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Codechange: Tweak coding style of tree shape.

pull/13515/head
Peter Nelson 2025-02-14 17:52:49 +00:00
parent 2c1fb5e567
commit a8006578bb
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GPG Key ID: 8EF8F0A467DF75ED
1 changed files with 48 additions and 60 deletions
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108
src/tree_cmd.cpp
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@ -179,11 +179,7 @@ static void PlaceTree(TileIndex tile, uint32_t r)
}
}
static const uint16_t GROVE_RESOLUTION = 16; ///< How many segments make up the tree group.
static const uint16_t GROVE_HARMONICS_COUNT = 4; ///< How many harmonics are used to generate the tree group.
struct BlobHarmonic
{
struct BlobHarmonic {
int amplitude;
float phase;
int frequency;
@ -191,112 +187,100 @@ struct BlobHarmonic
/**
* Creates a star-shaped polygon originating from (0, 0) as defined by the given harmonics.
*
* @param radius The maximum radius of the polygon. May be smaller, but will not be larger.
* @param harmonics Harmonics data for the polygon.
* @returns A star-shaped polygon.
* @param shape Shape to fill with points.
*/
std::array<Point, GROVE_RESOLUTION> CreateStarShapedPolygon(const int radius, const std::span<const BlobHarmonic> harmonics)
static void CreateStarShapedPolygon(const int radius, std::span<const BlobHarmonic> harmonics, std::span<Point> shape)
{
std::array<Point, GROVE_RESOLUTION> result;
float theta = 0;
auto step = (M_PI * 2) / GROVE_RESOLUTION;
float step = (M_PI * 2) / std::size(shape);
/* Divide a circle into a number of equally spaced divisions. */
for(int i = 0; i < GROVE_RESOLUTION; ++i) {
float deviation = 0;
for (Point &vertex : shape) {
/* Add up the values of each harmonic at this segment.*/
std::for_each(harmonics.begin(), harmonics.end(), [&deviation, theta](const BlobHarmonic &harmonic) {
deviation += sin((theta + harmonic.phase) * harmonic.frequency) * harmonic.amplitude;
float deviation = std::accumulate(std::begin(harmonics), std::end(harmonics), 0, [theta](float d, const BlobHarmonic &harmonic) {
return d + sin((theta + harmonic.phase) * harmonic.frequency) * harmonic.amplitude;
});
/* Smooth out changes. */
float adjusted_radius = (radius / 2.0) + (deviation / 2);
/* Add to the final polygon. */
Point vertex;
vertex.x = cos(theta) * adjusted_radius;
vertex.y = sin(theta) * adjusted_radius;
result.at(i) = vertex;
/* Proceed to the next segment. */
theta += step;
}
return result;
}
static const double PHASE_DIVISOR = INT32_MAX / (M_PI * 2); ///< Valid values for the phase of blob harmonics are between 0 and Tau. we can get a value in the correct range from Random() by dividing the maximum possible value by the desired maximum, and then dividing the random value by the result.
/**
* Creates a random star-shaped polygon originating from (0, 0).
*
* @param radius The maximum radius of the blob. May be smaller, but will not be larger.
* @param noOfSegments How many segments make up the blob.
* @returns A star-shaped polygon.
* @param[out] shape Shape to fill with polygon points.
*/
std::array<Point, GROVE_RESOLUTION> CreateRandomStarShapedPolygon(const int radius)
static void CreateRandomStarShapedPolygon(int radius, std::span<Point> shape)
{
/* These values are ones i found in my testing that result in suitable-looking polygons that did not self-intersect and fit within a square of radius * radius dimensions. */
/* Valid values for the phase of blob harmonics are between 0 and Tau. we can get a value in the correct range
* from Random() by dividing the maximum possible value by the desired maximum, and then dividing the random
* value by the result. */
static constexpr float PHASE_DIVISOR = INT32_MAX / (M_PI * 2);
std::array<BlobHarmonic, GROVE_HARMONICS_COUNT> harmonics = {
BlobHarmonic(radius / 2, Random() / PHASE_DIVISOR, 1),
BlobHarmonic(radius / 4, Random() / PHASE_DIVISOR, 2),
BlobHarmonic(radius / 8, Random() / PHASE_DIVISOR, 3),
BlobHarmonic(radius / 16, Random() / PHASE_DIVISOR, 4),
/* These values are ones found in testing that result in suitable-looking polygons that did not self-intersect
* and fit within a square of radius * radius dimensions. */
std::initializer_list<BlobHarmonic> harmonics = {
{radius / 2, Random() / PHASE_DIVISOR, 1},
{radius / 4, Random() / PHASE_DIVISOR, 2},
{radius / 8, Random() / PHASE_DIVISOR, 3},
{radius / 16, Random() / PHASE_DIVISOR, 4},
};
return CreateStarShapedPolygon(radius, harmonics);
CreateStarShapedPolygon(radius, harmonics, shape);
}
/**
* Returns true if the given coordinates lie within a triangle.
*
* @param x x.
* @param y y.
* @param vertex0
* @param vertex1
* @param vertex2 the triangle to check against.
* @param x X coordinate relative to centre of shape.
* @param y Y coordinate relative to centre of shape.
* @param v1 First vertex of triangle.
* @param v2 Second vertex of triangle.
* @param v3 Third vertic of triangle.
* @returns true if the given coordinates lie within a triangle.
*/
bool IsPointInTriangle(const int x, const int y, const Point & vertex0, const Point & vertex1, const Point & vertex2)
static bool IsPointInTriangle(const int x, const int y, const Point &v1, const Point &v2, const Point &v3)
{
const int s = ((vertex0.x - vertex2.x) * (y - vertex2.y)) - ((vertex0.y - vertex2.y) * (x - vertex2.x));
const int t = ((vertex1.x - vertex0.x) * (y - vertex0.y)) - ((vertex1.y - vertex0.y) * (x - vertex0.x));
const int s = ((v1.x - v3.x) * (y - v3.y)) - ((v1.y - v3.y) * (x - v3.x));
const int t = ((v2.x - v1.x) * (y - v1.y)) - ((v2.y - v1.y) * (x - v1.x));
if (s < 0 != t < 0 && s != 0 && t != 0) {
return false;
}
if (s < 0 != t < 0 && s != 0 && t != 0) return false;
const int d = (vertex2.x - vertex1.x) * (y - vertex1.y) - (vertex2.y - vertex1.y) * (x - vertex1.x);
const int d = (v3.x - v2.x) * (y - v2.y) - (v3.y - v2.y) * (x - v2.x);
return (d < 0) == (s + t <= 0);
}
/**
* Returns true if the given coordinates lie within a star shaped polygon.
* Breaks the polygon into a series of triangles around the centre point (0, 0) and then tests the coordinates against each triangle until a match is found [or not].
*
* @note There might be a better way to do this.
*
* @param x x.
* @param y y.
* @param polygon the polygon to check against.
* @returns true if the given coordinates lie within a star shaped polygon.
* @param x X coordinate relative to centre of shape.
* @param y Y coordinate relative to centre of shape.
* @param shape The shape to check against.
* @returns true if the given coordinates lie within the shape.star shaped polygon.
*/
bool IsPointInStarShapedPolygon(int x, int y, std::array<Point, GROVE_RESOLUTION> polygon)
static bool IsPointInStarShapedPolygon(int x, int y, std::span<Point> shape)
{
for (int i = 0; i < polygon.size(); ++i) {
if (IsPointInTriangle(x, y, polygon.at(i), polygon.at((i + 1) % polygon.size()), {0, 0})) {
return true;
}
for (auto it = std::begin(shape); it != std::end(shape); /* nothing */) {
const Point &v1 = *it;
++it;
const Point &v2 = (it == std::end(shape)) ? shape.front() : *it;
if (IsPointInTriangle(x, y, v1, v2, {0, 0})) return true;
}
return false;
}
static const uint16_t GROVE_RADIUS = 16; ///< Maximum radius of tree groups.
/**
* Creates a number of tree groups.
* The number of trees in each group depends on how many trees are actually placed around the given tile.
@ -305,10 +289,14 @@ static const uint16_t GROVE_RADIUS = 16; ///< Maximum radius
*/
static void PlaceTreeGroups(uint num_groups)
{
static constexpr uint GROVE_SEGMENTS = 16; ///< How many segments make up the tree group.
static constexpr uint GROVE_RADIUS = 16; ///< Maximum radius of tree groups.
std::array<Point, GROVE_SEGMENTS> grove;
do {
TileIndex center_tile = RandomTile();
std::array<Point, GROVE_RESOLUTION> grove = CreateRandomStarShapedPolygon(GROVE_RADIUS);
CreateRandomStarShapedPolygon(GROVE_RADIUS, grove);
for (uint i = 0; i < DEFAULT_TREE_STEPS; i++) {
IncreaseGeneratingWorldProgress(GWP_TREE);