cube-game-plus-plus/client/rendering/NoiseTexture.cpp

#include <png.h>
#include <vector>
#include <cstdlib>

#include "client/rendering/NoiseTexture.h"

NoiseTexture::NoiseTexture(u32 width, u32 height)
{
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    std::vector<float> data;
    for(u32 x = 0; x < width; x++)
    {
        for(u32 y = 0; y < height; y++)
        {
            data.push_back(getRandom());
            data.push_back(getRandom());
            data.push_back(getRandom());
        }
    }
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, width, height, 0, GL_RGB, GL_FLOAT, data.data());
}

NoiseTexture::~NoiseTexture()
{
    glDeleteTextures(1, &texture);
}

void NoiseTexture::bind(unsigned int index) const
{
    glActiveTexture(GL_TEXTURE0 + index);
    glBindTexture(GL_TEXTURE_2D, texture);
}

float NoiseTexture::getRandom() const
{
    float r = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
    return r * 2.0f - 1.0f;
}