#include <glerminal.h>

#include <cstdlib>
#include <cmath>

namespace
{
	void init()
	{
		for (int i = 1; i < 256; i++)
		{
			constexpr unsigned char c = 0;
			const unsigned char v = (255 - c) * powf((i - 1) / 256.0f, 4.0f) + c;
			glerminal_update_palette(i, (v << 24) | (v << 16) | (v << 8) | 0xE0);
		}

		for (int i = 1; i < 256; i++)
		{
			const unsigned char j = i;
			glerminal_update_sprite(i,
				{
					0,j,0,0,0,0,j,0,
					j,j,j,j,j,j,j,j,
					0,j,0,0,0,0,j,0,
					0,j,0,0,0,0,j,0,
					0,j,0,0,0,0,j,0,
					0,j,0,0,0,0,j,0,
					j,j,j,j,j,j,j,j,
					0,j,0,0,0,0,j,0,
				});
		}

		for (int i = 0; i < 40; i++)
		{
			for (int j = 0; j < 25; j++)
			{
				for (int k = 0; k < 256; k++)
				{
					glerminal_set(i, j, k, k);
				}
			}
		}
	}

	void mainloop(float dt)
	{
		static float time = 1;

		time += dt;

		if (time < 1.0f)
		{
			return;
		}
		else
		{
			time = 0;
		}

		const int cx = rand() % 40;
		const int cy = rand() % 25;

		for (int i = 0; i < 40; i++)
		{
			for (int j = 0; j < 25; j++)
			{
				for (int k = 0; k < 256; k++)
				{
					const float ox = 0.05f * powf(k, 0.55f) * copysignf(sqrtf((i - cx) * (i - cx)), i - cx);
					const float oy = 0.05f * powf(k, 0.55f) * copysignf(sqrtf((j - cy) * (j - cy)), j - cy);
					glerminal_offset(i, j, k, ox, oy);
				}
			}
		}

		glerminal_flush();
	}
}

int main(int argc, char** argv)
{
	glerminal_run(init, mainloop);
}