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anarch/raycastlib.h

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#ifndef RAYCASTLIB_H
#define RAYCASTLIB_H
/**
raycastlib (RCL) - Small C header-only raycasting library for embedded and
low performance computers, such as Arduino. Only uses integer math and stdint
standard library.
Check the defines below to fine-tune accuracy vs performance! Don't forget
to compile with optimizations.
Before including the library define RCL_PIXEL_FUNCTION to the name of the
function (with RCL_PixelFunction signature) that will render your pixels!
- All public (and most private) library identifiers start with RCL_.
- Game field's bottom left corner is at [0,0].
- X axis goes right in the ground plane.
- Y axis goes up in the ground plane.
- Height means the Z (vertical) coordinate.
- Each game square is RCL_UNITS_PER_SQUARE * RCL_UNITS_PER_SQUARE points.
- Angles are in RCL_Units, 0 means pointing right (x+) and positively rotates
clockwise. A full angle has RCL_UNITS_PER_SQUARE RCL_Units.
- Most things are normalized with RCL_UNITS_PER_SQUARE (sin, cos, vector
unit length, texture coordinates etc.).
- Screen coordinates are normal: [0,0] = top left, x goes right, y goes down.
author: Miloslav "drummyfish" Ciz
license: CC0 1.0
version: 0.908
*/
#include <stdint.h>
#ifndef RCL_RAYCAST_TINY /** Turns on super efficient version of this library.
Only use if neccesarry, looks ugly. Also not done
yet. */
#define RCL_UNITS_PER_SQUARE 1024 /**< Number of RCL_Units in a side of a
spatial square. */
typedef int32_t RCL_Unit; /**< Smallest spatial unit, there is
RCL_UNITS_PER_SQUARE units in a square's
length. This effectively serves the purpose of
a fixed-point arithmetic. */
#define RCL_INFINITY 2000000000
#else
#define RCL_UNITS_PER_SQUARE 32
typedef int16_t RCL_Unit;
#define RCL_INFINITY 30000
#define RCL_USE_DIST_APPROX 2
#endif
#ifndef RCL_COMPUTE_WALL_TEXCOORDS
#define RCL_COMPUTE_WALL_TEXCOORDS 1
#endif
#ifndef RCL_COMPUTE_FLOOR_TEXCOORDS
#define RCL_COMPUTE_FLOOR_TEXCOORDS 0
#endif
#ifndef RCL_FLOOR_TEXCOORDS_HEIGHT
#define RCL_FLOOR_TEXCOORDS_HEIGHT 0 /** If RCL_COMPUTE_FLOOR_TEXCOORDS == 1,
this says for what height level the
texture coords will be computed for
(for simplicity/performance only one
level is allowed). */
#endif
#ifndef RCL_USE_COS_LUT
#define RCL_USE_COS_LUT 0 /**< type of look up table for cos function:
0: none (compute)
1: 64 items
2: 128 items */
#endif
#ifndef RCL_USE_DIST_APPROX
#define RCL_USE_DIST_APPROX 0 /**< What distance approximation to use:
0: none (compute full Euclidean distance)
1: accurate approximation
2: octagonal approximation (LQ) */
#endif
#ifndef RCL_RECTILINEAR
#define RCL_RECTILINEAR 1 /**< Whether to use rectilinear perspective (normally
used), or curvilinear perspective (fish eye). */
#endif
#ifndef RCL_TEXTURE_VERTICAL_STRETCH
#define RCL_TEXTURE_VERTICAL_STRETCH 1 /**< Whether textures should be
stretched to wall height (possibly
slightly slower if on). */
#endif
#ifndef RCL_COMPUTE_FLOOR_DEPTH
#define RCL_COMPUTE_FLOOR_DEPTH 1 /**< Whether depth should be computed for
floor pixels - turns this off if not
needed. */
#endif
#ifndef RCL_COMPUTE_CEILING_DEPTH
#define RCL_COMPUTE_CEILING_DEPTH 1 /**< As RCL_COMPUTE_FLOOR_DEPTH but for
ceiling. */
#endif
#ifndef RCL_ROLL_TEXTURE_COORDS
#define RCL_ROLL_TEXTURE_COORDS 1 /**< Says whether rolling doors should also
roll the texture coordinates along (mostly
desired for doors). */
#endif
#ifndef RCL_VERTICAL_FOV
#define RCL_VERTICAL_FOV (RCL_UNITS_PER_SQUARE / 5)
#endif
#define RCL_VERTICAL_FOV_TAN (RCL_VERTICAL_FOV * 4) ///< tan approximation
#ifndef RCL_HORIZONTAL_FOV
#define RCL_HORIZONTAL_FOV (RCL_UNITS_PER_SQUARE / 4)
#endif
#define RCL_HORIZONTAL_FOV_TAN (RCL_VERTICAL_FOV * 4)
#define RCL_HORIZONTAL_FOV_HALF (RCL_HORIZONTAL_FOV / 2)
#ifndef RCL_CAMERA_COLL_RADIUS
#define RCL_CAMERA_COLL_RADIUS RCL_UNITS_PER_SQUARE / 4
#endif
#ifndef RCL_CAMERA_COLL_HEIGHT_BELOW
#define RCL_CAMERA_COLL_HEIGHT_BELOW RCL_UNITS_PER_SQUARE
#endif
#ifndef RCL_CAMERA_COLL_HEIGHT_ABOVE
#define RCL_CAMERA_COLL_HEIGHT_ABOVE (RCL_UNITS_PER_SQUARE / 3)
#endif
#ifndef RCL_CAMERA_COLL_STEP_HEIGHT
#define RCL_CAMERA_COLL_STEP_HEIGHT (RCL_UNITS_PER_SQUARE / 2)
#endif
#ifndef RCL_TEXTURE_INTERPOLATION_SCALE
#define RCL_TEXTURE_INTERPOLATION_SCALE 1024 /**< This says scaling of fixed
poit vertical texture coord
computation. This should be power
of two! Higher number can look more
accurate but may cause overflow. */
#endif
#define RCL_HORIZON_DEPTH (11 * RCL_UNITS_PER_SQUARE) /**< What depth the
horizon has (the floor
depth is only
approximated with the
help of this
constant). */
#ifndef RCL_VERTICAL_DEPTH_MULTIPLY
#define RCL_VERTICAL_DEPTH_MULTIPLY 2 /**< Defines a multiplier of height
difference when approximating floor/ceil
depth. */
#endif
#define RCL_min(a,b) ((a) < (b) ? (a) : (b))
#define RCL_max(a,b) ((a) > (b) ? (a) : (b))
#define RCL_nonZero(v) ((v) + ((v) == 0)) ///< To prevent zero divisions.
#define RCL_zeroClamp(x) ((x) * ((x) >= 0))
#define RCL_likely(cond) __builtin_expect(!!(cond),1)
#define RCL_unlikely(cond) __builtin_expect(!!(cond),0)
#define RCL_logV2D(v)\
printf("[%d,%d]\n",v.x,v.y);
#define RCL_logRay(r){\
printf("ray:\n");\
printf(" start: ");\
RCL_logV2D(r.start);\
printf(" dir: ");\
RCL_logV2D(r.direction);}
#define RCL_logHitResult(h){\
printf("hit:\n");\
printf(" square: ");\
RCL_logV2D(h.square);\
printf(" pos: ");\
RCL_logV2D(h.position);\
printf(" dist: %d\n", h.distance);\
printf(" dir: %d\n", h.direction);\
printf(" texcoord: %d\n", h.textureCoord);}
#define RCL_logPixelInfo(p){\
printf("pixel:\n");\
printf(" position: ");\
RCL_logV2D(p.position);\
printf(" texCoord: ");\
RCL_logV2D(p.texCoords);\
printf(" depth: %d\n", p.depth);\
printf(" height: %d\n", p.height);\
printf(" wall: %d\n", p.isWall);\
printf(" hit: ");\
RCL_logHitResult(p.hit);\
}
#define RCL_logCamera(c){\
printf("camera:\n");\
printf(" position: ");\
RCL_logV2D(c.position);\
printf(" height: %d\n",c.height);\
printf(" direction: %d\n",c.direction);\
printf(" shear: %d\n",c.shear);\
printf(" resolution: %d x %d\n",c.resolution.x,c.resolution.y);\
}
/// Position in 2D space.
typedef struct
{
RCL_Unit x;
RCL_Unit y;
} RCL_Vector2D;
typedef struct
{
RCL_Vector2D start;
RCL_Vector2D direction;
} RCL_Ray;
typedef struct
{
RCL_Unit distance; /**< Distance to the hit position, or -1 if no
collision happened. If RCL_RECTILINEAR != 0, then
the distance is perpendicular to the projection
plane (fish eye correction), otherwise it is
the straight distance to the ray start
position. */
uint8_t direction; /**< Direction of hit. The convention for angle
units is explained above. */
RCL_Unit textureCoord; /**< Normalized (0 to RCL_UNITS_PER_SQUARE - 1)
texture coordinate (horizontal). */
RCL_Vector2D square; ///< Collided square coordinates.
RCL_Vector2D position; ///< Exact collision position in RCL_Units.
RCL_Unit arrayValue; /** Value returned by array function (most often
this will be the floor height). */
RCL_Unit type; /**< Integer identifying type of square (number
returned by type function, e.g. texture
index).*/
RCL_Unit doorRoll; ///< Holds value of door roll.
} RCL_HitResult;
typedef struct
{
RCL_Vector2D position;
RCL_Unit direction; // TODO: rename to "angle" to keep consistency
RCL_Vector2D resolution;
int16_t shear; /**< Shear offset in pixels (0 => no shear), can simulate
looking up/down. */
RCL_Unit height;
} RCL_Camera;
/**
Holds an information about a single rendered pixel (for a pixel function
that works as a fragment shader).
*/
typedef struct
{
RCL_Vector2D position; ///< On-screen position.
int8_t isWall; ///< Whether the pixel is a wall or a floor/ceiling.
int8_t isFloor; ///< Whether the pixel is floor or ceiling.
int8_t isHorizon; ///< If the pixel belongs to horizon segment.
RCL_Unit depth; ///< Corrected depth.
RCL_Unit wallHeight;///< Only for wall pixels, says its height.
RCL_Unit height; ///< World height (mostly for floor).
RCL_HitResult hit; ///< Corresponding ray hit.
RCL_Vector2D texCoords; /**< Normalized (0 to RCL_UNITS_PER_SQUARE - 1)
texture coordinates. */
} RCL_PixelInfo;
void RCL_PIXEL_FUNCTION (RCL_PixelInfo *pixel);
typedef struct
{
uint16_t maxHits;
uint16_t maxSteps;
} RCL_RayConstraints;
/**
Function used to retrieve some information about cells of the rendered scene.
It should return a characteristic of given square as an integer (e.g. square
height, texture index, ...) - between squares that return different numbers
there is considered to be a collision.
This function should be as fast as possible as it will typically be called
very often.
*/
typedef RCL_Unit (*RCL_ArrayFunction)(int16_t x, int16_t y);
/*
TODO: maybe array functions should be replaced by defines of funtion names
like with pixelFunc? Could be more efficient than function pointers.
*/
/**
Function that renders a single pixel at the display. It is handed an info
about the pixel it should draw.
This function should be as fast as possible as it will typically be called
very often.
*/
typedef void (*RCL_PixelFunction)(RCL_PixelInfo *info);
typedef void
(*RCL_ColumnFunction)(RCL_HitResult *hits, uint16_t hitCount, uint16_t x,
RCL_Ray ray);
/**
Simple-interface function to cast a single ray.
@return The first collision result.
*/
RCL_HitResult RCL_castRay(RCL_Ray ray, RCL_ArrayFunction arrayFunc);
/**
Casts a 3D ray in 3D environment with floor and optional ceiling
(ceilingHeightFunc can be 0). This can be useful for hitscan shooting,
visibility checking etc.
@return normalized ditance (0 to RCL_UNITS_PER_SQUARE) along the ray at which
the environment was hit, RCL_UNITS_PER_SQUARE means nothing was hit
*/
RCL_Unit RCL_castRay3D(
RCL_Vector2D pos1, RCL_Unit height1, RCL_Vector2D pos2, RCL_Unit height2,
RCL_ArrayFunction floorHeightFunc, RCL_ArrayFunction ceilingHeightFunc,
RCL_RayConstraints constraints);
/**
Maps a single point in the world to the screen (2D position + depth).
*/
RCL_PixelInfo RCL_mapToScreen(RCL_Vector2D worldPosition, RCL_Unit height,
RCL_Camera camera);
/**
Casts a single ray and returns a list of collisions.
@param ray ray to be cast, if RCL_RECTILINEAR != 0 then the computed hit
distance is divided by the ray direction vector length (to correct
the fish eye effect)
@param arrayFunc function that will be used to determine collisions (hits)
with the ray (squares for which this function returns different values
are considered to have a collision between them), this will typically
be a function returning floor height
@param typeFunc optional (can be 0) function - if provided, it will be used
to mark the hit result with the number returned by this function
(it can be e.g. a texture index)
@param hitResults array in which the hit results will be stored (has to be
preallocated with at space for at least as many hit results as
maxHits specified with the constraints parameter)
@param hitResultsLen in this variable the number of hit results will be
returned
@param constraints specifies constraints for the ray cast
*/
void RCL_castRayMultiHit(RCL_Ray ray, RCL_ArrayFunction arrayFunc,
RCL_ArrayFunction typeFunc, RCL_HitResult *hitResults,
uint16_t *hitResultsLen, RCL_RayConstraints constraints);
RCL_Vector2D RCL_angleToDirection(RCL_Unit angle);
/**
Cos function.
@param input to cos in RCL_Units (RCL_UNITS_PER_SQUARE = 2 * pi = 360 degrees)
@return RCL_normalized output in RCL_Units (from -RCL_UNITS_PER_SQUARE to
RCL_UNITS_PER_SQUARE)
*/
RCL_Unit RCL_cos(RCL_Unit input);
RCL_Unit RCL_sin(RCL_Unit input);
RCL_Unit RCL_tan(RCL_Unit input);
RCL_Unit RCL_ctg(RCL_Unit input);
/// Normalizes given vector to have RCL_UNITS_PER_SQUARE length.
RCL_Vector2D RCL_normalize(RCL_Vector2D v);
/// Computes a cos of an angle between two vectors.
RCL_Unit RCL_vectorsAngleCos(RCL_Vector2D v1, RCL_Vector2D v2);
uint16_t RCL_sqrt(RCL_Unit value);
RCL_Unit RCL_dist(RCL_Vector2D p1, RCL_Vector2D p2);
RCL_Unit RCL_len(RCL_Vector2D v);
/**
Converts an angle in whole degrees to an angle in RCL_Units that this library
uses.
*/
RCL_Unit RCL_degreesToUnitsAngle(int16_t degrees);
///< Computes the change in size of an object due to perspective (vertical FOV).
RCL_Unit RCL_perspectiveScaleVertical(RCL_Unit originalSize, RCL_Unit distance);
RCL_Unit RCL_perspectiveScaleVerticalInverse(RCL_Unit originalSize,
RCL_Unit scaledSize);
RCL_Unit
RCL_perspectiveScaleHorizontal(RCL_Unit originalSize, RCL_Unit distance);
RCL_Unit RCL_perspectiveScaleHorizontalInverse(RCL_Unit originalSize,
RCL_Unit scaledSize);
/**
Casts rays for given camera view and for each hit calls a user provided
function.
*/
void RCL_castRaysMultiHit(RCL_Camera cam, RCL_ArrayFunction arrayFunc,
RCL_ArrayFunction typeFunction, RCL_ColumnFunction columnFunc,
RCL_RayConstraints constraints);
/**
Using provided functions, renders a complete complex (multilevel) camera
view.
This function should render each screen pixel exactly once.
function rendering summary:
- performance: slower
- accuracy: higher
- wall textures: yes
- different wall heights: yes
- floor/ceiling textures: no
- floor geometry: yes, multilevel
- ceiling geometry: yes (optional), multilevel
- rolling door: no
- camera shearing: yes
- rendering order: left-to-right, not specifically ordered vertically
@param cam camera whose view to render
@param floorHeightFunc function that returns floor height (in RCL_Units)
@param ceilingHeightFunc same as floorHeightFunc but for ceiling, can also be
0 (no ceiling will be rendered)
@param typeFunction function that says a type of square (e.g. its texture
index), can be 0 (no type in hit result)
@param pixelFunc callback function to draw a single pixel on screen
@param constraints constraints for each cast ray
*/
void RCL_renderComplex(RCL_Camera cam, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction ceilingHeightFunc, RCL_ArrayFunction typeFunction,
RCL_RayConstraints constraints);
/**
Renders given camera view, with help of provided functions. This function is
simpler and faster than RCL_renderComplex(...) and is meant to be rendering
flat levels.
function rendering summary:
- performance: faster
- accuracy: lower
- wall textures: yes
- different wall heights: yes
- floor/ceiling textures: yes (only floor, you can mirror it for ceiling)
- floor geometry: no (just flat floor, with depth information)
- ceiling geometry: no (just flat ceiling, with depth information)
- rolling door: yes
- camera shearing: no
- rendering order: left-to-right, top-to-bottom
Additionally this function supports rendering rolling doors.
This function should render each screen pixel exactly once.
@param rollFunc function that for given square says its door roll in
RCL_Units (0 = no roll, RCL_UNITS_PER_SQUARE = full roll right,
-RCL_UNITS_PER_SQUARE = full roll left), can be zero (no rolling door,
rendering should also be faster as fewer intersections will be tested)
*/
void RCL_renderSimple(RCL_Camera cam, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction typeFunc, RCL_ArrayFunction rollFunc,
RCL_RayConstraints constraints);
/**
Function that moves given camera and makes it collide with walls and
potentially also floor and ceilings. It's meant to help implement player
movement.
@param camera camera to move
@param planeOffset offset to move the camera in
@param heightOffset height offset to move the camera in
@param floorHeightFunc function used to retrieve the floor height
@param ceilingHeightFunc function for retrieving ceiling height, can be 0
(camera won't collide with ceiling)
@param computeHeight whether to compute height - if false (0), floor and
ceiling functions won't be used and the camera will
only collide horizontally with walls (good for simpler
game, also faster)
@param force if true, forces to recompute collision even if position doesn't
change
*/
void RCL_moveCameraWithCollision(RCL_Camera *camera, RCL_Vector2D planeOffset,
RCL_Unit heightOffset, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction ceilingHeightFunc, int8_t computeHeight, int8_t force);
void RCL_initCamera(RCL_Camera *camera);
void RCL_initRayConstraints(RCL_RayConstraints *constraints);
//=============================================================================
// privates
#define _RCL_UNUSED(what) (void)(what);
// global helper variables, for precomputing stuff etc.
RCL_Camera _RCL_camera;
RCL_Unit _RCL_horizontalDepthStep = 0;
RCL_Unit _RCL_startFloorHeight = 0;
RCL_Unit _RCL_startCeil_Height = 0;
RCL_Unit _RCL_camResYLimit = 0;
RCL_Unit _RCL_middleRow = 0;
RCL_ArrayFunction _RCL_floorFunction = 0;
RCL_ArrayFunction _RCL_ceilFunction = 0;
RCL_Unit _RCL_fHorizontalDepthStart = 0;
RCL_Unit _RCL_cHorizontalDepthStart = 0;
int16_t _RCL_cameraHeightScreen = 0;
RCL_ArrayFunction _RCL_rollFunction = 0; // says door rolling
RCL_Unit *_RCL_floorPixelDistances = 0;
RCL_Unit RCL_clamp(RCL_Unit value, RCL_Unit valueMin, RCL_Unit valueMax)
{
if (value >= valueMin)
{
if (value <= valueMax)
return value;
else
return valueMax;
}
else
return valueMin;
}
static inline RCL_Unit RCL_abs(RCL_Unit value)
{
return value * (((value >= 0) << 1) - 1);
}
/// Like mod, but behaves differently for negative values.
static inline RCL_Unit RCL_wrap(RCL_Unit value, RCL_Unit mod)
{
RCL_Unit cmp = value < 0;
return cmp * mod + (value % mod) - cmp;
}
/// Performs division, rounding down, NOT towards zero.
static inline RCL_Unit RCL_divRoundDown(RCL_Unit value, RCL_Unit divisor)
{
return value / divisor - ((value >= 0) ? 0 : 1);
}
// Bhaskara's cosine approximation formula
#define trigHelper(x) (((RCL_Unit) RCL_UNITS_PER_SQUARE) *\
(RCL_UNITS_PER_SQUARE / 2 * RCL_UNITS_PER_SQUARE / 2 - 4 * (x) * (x)) /\
(RCL_UNITS_PER_SQUARE / 2 * RCL_UNITS_PER_SQUARE / 2 + (x) * (x)))
#if RCL_USE_COS_LUT == 1
#ifdef RCL_RAYCAST_TINY
const RCL_Unit cosLUT[64] =
{
16,14,11,6,0,-6,-11,-14,-15,-14,-11,-6,0,6,11,14
};
#else
const RCL_Unit cosLUT[64] =
{
1024,1019,1004,979,946,903,851,791,724,649,568,482,391,297,199,100,0,-100,
-199,-297,-391,-482,-568,-649,-724,-791,-851,-903,-946,-979,-1004,-1019,
-1023,-1019,-1004,-979,-946,-903,-851,-791,-724,-649,-568,-482,-391,-297,
-199,-100,0,100,199,297,391,482,568,649,724,791,851,903,946,979,1004,1019
};
#endif
#elif RCL_USE_COS_LUT == 2
const RCL_Unit cosLUT[128] =
{
1024,1022,1019,1012,1004,993,979,964,946,925,903,878,851,822,791,758,724,
687,649,609,568,526,482,437,391,344,297,248,199,150,100,50,0,-50,-100,-150,
-199,-248,-297,-344,-391,-437,-482,-526,-568,-609,-649,-687,-724,-758,-791,
-822,-851,-878,-903,-925,-946,-964,-979,-993,-1004,-1012,-1019,-1022,-1023,
-1022,-1019,-1012,-1004,-993,-979,-964,-946,-925,-903,-878,-851,-822,-791,
-758,-724,-687,-649,-609,-568,-526,-482,-437,-391,-344,-297,-248,-199,-150,
-100,-50,0,50,100,150,199,248,297,344,391,437,482,526,568,609,649,687,724,
758,791,822,851,878,903,925,946,964,979,993,1004,1012,1019,1022
};
#endif
RCL_Unit RCL_cos(RCL_Unit input)
{
input = RCL_wrap(input,RCL_UNITS_PER_SQUARE);
#if RCL_USE_COS_LUT == 1
#ifdef RCL_RAYCAST_TINY
return cosLUT[input];
#else
return cosLUT[input / 16];
#endif
#elif RCL_USE_COS_LUT == 2
return cosLUT[input / 8];
#else
if (input < RCL_UNITS_PER_SQUARE / 4)
return trigHelper(input);
else if (input < RCL_UNITS_PER_SQUARE / 2)
return -1 * trigHelper(RCL_UNITS_PER_SQUARE / 2 - input);
else if (input < 3 * RCL_UNITS_PER_SQUARE / 4)
return -1 * trigHelper(input - RCL_UNITS_PER_SQUARE / 2);
else
return trigHelper(RCL_UNITS_PER_SQUARE - input);
#endif
}
#undef trigHelper
RCL_Unit RCL_sin(RCL_Unit input)
{
return RCL_cos(input - RCL_UNITS_PER_SQUARE / 4);
}
RCL_Unit RCL_tan(RCL_Unit input)
{
return (RCL_sin(input) * RCL_UNITS_PER_SQUARE) / RCL_cos(input);
}
RCL_Unit RCL_ctg(RCL_Unit input)
{
return (RCL_cos(input) * RCL_UNITS_PER_SQUARE) / RCL_sin(input);
}
RCL_Vector2D RCL_angleToDirection(RCL_Unit angle)
{
RCL_Vector2D result;
result.x = RCL_cos(angle);
result.y = -1 * RCL_sin(angle);
return result;
}
uint16_t RCL_sqrt(RCL_Unit value)
{
#ifdef RCL_RAYCAST_TINY
uint16_t result = 0;
uint16_t a = value;
uint16_t b = 1u << 14;
#else
uint32_t result = 0;
uint32_t a = value;
uint32_t b = 1u << 30;
#endif
while (b > a)
b >>= 2;
while (b != 0)
{
if (a >= result + b)
{
a -= result + b;
result = result + 2 * b;
}
b >>= 2;
result >>= 1;
}
return result;
}
RCL_Unit RCL_dist(RCL_Vector2D p1, RCL_Vector2D p2)
{
RCL_Unit dx = p2.x - p1.x;
RCL_Unit dy = p2.y - p1.y;
#if RCL_USE_DIST_APPROX == 2
// octagonal approximation
dx = RCL_abs(dx);
dy = RCL_abs(dy);
return dy > dx ? dx / 2 + dy : dy / 2 + dx;
#elif RCL_USE_DIST_APPROX == 1
// more accurate approximation
RCL_Unit a, b, result;
dx = ((dx < 0) * 2 - 1) * dx;
dy = ((dy < 0) * 2 - 1) * dy;
if (dx < dy)
{
a = dy;
b = dx;
}
else
{
a = dx;
b = dy;
}
result = a + (44 * b) / 102;
if (a < (b << 4))
result -= (5 * a) / 128;
return result;
#else
dx = dx * dx;
dy = dy * dy;
return RCL_sqrt((RCL_Unit) (dx + dy));
#endif
}
RCL_Unit RCL_len(RCL_Vector2D v)
{
RCL_Vector2D zero;
zero.x = 0;
zero.y = 0;
return RCL_dist(zero,v);
}
static inline int8_t RCL_pointIsLeftOfRay(RCL_Vector2D point, RCL_Ray ray)
{
RCL_Unit dX = point.x - ray.start.x;
RCL_Unit dY = point.y - ray.start.y;
return (ray.direction.x * dY - ray.direction.y * dX) > 0;
// ^ Z component of cross-product
}
void RCL_castRayMultiHit(RCL_Ray ray, RCL_ArrayFunction arrayFunc,
RCL_ArrayFunction typeFunc, RCL_HitResult *hitResults,
uint16_t *hitResultsLen, RCL_RayConstraints constraints)
{
RCL_Vector2D currentPos = ray.start;
RCL_Vector2D currentSquare;
currentSquare.x = RCL_divRoundDown(ray.start.x,RCL_UNITS_PER_SQUARE);
currentSquare.y = RCL_divRoundDown(ray.start.y,RCL_UNITS_PER_SQUARE);
*hitResultsLen = 0;
RCL_Unit squareType = arrayFunc(currentSquare.x,currentSquare.y);
// DDA variables
RCL_Vector2D nextSideDist; // dist. from start to the next side in given axis
RCL_Vector2D delta;
RCL_Vector2D step; // -1 or 1 for each axis
int8_t stepHorizontal = 0; // whether the last step was hor. or vert.
nextSideDist.x = 0;
nextSideDist.y = 0;
RCL_Unit dirVecLengthNorm = RCL_len(ray.direction) * RCL_UNITS_PER_SQUARE;
delta.x = RCL_abs(dirVecLengthNorm / RCL_nonZero(ray.direction.x));
delta.y = RCL_abs(dirVecLengthNorm / RCL_nonZero(ray.direction.y));
// init DDA
if (ray.direction.x < 0)
{
step.x = -1;
nextSideDist.x = (RCL_wrap(ray.start.x,RCL_UNITS_PER_SQUARE) * delta.x) /
RCL_UNITS_PER_SQUARE;
}
else
{
step.x = 1;
nextSideDist.x =
((RCL_wrap(RCL_UNITS_PER_SQUARE - ray.start.x,RCL_UNITS_PER_SQUARE)) *
delta.x) / RCL_UNITS_PER_SQUARE;
}
if (ray.direction.y < 0)
{
step.y = -1;
nextSideDist.y = (RCL_wrap(ray.start.y,RCL_UNITS_PER_SQUARE) * delta.y) /
RCL_UNITS_PER_SQUARE;
}
else
{
step.y = 1;
nextSideDist.y =
((RCL_wrap(RCL_UNITS_PER_SQUARE - ray.start.y,RCL_UNITS_PER_SQUARE)) *
delta.y) / RCL_UNITS_PER_SQUARE;
}
// DDA loop
#define RECIP_SCALE 65536
RCL_Unit rayDirXRecip = RECIP_SCALE / RCL_nonZero(ray.direction.x);
RCL_Unit rayDirYRecip = RECIP_SCALE / RCL_nonZero(ray.direction.y);
// ^ we precompute reciprocals to avoid divisions in the loop
for (uint16_t i = 0; i < constraints.maxSteps; ++i)
{
RCL_Unit currentType = arrayFunc(currentSquare.x,currentSquare.y);
if (RCL_unlikely(currentType != squareType))
{
// collision
RCL_HitResult h;
h.arrayValue = currentType;
h.doorRoll = 0;
h.position = currentPos;
h.square = currentSquare;
if (stepHorizontal)
{
h.position.x = currentSquare.x * RCL_UNITS_PER_SQUARE;
h.direction = 3;
if (step.x == -1)
{
h.direction = 1;
h.position.x += RCL_UNITS_PER_SQUARE;
}
RCL_Unit diff = h.position.x - ray.start.x;
h.position.y = // avoid division by multiplying with reciprocal
ray.start.y + (ray.direction.y * diff * rayDirXRecip) / RECIP_SCALE;
#if RCL_RECTILINEAR
/* Here we compute the fish eye corrected distance (perpendicular to
the projection plane) as the Euclidean distance (of hit from camera
position) divided by the length of the ray direction vector. This can
be computed without actually computing Euclidean distances as a
hypothenuse A (distance) divided by hypothenuse B (length) is equal to
leg A (distance along principal axis) divided by leg B (length along
the same principal axis). */
#define CORRECT(dir1,dir2)\
RCL_Unit tmp = diff / 4; /* 4 to prevent overflow */ \
h.distance = ((tmp / 8) != 0) ? /* prevent a bug with small dists */ \
((tmp * RCL_UNITS_PER_SQUARE * rayDir ## dir1 ## Recip) / (RECIP_SCALE / 4)):\
RCL_abs(h.position.dir2 - ray.start.dir2);
CORRECT(X,y)
#endif
}
else
{
h.position.y = currentSquare.y * RCL_UNITS_PER_SQUARE;
h.direction = 2;
if (step.y == -1)
{
h.direction = 0;
h.position.y += RCL_UNITS_PER_SQUARE;
}
RCL_Unit diff = h.position.y - ray.start.y;
h.position.x =
ray.start.x + (ray.direction.x * diff * rayDirYRecip) / RECIP_SCALE;
#if RCL_RECTILINEAR
CORRECT(Y,x) // same as above but for different axis
#undef CORRECT
// ^ / 4 is here to prevent overflow
#endif
}
#if !RCL_RECTILINEAR
h.distance = RCL_dist(h.position,ray.start);
#endif
if (typeFunc != 0)
h.type = typeFunc(currentSquare.x,currentSquare.y);
#if RCL_COMPUTE_WALL_TEXCOORDS == 1
switch (h.direction)
{
case 0: h.textureCoord =
RCL_wrap(-1 * h.position.x,RCL_UNITS_PER_SQUARE); break;
case 1: h.textureCoord =
RCL_wrap(h.position.y,RCL_UNITS_PER_SQUARE); break;
case 2: h.textureCoord =
RCL_wrap(h.position.x,RCL_UNITS_PER_SQUARE); break;
case 3: h.textureCoord =
RCL_wrap(-1 * h.position.y,RCL_UNITS_PER_SQUARE); break;
default: h.textureCoord = 0; break;
}
if (_RCL_rollFunction != 0)
{
h.doorRoll = _RCL_rollFunction(currentSquare.x,currentSquare.y);
if (h.direction == 0 || h.direction == 1)
h.doorRoll *= -1;
}
#else
h.textureCoord = 0;
#endif
hitResults[*hitResultsLen] = h;
*hitResultsLen += 1;
squareType = currentType;
if (*hitResultsLen >= constraints.maxHits)
break;
}
// DDA step
if (nextSideDist.x < nextSideDist.y)
{
nextSideDist.x += delta.x;
currentSquare.x += step.x;
stepHorizontal = 1;
}
else
{
nextSideDist.y += delta.y;
currentSquare.y += step.y;
stepHorizontal = 0;
}
}
}
RCL_HitResult RCL_castRay(RCL_Ray ray, RCL_ArrayFunction arrayFunc)
{
RCL_HitResult result;
uint16_t RCL_len;
RCL_RayConstraints c;
c.maxSteps = 1000;
c.maxHits = 1;
RCL_castRayMultiHit(ray,arrayFunc,0,&result,&RCL_len,c);
if (RCL_len == 0)
result.distance = -1;
return result;
}
void RCL_castRaysMultiHit(RCL_Camera cam, RCL_ArrayFunction arrayFunc,
RCL_ArrayFunction typeFunction, RCL_ColumnFunction columnFunc,
RCL_RayConstraints constraints)
{
RCL_Vector2D dir1 =
RCL_angleToDirection(cam.direction - RCL_HORIZONTAL_FOV_HALF);
RCL_Vector2D dir2 =
RCL_angleToDirection(cam.direction + RCL_HORIZONTAL_FOV_HALF);
/* We scale the side distances so that the middle one is
RCL_UNITS_PER_SQUARE, which has to be this way. */
RCL_Unit cos = RCL_nonZero(RCL_cos(RCL_HORIZONTAL_FOV_HALF));
dir1.x = (dir1.x * RCL_UNITS_PER_SQUARE) / cos;
dir1.y = (dir1.y * RCL_UNITS_PER_SQUARE) / cos;
dir2.x = (dir2.x * RCL_UNITS_PER_SQUARE) / cos;
dir2.y = (dir2.y * RCL_UNITS_PER_SQUARE) / cos;
RCL_Unit dX = dir2.x - dir1.x;
RCL_Unit dY = dir2.y - dir1.y;
RCL_HitResult hits[constraints.maxHits];
uint16_t hitCount;
RCL_Ray r;
r.start = cam.position;
RCL_Unit currentDX = 0;
RCL_Unit currentDY = 0;
for (int16_t i = 0; i < cam.resolution.x; ++i)
{
/* Here by linearly interpolating the direction vector its length changes,
which in result achieves correcting the fish eye effect (computing
perpendicular distance). */
r.direction.x = dir1.x + currentDX / cam.resolution.x;
r.direction.y = dir1.y + currentDY / cam.resolution.x;
RCL_castRayMultiHit(r,arrayFunc,typeFunction,hits,&hitCount,constraints);
columnFunc(hits,hitCount,i,r);
currentDX += dX;
currentDY += dY;
}
}
/**
Helper function that determines intersection with both ceiling and floor.
*/
RCL_Unit _RCL_floorCeilFunction(int16_t x, int16_t y)
{
RCL_Unit f = _RCL_floorFunction(x,y);
if (_RCL_ceilFunction == 0)
return f;
RCL_Unit c = _RCL_ceilFunction(x,y);
#ifndef RCL_RAYCAST_TINY
return ((f & 0x0000ffff) << 16) | (c & 0x0000ffff);
#else
return ((f & 0x00ff) << 8) | (c & 0x00ff);
#endif
}
RCL_Unit _floorHeightNotZeroFunction(int16_t x, int16_t y)
{
return _RCL_floorFunction(x,y) == 0 ? 0 :
RCL_nonZero((x & 0x00FF) | ((y & 0x00FF) << 8));
// ^ this makes collisions between all squares - needed for rolling doors
}
RCL_Unit RCL_adjustDistance(RCL_Unit distance, RCL_Camera *camera,
RCL_Ray *ray)
{
/* FIXME/TODO: The adjusted (=orthogonal, camera-space) distance could
possibly be computed more efficiently by not computing Euclidean
distance at all, but rather compute the distance of the collision
point from the projection plane (line). */
RCL_Unit result =
(distance *
RCL_vectorsAngleCos(RCL_angleToDirection(camera->direction),
ray->direction)) / RCL_UNITS_PER_SQUARE;
return RCL_nonZero(result);
// ^ prevent division by zero
}
/// Helper for drawing floor or ceiling. Returns the last drawn pixel position.
static inline int16_t _RCL_drawHorizontalColumn(
RCL_Unit yCurrent,
RCL_Unit yTo,
RCL_Unit limit1, // TODO: int16_t?
RCL_Unit limit2,
RCL_Unit verticalOffset,
int16_t increment,
int8_t computeDepth,
int8_t computeCoords,
int16_t depthIncrementMultiplier,
RCL_Ray *ray,
RCL_PixelInfo *pixelInfo
)
{
_RCL_UNUSED(ray);
RCL_Unit depthIncrement;
RCL_Unit dx;
RCL_Unit dy;
pixelInfo->isWall = 0;
int16_t limit = RCL_clamp(yTo,limit1,limit2);
RCL_Unit depth = 0; /* TODO: this is for clamping depth to 0 so that we don't
have negative depths, but we should do it more
elegantly and efficiently */
_RCL_UNUSED(depth);
/* for performance reasons have different version of the critical loop
to be able to branch early */
#define loop(doDepth,doCoords)\
{\
if (doDepth) /*constant condition - compiler should optimize it out*/\
{\
depth = pixelInfo->depth + RCL_abs(verticalOffset) *\
RCL_VERTICAL_DEPTH_MULTIPLY;\
depthIncrement = depthIncrementMultiplier *\
_RCL_horizontalDepthStep;\
}\
if (doCoords) /*constant condition - compiler should optimize it out*/\
{\
dx = pixelInfo->hit.position.x - _RCL_camera.position.x;\
dy = pixelInfo->hit.position.y - _RCL_camera.position.y;\
}\
for (int16_t i = yCurrent + increment;\
increment == -1 ? i >= limit : i <= limit; /* TODO: is efficient? */\
i += increment)\
{\
pixelInfo->position.y = i;\
if (doDepth) /*constant condition - compiler should optimize it out*/\
{\
depth += depthIncrement;\
pixelInfo->depth = RCL_zeroClamp(depth); \
/* ^ int comparison is fast, it is not braching! (= test instr.) */\
}\
if (doCoords) /*constant condition - compiler should optimize it out*/\
{\
RCL_Unit d = _RCL_floorPixelDistances[i];\
RCL_Unit d2 = RCL_nonZero(pixelInfo->hit.distance);\
pixelInfo->texCoords.x =\
_RCL_camera.position.x + ((d * dx) / d2);\
pixelInfo->texCoords.y =\
_RCL_camera.position.y + ((d * dy) / d2);\
}\
RCL_PIXEL_FUNCTION(pixelInfo);\
}\
}
if (computeDepth) // branch early
{
if (!computeCoords)
loop(1,0)
else
loop(1,1)
}
else
{
if (!computeCoords)
loop(0,0)
else
loop(1,1)
}
#undef loop
return limit;
}
/// Helper for drawing walls. Returns the last drawn pixel position.
static inline int16_t _RCL_drawWall(
RCL_Unit yCurrent,
RCL_Unit yFrom,
RCL_Unit yTo,
RCL_Unit limit1, // TODO: int16_t?
RCL_Unit limit2,
RCL_Unit height,
int16_t increment,
RCL_PixelInfo *pixelInfo
)
{
_RCL_UNUSED(height)
height = RCL_abs(height);
pixelInfo->isWall = 1;
RCL_Unit limit = RCL_clamp(yTo,limit1,limit2);
RCL_Unit wallLength = RCL_nonZero(RCL_abs(yTo - yFrom - 1));
RCL_Unit wallPosition = RCL_abs(yFrom - yCurrent) - increment;
RCL_Unit heightScaled = height * RCL_TEXTURE_INTERPOLATION_SCALE;
_RCL_UNUSED(heightScaled);
RCL_Unit coordStepScaled = RCL_COMPUTE_WALL_TEXCOORDS ?
#if RCL_TEXTURE_VERTICAL_STRETCH == 1
((RCL_UNITS_PER_SQUARE * RCL_TEXTURE_INTERPOLATION_SCALE) / wallLength)
#else
(heightScaled / wallLength)
#endif
: 0;
pixelInfo->texCoords.y = RCL_COMPUTE_WALL_TEXCOORDS ?
(wallPosition * coordStepScaled) : 0;
if (increment < 0)
{
coordStepScaled *= -1;
pixelInfo->texCoords.y =
#if RCL_TEXTURE_VERTICAL_STRETCH == 1
(RCL_UNITS_PER_SQUARE * RCL_TEXTURE_INTERPOLATION_SCALE)
- pixelInfo->texCoords.y;
#else
heightScaled - pixelInfo->texCoords.y;
#endif
}
else
{
// with floor wall, don't start under 0
pixelInfo->texCoords.y = RCL_zeroClamp(pixelInfo->texCoords.y);
}
RCL_Unit textureCoordScaled = pixelInfo->texCoords.y;
for (RCL_Unit i = yCurrent + increment;
increment == -1 ? i >= limit : i <= limit; // TODO: is efficient?
i += increment)
{
pixelInfo->position.y = i;
#if RCL_COMPUTE_WALL_TEXCOORDS == 1
pixelInfo->texCoords.y =
textureCoordScaled / RCL_TEXTURE_INTERPOLATION_SCALE;
textureCoordScaled += coordStepScaled;
#endif
RCL_PIXEL_FUNCTION(pixelInfo);
}
return limit;
}
/// Fills a RCL_HitResult struct with info for a hit at infinity.
static inline void _RCL_makeInfiniteHit(RCL_HitResult *hit, RCL_Ray *ray)
{
hit->distance = RCL_UNITS_PER_SQUARE * RCL_UNITS_PER_SQUARE;
/* ^ horizon is at infinity, but we can't use too big infinity
(RCL_INFINITY) because it would overflow in the following mult. */
hit->position.x = (ray->direction.x * hit->distance) / RCL_UNITS_PER_SQUARE;
hit->position.y = (ray->direction.y * hit->distance) / RCL_UNITS_PER_SQUARE;
hit->direction = 0;
hit->textureCoord = 0;
hit->arrayValue = 0;
hit->doorRoll = 0;
hit->type = 0;
}
void _RCL_columnFunctionComplex(RCL_HitResult *hits, uint16_t hitCount, uint16_t x,
RCL_Ray ray)
{
// last written Y position, can never go backwards
RCL_Unit fPosY = _RCL_camera.resolution.y;
RCL_Unit cPosY = -1;
// world coordinates (relative to camera height though)
RCL_Unit fZ1World = _RCL_startFloorHeight;
RCL_Unit cZ1World = _RCL_startCeil_Height;
RCL_PixelInfo p;
p.position.x = x;
p.height = 0;
p.wallHeight = 0;
p.texCoords.x = 0;
p.texCoords.y = 0;
// we'll be simulatenously drawing the floor and the ceiling now
for (RCL_Unit j = 0; j <= hitCount; ++j)
{ // ^ = add extra iteration for horizon plane
int8_t drawingHorizon = j == hitCount;
RCL_HitResult hit;
RCL_Unit distance = 1;
RCL_Unit fWallHeight = 0, cWallHeight = 0;
RCL_Unit fZ2World = 0, cZ2World = 0;
RCL_Unit fZ1Screen = 0, cZ1Screen = 0;
RCL_Unit fZ2Screen = 0, cZ2Screen = 0;
if (!drawingHorizon)
{
hit = hits[j];
distance = RCL_nonZero(hit.distance);
p.hit = hit;
fWallHeight = _RCL_floorFunction(hit.square.x,hit.square.y);
fZ2World = fWallHeight - _RCL_camera.height;
fZ1Screen = _RCL_middleRow - RCL_perspectiveScaleVertical(
(fZ1World * _RCL_camera.resolution.y) /
RCL_UNITS_PER_SQUARE,distance);
fZ2Screen = _RCL_middleRow - RCL_perspectiveScaleVertical(
(fZ2World * _RCL_camera.resolution.y) /
RCL_UNITS_PER_SQUARE,distance);
if (_RCL_ceilFunction != 0)
{
cWallHeight = _RCL_ceilFunction(hit.square.x,hit.square.y);
cZ2World = cWallHeight - _RCL_camera.height;
cZ1Screen = _RCL_middleRow - RCL_perspectiveScaleVertical(
(cZ1World * _RCL_camera.resolution.y) /
RCL_UNITS_PER_SQUARE,distance);
cZ2Screen = _RCL_middleRow - RCL_perspectiveScaleVertical(
(cZ2World * _RCL_camera.resolution.y) /
RCL_UNITS_PER_SQUARE,distance);
}
}
else
{
fZ1Screen = _RCL_middleRow;
cZ1Screen = _RCL_middleRow + 1;
_RCL_makeInfiniteHit(&p.hit,&ray);
}
RCL_Unit limit;
p.isWall = 0;
p.isHorizon = drawingHorizon;
// draw floor until wall
p.isFloor = 1;
p.height = fZ1World + _RCL_camera.height;
p.wallHeight = 0;
#if RCL_COMPUTE_FLOOR_DEPTH == 1
p.depth = (_RCL_fHorizontalDepthStart - fPosY) * _RCL_horizontalDepthStep;
#else
p.depth = 0;
#endif
limit = _RCL_drawHorizontalColumn(fPosY,fZ1Screen,cPosY + 1,
_RCL_camera.resolution.y,fZ1World,-1,RCL_COMPUTE_FLOOR_DEPTH,
// ^ purposfully allow outside screen bounds
RCL_COMPUTE_FLOOR_TEXCOORDS && p.height == RCL_FLOOR_TEXCOORDS_HEIGHT,
1,&ray,&p);
if (fPosY > limit)
fPosY = limit;
if (_RCL_ceilFunction != 0 || drawingHorizon)
{
// draw ceiling until wall
p.isFloor = 0;
p.height = cZ1World + _RCL_camera.height;
#if RCL_COMPUTE_CEILING_DEPTH == 1
p.depth = (cPosY - _RCL_cHorizontalDepthStart) *
_RCL_horizontalDepthStep;
#endif
limit = _RCL_drawHorizontalColumn(cPosY,cZ1Screen,
-1,fPosY - 1,cZ1World,1,RCL_COMPUTE_CEILING_DEPTH,0,1,&ray,&p);
// ^ purposfully allow outside screen bounds here
if (cPosY < limit)
cPosY = limit;
}
if (!drawingHorizon) // don't draw walls for horizon plane
{
p.isWall = 1;
p.depth = distance;
p.isFloor = 1;
p.texCoords.x = hit.textureCoord;
p.height = fZ1World + _RCL_camera.height;
p.wallHeight = fWallHeight;
// draw floor wall
if (fPosY > 0) // still pixels left?
{
p.isFloor = 1;
limit = _RCL_drawWall(fPosY,fZ1Screen,fZ2Screen,cPosY + 1,
_RCL_camera.resolution.y,
// ^ purposfully allow outside screen bounds here
#if RCL_TEXTURE_VERTICAL_STRETCH == 1
RCL_UNITS_PER_SQUARE
#else
fZ2World - fZ1World
#endif
,-1,&p);
if (fPosY > limit)
fPosY = limit;
fZ1World = fZ2World; // for the next iteration
} // ^ purposfully allow outside screen bounds here
// draw ceiling wall
if (_RCL_ceilFunction != 0 && cPosY < _RCL_camResYLimit) // pixels left?
{
p.isFloor = 0;
p.height = cZ1World + _RCL_camera.height;
p.wallHeight = cWallHeight;
limit = _RCL_drawWall(cPosY,cZ1Screen,cZ2Screen,
-1,fPosY - 1,
// ^ puposfully allow outside screen bounds here
#if RCL_TEXTURE_VERTICAL_STRETCH == 1
RCL_UNITS_PER_SQUARE
#else
cZ1World - cZ2World
#endif
,1,&p);
if (cPosY < limit)
cPosY = limit;
cZ1World = cZ2World; // for the next iteration
} // ^ puposfully allow outside screen bounds here
}
}
}
void _RCL_columnFunctionSimple(RCL_HitResult *hits, uint16_t hitCount,
uint16_t x, RCL_Ray ray)
{
RCL_Unit y = 0;
RCL_Unit wallHeightScreen = 0;
RCL_Unit wallStart = _RCL_middleRow;
RCL_Unit dist = 1;
RCL_PixelInfo p;
p.position.x = x;
p.wallHeight = RCL_UNITS_PER_SQUARE;
if (hitCount > 0)
{
RCL_HitResult hit = hits[0];
uint8_t goOn = 1;
if (_RCL_rollFunction != 0 && RCL_COMPUTE_WALL_TEXCOORDS == 1)
{
if (hit.arrayValue == 0)
{
// standing inside door square, looking out => move to the next hit
if (hitCount > 1)
hit = hits[1];
else
goOn = 0;
}
else
{
// normal hit, check the door roll
RCL_Unit texCoordMod = hit.textureCoord % RCL_UNITS_PER_SQUARE;
int8_t unrolled = hit.doorRoll >= 0 ?
(hit.doorRoll > texCoordMod) :
(texCoordMod > RCL_UNITS_PER_SQUARE + hit.doorRoll);
if (unrolled)
{
goOn = 0;
if (hitCount > 1) /* should probably always be true (hit on square
exit) */
{
if (hit.direction % 2 != hits[1].direction % 2)
{
// hit on the inner side
hit = hits[1];
goOn = 1;
}
else if (hitCount > 2)
{
// hit on the opposite side
hit = hits[2];
goOn = 1;
}
}
}
}
}
p.hit = hit;
if (goOn)
{
dist = hit.distance;
RCL_Unit wallHeightWorld = _RCL_floorFunction(hit.square.x,hit.square.y);
if (wallHeightWorld < 0)
{
/* We can't just do wallHeightWorld = max(0,wallHeightWorld) because
we would be processing an actual hit with height 0, which shouldn't
ever happen, so we assign some arbitrary height. */
wallHeightWorld = RCL_UNITS_PER_SQUARE;
}
RCL_Unit worldPointTop = wallHeightWorld - _RCL_camera.height;
RCL_Unit worldPointBottom = -1 * _RCL_camera.height;
wallStart = _RCL_middleRow -
(RCL_perspectiveScaleVertical(worldPointTop,dist)
* _RCL_camera.resolution.y) / RCL_UNITS_PER_SQUARE;
int16_t wallEnd = _RCL_middleRow -
(RCL_perspectiveScaleVertical(worldPointBottom,dist)
* _RCL_camera.resolution.y) / RCL_UNITS_PER_SQUARE;
wallHeightScreen = wallEnd - wallStart;
if (wallHeightScreen <= 0) // can happen because of rounding errors
wallHeightScreen = 1;
}
}
else
{
_RCL_makeInfiniteHit(&p.hit,&ray);
}
// draw ceiling
p.isWall = 0;
p.isFloor = 0;
p.isHorizon = 1;
p.depth = 1;
p.height = RCL_UNITS_PER_SQUARE;
y = _RCL_drawHorizontalColumn(-1,wallStart,-1,_RCL_middleRow,_RCL_camera.height,1,
RCL_COMPUTE_CEILING_DEPTH,0,1,&ray,&p);
// draw wall
p.isWall = 1;
p.isFloor = 1;
p.depth = dist;
p.height = 0;
#if RCL_ROLL_TEXTURE_COORDS == 1 && RCL_COMPUTE_WALL_TEXCOORDS == 1
p.hit.textureCoord -= p.hit.doorRoll;
#endif
p.texCoords.x = p.hit.textureCoord;
p.texCoords.y = 0;
RCL_Unit limit = _RCL_drawWall(y,wallStart,wallStart + wallHeightScreen - 1,
-1,_RCL_camResYLimit,p.hit.arrayValue,1,&p);
y = RCL_max(y,limit); // take max, in case no wall was drawn
y = RCL_max(y,wallStart);
// draw floor
p.isWall = 0;
#if RCL_COMPUTE_FLOOR_DEPTH == 1
p.depth = (_RCL_camera.resolution.y - y) * _RCL_horizontalDepthStep + 1;
#endif
_RCL_drawHorizontalColumn(y,_RCL_camResYLimit,-1,_RCL_camResYLimit,
_RCL_camera.height,1,RCL_COMPUTE_FLOOR_DEPTH,RCL_COMPUTE_FLOOR_TEXCOORDS,
-1,&ray,&p);
}
/**
Precomputes a distance from camera to the floor at each screen row into an
array (must be preallocated with sufficient (camera.resolution.y) length).
*/
static inline void _RCL_precomputeFloorDistances(RCL_Camera camera,
RCL_Unit *dest, uint16_t startIndex)
{
RCL_Unit camHeightScreenSize =
(camera.height * camera.resolution.y) / RCL_UNITS_PER_SQUARE;
for (uint16_t i = startIndex; i < camera.resolution.y; ++i)
dest[i] = RCL_perspectiveScaleVerticalInverse(camHeightScreenSize,
RCL_abs(i - _RCL_middleRow));
}
void RCL_renderComplex(RCL_Camera cam, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction ceilingHeightFunc, RCL_ArrayFunction typeFunction,
RCL_RayConstraints constraints)
{
_RCL_floorFunction = floorHeightFunc;
_RCL_ceilFunction = ceilingHeightFunc;
_RCL_camera = cam;
_RCL_camResYLimit = cam.resolution.y - 1;
uint16_t halfResY = cam.resolution.y / 2;
_RCL_middleRow = halfResY + cam.shear;
_RCL_fHorizontalDepthStart = _RCL_middleRow + halfResY;
_RCL_cHorizontalDepthStart = _RCL_middleRow - halfResY;
_RCL_startFloorHeight = floorHeightFunc(
RCL_divRoundDown(cam.position.x,RCL_UNITS_PER_SQUARE),
RCL_divRoundDown(cam.position.y,RCL_UNITS_PER_SQUARE)) -1 * cam.height;
_RCL_startCeil_Height =
ceilingHeightFunc != 0 ?
ceilingHeightFunc(
RCL_divRoundDown(cam.position.x,RCL_UNITS_PER_SQUARE),
RCL_divRoundDown(cam.position.y,RCL_UNITS_PER_SQUARE)) -1 * cam.height
: RCL_INFINITY;
_RCL_horizontalDepthStep = RCL_HORIZON_DEPTH / cam.resolution.y;
#if RCL_COMPUTE_FLOOR_TEXCOORDS == 1
RCL_Unit floorPixelDistances[cam.resolution.y];
_RCL_precomputeFloorDistances(cam,floorPixelDistances,0);
_RCL_floorPixelDistances = floorPixelDistances; // pass to column function
#endif
RCL_castRaysMultiHit(cam,_RCL_floorCeilFunction,typeFunction,
_RCL_columnFunctionComplex,constraints);
}
void RCL_renderSimple(RCL_Camera cam, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction typeFunc, RCL_ArrayFunction rollFunc,
RCL_RayConstraints constraints)
{
_RCL_floorFunction = floorHeightFunc;
_RCL_camera = cam;
_RCL_camResYLimit = cam.resolution.y - 1;
_RCL_middleRow = cam.resolution.y / 2;
_RCL_rollFunction = rollFunc;
_RCL_cameraHeightScreen =
(_RCL_camera.resolution.y * (_RCL_camera.height - RCL_UNITS_PER_SQUARE)) /
RCL_UNITS_PER_SQUARE;
_RCL_horizontalDepthStep = RCL_HORIZON_DEPTH / cam.resolution.y;
constraints.maxHits =
_RCL_rollFunction == 0 ?
1 : // no door => 1 hit is enough
3; // for correctly rendering rolling doors we'll need 3 hits (NOT 2)
#if RCL_COMPUTE_FLOOR_TEXCOORDS == 1
RCL_Unit floorPixelDistances[cam.resolution.y];
_RCL_precomputeFloorDistances(cam,floorPixelDistances,_RCL_middleRow);
_RCL_floorPixelDistances = floorPixelDistances; // pass to column function
#endif
RCL_castRaysMultiHit(cam,_floorHeightNotZeroFunction,typeFunc,
_RCL_columnFunctionSimple, constraints);
#if RCL_COMPUTE_FLOOR_TEXCOORDS == 1
_RCL_floorPixelDistances = 0;
#endif
}
RCL_Vector2D RCL_normalize(RCL_Vector2D v)
{
RCL_Vector2D result;
RCL_Unit l = RCL_len(v);
l = RCL_nonZero(l);
result.x = (v.x * RCL_UNITS_PER_SQUARE) / l;
result.y = (v.y * RCL_UNITS_PER_SQUARE) / l;
return result;
}
RCL_Unit RCL_vectorsAngleCos(RCL_Vector2D v1, RCL_Vector2D v2)
{
v1 = RCL_normalize(v1);
v2 = RCL_normalize(v2);
return (v1.x * v2.x + v1.y * v2.y) / RCL_UNITS_PER_SQUARE;
}
RCL_PixelInfo RCL_mapToScreen(RCL_Vector2D worldPosition, RCL_Unit height,
RCL_Camera camera)
{
RCL_PixelInfo result;
RCL_Vector2D toPoint;
toPoint.x = worldPosition.x - camera.position.x;
toPoint.y = worldPosition.y - camera.position.y;
RCL_Unit middleColumn = camera.resolution.x / 2;
// rotate the point to camera space (y left/right, x forw/backw)
RCL_Unit cos = RCL_cos(camera.direction);
RCL_Unit sin = RCL_sin(camera.direction);
RCL_Unit tmp = toPoint.x;
toPoint.x = (toPoint.x * cos - toPoint.y * sin) / RCL_UNITS_PER_SQUARE;
toPoint.y = (tmp * sin + toPoint.y * cos) / RCL_UNITS_PER_SQUARE;
result.depth = toPoint.x;
result.position.x =
middleColumn + (-1 * toPoint.y * middleColumn) / RCL_nonZero(result.depth);
result.position.y =
camera.resolution.y / 2 -
(RCL_perspectiveScaleVertical(height - camera.height,result.depth)
* camera.resolution.y) / RCL_UNITS_PER_SQUARE
+ camera.shear;
return result;
}
RCL_Unit RCL_degreesToUnitsAngle(int16_t degrees)
{
return (degrees * RCL_UNITS_PER_SQUARE) / 360;
}
RCL_Unit RCL_perspectiveScaleVertical(RCL_Unit originalSize, RCL_Unit distance)
{
return distance != 0 ?
(originalSize * RCL_UNITS_PER_SQUARE) /
((RCL_VERTICAL_FOV_TAN * 2 * distance) / RCL_UNITS_PER_SQUARE)
: 0;
}
RCL_Unit RCL_perspectiveScaleVerticalInverse(RCL_Unit originalSize,
RCL_Unit scaledSize)
{
return scaledSize != 0 ?
(originalSize * RCL_UNITS_PER_SQUARE + RCL_UNITS_PER_SQUARE / 2) /
// ^ take the middle
((RCL_VERTICAL_FOV_TAN * 2 * scaledSize) / RCL_UNITS_PER_SQUARE)
: RCL_INFINITY;
}
RCL_Unit
RCL_perspectiveScaleHorizontal(RCL_Unit originalSize, RCL_Unit distance)
{
return distance != 0 ?
(originalSize * RCL_UNITS_PER_SQUARE) /
((RCL_HORIZONTAL_FOV_TAN * 2 * distance) / RCL_UNITS_PER_SQUARE)
: 0;
}
RCL_Unit RCL_perspectiveScaleHorizontalInverse(RCL_Unit originalSize,
RCL_Unit scaledSize)
{
return scaledSize != 0 ?
(originalSize * RCL_UNITS_PER_SQUARE + RCL_UNITS_PER_SQUARE / 2) /
((RCL_HORIZONTAL_FOV_TAN * 2 * scaledSize) / RCL_UNITS_PER_SQUARE)
: RCL_INFINITY;
}
RCL_Unit RCL_castRay3D(
RCL_Vector2D pos1, RCL_Unit height1, RCL_Vector2D pos2, RCL_Unit height2,
RCL_ArrayFunction floorHeightFunc, RCL_ArrayFunction ceilingHeightFunc,
RCL_RayConstraints constraints)
{
RCL_HitResult hits[constraints.maxHits];
uint16_t numHits;
RCL_Ray ray;
ray.start = pos1;
RCL_Unit distance;
ray.direction.x = pos2.x - pos1.x;
ray.direction.y = pos2.y - pos1.y;
distance = RCL_len(ray.direction);
ray.direction = RCL_normalize(ray.direction);
RCL_Unit heightDiff = height2 - height1;
RCL_castRayMultiHit(ray,floorHeightFunc,0,hits,&numHits,constraints);
RCL_Unit result = RCL_UNITS_PER_SQUARE;
int16_t squareX = RCL_divRoundDown(pos1.x,RCL_UNITS_PER_SQUARE);
int16_t squareY = RCL_divRoundDown(pos1.y,RCL_UNITS_PER_SQUARE);
RCL_Unit startHeight = floorHeightFunc(squareX,squareY);
#define checkHits(comp,res) \
{ \
RCL_Unit currentHeight = startHeight; \
for (uint16_t i = 0; i < numHits; ++i) \
{ \
if (hits[i].distance > distance) \
break;\
RCL_Unit h = hits[i].arrayValue; \
if ((currentHeight comp h ? currentHeight : h) \
comp (height1 + (hits[i].distance * heightDiff) / distance)) \
{ \
res = (hits[i].distance * RCL_UNITS_PER_SQUARE) / distance; \
break; \
} \
currentHeight = h; \
} \
}
checkHits(>,result)
if (ceilingHeightFunc != 0)
{
RCL_Unit result2 = RCL_UNITS_PER_SQUARE;
startHeight = ceilingHeightFunc(squareX,squareY);
RCL_castRayMultiHit(ray,ceilingHeightFunc,0,hits,&numHits,constraints);
checkHits(<,result2)
if (result2 < result)
result = result2;
}
#undef checkHits
return result;
}
void RCL_moveCameraWithCollision(RCL_Camera *camera, RCL_Vector2D planeOffset,
RCL_Unit heightOffset, RCL_ArrayFunction floorHeightFunc,
RCL_ArrayFunction ceilingHeightFunc, int8_t computeHeight, int8_t force)
{
int8_t movesInPlane = planeOffset.x != 0 || planeOffset.y != 0;
int16_t xSquareNew, ySquareNew;
if (movesInPlane || force)
{
RCL_Vector2D corner; // BBox corner in the movement direction
RCL_Vector2D cornerNew;
int16_t xDir = planeOffset.x > 0 ? 1 : -1;
int16_t yDir = planeOffset.y > 0 ? 1 : -1;
corner.x = camera->position.x + xDir * RCL_CAMERA_COLL_RADIUS;
corner.y = camera->position.y + yDir * RCL_CAMERA_COLL_RADIUS;
int16_t xSquare = RCL_divRoundDown(corner.x,RCL_UNITS_PER_SQUARE);
int16_t ySquare = RCL_divRoundDown(corner.y,RCL_UNITS_PER_SQUARE);
cornerNew.x = corner.x + planeOffset.x;
cornerNew.y = corner.y + planeOffset.y;
xSquareNew = RCL_divRoundDown(cornerNew.x,RCL_UNITS_PER_SQUARE);
ySquareNew = RCL_divRoundDown(cornerNew.y,RCL_UNITS_PER_SQUARE);
RCL_Unit bottomLimit = -1 * RCL_INFINITY;
RCL_Unit topLimit = RCL_INFINITY;
RCL_Unit currCeilHeight = RCL_INFINITY;
if (computeHeight)
{
bottomLimit = camera->height - RCL_CAMERA_COLL_HEIGHT_BELOW +
RCL_CAMERA_COLL_STEP_HEIGHT;
topLimit = camera->height + RCL_CAMERA_COLL_HEIGHT_ABOVE;
if (ceilingHeightFunc != 0)
currCeilHeight = ceilingHeightFunc(xSquare,ySquare);
}
// checks a single square for collision against the camera
#define collCheck(dir,s1,s2)\
if (computeHeight)\
{\
RCL_Unit height = floorHeightFunc(s1,s2);\
if (height > bottomLimit || \
currCeilHeight - height < \
RCL_CAMERA_COLL_HEIGHT_BELOW + RCL_CAMERA_COLL_HEIGHT_ABOVE)\
dir##Collides = 1;\
else if (ceilingHeightFunc != 0)\
{\
RCL_Unit height2 = ceilingHeightFunc(s1,s2);\
if ((height2 < topLimit) || ((height2 - height) < \
(RCL_CAMERA_COLL_HEIGHT_ABOVE + RCL_CAMERA_COLL_HEIGHT_BELOW)))\
dir##Collides = 1;\
}\
}\
else\
dir##Collides = floorHeightFunc(s1,s2) > RCL_CAMERA_COLL_STEP_HEIGHT;
// check collision against non-diagonal square
#define collCheckOrtho(dir,dir2,s1,s2,x)\
if (dir##SquareNew != dir##Square)\
{\
collCheck(dir,s1,s2)\
}\
if (!dir##Collides)\
{ /* now also check for coll on the neighbouring square */ \
int16_t dir2##Square2 = RCL_divRoundDown(corner.dir2 - dir2##Dir *\
RCL_CAMERA_COLL_RADIUS * 2,RCL_UNITS_PER_SQUARE);\
if (dir2##Square2 != dir2##Square)\
{\
if (x)\
collCheck(dir,dir##SquareNew,dir2##Square2)\
else\
collCheck(dir,dir2##Square2,dir##SquareNew)\
}\
}
int8_t xCollides = 0;
collCheckOrtho(x,y,xSquareNew,ySquare,1)
int8_t yCollides = 0;
collCheckOrtho(y,x,xSquare,ySquareNew,0)
if (xCollides || yCollides)
{
if (movesInPlane)
{
#define collHandle(dir)\
if (dir##Collides)\
cornerNew.dir = (dir##Square) * RCL_UNITS_PER_SQUARE +\
RCL_UNITS_PER_SQUARE / 2 + dir##Dir * (RCL_UNITS_PER_SQUARE / 2) -\
dir##Dir;\
collHandle(x)
collHandle(y)
#undef collHandle
}
else
{
/* Player collides without moving in the plane; this can happen e.g. on
elevators due to vertical only movement. This code can get executed
when force == 1. */
RCL_Vector2D squarePos;
RCL_Vector2D newPos;
squarePos.x = xSquare * RCL_UNITS_PER_SQUARE;
squarePos.y = ySquare * RCL_UNITS_PER_SQUARE;
newPos.x =
RCL_max(squarePos.x + RCL_CAMERA_COLL_RADIUS + 1,
RCL_min(squarePos.x + RCL_UNITS_PER_SQUARE - RCL_CAMERA_COLL_RADIUS - 1,
camera->position.x));
newPos.y =
RCL_max(squarePos.y + RCL_CAMERA_COLL_RADIUS + 1,
RCL_min(squarePos.y + RCL_UNITS_PER_SQUARE - RCL_CAMERA_COLL_RADIUS - 1,
camera->position.y));
cornerNew.x = corner.x + (newPos.x - camera->position.x);
cornerNew.y = corner.y + (newPos.y - camera->position.y);
}
}
else
{
/* If no non-diagonal collision is detected, a diagonal/corner collision
can still happen, check it here. */
if (xSquare != xSquareNew && ySquare != ySquareNew)
{
int8_t xyCollides = 0;
collCheck(xy,xSquareNew,ySquareNew)
if (xyCollides)
{
// normally should slide, but let's KISS and simply stop any movement
cornerNew = corner;
}
}
}
#undef collCheck
camera->position.x = cornerNew.x - xDir * RCL_CAMERA_COLL_RADIUS;
camera->position.y = cornerNew.y - yDir * RCL_CAMERA_COLL_RADIUS;
}
if (computeHeight && (movesInPlane || (heightOffset != 0) || force))
{
camera->height += heightOffset;
int16_t xSquare1 = RCL_divRoundDown(camera->position.x -
RCL_CAMERA_COLL_RADIUS,RCL_UNITS_PER_SQUARE);
int16_t xSquare2 = RCL_divRoundDown(camera->position.x +
RCL_CAMERA_COLL_RADIUS,RCL_UNITS_PER_SQUARE);
int16_t ySquare1 = RCL_divRoundDown(camera->position.y -
RCL_CAMERA_COLL_RADIUS,RCL_UNITS_PER_SQUARE);
int16_t ySquare2 = RCL_divRoundDown(camera->position.y +
RCL_CAMERA_COLL_RADIUS,RCL_UNITS_PER_SQUARE);
RCL_Unit bottomLimit = floorHeightFunc(xSquare1,ySquare1);
RCL_Unit topLimit = ceilingHeightFunc != 0 ?
ceilingHeightFunc(xSquare1,ySquare1) : RCL_INFINITY;
RCL_Unit height;
#define checkSquares(s1,s2)\
{\
height = floorHeightFunc(xSquare##s1,ySquare##s2);\
bottomLimit = RCL_max(bottomLimit,height);\
height = ceilingHeightFunc != 0 ?\
ceilingHeightFunc(xSquare##s1,ySquare##s2) : RCL_INFINITY;\
topLimit = RCL_min(topLimit,height);\
}
if (xSquare2 != xSquare1)
checkSquares(2,1)
if (ySquare2 != ySquare1)
checkSquares(1,2)
if (xSquare2 != xSquare1 && ySquare2 != ySquare1)
checkSquares(2,2)
camera->height = RCL_clamp(camera->height,
bottomLimit + RCL_CAMERA_COLL_HEIGHT_BELOW,
topLimit - RCL_CAMERA_COLL_HEIGHT_ABOVE);
#undef checkSquares
}
}
void RCL_initCamera(RCL_Camera *camera)
{
camera->position.x = 0;
camera->position.y = 0;
camera->direction = 0;
camera->resolution.x = 20;
camera->resolution.y = 15;
camera->shear = 0;
camera->height = RCL_UNITS_PER_SQUARE;
}
void RCL_initRayConstraints(RCL_RayConstraints *constraints)
{
constraints->maxHits = 1;
constraints->maxSteps = 20;
}
#endif
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