#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glut.h>

#define PIXEL_CENTER(x) ((long)(x) + 0.5)

#define GAP 10
#define ROWS 3
#define COLS 4

#define OPENGL_WIDTH 48
#define OPENGL_HEIGHT 13


GLenum rgb, doubleBuffer, windType;
GLint windW, windH;

GLint boxW, boxH;
float color[3];


// Function called when window is resized.
static void Reshape(int width, int height)
{

    windW = (GLint)width;
    windH = (GLint)height;
}

// Function to catch keyboard input
static void Key(unsigned char key, int x, int y)
{

    switch (key) {
      case 27:
	exit(1);
       default:
	return;
    }

    glutPostRedisplay();
}

// Function draws a series of points to the screen
static void Point(void)
{
    GLint i;

    glBegin(GL_POINTS);
	glColor3f(1.0,0.0,0.0);
	glVertex2i(0, 0);
	//for (i = 1; i < windH/2; i++) {
	for (i = 0; i < windH; i++) {
	    glVertex2i(i,i);
	    glVertex2i(i, windH/2);
	    glVertex2i(600-i, i);
	    glVertex2i(windW/2, i);
	}
    glEnd();
}

// Function draws a square to the screen
static void PointBox(GLint xstart, GLint xend, GLint ystart, GLint yend,
                     float* color)
{
    GLint i,j;

    glBegin(GL_POINTS);
	glColor3f(color[0], color[1], color[2]);
	for (i = xstart; i <= xend; i++) {
	  for (j = ystart; j <= yend; j++) {
	    glVertex2i(i,j);
	  }
	}
    glEnd();
}

// Draw function is called to redraw the screen.  This function
// calls Point and PointBox to draw boxes of various colors, sizes, and locations.
static void Draw(void)
{
    // Create viewpoint specifications.
    glViewport(0, 0, windW, windH);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0f, windH, 0.0f, windH, 0.0, 1.0);

    // Clear background color to black
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Call drawing functions
    Point();
    color[0] = 1.0; color[1] = 1.0; color[2] = 1.0;
    PointBox(windW/2,windW/2 + 16, windH/2, windH/2 + 16, color);

    color[0] = 1.0; color[1] = 0.0; color[2] = 0.0;
    PointBox(0,30, 0,30, color);

    color[0] = 0.0; color[1] = 1.0; color[2] = 0.0;
    PointBox(0,30, 600 - 30, 600, color);

    color[0] = 0.0; color[1] = 0.0; color[2] = 1.0;
    PointBox(600 - 30, 600, 0, 30, color);

    color[0] = 1.0; color[1] = 1.0; color[2] = 0.0;
    PointBox(600-30, 600, 600-30, 600, color);

    glFlush();

    if (doubleBuffer) {
	glutSwapBuffers();
    }
}

// Function handles input arguments.  Add handling of your input arguments here.
static GLenum Args(int argc, char **argv)
{
    GLint i;

    rgb = GL_TRUE;
    doubleBuffer = GL_FALSE;

    for (i = 1; i < argc; i++) {
	if (strcmp(argv[i], "-ci") == 0) {
	    rgb = GL_FALSE;
	} else if (strcmp(argv[i], "-rgb") == 0) {
	    rgb = GL_TRUE;
	} else if (strcmp(argv[i], "-sb") == 0) {
	    doubleBuffer = GL_FALSE;
	} else if (strcmp(argv[i], "-db") == 0) {
	    doubleBuffer = GL_TRUE;
	} else {
	    printf("%s (Bad option).\n", argv[i]);
	    return GL_FALSE;
	}
    }
    return GL_TRUE;
}

// Main function.
int main(int argc, char **argv)
{
    glutInit(&argc, argv);

    if (Args(argc, argv) == GL_FALSE) {
	exit(1);
    }

    // Initialize OpenGL window.
    windW = 600;
    windH = 600;
    glutInitWindowPosition(0, 0); glutInitWindowSize( windW, windH);

    windType = (rgb) ? GLUT_RGB : GLUT_INDEX;
    windType |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
    glutInitDisplayMode(windType);

    if (glutCreateWindow("Primitive Test") == GL_FALSE) {
	exit(1);
    }

    // Set functions to be called when window is resized (Reshape),
    // for keyboard input (Key), and for drawing (Draw).
    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutDisplayFunc(Draw);
    glutMainLoop();
	return 0;
}