#version 460

layout (local_size_x = 1,local_size_y = 1,local_size_z = 1) in;

layout (std430, binding = 0) buffer Samples
{
    float AudioSamples[];
};
layout (std430, binding = 1) buffer Params
{
	vec4 WaveColor;
	vec4 BgColor;
	float LineUV;
};
layout (binding = 2) writeonly uniform image2D Result;

vec4 lerp(vec4 a, vec4 b, float x)
{
	return a + x * (b - a);
}

void main()
{
	vec2 size = vec2(imageSize(Result));
	ivec2 pos = ivec2(gl_GlobalInvocationID.xy);

	int X = pos.x;
	int Y = pos.y;

	float height = size.y;
	float Top = AudioSamples[X * 2] + 1; // -1;
	float Bottom = AudioSamples[X * 2 + 1] + 1; // 1;
	Top = min(Top, 1);
	Bottom = max(Bottom, 0);
	Top *= height;
	Top *= 0.5;
	Bottom *= height;
	Bottom *= 0.5;


	// (id.y >= Top && id.y <= Bottom)
	float b1 = min(step(Top, Y), step(Y , Bottom));
	// (Y == height / 2)
	float b2 = step(Y, height * LineUV) * step(height * LineUV, Y);
	float b3 = max(b1, b2);
	imageStore(Result, pos, lerp(BgColor, WaveColor, b3));
}