深度クリッピング < 点からはじめるラスタライザ

どれ、perspectiveにかけられる前後のワールド座標でもみるか

code:canvas/camera.rs

code:rs

code:rs

pub fn view_conversion(&self) -> Mat4x4 {

Mat4x4::translate(&-(&self.position))

}

いやちょっと待って。オブジェクトの置き方が変じゃないか？（カメラの裏側）

オブジェクトの位置を次のように修正

code:main.rs

Actor{

:

},

Actor{

:

}

code:main.rs

code:util/Vec4.rs

pub struct Vec4Project(Vec4);

impl Vec4Project {

pub fn new(v:Vec4) -> Self {

if v.w() < 1e-6 { Self(v*1e6) } else { Self(&v/v.w()) }

}

pub fn into_screen(&self, size:Point2) -> Vec4Screen {

let scale = size.y as f64 / 2.;

let v = &self.0 * scale + size.to_vec4() / 2.;

Vec4Screen(v)

}

}

code:camera.rs

pub fn snapshot(&mut self, canvas:&mut Canvas, actors:&Vec<Actor>) {

let perspective = self.perspective_conversion();

let view = self.view_conversion();

let pv = perspective*view;

for actor in actors {

let model = actor.model_conversion();

let pvm = &pv * &model;

];

canvas.draw_triangle(&projected, &actor.color);

}

}

code:bin/affine.rs

// ループ中

let t = stopwatch.elapsed_as_sec();

let points:Vec<_> = points.iter().map(|e| {

let m =

Mat4x4::translate(&Vec4::newvec( -0.5, -0.25, 0.))

* Mat4x4::rotation(&Vec4::newvec(0., 0., 1.), PI*t/6.)

* Mat4x4::scale(&Vec4::newvec(0.8, 0.5, 1.));

Vec4Project::new(m * e).into_screen(&canvas.size()).to_point2()

}).collect();

let white = Color::new(1., 1., 1., 1.);

for point in &points {

canvas.draw_point(point, &white);

}

canvas.draw_line(p1, p2, &white);

}

code:bin/triangle.rs

Vec4::newpoint(0.5, 0.2, 0.),

Vec4::newpoint(-0.8, -0.5, 0.),

Vec4::newpoint(-0.5, 0.5, 0.)

];

points.map(|e| Vec4Project::new(e).into_screen(&canvas.size()).to_point2());

という感じに書き換えていく。

カメラが本来必要ないコード（canvasに直接書き込んでいくコード）でcameraへの依存がなくなった

（ちょっと図形の配置を変えた）

https://gyazo.com/8b53bae6999168494a1503228eb95d68

そもそもの話

code:rs

fn area(p0:&Vec4, p1:&Vec4, p2:&Vec4) -> f64 {

let dx = p1 - p0;

let dy = p2 - p0;

dx.cross2d(&dy) // cross2dはよしなに定義

}

pub fn draw_triangle(

&mut self,

) {

// y基準でソート

let mut points = points.map(|p| p.0);

points.sort_by(|a, b| a.y().partial_cmp(&b.y()).unwrap_or(std::cmp::Ordering::Equal));

let bound_x = ClosedInterval::between(0,(self.width-1) as i32);

let bound_y = ClosedInterval::between(0,(self.height-1) as i32);

let bound_z = ClosedInterval::between(0.,1.);

let x_segment = ClosedInterval::range(points.iter().map(|p| p.x() as i32).collect::<Vec<_>>());

let y_segment = ClosedInterval::range(points.iter().map(|p| p.y() as i32).collect::<Vec<_>>());

let z_segment = ClosedInterval::range(points.iter().map(|p| p.z()).collect::<Vec<_>>());

let bound_w = ClosedInterval::between(0.,1.);

for y in &y_segment.and(&bound_y) {

for x in &x_segment.and(&bound_x) {

let p = Vec4::newpixel(x, y); // (x + 0.5, y + 0.5, 0, 0)に相当

if !bound_w.includes(w0) || !bound_w.includes(w1) || !bound_w.includes(w2) { continue; } // includesもよしなに定義

}

}

}

しかし めのまえがまっくらになった！

code:rs

二つの点が同じ場所に来るのはなんか変ではないか

Vec4 { e: [0.0, 0.0, 9.801980198019804, 10.0] } --> Vec4Screen(Vec4 { e: [320.0, 240.0, 0.9801980198019804, 1.0] }

Vec4 { e: [0.0, -2.0, 5.8011801180118026, 6.0] } ---> Vec4Screen(Vec4 { e: [320.0, 240.0, 0.9668633530019671, 1.0] }

はい

code:canvas/vec.rs

^

y

はぁ〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜

https://gyazo.com/8433e9e5ed71b08b988880235c24c258

https://gyazo.com/1900f8b29e11bf8bf78196b75c320efa

https://gyazo.com/6d6a6bc0e3df9ede467dae403ba0f425