godot/modules/noise/noise.h
Rémi Verschelde f8ab79e68a Zero initialize all pointer class and struct members
This prevents the pitfall of UB when checking if they have been
assigned something valid by comparing to nullptr.
2022-04-04 19:49:50 +02:00

240 lines
8.9 KiB
C++

/*************************************************************************/
/* noise.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#ifndef NOISE_H
#define NOISE_H
#include "core/io/image.h"
class Noise : public Resource {
GDCLASS(Noise, Resource);
// Helper struct for get_seamless_image(). See comments in .cpp for usage.
template <typename T>
struct img_buff {
T *img = nullptr;
int width; // Array dimensions & default modulo for image.
int height;
int offset_x; // Offset index location on image (wrapped by specified modulo).
int offset_y;
int alt_width; // Alternate module for image.
int alt_height;
enum ALT_MODULO {
DEFAULT = 0,
ALT_X,
ALT_Y,
ALT_XY
};
// Multi-dimensional array indexer (e.g. img[x][y]) that supports multiple modulos.
T &operator()(int x, int y, ALT_MODULO mode = DEFAULT) {
switch (mode) {
case ALT_XY:
return img[(x + offset_x) % alt_width + ((y + offset_y) % alt_height) * width];
case ALT_X:
return img[(x + offset_x) % alt_width + ((y + offset_y) % height) * width];
case ALT_Y:
return img[(x + offset_x) % width + ((y + offset_y) % alt_height) * width];
default:
return img[(x + offset_x) % width + ((y + offset_y) % height) * width];
}
}
};
union l2c {
uint32_t l;
uint8_t c[4];
struct {
uint8_t r;
uint8_t g;
uint8_t b;
uint8_t a;
};
};
template <typename T>
Ref<Image> _generate_seamless_image(Ref<Image> p_src, int p_width, int p_height, bool p_invert, real_t p_blend_skirt) {
/*
To make a seamless image, we swap the quadrants so the edges are perfect matches.
We initially get a 10% larger image so we have an overlap we can use to blend over the seams.
Noise::img_buff::operator() acts as a multi-dimensional array indexer.
It does the array math, translates between the flipped and non-flipped quadrants, and manages offsets and modulos.
Here is how the larger source image and final output image map to each other:
Output size = p_width*p_height Source w/ extra 10% skirt `s` size = src_width*src_height
Q1 Q2 Q4 Q3 s1
Q3 Q4 Q2 Q1 s2
s5 s4 s3
All of the loops use output coordinates, so Output:Q1 == Source:Q1
Ex: Output(half_width, half_height) [the midpoint, corner of Q1/Q4] =>
on Source it's translated to
corner of Q1/s3 unless the ALT_XY modulo moves it to Q4
*/
int skirt_width = MAX(1, p_width * p_blend_skirt);
int skirt_height = MAX(1, p_height * p_blend_skirt);
int src_width = p_width + skirt_width;
int src_height = p_height + skirt_height;
int half_width = p_width * .5;
int half_height = p_height * .5;
int skirt_edge_x = half_width + skirt_width;
int skirt_edge_y = half_height + skirt_height;
Vector<uint8_t> dest;
dest.resize(p_width * p_height * Image::get_format_pixel_size(p_src->get_format()));
img_buff<T> rd_src = {
(T *)p_src->get_data().ptr(),
src_width, src_height,
half_width, half_height,
p_width, p_height
};
// `wr` is setup for straight x/y coordinate array access.
img_buff<T> wr = {
(T *)dest.ptrw(),
p_width, p_height,
0, 0, 0, 0
};
// `rd_dest` is a readable pointer to `wr`, i.e. what has already been written to the output buffer.
img_buff<T> rd_dest = {
(T *)dest.ptr(),
p_width, p_height,
0, 0, 0, 0
};
// Swap the quadrants to make edges seamless.
for (int y = 0; y < p_height; y++) {
for (int x = 0; x < p_width; x++) {
// rd_src has a half offset and the shorter modulo ignores the skirt.
// It reads and writes in Q1-4 order (see map above), skipping the skirt.
wr(x, y) = rd_src(x, y, img_buff<T>::ALT_XY);
}
}
// Blend the vertical skirt over the middle seam.
for (int x = half_width; x < skirt_edge_x; x++) {
int alpha = 255 * (1 - Math::smoothstep(.1f, .9f, float(x - half_width) / float(skirt_width)));
for (int y = 0; y < p_height; y++) {
// Skip the center square
if (y == half_height) {
y = skirt_edge_y - 1;
} else {
// Starts reading at s2, ALT_Y skips s3, and continues with s1.
wr(x, y) = _alpha_blend<T>(rd_dest(x, y), rd_src(x, y, img_buff<T>::ALT_Y), alpha);
}
}
}
// Blend the horizontal skirt over the middle seam.
for (int y = half_height; y < skirt_edge_y; y++) {
int alpha = 255 * (1 - Math::smoothstep(.1f, .9f, float(y - half_height) / float(skirt_height)));
for (int x = 0; x < p_width; x++) {
// Skip the center square
if (x == half_width) {
x = skirt_edge_x - 1;
} else {
// Starts reading at s4, skips s3, continues with s5.
wr(x, y) = _alpha_blend<T>(rd_dest(x, y), rd_src(x, y, img_buff<T>::ALT_X), alpha);
}
}
}
// Fill in the center square. Wr starts at the top left of Q4, which is the equivalent of the top left of s3, unless a modulo is used.
for (int y = half_height; y < skirt_edge_y; y++) {
for (int x = half_width; x < skirt_edge_x; x++) {
int xpos = 255 * (1 - Math::smoothstep(.1f, .9f, float(x - half_width) / float(skirt_width)));
int ypos = 255 * (1 - Math::smoothstep(.1f, .9f, float(y - half_height) / float(skirt_height)));
// Blend s3(Q1) onto s5(Q2) for the top half.
T top_blend = _alpha_blend<T>(rd_src(x, y, img_buff<T>::ALT_X), rd_src(x, y, img_buff<T>::DEFAULT), xpos);
// Blend s1(Q3) onto Q4 for the bottom half.
T bottom_blend = _alpha_blend<T>(rd_src(x, y, img_buff<T>::ALT_XY), rd_src(x, y, img_buff<T>::ALT_Y), xpos);
// Blend the top half onto the bottom half.
wr(x, y) = _alpha_blend<T>(bottom_blend, top_blend, ypos);
}
}
Ref<Image> image = memnew(Image(p_width, p_height, false, p_src->get_format(), dest));
p_src.unref();
return image;
}
template <typename T>
T _alpha_blend(T p_bg, T p_fg, int p_alpha) const {
l2c fg, bg, out;
fg.l = p_fg;
bg.l = p_bg;
uint16_t alpha;
uint16_t inv_alpha;
// If no alpha argument specified, use the alpha channel in the color
if (p_alpha == -1) {
alpha = fg.c[3] + 1;
inv_alpha = 256 - fg.c[3];
} else {
alpha = p_alpha + 1;
inv_alpha = 256 - p_alpha;
}
out.c[0] = (uint8_t)((alpha * fg.c[0] + inv_alpha * bg.c[0]) >> 8);
out.c[1] = (uint8_t)((alpha * fg.c[1] + inv_alpha * bg.c[1]) >> 8);
out.c[2] = (uint8_t)((alpha * fg.c[2] + inv_alpha * bg.c[2]) >> 8);
out.c[3] = 0xFF;
return out.l;
}
protected:
static void _bind_methods();
public:
// Virtual destructor so we can delete any Noise derived object when referenced as a Noise*.
virtual ~Noise() {}
virtual real_t get_noise_1d(real_t p_x) = 0;
virtual real_t get_noise_2dv(Vector2 p_v) = 0;
virtual real_t get_noise_2d(real_t p_x, real_t p_y) = 0;
virtual real_t get_noise_3dv(Vector3 p_v) = 0;
virtual real_t get_noise_3d(real_t p_x, real_t p_y, real_t p_z) = 0;
virtual Ref<Image> get_image(int p_width, int p_height, bool p_invert = false) = 0;
virtual Ref<Image> get_seamless_image(int p_width, int p_height, bool p_invert = false, real_t p_blend_skirt = 0.1);
};
#endif // NOISE_H