/****************************************************************************
* apps/graphics/traveler/trv_pov.c
* This file contains the logic which manages player's point-of-view (POV)
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include "trv_types.h"
#include "trv_input.h"
#include "trv_trigtbl.h"
#include "trv_rayavoid.h"
#include "trv_pov.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/* This structure defines the current camera position of the player's eyes */
struct trv_camera_s g_player;
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: trv_new_viewangle
* Description:
* This function determines the new POV to use on this cycle
****************************************************************************/
static void trv_new_viewangle(void)
{
/* Are we turning to the left or right (yaw)? */
if (g_trv_input.yawrate != 0)
{
/* Determine the amount to rotate on this cycle */
g_player.yaw += g_trv_input.yawrate;
/* Make sure that yaw is still within range */
if (g_player.yaw >= ANGLE_360)
{
g_player.yaw -= ANGLE_360;
}
else if (g_player.yaw < ANGLE_0)
{
g_player.yaw += ANGLE_360;
}
}
/* Are we "nodding" up or down (pitch) */
if (g_trv_input.pitchrate != 0)
{
g_player.pitch += g_trv_input.pitchrate;
/* Make sure that pitch is still within range */
if (g_player.pitch >= ANGLE_360)
{
g_player.pitch -= ANGLE_360;
}
else if (g_player.pitch < ANGLE_0)
{
g_player.pitch += ANGLE_360;
}
/* Don't let the player look up more than thirty degrees */
if (g_player.pitch > ANGLE_30 &&
g_player.pitch < ANGLE_180)
{
g_player.pitch = ANGLE_30;
}
/* Don't let the player look down more than thirty degrees */
else if (g_player.pitch < (ANGLE_360 - ANGLE_30) &&
g_player.pitch > ANGLE_180)
{
g_player.pitch = (ANGLE_360 - ANGLE_30);
}
}
}
/****************************************************************************
* Name: trv_new_playerposition
*
* Description:
* This function determines the new POV to use on this cycle
*
****************************************************************************/
static void trv_new_playerposition(void)
{
int16_t move_angle;
int16_t left_angle;
trv_coord_t fwd_distance;
trv_coord_t left_distance;
trv_coord_t move_distance;
/* Assume that we are moving forward */
move_angle = g_player.yaw;
left_angle = ANGLE_90;
fwd_distance = g_trv_input.fwdrate;
left_distance = g_trv_input.leftrate;
/* Are we are moving "backward" */
if (fwd_distance < 0)
{
/* Yes.. switch to moving backward at 180 degrees. Moving left now
* becomes moving right.
*/
fwd_distance = -fwd_distance;
left_distance = -left_distance;
move_angle += ANGLE_180;
if (move_angle >= ANGLE_360)
{
move_angle -= (int16_t)ANGLE_360;
}
/* If we also doing horizontal movement, it the angle should actually
* be based on the relative magnitude forward and lateral movement
* distance. But we will just use 45 degrees which should be good
* enough for out purposes.
*/
left_angle = ANGLE_45;
}
/* Are we moving left or right? */
if (left_distance > 0)
{
move_angle = g_player.yaw - left_angle;
}
else if (left_distance < 0)
{
left_distance = -left_distance;
move_angle = g_player.yaw + left_angle;
}
if (move_angle < ANGLE_0)
{
move_angle += (int16_t)ANGLE_360;
}
else if (move_angle >= ANGLE_360)
{
move_angle -= (int16_t)ANGLE_360;
}
/* The move distance is approximated as follows */
if (left_distance > fwd_distance)
{
move_distance = left_distance + (fwd_distance >> 1);
}
else
{
move_distance = fwd_distance + (left_distance >> 1);
}
/* Decompose the desired move distance into X and Y components
* and clip these components to avoid collisions with walls and objects
*/
g_player.x +=
trv_rayclip_player_xmotion(&g_player, move_distance,
move_angle, g_trv_input.stepheight);
g_player.y +=
trv_rayclip_player_ymotion(&g_player, move_distance,
move_angle, g_trv_input.stepheight);
/* Adjust the player's vertical position (he may have fallen down or
* stepped up something.
*/
g_player.z += trv_ray_adjust_zpos(&g_player, g_player_height);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: trv_pov_reset
*
* Description:
* This function returns the player to the starting position
*
****************************************************************************/
void trv_pov_reset(void)
{
g_player = g_initial_camera;
}
/****************************************************************************
* Name: trv_pov_new
*
* Description:
* This function determines the new POV to use on this cycle based on the
* current inputs
****************************************************************************/
void trv_pov_new(void)
{
/* Get angular changes first */
trv_new_viewangle();
/* The get the player motion along the new angles */
trv_new_playerposition();
}
