#include "Scene.h"

// Scene constructor, initilises OpenGL
// You should add further variables to need initilised.
Scene::Scene(Input *in)
{
    // Store pointer for input class
    input = in;

    //OpenGL settings
    glShadeModel(GL_SMOOTH);                            // Enable Smooth Shading
    glClearColor(0.39f, 0.58f, 93.0f, 1.0f);            // Cornflour Blue Background
    glClearDepth(1.0f);                                 // Depth Buffer Setup
    glClearStencil(0);                                  // Clear stencil buffer
    glEnable(GL_DEPTH_TEST);                            // Enables Depth Testing
    glDepthFunc(GL_LEQUAL);                             // The Type Of Depth Testing To Do
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);  // Really Nice Perspective Calculations
    glLightModelf(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);

    // Other OpenGL / render setting should be applied here.
    glPolygonMode(GL_FRONT, GL_LINE);

    // Initialise scene variables

}

void Scene::handleInput(float dt)
{
    // Handle user input
}

void Scene::update(float dt)
{
    // update scene related variables.

    // Calculate FPS for output
    calculateFPS();
}

void Scene::render() {

    // Clear Color and Depth Buffers
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );


    // Reset transformations
    glLoadIdentity();
    // Set the camera
    gluLookAt(0.0f, 0.0f, 6.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);

    // Render geometry/scene here -------------------------------------
    glBegin(GL_TRIANGLE_STRIP);



    glColor3f(1, 0, 0);
    glVertex3f(2, 0, 0);
    glColor3f(0, 1, 0);
    glVertex3f(2, -1, 0);
    glColor3f(0, 0, 1);
    glVertex3f(1, -1, 0);


    glEnd();

    // End render geometry --------------------------------------

    // Render text, should be last object rendered.
    renderTextOutput();

    // Swap buffers, after all objects are rendered.
    glutSwapBuffers();
}

// Handles the resize of the window. If the window changes size the perspective matrix requires re-calculation to match new window size.
void Scene::resize(int w, int h)
{
    width = w;
    height = h;
    // Prevent a divide by zero, when window is too short
    // (you cant make a window of zero width).
    if (h == 0)
        h = 1;

    float ratio = (float)w / (float)h;
    fov = 45.0f;
    nearPlane = 0.1f;
    farPlane = 100.0f;

    // Use the Projection Matrix
    glMatrixMode(GL_PROJECTION);

    // Reset Matrix
    glLoadIdentity();

    // Set the viewport to be the entire window
    glViewport(0, 0, w, h);

    // Set the correct perspective.
    gluPerspective(fov, ratio, nearPlane, farPlane);

    // Get Back to the Modelview
    glMatrixMode(GL_MODELVIEW);


}

// Calculates FPS
void Scene::calculateFPS()
{

    frame++;
    time = glutGet(GLUT_ELAPSED_TIME);

    if (time - timebase > 1000) {
        sprintf_s(fps, "FPS: %4.2f", frame*1000.0 / (time - timebase));
        timebase = time;
        frame = 0;
    }
}

// Compiles standard output text including FPS and current mouse position.
void Scene::renderTextOutput()
{
    // Render current mouse position and frames per second.
    sprintf_s(mouseText, "Mouse: %i, %i", input->getMouseX(), input->getMouseY());
    displayText(-1.f, 0.96f, 1.f, 0.f, 0.f, mouseText);
    displayText(-1.f, 0.90f, 1.f, 0.f, 0.f, fps);
}

// Renders text to screen. Must be called last in render function (before swap buffers)
void Scene::displayText(float x, float y, float r, float g, float b, char* string) {
    // Get Lenth of string
    int j = strlen(string);

    // Swap to 2D rendering
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1.0, 1.0, -1.0, 1.0, 5, 100);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    // Orthographic lookAt (along the z-axis).
    gluLookAt(0.0f, 0.0f, 10.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);

    // Set text colour and position.
    glColor3f(r, g, b);
    glRasterPos2f(x, y);
    // Render text.
    for (int i = 0; i < j; i++) {
        glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, string[i]);
    }
    // Reset colour to white.
    glColor3f(1.f, 1.f, 1.f);

    // Swap back to 3D rendering.
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(fov, ((float)width/(float)height), nearPlane, farPlane);
    glMatrixMode(GL_MODELVIEW);
}