geekosphere/camera.c at master · plutonull/geekosphere · GitHub

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/*
 * Final project, CMPS 160, Fall 1999
 * Ben Gertzfield <ben@cse.ucsc.edu>
 *
 * This program is released under the GNU GPL, version 2 or later.
 */

/* Main routines */

#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <gtk/gtk.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glx.h>
#include <pthread.h>

#include <stdlib.h>
#include <stdio.h>
#include "prog.h"

struct camera *gkos_first_camera;
struct camera *gkos_cur_camera;

static unsigned long cam_id = 0;

/*
 * Create a new camera and add it to the camera list.
 */

struct camera *gkos_new_camera(void)
{
    struct camera *camera, *temp;

    camera = (struct camera *) malloc(sizeof(struct camera));

    if (camera == NULL) {	/* malloc failed :( */
	fprintf(stderr, "Cannot allocate memory for light %li, exiting\n",
		cam_id);
	exit(1);
    }

    camera->id = cam_id++;

    camera->rot_angle.x = camera->rot_angle.y = camera->rot_angle.z =
	camera->zoom = 0.0;

    camera->fovy = 45.0;
    camera->near_clip = 1.0;
    camera->far_clip = 30.0;

    camera->prev = camera->next = NULL;

    gkos_cur_camera = camera;

    if (gkos_first_camera == NULL) {
	gkos_first_camera = camera;
	return camera;
    }

    temp = gkos_first_camera;

    while (temp->next != NULL)
	temp = temp->next;

    temp->next = camera;
    camera->prev = temp;

    return camera;
}

void gkos_pop_camera(void)
{
    struct camera *first, *next;

    if (gkos_first_camera == NULL)
	return;

    first = gkos_first_camera;
    next = gkos_first_camera->next;

    if (gkos_cur_camera == first)
	gkos_cur_camera = next;

    free(first);

    gkos_first_camera = next;
}

/*
 * Rotate the given camera about dx, dy, and dz.
 */

void gkos_rotate_camera(struct camera *camera, int x0, int y0, int z0,
			int x, int y, int z)
{
    int dx, dy, dz;

    dx = x0 - x;
    dy = y0 - y;
    dz = z0 - z;

    camera->rot_angle.x -= dx;
    camera->rot_angle.y += dy;
    camera->rot_angle.z -= dz;

    if (camera->rot_angle.x > 360.0)
	camera->rot_angle.x -= 360.0;
    if (camera->rot_angle.x < 0.0)
	camera->rot_angle.x += 360.0;

    if (camera->rot_angle.y > 360.0)
	camera->rot_angle.y -= 360.0;
    if (camera->rot_angle.y < 0.0)
	camera->rot_angle.y += 360.0;

    if (camera->rot_angle.z > 360.0)
	camera->rot_angle.z -= 360.0;
    if (camera->rot_angle.z < 0.0)
	camera->rot_angle.z += 360.0;
}

/*
 * Zoom the camera in. We munge dz to be divided by 5, this is
 * totally arbitrary.
 */

void gkos_zoom_camera(struct camera *camera, int z0, int z)
{
    camera->zoom += (GLfloat) (z0 - z) / 5.0;
}

void gkos_setup_projection(struct camera *camera)
{
    if (camera == NULL) {
	fprintf(stderr, "setup_projection(): camera is null!\n");
	return;
    }

    glMatrixMode(GL_PROJECTION); /* Modify the projection matrix */
    glLoadIdentity();		/* Initialize to the identity matrix */

    gluPerspective(camera->fovy, gkos_winw / gkos_winh,
		   camera->near_clip, camera->far_clip);

				/* Set our camera up */
    gluLookAt(0.0, 0.0, 20.0, 0.0, 0.0, -100.0,
	      0.0, 1.0, 0.0);

				/* Move to where the current camera is */
    glTranslatef(0.0, 0.0, -camera->zoom);

				/* Rotate as the current camera is rotated */
    glRotatef(camera->rot_angle.x, 1.0, 0.0, 0.0);
    glRotatef(camera->rot_angle.y, 0.0, 1.0, 0.0);
    glRotatef(camera->rot_angle.z, 0.0, 0.0, 1.0);

    glMatrixMode(GL_MODELVIEW);
}

// Local variables:
// c-file-style:"cc-mode"
// End: