[Add] Ground plane.

assets/shaders/simple.frag

@@ -2,6 +2,8 @@
 
 out vec4 FragColor;
 
+uniform vec3 overrideColor;
+
 void main() {
-  FragColor = vec4(0.2f, 0.5f, 0.8f, 1.0f);
+  FragColor = vec4(overrideColor, 1.0f);
 }

src/graphics/renderer.cpp

@@ -20,7 +20,7 @@
      } \
   } while(0)
 
-Renderer::Renderer(void) : _vao(0), _vbo(0) {}
+Renderer::Renderer(void) : _vao(0), _vbo(0), _ground_vao(0), _ground_vbo(0) {}
 
 Renderer::~Renderer(void) {
   if(_vao != 0) {
@@ -29,6 +29,12 @@ Renderer::~Renderer(void) {
   if(_vbo != 0) {
     glDeleteBuffers(1, &_vbo);
   }
+  if(_ground_vao != 0) {
+    glDeleteVertexArrays(1, &_ground_vao);
+  }
+  if(_ground_vbo != 0) {
+    glDeleteBuffers(1, &_ground_vbo);
+  }
 }
 
 bool Renderer::init(int screen_width, int screen_height) {
@@ -98,6 +104,28 @@ bool Renderer::init(int screen_width, int screen_height) {
   glBindBuffer(GL_ARRAY_BUFFER, 0);
   glBindVertexArray(0);
 
+  /* Setup ground plane. */
+  float ground_vertices[] = {
+    /* Positions. */
+     500.0f, -0.5f,  500.0f,
+    -500.0f, -0.5f,  500.0f,
+    -500.0f, -0.5f, -500.0f,
+
+     500.0f, -0.5f,  500.0f,
+    -500.0f, -0.5f, -500.0f,
+     500.0f, -0.5f, -500.0f,
+  };
+
+  glGenVertexArrays(1, &_ground_vao);
+  glGenBuffers(1, &_ground_vbo);
+  glBindVertexArray(_ground_vao);
+  glBindBuffer(GL_ARRAY_BUFFER, _ground_vbo);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(ground_vertices), ground_vertices, GL_STATIC_DRAW);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), (void*)0);
+  glEnableVertexAttribArray(0);
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
+
   glViewport(0,0,screen_width, screen_height);
   GL_CHECK_ERROR();
   glEnable(GL_DEPTH_TEST); /* Depth testing for 3D! */
@@ -124,32 +152,42 @@ void Renderer::render(const Player& player, const std::vector<RemotePlayer>& rem
   GLint view_loc  = glGetUniformLocation(_shader.get_id(), "view");
   GLint proj_loc  = glGetUniformLocation(_shader.get_id(), "projection");
   GLint model_loc = glGetUniformLocation(_shader.get_id(), "model");
+  GLint color_loc = glGetUniformLocation(_shader.get_id(), "overrideColor");
 
   glUniformMatrix4fv(view_loc, 1, GL_FALSE, view.get_ptr());
   GL_CHECK_ERROR();
   glUniformMatrix4fv(proj_loc, 1, GL_FALSE, projection.get_ptr());
   GL_CHECK_ERROR();
 
+  /* Draw the ground. */
+  BettolaMath::Mat4 ground_model = BettolaMath::Mat4::translation(0.0f, 0.0f, 0.0f);
+  glUniformMatrix4fv(model_loc, 1, GL_FALSE, ground_model.get_ptr());
+  glUniform3f(color_loc, 0.2f, 0.4f, 0.2f);
+  glBindVertexArray(_ground_vao);
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glBindVertexArray(0); /* WHOOAAA! Got to make sure we unbind the VAO! */
+
+  /* Set players colour back. */
+  glUniform3f(color_loc, 0.2f, 0.5f, 0.8f);
+
   /* Draw the local player's cube. */
   BettolaMath::Mat4 model = BettolaMath::Mat4::translation(player.get_x(), 0.0f, player.get_y());
   glUniformMatrix4fv(model_loc, 1, GL_FALSE, model.get_ptr());
   GL_CHECK_ERROR();
 
   glBindVertexArray(_vao);
-  GL_CHECK_ERROR();
   glDrawArrays(GL_TRIANGLES, 0, 36);
-  GL_CHECK_ERROR();
+  glBindVertexArray(0); /* F.ck me! Forgot to unbind here too?!?!? */
 
   /* Draw remote players' cube. */
   for(const auto& remote_player : remote_players) {
+    glBindVertexArray(_vao); /* bind cube VAO for each remote player. */
     BettolaMath::Mat4 remote_model = BettolaMath::Mat4::translation(remote_player.get_x(),
                                                                     0.0f, remote_player.get_y());
     glUniformMatrix4fv(model_loc, 1, GL_FALSE, remote_model.get_ptr());
     glDrawArrays(GL_TRIANGLES, 0, 36);
-  GL_CHECK_ERROR();
+    glBindVertexArray(0); /* Unbind it! */
   }
-
-  glBindVertexArray(0);
 }
 
 bool Renderer::_init_shaders(void) {

src/graphics/renderer.h

@@ -20,6 +20,8 @@ private:
   Shader _shader;
   unsigned int _vao;
   unsigned int _vbo;
+  unsigned int _ground_vao;
+  unsigned int _ground_vbo;
   BettolaMath::Mat4 _projection;
 };