#version 450

// This file contains the raw math performed by the matrices in vert.vert
// Matrices are still used for rotation, though.

layout(std430, set = 0, binding = 0) buffer positions_buffer {
	mat2x4 posnrm[];
} pos;

layout(push_constant, std430) uniform pc {
  layout(offset=0)   mat4 data;
  layout(offset=64)  vec4 offst;
};

layout (location = 0) out vec4 normal;
layout (location = 1) out vec4 pos_pre;
layout (location = 2) out vec4 pos_post;

const float PI = 3.14159;
const float TAU = PI*2.0;

void main() {
  normal = pos.posnrm[gl_VertexIndex][1];
  pos_pre = pos.posnrm[gl_VertexIndex][0];
  float zFar = 100.0;
  float zNear = 0.1;
  gl_Position = pos.posnrm[gl_VertexIndex][0];
  gl_Position.xyz += offst.xyz;
  pos_post = gl_Position;
  mat2 xz_rot;
  xz_rot[0] = vec2(cos(offst.w), -sin(offst.w));
  xz_rot[1] = vec2(sin(offst.w), cos(offst.w));
  gl_Position.xz *= inverse(xz_rot);
  mat2 yz_rot;
  yz_rot[0] = vec2(cos(data[3].w), -sin(data[3].w));
  yz_rot[1] = vec2(sin(data[3].w), cos(data[3].w));
  gl_Position.yz *= inverse(yz_rot);
  gl_Position.x *= (1080.0/1920.0);
  gl_Position.w = (gl_Position.z*sin(140.0/360.0*TAU));
  gl_Position.z -= zNear;
  gl_Position.z /= zFar;
}