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/****************************************************************************
* apps/graphics/traveler/include/trv_raycast.h
* This is the header file associated with trv_raycast.c
*
* 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.
*
****************************************************************************/
#ifndef __APPS_GRAPHICS_TRAVELER_INCLUDE_TRV_RAYCAST_H
#define __APPS_GRAPHICS_TRAVELER_INCLUDE_TRV_RAYCAST_H
/****************************************************************************
* Included Files
****************************************************************************/
#include "trv_types.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* The following definitions define the world view window in terms of the
* 320x200 display coordinates.
*/
#define WINDOW_LEFT 0 /* Offset (in bytes) to the left side
* of the world window */
#define WINDOW_WIDTH 320 /* Width of the world window */
#define WINDOW_TOP 0 /* Offset (in multiples of TRV_SCREEN_WIDTH)
* to the top of world window */
#define WINDOW_HEIGHT 200 /* height of the world window */
#define WINDOW_MIDDLE 100 /* Center or horizon of the world window */
/* This calculation tends to overflow unless it is cast carefully */
#define WINDOW_SIZE (((int32_t)WINDOW_WIDTH)*((int32_t)WINDOW_HEIGHT))
/* This is the biggest distance that can be represented with int16_t */
#define TRV_INFINITY 0x7fff
/* The actual size of the image will be determined by the
* both the WINDOW size as well as the GULP size
*/
#define NUMBER_HGULPS (WINDOW_WIDTH/HGULP_SIZE)
#define IMAGE_WIDTH (HGULP_SIZE*NUMBER_HGULPS)
#define IMAGE_LEFT (((WINDOW_WIDTH-IMAGE_WIDTH) >> 1) + WINDOW_LEFT)
#define IMAGE_HEIGHT WINDOW_HEIGHT
#define IMAGE_TOP WINDOW_TOP
/* This defines the number of pixels (in each direction) with will be
* processed on each pass through the innermost ray casting loop
*/
#define HGULP_SIZE 7
#define VGULP_SIZE 16
/* The following define the various meanings of hit.type */
#define NO_HIT 0x00
#define FRONT_HIT 0x00
#define BACK_HIT 0x01
#define FB_MASK 0x01
#define X_HIT 0x00
#define Y_HIT 0x02
#define Z_HIT 0x04
#define XYZ_MASK 0x06
#define IS_FRONT_HIT(h) (((h)->type & FB_MASK) == FRONT_HIT)
#define IS_BACK_HIT(h) (((h)->type & FB_MASK) == BACK_HIT)
#define IS_XRAY_HIT(h) (((h)->type & XYZ_MASK) == X_HIT)
#define IS_YRAY_HIT(h) (((h)->type & XYZ_MASK) == Y_HIT)
#define IS_ZRAY_HIT(h) (((h)->type & XYZ_MASK) == Z_HIT)
#define MK_HIT_TYPE(fb,xyz) ((fb)|(xyz))
/****************************************************************************
* Public Types
****************************************************************************/
/* This structure provides the return values for each ray caster. For
* performance reasons, the size of this structure should be an even
* power of two (makes index calculation faster).
*/
struct trv_rect_data_s;
struct trv_raycast_s
{
/* 'rect' points to the rectangle that was hit (if any) */
FAR struct trv_rect_data_s *rect;
uint8_t type; /* Type of hit: X/Y/Z cast, front/back */
uint8_t unused2; /* Padding to force power of two size */
int16_t xpos; /* Horizontal position on surface of the hit */
int16_t ypos; /* Vertical position on surface of the hit */
int16_t xdist; /* X distance to the hit */
int16_t ydist; /* Y distance to the hit */
int16_t zdist; /* Z distance to the hit (not used) */
};
/****************************************************************************
* Public Data
****************************************************************************/
/* This structure holds pre-calculated pitch data for all ray casts. NOTE:
* would be a performance improvement if this structure is an even power of
*two in size (don't have to multiply to calculate indices)
*/
/* The following array describes the hits from X/Y/Z-ray casting for the
* current HGULP_SIZE x VGULP_SIZE cell
*/
extern struct trv_raycast_s g_ray_hit[VGULP_SIZE][HGULP_SIZE+1];
/* This structure points to the double buffer row corresponding to the
* pitch angle
*/
extern uint8_t *g_buffer_row[VGULP_SIZE];
/* The is the "column" offset in g_buffer_row for the current cell being
* operated on. This value is updated in a loop by trv_raycaster.
*/
extern int16_t g_cell_column;
/* This structure holds the parameters used in the current ray cast */
extern struct trv_camera_s g_camera;
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#endif /* __APPS_GRAPHICS_TRAVELER_INCLUDE_TRV_RAYCAST_H */
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