matrix4.cpp

/**
Copyright (c) 2018 Gombe.

This software is released under the MIT License.
http://opensource.org/licenses/mit-license.php
*/
#include "matrix4.hpp"

Matrix4 loadPerspective(float fovy,float aspect,float zNear,float zFar,int width,int height){
  Matrix4 m;
  const float dz(zFar - zNear);
  (void)width;
  (void)height;

  if (dz != 0.0f) {
    m.set( 5 , 1.f / tanf(fovy*3.1415926535898f));
    m.set( 0, m[5]*aspect );
    m.set(10, -(zFar + zNear) / dz);
    m.set(11, -1.f);
    m.set(14, -2.f * zFar * zNear / dz);
  }
  return m;
}

Matrix4 lookat(fvector3 goal,fvector3 eye){
  Matrix4 m,rm;

  fvector3 t,r,s;
  t=eye-goal;
  r=cross(fvector3(0.f,-1.f,0.f),t);
  s=cross(t,r);

  float rrs,rss,rts;
  rrs = 1.f/r.abs();
  rss = 1.f/s.abs();
  rts = 1.f/t.abs();

  m.set(0, r.x*rrs);
  m.set(4, r.y*rrs);
  m.set(8, r.z*rrs);

  m.set(1, s.x*rss);
  m.set(5, s.y*rss);
  m.set(9, s.z*rss);

  m.set(2, t.x*rts);
  m.set(6, t.y*rts);
  m.set(10, t.z*rts);
  // print(m);

  return m*translation(-eye);
}

#include <iostream>
void Matrix4::print(){
  for(int i=0;i<16;i++){
    std::cout<<m[i]<< ",";
    if(i%4==3)std::cout<<std::endl;
  }
  std::cout<<std::endl;
}

float sin16(uint16_t ang){
  return sinf(ang*(2.f*3.14159265359f/65536.f));
}

float cos16(uint16_t ang){
  return sin16(ang + 65536/4);
}

float tan16(uint16_t ang){
  return sin16(ang) / cos16(ang);;
}

Matrix4 rotatex(uint16_t ang){
  Matrix4 r;
  float sint,cost;
  sint = sin16(ang);
  cost = cos16(ang);

  return Matrix4(1.f,   0,      0, 0,
		 0,  cost, -sint , 0,
		 0,  sint, cost  , 0,
		 0,     0,      0, 1.f);
}

Matrix4 rotatey(uint16_t ang){
  Matrix4 r;
  float sint,cost;
  sint = sin16(ang);
  cost = cos16(ang);

  return Matrix4(   cost, 0    , sint , 0,
		    0   , 1.f  , 0    , 0,
		   -sint, 0    , cost , 0,
		    0   , 0    , 0    , 1.f);
}

Matrix4 rotatez(uint16_t ang){
  float sint,cost;
  sint = sin16(ang);
  cost = cos16(ang);
  return Matrix4(cost , -sint , 0    , 0,
		 sint , cost  , 0    , 0,
		 0    , 0     , 1.f  , 0,
		 0    , 0     , 0    , 1.f);
}

Matrix4 translation(fvector3 v){
  return Matrix4(1.f,0,0,0,
		 0,1.f,0,0,
		 0,0,1.f,0,
		 v.x,v.y,v.z,1.f);
}

Matrix4 magnify(float n){
  return Matrix4(1.f*n,0,0,0,
		 0,1.f*n,0,0,
		 0,0,1.f*n,0,
		 0,0,0,1.f);
}

Matrix4 magnify_y(float n){
  return Matrix4(1.f,0,0,0,
		 0,n,0,0,
		 0,0,1.f,0,
		 0,0,0,1.f);
}

// assert that len of axis must be 1.
Matrix4 rotation_axis_and_cosv(fvector3 u,float cosv){
  float s;
  float c;
  float oc;//one minus c

  c = cosv;
  s = sqrt(1-c*c);
  oc = 1.f-c;

  // return Matrix4(c+u.x*u.x*oc,
  // 		 u.y*u.x*oc+u.z*s,
  // 		 u.z*u.x*oc-u.y*s,
  // 		 0.f,

  // 		 u.x*u.y*oc-u.z*s,
  // 		 c+u.y*u.y*oc,
  // 		 u.z*u.y*oc+u.x*s,
  // 		 0.f,

  // 		 u.x*u.z*oc+u.y*s,
  // 		 u.y*u.z*oc-u.x*s,
  // 		 c+u.z*u.z*oc,
  // 		 0.f,
		 
  // 		 0.f,0.f,0.f,1.f);
		 
  
  return Matrix4(c+u.x*u.x*oc,u.x*u.y*oc-u.z*s,u.x*u.z*oc+u.y*s,0.f,
		 u.y*u.x*oc+u.z*s,c+u.y*u.y*oc,u.y*u.z*oc-u.x*s,0.f,
		 u.z*u.x*oc-u.y*s,u.z*u.y*oc+u.x*s,c+u.z*u.z*oc,0.f,
		 0.f,0.f,0.f,1.f);
		 
  
  //TODO
}




// assert that len of axis must be 1.
Matrix4 rotation_axis_and_angle(fvector3 u,float angle){
  float s;
  float c;
  float oc;//one minus c

  s = sinf(-angle);
  c = cosf(-angle);
  oc = 1.f-c;

  return Matrix4(c+u.x*u.x*oc,u.x*u.y*oc-u.z*s,u.x*u.z*oc+u.y*s,0.f,
		 u.y*u.x*oc+u.z*s,c+u.y*u.y*oc,u.y*u.z*oc-u.x*s,0.f,
		 u.z*u.x*oc-u.y*s,u.z*u.y*oc+u.x*s,c+u.z*u.z*oc,0.f,
		 0.f,0.f,0.f,1.f);
		 
  
  //TODO
}