D言語でGLFW使って逆方向に回る２つの三角形を描画させてみた : $ dmd two_triangles.d lib/libDerelictGL3.a lib/libDerelictUtil.a lib/libDerelictGLFW3.a -L/usr/lib/libdl.so

two_triangles.d

import derelict.opengl3.gl,
       derelict.opengl3.gl3,
       derelict.glfw3.glfw3;

class TestGl{
  static int width  = 800;
  static int height = 600;
  static GLFWwindow* window;
  static const float Pi = 3.1415926535897932384626433832795;
  
  this(){
    DerelictGL.load();
    DerelictGL3.load();
    DerelictGLFW3.load();
    
    if (!glfwInit())
      throw new Error("GLFW Initialize failed.");
    window = glfwCreateWindow(width, height, "GLFW3 and OpenGL Test", null, null); 
    if (!window){
      glfwTerminate();
      throw new Error("Falied to Create GLFW Window.");
    }
    
    glfwMakeContextCurrent(window); 
  }


  void drawInit(){
    float ratio;
    glfwGetFramebufferSize(window, &width, &height);
    ratio = width / cast(float)height;

    glViewport(0,0, width, height);
    glClear(GL_COLOR_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-ratio, ratio, -1.0f, 1.0f, 1.0f, -1.0f);
    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();
  }

  void turnLeft(){
    glRotatef(cast(float)glfwGetTime() * 100.0f, 0.0f, 0.0f, 1.0f);
  }
  // -X = 2X
  void turnRight(){
    glRotatef(cast(float)glfwGetTime() * -400.0f, 0.0f, 0.0f, 1.0f);
  }

  void drawTriangleRight(){
    glBegin(GL_TRIANGLES);
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex3f(-0.6f, -0.4f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex3f(0.6f, -0.4f, 0.0f);
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex3f(0.0f, 0.6f, 0.0f);
    glEnd();
  }

  void drawTriangleLeft(){     
      import std.math;
      glBegin(GL_POLYGON);
      const int n = 3;
      //n is number of sides 
      for(int i=0 ; i<n ; i++){
        auto mycos = cos(i*2*Pi/n);
        auto mysin = sin(i*2*Pi/n);
        glColor3f(1.0 , 0.5 , 0.0);
        glVertex2f(mycos, mysin);
      }
      glEnd();
  }
  void mainLoop(){
    while(!checkEndKey(window)){
      drawInit();
      turnLeft();
      drawTriangleLeft();
      turnRight();
      drawTriangleRight();

      glfwSwapBuffers(window);
      glfwPollEvents();
    }

    glfwDestroyWindow(window);
    glfwTerminate();
    return;
  }

  bool checkEndKey(GLFWwindow* window){
    int keyArray[] = [GLFW_KEY_ESCAPE];
    foreach(k; keyArray){
      if(glfwGetKey(window, k) == GLFW_PRESS)
        return true;
    }
    return false;
  }
}

void main(){
  TestGl tl = new TestGl();

  with(tl){
    mainLoop();
  }
}