cloudy-raytracer/common/texture.cpp

#include "common/texture.h"
#include <cmath>
#include <fstream>
#include <iostream>
#include <string>

Texture::Texture(int width, int height) { this->resize(width, height); }

Texture::Texture(char const *fileName) { this->load(fileName); }

bool Texture::load(char const *fileName) {
    CImg<unsigned char> img_char(fileName);
    if (img_char.is_empty()) {
        std::cerr << "(Image): Could not open file " << fileName << std::endl;
        return false;
    }

    this->image_ = CImg<float>(img_char.width(), img_char.height(), img_char.depth(), 3, 0);
    for (int c = 0; c < 3; c++)
        cimg_forXYZ(img_char, x, y, z) {
                    this->image_(x, y, z, c) = img_char(x, y, z, std::min(c, img_char.spectrum() - 1)) / 255.0f;
                }

    return true;
}

bool Texture::save(char const *fileName) const {
    CImg<unsigned char> img_char;
    img_char = 255 * this->image_;

    img_char.save(fileName);
    return true;
}

Color Texture::getPixelAt(int x, int y) const {
    if ((x %= this->width()) < 0)
        x += this->width();
    if ((y %= this->height()) < 0)
        y += this->height();
    return Color(this->image_.atXY(x, y, 0), this->image_.atXY(x, y, 1), this->image_.atXY(x, y, 2));
}

void Texture::setPixelAt(int x, int y, Color const &color) {
    if ((x %= this->width()) < 0)
        x += this->width();
    if ((y %= this->height()) < 0)
        y += this->height();
    this->image_(x, y, 0) = color.r;
    this->image_(x, y, 1) = color.g;
    this->image_(x, y, 2) = color.b;
}

Color Texture::color(float u, float v, bool interpolate) const {
    Color color;
    if (!interpolate) {
        color = this->getPixelAt(int(roundf(u * this->width())), int(roundf(v * this->height())));
    } else {
        // IMPLEMENT bilinear interpolation
        float x1 = std::floor(u * this->width());
        float x2 = std::ceil(u * this->width());
        float y1 = std::floor(v * this->height());
        float y2 = std::ceil(v * this->height());
        float x = u * this->width();
        float y = v * this->height();
        Color x1y1 = this->getPixelAt(static_cast<int>(x1), static_cast<int>(y1));
        Color x2y1 = this->getPixelAt(static_cast<int>(x2), static_cast<int>(y1));
        Color x1y2 = this->getPixelAt(static_cast<int>(x1), static_cast<int>(y2));
        Color x2y2 = this->getPixelAt(static_cast<int>(x2), static_cast<int>(y2));
        Color fxy1 = ((x2 - x) / (x2 - x1)) * x1y1 + ((x - x1) / (x2 - x1)) * x2y1;
        Color fxy2 = ((x2 - x) / (x2 - x1)) * x1y2 + ((x - x1) / (x2 - x1)) * x2y2;
        color = ((y2 - y) / (y2 - y1)) * fxy1 + ((y - y1) / (y2 - y1)) * fxy2;
    }
    return color;
}

Color Texture::color(Vector2d const &surfacePosition, bool interpolate) const {
    return color(surfacePosition.u, surfacePosition.v, interpolate);
}