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//
// Created by Keuin on 2022/4/11.
//
#include <cstdint>
#include <iostream>
#include "vec.h"
#include "ray.h"
#include "bitmap.h"
#include "timer.h"
class viewport {
uint16_t width, height;
vec3d center;
bitmap8b bitmap_{width, height};
static pixel8b color(const ray3d &r) {
const auto u = (r.direction().y + 1.0) * 0.5;
return mix(
pixel8b::from_normalized(1.0, 1.0, 1.0),
pixel8b::from_normalized(0.5, 0.7, 1.0),
1.0 - u,
u
);
}
public:
viewport() = delete;
viewport(uint16_t width, uint16_t height, vec3d viewport_center) :
width(width), height(height), center(viewport_center) {}
void render(vec3d viewpoint) {
const auto r = center - viewpoint;
const int half_width = width / 2, half_height = height / 2;
for (int j = -half_height; j < half_height; ++j) {
for (int i = -half_width; i < half_width; ++i) {
const auto dir = r + vec3d{static_cast<double>(i), static_cast<double>(j), 0};
const ray3d ray{viewpoint, dir}; // from camera to pixel (on the viewport)
const auto pixel = color(ray);
bitmap_.set(i + half_width, j + half_height, pixel);
}
}
}
const bitmap8b &bitmap() const {
return bitmap_;
}
};
int main() {
viewport vp{1920, 1080, vec3d{0, 0, -100}};
timer tm;
tm.start_measure();
vp.render(vec3d{0, 0, 0}); // camera position as the coordinate origin
tm.stop_measure();
vp.bitmap().write_plain_ppm(std::cout);
}
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