PathTracing/Texture.cpp at main · marko176/PathTracing · GitHub

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#include "Texture.hpp"
#include <iostream>

Image::Image(const std::string_view filename, bool gammaCorrection){
    data = stbi_load(filename.data(), &width, &height, &channels, 0);
    if(data == nullptr){
        std::cerr << "Failed to load image: " << filename << std::endl;
        std::abort();
    }
    if(gammaCorrection && data){
        for(int y = 0;y < height;y++){
            for(int x = 0;x < width;x++){
                for(int i = 0;i < std::min(channels, 3);i++){
                    data[(y * width + x) * channels + i] = sRGBLUT[data[(y * width + x) * channels + i]];
                }
            }
        }
    }
}

Image::~Image(){
    stbi_image_free((void*)data);
}


FloatImage::FloatImage(const std::string_view filename){
    data = stbi_loadf(filename.data(), &width, &height, &channels, 0);
    if(data == nullptr){
        std::cerr << "Failed to load image: " << filename << std::endl;
        std::abort();
    }
}

FloatImage::~FloatImage(){
    stbi_image_free((void*)data);
}

SolidColor::SolidColor(const glm::vec3& color, const glm::vec3& colorScale, bool invertTex) : Texture(colorScale, invertTex), albedo(color){}
SolidColor::SolidColor(float r, float g, float b, const glm::vec3& colorScale, bool invertTex) : Texture(colorScale, invertTex), albedo(r, g, b){}

glm::vec3 ImageTexture::texel(int x, int y) const{
    glm::ivec2 p = { x,y };
    return { image.GetChannelAt(p,1),image.GetChannelAt(p,2),image.GetChannelAt(p,3) };
}

float ImageTexture::alpha(const glm::vec2& uv) const{
    if(image.Channels() != 4)return 1;
    glm::ivec2 res = image.Resolution();
    float x = uv.x * res.x - 0.5f;
    float y = uv.y * res.y - 0.5f;
    int xi = std::floor(x);
    int yi = std::floor(y);
    float dx = x - xi;
    float dy = y - yi;

    float a = image.GetChannelAt({ xi,yi }, 4);
    float b = image.GetChannelAt({ xi + 1,yi }, 4);
    float c = image.GetChannelAt({ xi,yi + 1 }, 4);
    float d = image.GetChannelAt({ xi + 1,yi + 1 }, 4);
    return ((1 - dx) * (1 - dy) * a + dx * (1 - dy) * b +
        (1 - dx) * dy * c + dx * dy * d);
}

glm::vec3 FloatImageTexture::texel(int x, int y) const{
    // repeat wrap:
    glm::ivec2 p = { x,y };
    return { image.GetChannelAt(p,1),image.GetChannelAt(p,2),image.GetChannelAt(p,3) };
}


float FloatImageTexture::alpha(const glm::vec2& uv) const{
    if(image.Channels() != 4)return 1;
    glm::ivec2 res = image.Resolution();
    float x = uv.x * res.x - 0.5f;
    float y = uv.y * res.y - 0.5f;
    int xi = std::floor(x);
    int yi = std::floor(y);
    float dx = x - xi;
    float dy = y - yi;

    float a = image.GetChannelAt({ xi,yi }, 4);//image.image.GetChannelAt
    float b = image.GetChannelAt({ xi + 1,yi }, 4);
    float c = image.GetChannelAt({ xi,yi + 1 }, 4);
    float d = image.GetChannelAt({ xi + 1,yi + 1 }, 4);
    return ((1 - dx) * (1 - dy) * a + dx * (1 - dy) * b +
        (1 - dx) * dy * c + dx * dy * d);
}

float CheckerTexture::alpha(const glm::vec2& uv) const{
    glm::ivec2 iuv = glm::floor(uv * invScale);
    if((iuv.x + iuv.y) % 2 == 0)return tex1->alpha(uv);
    return tex2->alpha(uv);
}