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//! Methods for converting shapes into triangles.
use interpolation::lerp;
use crate::{
math::{multiply, orient, translate, Matrix2d, Scalar, Vec2d},
radians::Radians,
types::{Line, Polygon, Polygons, Radius, Rectangle, Resolution, SourceRectangle},
ImageSize, BACK_END_MAX_VERTEX_COUNT as BUFFER_SIZE,
};
/// Transformed x coordinate as f32.
#[inline(always)]
pub fn tx(m: Matrix2d, x: Scalar, y: Scalar) -> f32 {
(m[0][0] * x + m[0][1] * y + m[0][2]) as f32
}
/// Transformed y coordinate as f32.
#[inline(always)]
pub fn ty(m: Matrix2d, x: Scalar, y: Scalar) -> f32 {
(m[1][0] * x + m[1][1] * y + m[1][2]) as f32
}
/// Streams tweened polygons using linear interpolation.
#[inline(always)]
pub fn with_lerp_polygons_tri_list<F>(
m: Matrix2d,
polygons: Polygons<'_>,
tween_factor: Scalar,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
let poly_len = polygons.len() as Scalar;
// Map to interval between 0 and 1.
let tw = tween_factor % 1.0;
// Map negative values to positive.
let tw = if tw < 0.0 { tw + 1.0 } else { tw };
// Map to frame.
let tw = tw * poly_len;
// Get the current frame.
let frame = tw as usize;
// Get the next frame.
let next_frame = (frame + 1) % polygons.len();
let p0 = polygons[frame];
let p1 = polygons[next_frame];
// Get factor between frames.
let tw = tw - frame as Scalar;
let n = polygons[0].len();
stream_polygon_tri_list(m, (0..n).map(|j| lerp(&p0[j], &p1[j], &tw)), f);
}
/// Streams an ellipse specified by a resolution.
#[inline(always)]
pub fn with_ellipse_tri_list<F>(resolution: Resolution, m: Matrix2d, rect: Rectangle, f: F)
where
F: FnMut(&[[f32; 2]]),
{
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let (cw, ch) = (0.5 * w, 0.5 * h);
let (cx, cy) = (x + cw, y + ch);
let n = resolution;
stream_polygon_tri_list(
m,
(0..n).map(|i| {
let angle = i as Scalar / n as Scalar * <Scalar as Radians>::_360();
[cx + angle.cos() * cw, cy + angle.sin() * ch]
}),
f,
);
}
/// Streams a round border line.
#[inline(always)]
pub fn with_round_border_line_tri_list<F>(
resolution_cap: Resolution,
m: Matrix2d,
line: Line,
round_border_radius: Radius,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
let radius = round_border_radius;
let (x1, y1, x2, y2) = (line[0], line[1], line[2], line[3]);
let (dx, dy) = (x2 - x1, y2 - y1);
let w = (dx * dx + dy * dy).sqrt();
let m = multiply(m, translate([x1, y1]));
let m = multiply(m, orient(dx, dy));
let n = resolution_cap * 2;
stream_polygon_tri_list(
m,
(0..n).map(|j| {
// Detect the half circle from index.
// There is one half circle at each end of the line.
// Together they form a full circle if
// the length of the line is zero.
match j {
j if j >= resolution_cap => {
// Compute the angle to match start and end
// point of half circle.
// This requires an angle offset since
// the other end of line is the first half circle.
let angle = (j - resolution_cap) as Scalar / (resolution_cap - 1) as Scalar
* <Scalar as Radians>::_180()
+ <Scalar as Radians>::_180();
// Rotate 90 degrees since the line is horizontal.
let angle = angle + <Scalar as Radians>::_90();
[w + angle.cos() * radius, angle.sin() * radius]
}
j => {
// Compute the angle to match start and end
// point of half circle.
let angle =
j as Scalar / (resolution_cap - 1) as Scalar * <Scalar as Radians>::_180();
// Rotate 90 degrees since the line is horizontal.
let angle = angle + <Scalar as Radians>::_90();
[angle.cos() * radius, angle.sin() * radius]
}
}
}),
f,
);
}
/// Streams a round rectangle.
#[inline(always)]
pub fn with_round_rectangle_tri_list<F>(
resolution_corner: Resolution,
m: Matrix2d,
rect: Rectangle,
round_radius: Radius,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
use vecmath::traits::FromPrimitive;
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let radius = round_radius;
let n = resolution_corner * 4;
stream_polygon_tri_list(
m,
(0..n).map(|j| {
// Detect quarter circle from index.
// There is one quarter circle at each corner.
// Together they form a full circle if
// each side of rectangle is 2 times the radius.
match j {
j if j >= resolution_corner * 3 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since this
// is the last quarter.
let angle: Scalar = (j - resolution_corner * 3) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as FromPrimitive>::from_f64(3.0) * <Scalar as Radians>::_90();
// Set center of the circle to the last corner.
let (cx, cy) = (x + w - radius, y + radius);
[cx + angle.cos() * radius, cy + angle.sin() * radius]
}
j if j >= resolution_corner * 2 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since
// this is the second last quarter.
let angle = (j - resolution_corner * 2) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as Radians>::_180();
// Set center of the circle to the second last corner.
let (cx, cy) = (x + radius, y + radius);
[cx + angle.cos() * radius, cy + angle.sin() * radius]
}
j if j >= resolution_corner * 1 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since
// this is the second quarter.
let angle = (j - resolution_corner) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as Radians>::_90();
// Set center of the circle to the second corner.
let (cx, cy) = (x + radius, y + h - radius);
[cx + angle.cos() * radius, cy + angle.sin() * radius]
}
j => {
// Compute the angle to match start and end
// point of quarter circle.
let angle = j as Scalar / (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90();
// Set center of the circle to the first corner.
let (cx, cy) = (x + w - radius, y + h - radius);
[cx + angle.cos() * radius, cy + angle.sin() * radius]
}
}
}),
f,
);
}
/// Streams a polygon into tri list.
/// Uses buffers that fit inside L1 cache.
///
/// `polygon` is a function that provides the vertices that comprise the polygon. Each
/// call to E will return a new vertex until there are none left.
///
/// `f` is a function that consumes the tri list constructed by the output of `polygon`,
/// one chunk (buffer) at a time.
///
/// Each chunk (buffer) is a fixed size array) of the format:
///
/// ```
/// // [[x0, y0], [x1, y1], [x2, y2], [x3, y3], ... [y4, y5], ...]
/// // ^--------------------------^ ^--------------------^
/// // 3 Points of triangle 3 points of second triangle,
/// ```
///
/// Together all the chunks comprise the full tri list. Each time the buffer size is
/// reached, that chunk is fed to `f`, then this function proceeds using a new buffer
/// until a call to `polygon` returns `None`, indicating there are no points left in
/// the polygon. (in which case the last partially filled buffer is sent to `f`)
pub fn stream_polygon_tri_list<E, F>(m: Matrix2d, mut polygon: E, mut f: F)
where
E: Iterator<Item = Vec2d>,
F: FnMut(&[[f32; 2]]),
{
let mut vertices: [[f32; 2]; BUFFER_SIZE] = [[0.0; 2]; BUFFER_SIZE];
// Get the first point which will be used a lot.
let fp = match polygon.next() {
None => return,
Some(val) => val,
};
let f1 = [tx(m, fp[0], fp[1]), ty(m, fp[0], fp[1])];
let gp = match polygon.next() {
None => return,
Some(val) => val,
};
let mut g1 = [tx(m, gp[0], gp[1]), ty(m, gp[0], gp[1])];
let mut i = 0;
let vertices_per_triangle = 3;
let align_vertices = vertices_per_triangle;
'read_vertices: loop {
let ind_out = i * align_vertices;
vertices[ind_out] = f1;
// Copy vertex.
let p = match polygon.next() {
None => break 'read_vertices,
Some(val) => val,
};
let pos = [tx(m, p[0], p[1]), ty(m, p[0], p[1])];
vertices[ind_out + 1] = g1;
vertices[ind_out + 2] = pos;
g1 = pos;
i += 1;
// Buffer is full.
if (i + 1) * align_vertices > BUFFER_SIZE {
// Send chunk and start over.
f(&vertices[0..i * align_vertices]);
i = 0;
}
}
if i > 0 {
f(&vertices[0..i * align_vertices]);
}
}
/// Streams an ellipse border specified by a resolution.
#[inline(always)]
pub fn with_ellipse_border_tri_list<F>(
resolution: Resolution,
m: Matrix2d,
rect: Rectangle,
border_radius: Radius,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let (cw, ch) = (0.5 * w, 0.5 * h);
let (cw1, ch1) = (cw + border_radius, ch + border_radius);
let (cw2, ch2) = (cw - border_radius, ch - border_radius);
let (cx, cy) = (x + cw, y + ch);
let n = resolution;
let mut i = 0;
stream_quad_tri_list(
m,
|| {
if i > n {
return None;
}
let angle = i as Scalar / n as Scalar * <Scalar as Radians>::_360();
let cos = angle.cos();
let sin = angle.sin();
i += 1;
Some((
[cx + cos * cw1, cy + sin * ch1],
[cx + cos * cw2, cy + sin * ch2],
))
},
f,
);
}
/// Streams an arc between the two radian boundaries.
#[inline(always)]
pub fn with_arc_tri_list<F>(
start_radians: Scalar,
end_radians: Scalar,
resolution: Resolution,
m: Matrix2d,
rect: Rectangle,
border_radius: Radius,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let (cw, ch) = (0.5 * w, 0.5 * h);
let (cw1, ch1) = (cw + border_radius, ch + border_radius);
let (cw2, ch2) = (cw - border_radius, ch - border_radius);
let (cx, cy) = (x + cw, y + ch);
let mut i = 0;
let twopi = <Scalar as Radians>::_360();
let max_seg_size = twopi / resolution as Scalar;
let (start_radians, delta) = if (end_radians - start_radians).abs() >= twopi {
// Remove overlap.
(0.0, twopi)
} else {
// Take true modulus by 2pi.
(
start_radians,
(((end_radians - start_radians) % twopi) + twopi) % twopi,
)
};
// Taking ceiling here implies that the resolution parameter provides a
// lower bound on the drawn resolution.
let n_quads = (delta / max_seg_size).ceil() as u64;
// n_quads * seg_size exactly spans the included angle.
let seg_size = delta / n_quads as Scalar;
stream_quad_tri_list(
m,
|| {
if i > n_quads {
return None;
}
let angle = start_radians + (i as Scalar * seg_size);
let cos = angle.cos();
let sin = angle.sin();
i += 1;
Some((
[cx + cos * cw1, cy + sin * ch1],
[cx + cos * cw2, cy + sin * ch2],
))
},
f,
);
}
/// Streams a round rectangle border.
#[inline(always)]
pub fn with_round_rectangle_border_tri_list<F>(
resolution_corner: Resolution,
m: Matrix2d,
rect: Rectangle,
round_radius: Radius,
border_radius: Radius,
f: F,
) where
F: FnMut(&[[f32; 2]]),
{
use vecmath::traits::FromPrimitive;
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let radius = round_radius;
let radius1 = round_radius + border_radius;
let radius2 = round_radius - border_radius;
let n = resolution_corner * 4;
let mut i = 0;
stream_quad_tri_list(
m,
|| {
if i > n {
return None;
}
let j = i;
i += 1;
// Detect quarter circle from index.
// There is one quarter circle at each corner.
// Together they form a full circle if
// each side of rectangle is 2 times the radius.
match j {
j if j == n => {
let (cx, cy) = (x + w - radius, y + h - radius);
Some(([cx + radius1, cy], [cx + radius2, cy]))
}
j if j >= resolution_corner * 3 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since this
// is the last quarter.
let angle: Scalar = (j - resolution_corner * 3) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as FromPrimitive>::from_f64(3.0) * <Scalar as Radians>::_90();
// Set center of the circle to the last corner.
let (cx, cy) = (x + w - radius, y + radius);
let cos = angle.cos();
let sin = angle.sin();
Some((
[cx + cos * radius1, cy + sin * radius1],
[cx + cos * radius2, cy + sin * radius2],
))
}
j if j >= resolution_corner * 2 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since
// this is the second last quarter.
let angle = (j - resolution_corner * 2) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as Radians>::_180();
// Set center of the circle to the second last corner.
let (cx, cy) = (x + radius, y + radius);
let cos = angle.cos();
let sin = angle.sin();
Some((
[cx + cos * radius1, cy + sin * radius1],
[cx + cos * radius2, cy + sin * radius2],
))
}
j if j >= resolution_corner * 1 => {
// Compute the angle to match start and end
// point of quarter circle.
// This requires an angle offset since
// this is the second quarter.
let angle = (j - resolution_corner) as Scalar
/ (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90()
+ <Scalar as Radians>::_90();
// Set center of the circle to the second corner.
let (cx, cy) = (x + radius, y + h - radius);
let cos = angle.cos();
let sin = angle.sin();
Some((
[cx + cos * radius1, cy + sin * radius1],
[cx + cos * radius2, cy + sin * radius2],
))
}
j => {
// Compute the angle to match start and end
// point of quarter circle.
let angle = j as Scalar / (resolution_corner - 1) as Scalar
* <Scalar as Radians>::_90();
// Set center of the circle to the first corner.
let (cx, cy) = (x + w - radius, y + h - radius);
let cos = angle.cos();
let sin = angle.sin();
Some((
[cx + cos * radius1, cy + sin * radius1],
[cx + cos * radius2, cy + sin * radius2],
))
}
}
},
f,
);
}
/// Streams a quad into tri list.
///
/// Uses buffers that fit inside L1 cache.
/// The 'quad_edge' stream returns two points
/// defining the next edge.
///
/// `quad_edge` is a function that returns two vertices, which together comprise
/// one edge of a quad
///
///
/// `f` is a function that consumes the tri list constructed by the output of
/// `quad_edge`, one chunk (buffer) at a time
///
/// The tri list is series of buffers (fixed size array) of the format:
///
/// ```
/// // [[x0, y0], [x1, y1], [x2, y2], [x3, y3], ... [y4, y5], ...]
/// // ^--------------------------^ ^--------------------^
/// // 3 Points of triangle 3 points of second triangle,
/// // ^------------------------------------^ __
/// // Two triangles together form a single quad |\\ 2|
/// // |1\\ |
/// // |__\\|
/// ```
/// Together all the chunks comprise the full tri list. Each time the buffer size is
/// reached, that chunk is fed to `f`, then this function proceeds using a new buffer
/// until a call to `quad_edge` returns `None`, indicating there are no more edges left.
/// (in which case the last partially filled buffer is sent to `f`)
pub fn stream_quad_tri_list<E, F>(m: Matrix2d, mut quad_edge: E, mut f: F)
where
E: FnMut() -> Option<(Vec2d, Vec2d)>,
F: FnMut(&[[f32; 2]]),
{
let mut vertices: [[f32; 2]; BUFFER_SIZE] = [[0.0; 2]; BUFFER_SIZE];
// Get the two points .
let (fp1, fp2) = match quad_edge() {
None => return,
Some((val1, val2)) => (val1, val2),
};
// Transform the points using the matrix.
let mut f1 = [tx(m, fp1[0], fp1[1]), ty(m, fp1[0], fp1[1])];
let mut f2 = [tx(m, fp2[0], fp2[1]), ty(m, fp2[0], fp2[1])];
// Counts the quads.
let mut i = 0;
let triangles_per_quad = 2;
let vertices_per_triangle = 3;
let align_vertices = triangles_per_quad * vertices_per_triangle;
loop {
// Read two more points.
let (gp1, gp2) = match quad_edge() {
None => break,
Some((val1, val2)) => (val1, val2),
};
// Transform the points using the matrix.
let g1 = [tx(m, gp1[0], gp1[1]), ty(m, gp1[0], gp1[1])];
let g2 = [tx(m, gp2[0], gp2[1]), ty(m, gp2[0], gp2[1])];
let ind_out = i * align_vertices;
// First triangle.
vertices[ind_out + 0] = f1;
vertices[ind_out + 1] = f2;
vertices[ind_out + 2] = g1;
// Second triangle.
vertices[ind_out + 3] = f2;
vertices[ind_out + 4] = g1;
vertices[ind_out + 5] = g2;
// Next quad.
i += 1;
// Set next current edge.
f1 = g1;
f2 = g2;
// Buffer is full.
if (i + 1) * align_vertices > BUFFER_SIZE {
// Send chunk and start over.
f(&vertices[0..i * align_vertices]);
i = 0;
}
}
if i > 0 {
f(&vertices[0..i * align_vertices]);
}
}
/// Splits polygon into convex segments.
/// Create a buffer that fits into L1 cache with 1KB overhead.
///
/// See stream_polygon_tri_list docs for detailed explanation.
pub fn with_polygon_tri_list<F>(m: Matrix2d, polygon: Polygon<'_>, f: F)
where
F: FnMut(&[[f32; 2]]),
{
stream_polygon_tri_list(m, (0..polygon.len()).map(|i| polygon[i]), f);
}
/// Creates triangle list vertices from rectangle.
#[inline(always)]
pub fn rect_tri_list_xy(m: Matrix2d, rect: Rectangle) -> [[f32; 2]; 6] {
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let (x2, y2) = (x + w, y + h);
[
[tx(m, x, y), ty(m, x, y)],
[tx(m, x2, y), ty(m, x2, y)],
[tx(m, x, y2), ty(m, x, y2)],
[tx(m, x2, y), ty(m, x2, y)],
[tx(m, x2, y2), ty(m, x2, y2)],
[tx(m, x, y2), ty(m, x, y2)],
]
}
/// Creates triangle list vertices from rectangle.
#[inline(always)]
pub fn rect_border_tri_list_xy(
m: Matrix2d,
rect: Rectangle,
border_radius: Radius,
) -> [[f32; 2]; 24] {
let (x, y, w, h) = (rect[0], rect[1], rect[2], rect[3]);
let (w1, h1) = (w + border_radius, h + border_radius);
let (w2, h2) = (w - border_radius, h - border_radius);
let (x11, y11) = (x - border_radius, y - border_radius);
let (x21, y21) = (x + border_radius, y + border_radius);
let (x12, y12) = (x + w1, y + h1);
let (x22, y22) = (x + w2, y + h2);
[
[tx(m, x11, y11), ty(m, x11, y11)],
[tx(m, x12, y11), ty(m, x12, y11)],
[tx(m, x21, y21), ty(m, x21, y21)],
[tx(m, x21, y21), ty(m, x21, y21)],
[tx(m, x12, y11), ty(m, x12, y11)],
[tx(m, x22, y21), ty(m, x22, y21)],
[tx(m, x22, y21), ty(m, x22, y21)],
[tx(m, x12, y11), ty(m, x12, y11)],
[tx(m, x12, y12), ty(m, x12, y12)],
[tx(m, x22, y21), ty(m, x22, y21)],
[tx(m, x12, y12), ty(m, x12, y12)],
[tx(m, x22, y22), ty(m, x22, y22)],
[tx(m, x12, y12), ty(m, x12, y12)],
[tx(m, x22, y22), ty(m, x22, y22)],
[tx(m, x11, y12), ty(m, x11, y12)],
[tx(m, x22, y22), ty(m, x22, y22)],
[tx(m, x11, y12), ty(m, x11, y12)],
[tx(m, x21, y22), ty(m, x21, y22)],
[tx(m, x11, y12), ty(m, x11, y12)],
[tx(m, x21, y21), ty(m, x21, y21)],
[tx(m, x21, y22), ty(m, x21, y22)],
[tx(m, x11, y12), ty(m, x11, y12)],
[tx(m, x11, y11), ty(m, x11, y11)],
[tx(m, x21, y21), ty(m, x21, y21)],
]
}
/// Creates triangle list texture coords from image.
#[inline(always)]
pub fn rect_tri_list_uv<I: ImageSize>(image: &I, source_rect: SourceRectangle) -> [[f32; 2]; 6] {
let (w, h) = image.get_size();
let (src_x, src_y, src_w, src_h) = (
source_rect[0],
source_rect[1],
source_rect[2],
source_rect[3],
);
let x1 = src_x as f32 / w as f32;
let y1 = src_y as f32 / h as f32;
let x2 = (src_w + src_x) as f32 / w as f32;
let y2 = (src_h + src_y) as f32 / h as f32;
[[x1, y1], [x2, y1], [x1, y2], [x2, y1], [x2, y2], [x1, y2]]
}