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//
// Created by Keuin on 2022/4/11.
//
#ifndef RT_BITMAP_H
#define RT_BITMAP_H
#include <vector>
#include <cstdint>
#include <ostream>
#include <cassert>
#define COLORMIX_OVERFLOW_CHECK
//// T is some unsigned integer
//template<typename T>
//T saturate_add(T a, T b) {
// T c = a + b;
// if (a > c || b > c) {
// c = (1ULL << (sizeof(T) * 8U)) - 1ULL;
// }
// return c;
//}
// T is some unsigned integer, do not use float point types!
template<typename T>
struct pixel {
T r, g, b;
/**
* Create a pixel with given depth, from normalized color values.
* For example: for 8bit pixel, with (1, 0.5, 0.25), we get: (255, 127, 63).
*/
static inline pixel<T> from_normalized(double r, double g, double b) {
const auto mod = (1ULL << (sizeof(T) * 8U)) - 1ULL;
return pixel<T>{.r = (T) (mod * r), .g = (T) (mod * g), .b = (T) (mod * b)};
}
// v3d must be a normalized vector
static inline pixel<T> from_normalized(const vec3d &v3d) {
return from_normalized(v3d.x / 2.0 + 0.5, v3d.y / 2.0 + 0.5, v3d.z / 2.0 + 0.5);
}
};
// Mix two colors a and b. Returns a*u + b*v
template<typename T>
inline pixel<T> mix(const pixel<T> &a, const pixel<T> &b, double u, double v) {
assert(u >= 0);
assert(v >= 0);
assert(u <= 1);
assert(v <= 1);
assert(u + v <= 1);
pixel<T> c{0, 0, 0};
c.r = (T) (u * a.r + v * b.r);
c.g = (T) (u * a.g + v * b.g);
c.b = (T) (u * a.b + v * b.b);
return c;
}
// 8 bit pixel
using pixel8b = pixel<uint8_t>;
template<typename T>
class bitmap {
const unsigned width, height;
std::vector<pixel<T>> content; // pixels scanned by rows, from top to bottom
pixel<T> &image(unsigned x, unsigned y) {
assert(x < width);
assert(y < height);
return content[x + y * width];
}
pixel<T> &image(unsigned x, unsigned y) const {
assert(x < width);
assert(y < height);
return content[x + y * width];
}
public:
bitmap() = delete;
bitmap(unsigned int width, unsigned int height) : width(width), height(height) {
content.resize(width * height, pixel<T>{});
}
void set(unsigned x, unsigned y, const pixel<T> &pixel) {
image(x, y) = pixel;
}
pixel<T> get(unsigned x, unsigned y) const {
return image(x, y);
}
// Do not use float-point pixels, or this routine will break.
void write_plain_ppm(std::ostream &out) const;
};
template<typename T>
void bitmap<T>::write_plain_ppm(std::ostream &out) const {
const auto depth = (1ULL << (sizeof(T) * 8)) - 1ULL; // color depth of pixels
out << "P3\n" // file header
<< width << ' ' << height << '\n' // image width and height
<< depth << '\n'; // normalized max color depth (e.g. 255 for 8bit image)
for (const auto &pixel: content) {
out << (unsigned long long) pixel.r << ' '
<< (unsigned long long) pixel.g << ' '
<< (unsigned long long) pixel.b << '\n';
}
}
using bitmap8b = bitmap<uint8_t>;
#endif //RT_BITMAP_H
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