18 @@
 
 class GShader {
 public:
-  GShader(Logger *l) : logger(l) {};
-  ~GShader() {};
+  GShader(Logger *l) : logger(l), vertex_shader(0), fragment_shader(0) {};
+  ~GShader();
+
   void init();
+  void vertex_init();
+  void fragment_init();
+
+  unsigned int getProgram() { return this->program; }
 
 private:
   Logger *logger;
+  unsigned int vertex_shader;
+  unsigned int fragment_shader;
+  unsigned int program;
 };

src/grenderer.cpp

@@ -1,25 +1,61 @@
-#include "GLFW/glfw3.h"
-#define GLFW_EXPOSE_NATIVE_X11
-#include "GLFW/glfw3native.h"
+#include "glad/glad.h"
 
 #include "env-vars.h"
 #include "grenderer.h"
+#include "gshader.h"
 #include "logger.h"
 
-GRenderer::GRenderer(GWindow *w, Logger *l) : window(w), logger(l) {
+float vertices[] = {
+    -0.5f, -0.5f, 0.0f, // left
+    0.5f,  -0.5f, 0.0f, // right
+    0.0f,  0.5f,  0.0f  // top
+};
+
+unsigned int indices[] = {
+    // note that we start from 0!
+    0, 1, 3, // first triangle
+    1, 2, 3  // second triangle
+};
+
+GRenderer::GRenderer(GWindow *w, Logger *l) : window(w), logger(l), VAO(0), VBO(0) {
+  this->shader = new GShader(l);
 }
 
 GRenderer::~GRenderer() {
   LOG_DEBUG("Shutting down renderer...");
+  delete this->shader;
 }
 
 void GRenderer::init() {
   LOG_DEBUG("Initializing the GRenderer...");
+  this->shader->init();
+
+  // Create Vertex attribute object and vertex buffer objects
+  glGenVertexArrays(1, &this->VAO);
+  glGenBuffers(1, &this->VBO);
+
+  // Bind both of them
+  glBindVertexArray(this->VAO);
+  glBindBuffer(GL_ARRAY_BUFFER, this->VBO);
+
+  // Send data to VBO
+  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+  // Describe data send to VBO
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), nullptr);
+  glEnableVertexAttribArray(0);
+
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
 }
 
 void GRenderer::update() {
   glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
   glClear(GL_COLOR_BUFFER_BIT);
 
+  glUseProgram(this->shader->getProgram());
+  glBindVertexArray(this->VAO);
+  glDrawArrays(GL_TRIANGLES, 0, 3);
+
   glfwSwapBuffers(this->window->getWindow());
 }

src/gshader.cpp

@@ -1,5 +1,115 @@
-#include "logger.h"
+#include "glad/glad.h"
+
+#include "env-vars.h"
 #include "gshader.h"
+#include "logger.h"
 
 void GShader::init() {
+  LOG_DEBUG("Initializing the GShader...");
+  this->vertex_init();
+  this->fragment_init();
+
+  unsigned int program = glCreateProgram();
+
+  glAttachShader(program, this->vertex_shader);
+  glAttachShader(program, this->fragment_shader);
+  glLinkProgram(program);
+
+  // Check for errors
+  int success;
+  char info_log[512];
+  glGetProgramiv(program, GL_LINK_STATUS, &success);
+  if (!success) {
+    glGetProgramInfoLog(program, 512, NULL, info_log);
+
+    LOG_ERROR("Failed to link the shaders");
+    LOG_ERROR(info_log);
+
+    glDeleteShader(this->vertex_shader);
+    glDeleteShader(this->fragment_shader);
+    throw std::runtime_error("Failed to link the shaders");
+  }
+
+  // Not needed after binding
+  glDeleteShader(this->vertex_shader);
+  glDeleteShader(this->fragment_shader);
+
+  this->program = program;
+  glUseProgram(this->program);
+
+  // Test variable to enable wireframe rendering
+  if (WIREFRAME_RENDERING) {
+    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+  }
 };
+
+GShader::~GShader() {
+  glDeleteShader(this->vertex_shader);
+  glDeleteShader(this->fragment_shader);
+}
+
+void GShader::vertex_init() {
+  const char *vertex_shader_source =
+      "#version 330 core\n"
+      "layout (location = 0) in vec3 aPos;\n"
+      "void main()\n"
+      "{\n"
+      "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+      "}\n\0";
+
+  // Create empty vertex shader
+  unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
+
+  // Add source and compile the vertex shader created above
+  glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
+  glCompileShader(vertex_shader);
+
+  // Check for errors
+  int success;
+  char info_log[512];
+  glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
+
+  if (!success) {
+    glGetShaderInfoLog(vertex_shader, 512, NULL, info_log);
+
+    LOG_ERROR("Creating the shader failed: ");
+    LOG_ERROR(info_log);
+
+    throw std::runtime_error("Creating the shader failed");
+  }
+
+  // Success
+  this->vertex_shader = vertex_shader;
+}
+
+void GShader::fragment_init() {
+  const char *fragment_shader_source =
+      "#version 330 core\n"
+      "out vec4 FragColor;\n"
+
+      "void main()\n"
+      "{\n"
+      "  FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+      "}\0";
+
+  // Create empty fragment shader
+  unsigned int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
+
+  // Add source to the shader and compile it
+  glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
+  glCompileShader(fragment_shader);
+
+  // Check for errors
+  int success;
+  char info_log[512];
+  glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    glGetShaderInfoLog(fragment_shader, 512, NULL, info_log);
+    LOG_ERROR("Creating the shader failed:");
+    LOG_ERROR(info_log);
+    throw std::runtime_error("Creating the shader failed");
+  }
+
+  // Success
+  this->fragment_shader = fragment_shader;
+}