PerlinNoise

PerlinNoise.cpp

void BringTheNoise()
{
/*
		To start with, we will be using glm’s perlin noise function to generate our noise instead of
		implementing our own. The glm function simply takes in a vec2 and returns a float between -1 and 1.
		Before just passing in our x and y we want to make some changes to them. First, we scale our point
		down, in this case by 10. This is because Perlin noise always returns 0 on integer boundaries. The
		Perlin noise function also returns a number between -1 and 1. For our height map we want a
		number between 0 and 1 so we can later multiply it by our max height. To do this we multiply by 0.5
		and then add by 0.5.
	*/
	m_perlinDimensions = 64;
	m_perlinData = new float[m_perlinDimensions * m_perlinDimensions];

	// scale helps to control the noise
	float scale = (1.0f / m_perlinDimensions) * 3;

	int octaves = 6;
	for (unsigned int x = 0; x < m_perlinDimensions; ++x) {
		for (unsigned int y = 0; y < m_perlinDimensions; ++y) {

			float amplitude = 1.f;
			float persistence = 0.3f;

			m_perlinData[x * m_perlinDimensions + y] = 0;

			for (int o = 0; o < octaves; ++o)
			{
				float freq = powf(2, (float)o);

				float perlin_sample = glm::perlin(vec2((float)x, (float)y) * scale * freq) * 0.5f + 0.5f;

				m_perlinData[x * m_perlinDimensions + y] += perlin_sample * amplitude;

				amplitude *= persistence;
			}
		}