makepad_draw/shader/
draw_trapezoid.rs

1pub use {
2    std::{
3        rc::Rc,
4        cell::RefCell,
5        io::prelude::*,
6        fs::File,
7        collections::HashMap,
8    },
9    crate::{
10        makepad_platform::*,
11        cx_2d::Cx2d,
12        turtle::{Walk, Layout},
13        draw_list_2d::{ManyInstances, DrawList2d, RedrawingApi},
14        geometry::GeometryQuad2D,
15        makepad_vector::font::Glyph,
16        makepad_vector::trapezoidator::Trapezoidator,
17        makepad_vector::geometry::{AffineTransformation, Transform, Vector},
18        makepad_vector::internal_iter::*,
19        makepad_vector::path::PathIterator,
20    }
21};
22
23live_design!{
24    pub DrawTrapezoidVector= {{DrawTrapezoidVector}} {
25        varying v_p0: vec2;
26        varying v_p1: vec2;
27        varying v_p2: vec2;
28        varying v_p3: vec2;
29        varying v_pixel: vec2;
30        
31        fn intersect_line_segment_with_vertical_line(p0: vec2, p1: vec2, x: float) -> vec2 {
32            return vec2(
33                x,
34                mix(p0.y, p1.y, (x - p0.x) / (p1.x - p0.x))
35            );
36        }
37        
38        fn intersect_line_segment_with_horizontal_line(p0: vec2, p1: vec2, y: float) -> vec2 {
39            return vec2(
40                mix(p0.x, p1.x, (y - p0.y) / (p1.y - p0.y)),
41                y
42            );
43        }
44        
45        fn compute_clamped_right_trapezoid_area(p0: vec2, p1: vec2, p_min: vec2, p_max: vec2) -> float {
46            let x0 = clamp(p0.x, p_min.x, p_max.x);
47            let x1 = clamp(p1.x, p_min.x, p_max.x);
48            if (p0.x < p_min.x && p_min.x < p1.x) {
49                p0 = intersect_line_segment_with_vertical_line(p0, p1, p_min.x);
50            }
51            if (p0.x < p_max.x && p_max.x < p1.x) {
52                p1 = intersect_line_segment_with_vertical_line(p0, p1, p_max.x);
53            }
54            if (p0.y < p_min.y && p_min.y < p1.y) {
55                p0 = intersect_line_segment_with_horizontal_line(p0, p1, p_min.y);
56            }
57            if (p1.y < p_min.y && p_min.y < p0.y) {
58                p1 = intersect_line_segment_with_horizontal_line(p1, p0, p_min.y);
59            }
60            if (p0.y < p_max.y && p_max.y < p1.y) {
61                p1 = intersect_line_segment_with_horizontal_line(p0, p1, p_max.y);
62            }
63            if (p1.y < p_max.y && p_max.y < p0.y) {
64                p0 = intersect_line_segment_with_horizontal_line(p1, p0, p_max.y);
65            }
66            p0 = clamp(p0, p_min, p_max);
67            p1 = clamp(p1, p_min, p_max);
68            let h0 = p_max.y - p0.y;
69            let h1 = p_max.y - p1.y;
70            let a0 = (p0.x - x0) * h0;
71            let a1 = (p1.x - p0.x) * (h0 + h1) * 0.5;
72            let a2 = (x1 - p1.x) * h1;
73            return a0 + a1 + a2;
74        }
75        
76        fn compute_clamped_trapezoid_area(self, p_min: vec2, p_max: vec2) -> float {
77            let a0 = compute_clamped_right_trapezoid_area(self.v_p0, self.v_p1, p_min, p_max);
78            let a1 = compute_clamped_right_trapezoid_area(self.v_p2, self.v_p3, p_min, p_max);
79            return a0 - a1;
80        }
81        
82        fn fragment(self) -> vec4 {
83            let p_min = self.v_pixel.xy - 0.5;
84            let p_max = self.v_pixel.xy + 0.5;
85            let t_area = self.compute_clamped_trapezoid_area(p_min, p_max);
86            if self.chan < 0.5 {
87                return vec4(t_area, 0., 0., 0.);
88            }
89            if self.chan < 1.5 {
90                return vec4(0., t_area, 0., 0.);
91            }
92            if self.chan < 2.5 {
93                return vec4(0., 0., t_area, 0.);
94            }
95            return vec4(t_area, t_area, t_area, 0.);
96        }
97        
98        fn vertex(self) -> vec4 {
99            let pos_min = vec2(self.a_xs.x, min(self.a_ys.x, self.a_ys.y));
100            let pos_max = vec2(self.a_xs.y, max(self.a_ys.z, self.a_ys.w));
101            let pos = mix(pos_min - 1.0, pos_max + 1.0, self.geom_pos);
102            
103            // set the varyings
104            self.v_p0 = vec2(self.a_xs.x, self.a_ys.x);
105            self.v_p1 = vec2(self.a_xs.y, self.a_ys.y);
106            self.v_p2 = vec2(self.a_xs.x, self.a_ys.z);
107            self.v_p3 = vec2(self.a_xs.y, self.a_ys.w);
108            self.v_pixel = pos;
109            return self.camera_projection * vec4(pos, 0.0, 1.0);
110        }
111    }
112}
113
114
115#[derive(Live, LiveRegister)]
116#[repr(C)]
117pub struct DrawTrapezoidVector {
118    #[rust] pub trapezoidator: Trapezoidator,
119    #[live] pub geometry: GeometryQuad2D,
120    #[deref] pub draw_vars: DrawVars,
121    #[calc] pub a_xs: Vec2,
122    #[calc] pub a_ys: Vec4,
123    #[calc] pub chan: f32,
124}
125
126impl LiveHook for DrawTrapezoidVector{
127    fn before_apply(&mut self, cx: &mut Cx, apply: &mut Apply, index: usize, nodes: &[LiveNode]){
128        self.draw_vars.before_apply_init_shader(cx, apply, index, nodes, &self.geometry);
129    }
130    fn after_apply(&mut self, cx: &mut Cx, apply: &mut Apply, index: usize, nodes: &[LiveNode]) {
131        self.draw_vars.after_apply_update_self(cx, apply, index, nodes, &self.geometry);
132    }
133}
134
makepad_draw/shader/draw_trapezoid.rs

makepad_draw/shader/
draw_trapezoid.rs
