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


GLenum doubleBuffer;
GLint windW = 300, windH = 300;

RGBImageRec *image = NULL;
float point[3];
float zoom;
GLint x, y;


static void Init(void)
{

    glClearColor(0.0, 0.0, 0.0, 0.0);

    x = 0;
    y = windH;
    zoom = 1.8;
}

static void Reshape(int width, int height)
{

    windW = width;
    windH = height;

    glViewport(0, 0, windW, windH);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, windW, 0, windH);
    glMatrixMode(GL_MODELVIEW);
}

static void Key(unsigned char key, int x, int y)
{

    switch (key) {
      case 27:
        exit(0);
    }
}

static void SpecialKey(int key, int x, int y)
{

    switch (key) {
      case GLUT_KEY_UP:
	zoom += 0.2;
	glutPostRedisplay();
	break;
      case GLUT_KEY_DOWN:
	zoom -= 0.2;
	if (zoom < 0.2) {
	    zoom = 0.2;
	}
	glutPostRedisplay();
	break;
    }
}

static void Mouse(int button, int state, int mouseX, int mouseY)
{

    if (state == GLUT_DOWN) {
	x = mouseX;
	y = mouseY;
	glutPostRedisplay();
    }
}

static void Draw(void)
{

    glClear(GL_COLOR_BUFFER_BIT);

    point[0] = (windW / 2) - (image->sizeX / 2);
    point[1] = (windH / 2) - (image->sizeY / 2);
    point[2] = 0;
    glRasterPos3fv(point);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glPixelZoom(1.0, 1.0);
    glDrawPixels(image->sizeX, image->sizeY, GL_RGB, GL_UNSIGNED_BYTE,
		 image->data);

    point[0] = (float)x;
    point[1] = windH - (float)y;
    point[2] = 0.0;
    glRasterPos3fv(point);

    glPixelZoom(zoom, zoom);
    glCopyPixels((windW/2)-(image->sizeX/2), (windH/2)-(image->sizeY/2),
		 image->sizeX, image->sizeY, GL_COLOR);

    if (doubleBuffer) {
	glutSwapBuffers();
    } else {
	glFlush();
    }
}

static void Args(int argc, char **argv)
{
    GLint i;

    doubleBuffer = GL_FALSE;

    for (i = 1; i < argc; i++) {
	if (strcmp(argv[i], "-sb") == 0) {
	    doubleBuffer = GL_FALSE;
	} else if (strcmp(argv[i], "-db") == 0) {
	    doubleBuffer = GL_TRUE;
	} else if (strcmp(argv[i], "-f") == 0) {
	    if (i+1 >= argc || argv[i+1][0] == '-') {
		printf("-f (No file name).\n");
		exit(1);
	    } else {
		image = rgbImageLoad(argv[++i]);
		if (image == NULL) {
		    printf("-f (bad file name).\n");
		    exit(1);
		}
	    }
	}
    }
}

int main(int argc, char **argv)
{
    GLenum type;

    glutInit(&argc, argv);
    Args(argc, argv);

    if (image == NULL) {
	printf("No texture file.\n");
	exit(1);
    }

    type = GLUT_RGB;
    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
    glutInitDisplayMode(type);
    glutInitWindowSize(windW, windH);
    glutCreateWindow("Copy Test");

    Init();

    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutSpecialFunc(SpecialKey);
    glutMouseFunc(Mouse);
    glutDisplayFunc(Draw);
    glutMainLoop();
}