126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* mat4_lookat.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: gbrochar <gbrochar@student.42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2020/12/23 16:14:47 by gbrochar #+# #+# */
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/* Updated: 2020/12/23 17:05:21 by gbrochar ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "mat4.h"
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#include "vec3.h"
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#include "scop.h"
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t_mat4 mat4_lookat_make_mat(t_vec3 x, t_vec3 y, t_vec3 z, t_vec3 eye)
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{
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t_mat4 ret;
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ret.data[0] = x.x;
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ret.data[1] = x.y;
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ret.data[2] = x.z;
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ret.data[3] = 0;
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ret.data[4] = y.x;
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ret.data[5] = y.y;
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ret.data[6] = y.z;
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ret.data[7] = 0;
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ret.data[8] = z.x;
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ret.data[9] = z.y;
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ret.data[10] = z.z;
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ret.data[11] = 0;
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ret.data[12] = -(x.x * eye.x + x.y * eye.y + x.z * eye.z);
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ret.data[13] = -(y.x * eye.x + y.y * eye.y + y.z * eye.z);
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ret.data[14] = -(z.x * eye.x + z.y * eye.y + z.z * eye.z);
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ret.data[15] = 1;
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return (ret);
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}
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t_vec3 mat4_lookat_make_y(t_vec3 x, t_vec3 z)
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{
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t_vec3 y;
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double len;
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y.x = z.y * x.z - z.z * x.y;
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y.y = z.z * x.x - z.x * x.z;
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y.z = z.x * x.y - z.y * x.x;
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len = y.x * y.x + y.y * y.y + y.z * y.z;
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if (len - EPSILON < 0 && len + EPSILON > 0)
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{
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y.x = 0;
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y.y = 0;
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y.z = 0;
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}
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else
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{
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len = 1.0 / sqrt(len);
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y.x *= len;
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y.y *= len;
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y.z *= len;
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}
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return (y);
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}
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t_vec3 mat4_lookat_make_x(t_vec3 z, t_vec3 up)
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{
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t_vec3 x;
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double len;
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x.x = up.y * z.z - up.z * z.y;
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x.y = up.z * z.x - up.x * z.z;
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x.z = up.x * z.y - up.y * z.x;
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len = x.x * x.x + x.y * x.y + x.z * x.z;
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if (len - EPSILON < 0 && len + EPSILON > 0)
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{
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x.x = 0;
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x.y = 0;
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x.z = 0;
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}
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else
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{
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len = 1.0 / sqrt(len);
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x.x *= len;
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x.y *= len;
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x.z *= len;
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}
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return (x);
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}
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t_vec3 mat4_lookat_make_z(t_vec3 eye, t_vec3 target)
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{
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t_vec3 z;
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double len;
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z.x = eye.x - target.x;
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z.y = eye.y - target.y;
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z.z = eye.z - target.z;
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len = z.x * z.x + z.y * z.y + z.z * z.z;
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if (len - EPSILON < 0 && len + EPSILON > 0)
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{
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z.x = 0;
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z.y = 0;
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z.z = 1;
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}
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else
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{
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len = 1.0 / sqrt(len);
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z.x *= len;
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z.y *= len;
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z.z *= len;
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}
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return (z);
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}
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t_mat4 mat4_lookat(t_vec3 eye, t_vec3 up, t_vec3 target)
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{
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t_vec3 z;
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t_vec3 x;
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t_vec3 y;
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z = mat4_lookat_make_z(eye, target);
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x = mat4_lookat_make_x(z, up);
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y = mat4_lookat_make_y(x, z);
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return (mat4_lookat_make_mat(x, y, z, eye));
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}
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