renderer.cpp

#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <GLFW/glfw3.h>
#include <stdexcept>
#include "renderer.h"
#include "game_state.h"
#include "pos.h"

extern GLFWwindow *window;

namespace CH {
  void set_gl_color(color c) {
    switch (c) {
    case RED:
      glColor4f(1, 0, 0, 1);
      break;
    case YELLOW:
      glColor4f(1, 1, 0, 1);
      break;
    case GREEN:
      glColor4f(0, 1, 0, 1);
      break;
    case BLUE:
      glColor4f(0, 0, 1, 1);
      break;
    case WALL:
      glColor4f(0, 0, 0, 1);
      break;
    }
  }

  void draw_game_object(const game_object &go) {
    set_gl_color(go.get_color());

    glPushMatrix();
    glTranslatef(go.get_position().x, go.get_position().y, 0.f);

    glBegin(GL_QUADS);

    glVertex3f(0.0f, 0.0f, -1.0f);
    glVertex3f(0.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 0.0f, -1.0f);

    glEnd();

    glPopMatrix();

  }

  void renderer::render(const game_state gs) {
    float w = static_cast<float>(gs.width), 
      h = static_cast<float>(gs.height);
    float ratio = 1.0f / (480.0f / 640.0f);

    glClear(GL_COLOR_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-ratio, ratio, -1, 1, 0.01, 4096.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    // Set up camera
    glScalef(1.f, -1.f, 1.f);
    glScalef(1.8f/w, 1.8f/h, 1.f);
    glTranslatef(-w/2.0f, -h/2.0f, 0.0f);
    glTranslatef(0.0f, 0.0f, -1.0f);

    // Draw the walls
    set_gl_color(WALL);
    glBegin(GL_LINE_LOOP);

    glVertex3f(0.0f, 0.0f, 0.0f);
    glVertex3f(0.0f, h, 0.0f);
    glVertex3f(w, h, 0.0f);
    glVertex3f(w, 0.0f, 0.0f);

    glEnd();
    
    // Draw the game objects
    for (auto& pos_to_tail: gs.tails) {
      draw_game_object(pos_to_tail.second);
    }

    for (auto& player: gs.players) {
      draw_game_object(player);
    }

    glfwSwapBuffers(window);
  }
}