neocogi 0.2.0

neocogi rendering lib
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224

//
// Copyright 2021-Present (c) Raja Lehtihet & Wael El Oraiby
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors
// may be used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
use crate::rs_math3d::*;

const TRACKBALL_SIZE    : f32 = 0.8;
const EPSILON           : f32 = 1.0 / (1024.0 * 1024.0);

#[repr(C)]
#[derive(Copy, Clone, Debug)]
pub struct Camera {
    target          : Vec3f,
    distance        : f32,
    rotation        : Quatf,

    pos             : Vec3f,
    up              : Vec3f,
    direction       : Vec3f,

    view            : Mat4f,
    projection      : Mat4f,

    fov             : f32,
    aspect          : f32,
    near_plane      : f32,
    far_plane       : f32,
}

impl Camera {
    fn project_to_track_ball(pt: &Vec2f, r: f32) -> f32 {
        let d = Vec2f::length(&pt);
        if d < r * 0.70710678118654752440 {
            // inside the sphere
            (r * r - d * d).sqrt()
        } else {
            // project on a hyperbola
            let t = r / 1.41421356237309504880;
            t * t / d
        }
    }

    pub fn tracball_rotate(&self, viewport: Dimensioni, from: &Vec2f, to: &Vec2f) -> Self {
        if Vec2f::length(&(*to - *from)).abs() == 0.0 {
            return *self;
        }

        let aspect    = (viewport.width as f32) / (viewport.height as f32);

        let start       = from;
        let end         = to;   // do we need to divide by aspect ?

        if Vec2f::length(&start) > TRACKBALL_SIZE || Vec2f::length(&end) > TRACKBALL_SIZE {
            return *self;
        }

        let zs = Self::project_to_track_ball(&start, TRACKBALL_SIZE);
        let ze = Self::project_to_track_ball(&end,   TRACKBALL_SIZE);

        let start_axis  = Vec3f::normalize(&Vec3f::new(start.x, start.y, zs));
        let end_axis    = Vec3f::normalize(&Vec3f::new(end.x  , end.y  , ze));

        // compute rotation axis
        let rot_axis    = -Vec3f::cross(&start_axis, &end_axis);
        let rot_axis_len= Vec3f::length(&rot_axis);

        if rot_axis_len < EPSILON {
            return *self;
        }

        let t = Vec3f::dot(&start_axis, &end_axis);
        let n = Quatf::normalize(&Quatf::new(rot_axis.x, rot_axis.y, rot_axis.z, 1.0 + t));
        Self::new(self.target, self.distance, Quatf::normalize(&(self.rotation * n)), self.fov, aspect, self.near_plane, self.far_plane)
    }

    fn unproject(pvm: &Mat4f, pt: &Vec3f) -> Vec3f {
        let lb      = Vec2f::new(-1.0, -1.0);
        let tr      = Vec2f::new(1.0, 1.0);
        unproject3(&Mat4f::identity(), &pvm, &lb, &tr, pt)
    }

    pub fn pan(&self, viewport: Dimensioni, from: &Vec2f, to: &Vec2f) -> Self {
        if Vec2f::length(&(*to - *from)).abs() == 0.0 {
            return *self;
        }

        let aspect    = (viewport.width as f32) / (viewport.height as f32);

        let pv_mat  = self.projection * self.view;

        //
        // these 2 are always going to give the normal as (0, 0, 1)
        // Keep them for informative reason
        //
        let near_center_proj= Vec3f::new(0.0, 0.0, -1.0);
        let near_center     = Self::unproject(&pv_mat, &near_center_proj);

        let far_center_proj = Vec3f::new(0.0, 0.0, 1.0);
        let far_center      = Self::unproject(&pv_mat, &far_center_proj);

        let normal          = Vec3f::normalize(&(near_center - far_center));
        let p               = Planef::new(&normal, &self.target);

        let near_prev_proj  = Vec3f::new(from.x, from.y, -1.0);
        let near_prev       = Self::unproject(&pv_mat, &near_prev_proj);
        let far_prev_proj   = Vec3f::new(from.x, from.y, 1.0);
        let far_prev        = Self::unproject(&pv_mat, &far_prev_proj);
        let prev_center     = p.intersect_ray(&Ray3f::new(&near_prev, &(far_prev - near_prev)));

        let near_curr_proj  = Vec3f::new(to.x, to.y, -1.0);
        let near_curr       = Self::unproject(&pv_mat, &near_curr_proj);
        let far_curr_proj   = Vec3f::new(to.x, to.y, 1.0);
        let far_curr        = Self::unproject(&pv_mat, &far_curr_proj);
        let curr_center     = p.intersect_ray(&Ray3f::new(&near_curr, &(far_curr - near_curr)));

        match (prev_center, curr_center) {
            (Some(p), Some(c)) => Self::new(self.target + (p - c), self.distance, self.rotation, self.fov, aspect, self.near_plane, self.far_plane),
            _ => *self
        }
    }

    pub fn new(target: Vec3f, distance: f32, rotation: Quatf, fov: f32, aspect: f32, near: f32, far: f32) -> Self {
        let pos = Vec3f::new(0.0, 0.0, 1.0);
        let up  = Vec3f::new(0.0, 1.0, 0.0);

        let rot_matrix  = Quatf::mat4(&rotation);
        let cam_pos     = target + transform_vec3(&rot_matrix, &pos) * distance;
        let cam_up      = transform_vec3(&rot_matrix, &up);
        let cam_dir     = Vec3f::normalize(&(target - cam_pos));

        let view        = lookat(&cam_pos, &target, &cam_up);
        let projection  = perspective(fov, aspect, near, far);

        Self {
            target          : target  ,
            distance        : distance,
            rotation        : rotation,

            pos             : cam_pos,
            up              : cam_up,
            direction       : cam_dir,

            view            : view,
            projection      : projection,

            fov             : fov,
            aspect          : aspect,
            near_plane      : near,
            far_plane       : far,
        }
    }

    fn update_matrices(&mut self) {
        let pos = Vec3f::new(0.0, 0.0, 1.0);
        let up  = Vec3f::new(0.0, 1.0, 0.0);

        let rot_matrix  = Quatf::mat4(&self.rotation);
        let cam_pos     = self.target + transform_vec3(&rot_matrix, &pos) * self.distance;
        let cam_up      = transform_vec3(&rot_matrix, &up);
        let cam_dir     = Vec3f::normalize(&(self.target - cam_pos));

        self.view        = lookat(&cam_pos, &self.target, &cam_up);
        self.projection = perspective(self.fov, self.aspect, self.near_plane, self.far_plane);
    }

    pub fn position(&self) -> Vec3f { self.pos }
    pub fn rotation(&self) -> Quatf { self.rotation }
    pub fn up(&self) -> Vec3f { self.up }
    pub fn direction(&self) -> Vec3f { self.direction }
    pub fn distance(&self) -> f32 { self.distance }
    pub fn target(&self) -> Vec3f { self.target }
    pub fn view_matrix(&self) -> Mat4f { self.view }
    pub fn projection_matrix(&self) -> Mat4f { self.projection }
    pub fn with_aspect(mut self, aspect: f32) -> Self {
        self.aspect = aspect;
        self.update_matrices();
        self
    }
    pub fn fov(&self) -> f32 { self.fov }
    pub fn with_fov(mut self, fov: f32) -> Self {
        self.fov    = fov;
        self.projection = perspective(self.fov, self.aspect, self.near_plane, self.far_plane);
        self
    }

    pub fn near_plane(&self) -> f32 { self.near_plane }
    pub fn with_near_plane(mut self, np: f32) -> Self {
        self.near_plane = np;
        self.update_matrices();
        self
    }

    pub fn far_plane(&self) -> f32 { self.far_plane }
    pub fn with_far_plane(mut self, fp: f32) -> Self {
        self.far_plane  = fp;
        self.update_matrices();
        self
    }
}