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v/vlib/gg/draw.c.v

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// Copyright (c) 2019-2023 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license that can be found in the LICENSE file.
module gg
import gx
import sokol
import sokol.sgl
import math
// draw_pixel draws one pixel on the screen.
//
// NOTE calling this function frequently is very *inefficient*,
// for drawing shapes it's recommended to draw whole primitives with
// functions like `draw_rect_empty` or `draw_triangle_empty` etc.
[inline]
pub fn (ctx &Context) draw_pixel(x f32, y f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_points()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.end()
}
// draw_pixels draws pixels from an array of points [x, y, x2, y2, etc...]
//
// NOTE calling this function frequently is very *inefficient*,
// for drawing shapes it's recommended to draw whole primitives with
// functions like `draw_rect_empty` or `draw_triangle_empty` etc.
[direct_array_access; inline]
pub fn (ctx &Context) draw_pixels(points []f32, c gx.Color) {
if points.len % 2 != 0 {
return
}
len := points.len / 2
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_points()
for i in 0 .. len {
x, y := points[i * 2], points[i * 2 + 1]
sgl.v2f(x * ctx.scale, y * ctx.scale)
}
sgl.end()
}
// draw_line draws a line between the points `x,y` and `x2,y2` in color `c`.
pub fn (ctx &Context) draw_line(x f32, y f32, x2 f32, y2 f32, c gx.Color) {
$if macos {
if ctx.native_rendering {
// Make the line more clear on hi dpi screens: draw a rectangle
mut width := math.abs(x2 - x)
mut height := math.abs(y2 - y)
if width == 0 {
width = 1
} else if height == 0 {
height = 1
}
ctx.draw_rect_filled(x, y, f32(width), f32(height), c)
return
}
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.v2f(x2 * ctx.scale, y2 * ctx.scale)
sgl.end()
}
// draw_line_with_config draws a line between the points `x,y` and `x2,y2` using `PenConfig`.
pub fn (ctx &Context) draw_line_with_config(x f32, y f32, x2 f32, y2 f32, config PenConfig) {
if config.color.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
if config.thickness <= 0 {
return
}
nx := x * ctx.scale
ny := y * ctx.scale
nx2 := x2 * ctx.scale
ny2 := y2 * ctx.scale
dx := nx2 - nx
dy := ny2 - ny
length := math.sqrtf(math.powf(x2 - x, 2) + math.powf(y2 - y, 2))
theta := f32(math.atan2(dy, dx))
sgl.push_matrix()
sgl.translate(nx, ny, 0)
sgl.rotate(theta, 0, 0, 1)
sgl.translate(-nx, -ny, 0)
if config.line_type == .solid {
ctx.draw_rect_filled(x, y, length, config.thickness, config.color)
} else {
size := if config.line_type == .dotted { config.thickness } else { config.thickness * 3 }
space := if size == 1 { 2 } else { size }
mut available := length
mut start_x := x
for i := 0; available > 0; i++ {
if i % 2 == 0 {
ctx.draw_rect_filled(start_x, y, size, config.thickness, config.color)
available -= size
start_x += size
continue
}
available -= space
start_x += space
}
}
sgl.pop_matrix()
}
// draw_poly_empty draws the outline of a polygon, given an array of points, and a color.
// NOTE that the points must be given in clockwise winding order.
pub fn (ctx &Context) draw_poly_empty(points []f32, c gx.Color) {
len := points.len / 2
if points.len % 2 != 0 || len < 3 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
for i in 0 .. len {
sgl.v2f(points[2 * i] * ctx.scale, points[2 * i + 1] * ctx.scale)
}
sgl.v2f(points[0] * ctx.scale, points[1] * ctx.scale)
sgl.end()
}
// draw_convex_poly draws a convex polygon, given an array of points, and a color.
// NOTE that the points must be given in clockwise winding order.
// The contents of the `points` array should be `x` and `y` coordinate pairs.
pub fn (ctx &Context) draw_convex_poly(points []f32, c gx.Color) {
len := points.len / 2
if points.len % 2 != 0 || len < 3 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_triangle_strip()
x0 := points[0] * ctx.scale
y0 := points[1] * ctx.scale
for i in 1 .. len {
x := points[i * 2] * ctx.scale
y := points[i * 2 + 1] * ctx.scale
sgl.v2f(x, y)
if i & 0 == 0 {
sgl.v2f(x0, y0)
}
}
sgl.end()
}
// draw_rect_empty draws the outline of a rectangle.
// `x`,`y` is the top-left corner of the rectangle.
// `w` is the width, `h` is the height and `c` is the color of the outline.
pub fn (ctx &Context) draw_rect_empty(x f32, y f32, w f32, h f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.v2f((x + w) * ctx.scale, y * ctx.scale)
sgl.v2f((x + w) * ctx.scale, (y + h) * ctx.scale)
sgl.v2f(x * ctx.scale, (y + h) * ctx.scale)
sgl.v2f(x * ctx.scale, (y - 1) * ctx.scale)
sgl.end()
}
// draw_rect_filled draws a filled rectangle.
// `x`,`y` is the top-left corner of the rectangle.
// `w` is the width, `h` is the height and `c` is the color of the fill.
pub fn (ctx &Context) draw_rect_filled(x f32, y f32, w f32, h f32, c gx.Color) {
$if macos {
if ctx.native_rendering {
C.darwin_draw_rect(x, ctx.height - (y + h), w, h, c)
return
}
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_quads()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.v2f((x + w) * ctx.scale, y * ctx.scale)
sgl.v2f((x + w) * ctx.scale, (y + h) * ctx.scale)
sgl.v2f(x * ctx.scale, (y + h) * ctx.scale)
sgl.end()
}
// draw_rounded_rect_empty draws the outline of a rounded rectangle with a thickness of 1 px.
// `x`,`y` is the top-left corner of the rectangle.
// `w` is the width, `h` is the height.
// `radius` is the radius of the corner-rounding in pixels.
// `c` is the color of the outline.
pub fn (ctx &Context) draw_rounded_rect_empty(x f32, y f32, w f32, h f32, radius f32, c gx.Color) {
if w <= 0 || h <= 0 || radius < 0 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
mut new_radius := radius
if w >= h && radius > h / 2 {
new_radius = h / 2
} else if radius > w / 2 {
new_radius = w / 2
}
r := new_radius * ctx.scale
sx := x * ctx.scale // start point x
sy := y * ctx.scale
width := w * ctx.scale
height := h * ctx.scale
// circle center coordinates
ltx := sx + r
lty := sy + r
rtx := sx + width - r
rty := lty
rbx := rtx
rby := sy + height - r
lbx := ltx
lby := rby
mut rad := f32(0)
mut dx := f32(0)
mut dy := f32(0)
if r != 0 {
// left top quarter
sgl.begin_line_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(ltx - dx, lty - dy)
}
sgl.end()
// right top quarter
sgl.begin_line_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(rtx + dx, rty - dy)
}
sgl.end()
// right bottom quarter
sgl.begin_line_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(rbx + dx, rby + dy)
}
sgl.end()
// left bottom quarter
sgl.begin_line_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(lbx - dx, lby + dy)
}
sgl.end()
}
// Currently don't use 'gg.draw_line()' directly, it will repeatedly execute '*ctx.scale'.
sgl.begin_lines()
// top
sgl.v2f(ltx, sy)
sgl.v2f(rtx, sy)
// right
sgl.v2f(rtx + r, rty)
sgl.v2f(rtx + r, rby)
// bottom
sgl.v2f(lbx, lby + r)
sgl.v2f(rbx, rby + r)
// left
sgl.v2f(sx, lty)
sgl.v2f(sx, lby)
sgl.end()
}
// draw_rounded_rect_filled draws a filled rounded rectangle.
// `x`,`y` is the top-left corner of the rectangle.
// `w` is the width, `h` is the height .
// `radius` is the radius of the corner-rounding in pixels.
// `c` is the color of the filled.
pub fn (ctx &Context) draw_rounded_rect_filled(x f32, y f32, w f32, h f32, radius f32, c gx.Color) {
if w <= 0 || h <= 0 || radius < 0 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
mut new_radius := radius
if w >= h && radius > h / 2 {
new_radius = h / 2
} else if radius > w / 2 {
new_radius = w / 2
}
r := new_radius * ctx.scale
sx := x * ctx.scale // start point x
sy := y * ctx.scale
width := w * ctx.scale
height := h * ctx.scale
// circle center coordinates
ltx := sx + r
lty := sy + r
rtx := sx + width - r
rty := lty
rbx := rtx
rby := sy + height - r
lbx := ltx
lby := rby
mut rad := f32(0)
mut dx := f32(0)
mut dy := f32(0)
if r != 0 {
// left top quarter
sgl.begin_triangle_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(ltx - dx, lty - dy)
sgl.v2f(ltx, lty)
}
sgl.end()
// right top quarter
sgl.begin_triangle_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(rtx + dx, rty - dy)
sgl.v2f(rtx, rty)
}
sgl.end()
// right bottom quarter
sgl.begin_triangle_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(rbx + dx, rby + dy)
sgl.v2f(rbx, rby)
}
sgl.end()
// left bottom quarter
sgl.begin_triangle_strip()
for i in 0 .. 31 {
rad = f32(math.radians(i * 3))
dx = r * math.cosf(rad)
dy = r * math.sinf(rad)
sgl.v2f(lbx - dx, lby + dy)
sgl.v2f(lbx, lby)
}
sgl.end()
}
// Separate drawing is to prevent transparent color overlap
// top rectangle
sgl.begin_quads()
sgl.v2f(ltx, sy)
sgl.v2f(rtx, sy)
sgl.v2f(rtx, rty)
sgl.v2f(ltx, lty)
sgl.end()
// middle rectangle
sgl.begin_quads()
sgl.v2f(sx, lty)
sgl.v2f(rtx + r, rty)
sgl.v2f(rbx + r, rby)
sgl.v2f(sx, lby)
sgl.end()
// bottom rectangle
sgl.begin_quads()
sgl.v2f(lbx, lby)
sgl.v2f(rbx, rby)
sgl.v2f(rbx, rby + r)
sgl.v2f(lbx, rby + r)
sgl.end()
}
// draw_triangle_empty draws the outline of a triangle.
// `x`,`y` defines the first point
// `x2`,`y2` defines the second point
// `x3`,`y3` defines the third point
// `c` is the color of the outline.
pub fn (ctx &Context) draw_triangle_empty(x f32, y f32, x2 f32, y2 f32, x3 f32, y3 f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.v2f(x2 * ctx.scale, y2 * ctx.scale)
sgl.v2f(x3 * ctx.scale, y3 * ctx.scale)
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.end()
}
// draw_triangle_filled draws a filled triangle.
// `x`,`y` defines the first point
// `x2`,`y2` defines the second point
// `x3`,`y3` defines the third point
// `c` is the color of the outline.
pub fn (ctx &Context) draw_triangle_filled(x f32, y f32, x2 f32, y2 f32, x3 f32, y3 f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_triangles()
sgl.v2f(x * ctx.scale, y * ctx.scale)
sgl.v2f(x2 * ctx.scale, y2 * ctx.scale)
sgl.v2f(x3 * ctx.scale, y3 * ctx.scale)
sgl.end()
}
// draw_square_empty draws the outline of a square.
// `x`,`y` is the top-left corner of the square.
// `s` is the length of each side of the square.
// `c` is the color of the outline.
[inline]
pub fn (ctx &Context) draw_square_empty(x f32, y f32, s f32, c gx.Color) {
ctx.draw_rect_empty(x, y, s, s, c)
}
// draw_square_filled draws a filled square.
// `x`,`y` is the top-left corner of the square.
// `s` is the length of each side of the square.
// `c` is the fill color.
[inline]
pub fn (ctx &Context) draw_square_filled(x f32, y f32, s f32, c gx.Color) {
ctx.draw_rect_filled(x, y, s, s, c)
}
// The table here is derived by looking at the result of vlib/gg/testdata/tweak_circles.vv
// and then choosing the most circle-ish drawing with the minimum number of segments.
const small_circle_segments = [0, 2, 4, 6, 6, 8, 8, 13, 10, 18, 12, 12, 10, 13, 16, 15, 16]!
[direct_array_access]
fn radius_to_segments(r f32) int {
if r < 30 {
ir := int(math.ceil(r))
if ir > 0 && ir < gg.small_circle_segments.len {
return gg.small_circle_segments[ir]
}
return ir
}
return int(math.ceil(math.tau * r / 8))
}
// draw_circle_empty draws the outline of a circle.
// `x`,`y` defines the center of the circle.
// `radius` defines the radius of the circle.
// `c` is the color of the outline.
pub fn (ctx &Context) draw_circle_empty(x f32, y f32, radius f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
nr := radius * ctx.scale
mut theta := f32(0)
mut xx := f32(0)
mut yy := f32(0)
segments := radius_to_segments(radius * ctx.scale)
sgl.begin_line_strip()
for i := 0; i < segments + 1; i++ {
theta = f32(math.tau) * f32(i) / f32(segments)
xx = nr * math.cosf(theta)
yy = nr * math.sinf(theta)
sgl.v2f(xx + nx, yy + ny)
}
sgl.end()
}
// draw_circle_filled draws a filled circle.
// `x`,`y` defines the center of the circle.
// `radius` defines the radius of the circle.
// `c` is the fill color.
pub fn (ctx &Context) draw_circle_filled(x f32, y f32, radius f32, c gx.Color) {
$if macos {
if ctx.native_rendering {
C.darwin_draw_circle(x - radius + 1, ctx.height - (y + radius + 3), radius,
c)
return
}
}
ctx.draw_polygon_filled(x, y, radius, radius_to_segments(radius * ctx.scale), 0, c)
}
// draw_polygon_filled draws a filled polygon.
// `x`,`y` defines the center of the polygon.
// `size` defines the size of the polygon.
// `edges` defines number of edges in the polygon.
// `rotation` defines rotation of the polygon.
// `c` is the fill color.
pub fn (ctx &Context) draw_polygon_filled(x f32, y f32, size f32, edges int, rotation f32, c gx.Color) {
if edges <= 0 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
nr := size * ctx.scale
mut theta := f32(0)
mut xx := f32(0)
mut yy := f32(0)
sgl.begin_triangle_strip()
for i := 0; i < edges + 1; i++ {
theta = f32(math.tau) * f32(i) / f32(edges)
xx = nr * math.cosf(theta + f32(math.radians(rotation)))
yy = nr * math.sinf(theta + f32(math.radians(rotation)))
sgl.v2f(xx + nx, yy + ny)
sgl.v2f(nx, ny)
}
sgl.end()
}
// draw_circle_with_segments draws a filled circle with a specific number of segments.
// `x`,`y` defines the center of the circle.
// `radius` defines the radius of the circle.
// `segments` affects how smooth/round the circle is.
// `c` is the fill color.
pub fn (ctx &Context) draw_circle_with_segments(x f32, y f32, radius f32, segments int, c gx.Color) {
ctx.draw_polygon_filled(x, y, radius, segments, 0, c)
}
// draw_circle_line draws the outline of a circle with a specific number of segments.
// `x`,`y` defines the center of the circle.
// `radius` defines the radius of the circle.
// `segments` affects how smooth/round the circle is.
// `c` is the color of the outline.
pub fn (ctx &Context) draw_circle_line(x f32, y f32, radius int, segments int, c gx.Color) {
if segments <= 0 {
return
}
$if macos {
if ctx.native_rendering {
C.darwin_draw_circle(x - radius + 1, ctx.height - (y + radius + 3), radius,
c)
return
}
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
nr := radius * ctx.scale
mut theta := f32(0)
mut xx := f32(0)
mut yy := f32(0)
sgl.begin_line_strip()
for i := 0; i < segments + 1; i++ {
theta = f32(math.tau) * f32(i) / f32(segments)
xx = nr * math.cosf(theta)
yy = nr * math.sinf(theta)
sgl.v2f(xx + nx, yy + ny)
}
sgl.end()
}
// draw_slice_empty draws the outline of a circle slice/pie
pub fn (ctx &Context) draw_slice_empty(x f32, y f32, radius f32, start_angle f32, end_angle f32, segments int, c gx.Color) {
if segments <= 0 || radius <= 0 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
theta := f32(end_angle - start_angle) / f32(segments)
tan_factor := math.tanf(theta)
rad_factor := math.cosf(theta)
mut xx := radius * ctx.scale * math.sinf(start_angle)
mut yy := radius * ctx.scale * math.cosf(start_angle)
sgl.begin_line_strip()
sgl.v2f(nx, ny)
for i := 0; i < segments + 1; i++ {
sgl.v2f(xx + nx, yy + ny)
xx, yy = xx + yy * tan_factor, yy - xx * tan_factor
xx *= rad_factor
yy *= rad_factor
}
sgl.v2f(nx, ny)
sgl.end()
}
// draw_slice_filled draws a filled circle slice/pie
// `x`,`y` defines the end point of the slice (center of the circle that the slice is part of).
// `radius` defines the radius ("length") of the slice.
// `start_angle` is the angle in radians at which the slice starts.
// `end_angle` is the angle in radians at which the slice ends.
// `segments` affects how smooth/round the slice is.
// `c` is the fill color.
pub fn (ctx &Context) draw_slice_filled(x f32, y f32, radius f32, start_angle f32, end_angle f32, segments int, c gx.Color) {
if segments <= 0 || radius < 0 {
return
}
if start_angle == end_angle {
ctx.draw_slice_empty(x, y, radius, start_angle, end_angle, 1, c)
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
theta := f32(end_angle - start_angle) / f32(segments)
tan_factor := math.tanf(theta)
rad_factor := math.cosf(theta)
mut xx := radius * ctx.scale * math.sinf(start_angle)
mut yy := radius * ctx.scale * math.cosf(start_angle)
sgl.begin_triangle_strip()
sgl.v2f(xx + nx, yy + ny)
for i := 0; i < segments; i++ {
xx, yy = xx + yy * tan_factor, yy - xx * tan_factor
xx *= rad_factor
yy *= rad_factor
sgl.v2f(xx + nx, yy + ny)
if i & 1 == 0 {
sgl.v2f(nx, ny)
}
}
sgl.end()
}
// draw_arc_line draws a line arc.
// `x`,`y` defines the end point of the arc (center of the circle that the arc is part of).
// `radius` defines the radius of the arc (length from the center point where the arc is drawn).
// `start_angle` is the angle in radians at which the arc starts.
// `end_angle` is the angle in radians at which the arc ends.
// `segments` affects how smooth/round the arc is.
// `c` is the color of the arc/outline.
pub fn (ctx Context) draw_arc_line(x f32, y f32, radius f32, start_angle f32, end_angle f32, segments int, c gx.Color) {
if segments <= 0 || radius < 0 {
return
}
if radius == 0 {
ctx.draw_pixel(x, y, c)
return
}
if start_angle == end_angle {
xx := x + radius * math.sinf(start_angle)
yy := y + radius * math.cosf(start_angle)
ctx.draw_pixel(xx, yy, c)
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
theta := f32(end_angle - start_angle) / f32(segments)
tan_factor := math.tanf(theta)
rad_factor := math.cosf(theta)
mut xx := radius * ctx.scale * math.sinf(start_angle)
mut yy := radius * ctx.scale * math.cosf(start_angle)
sgl.begin_line_strip()
sgl.v2f(nx + xx, ny + yy)
for i := 0; i < segments; i++ {
xx, yy = xx + yy * tan_factor, yy - xx * tan_factor
xx *= rad_factor
yy *= rad_factor
sgl.v2f(nx + xx, ny + yy)
}
sgl.end()
}
// draw_arc_empty draws the outline of an arc.
// `x`,`y` defines the end point of the arc (center of the circle that the arc is part of).
// `inner_radius` defines the radius of the arc (length from the center point where the arc is drawn).
// `thickness` defines how wide the arc is drawn.
// `start_angle` is the angle in radians at which the arc starts.
// `end_angle` is the angle in radians at which the arc ends.
// `segments` affects how smooth/round the arc is.
// `c` is the color of the arc outline.
pub fn (ctx &Context) draw_arc_empty(x f32, y f32, inner_radius f32, thickness f32, start_angle f32, end_angle f32, segments int, c gx.Color) {
outer_radius := inner_radius + thickness
if segments <= 0 || outer_radius < 0 {
return
}
if inner_radius <= 0 {
ctx.draw_slice_empty(x, y, outer_radius, start_angle, end_angle, segments, c)
return
}
if inner_radius == outer_radius {
ctx.draw_arc_line(x, y, outer_radius, start_angle, end_angle, segments, c)
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
theta := f32(end_angle - start_angle) / f32(segments)
tan_factor := math.tanf(theta)
rad_factor := math.cosf(theta)
sgl.begin_line_strip()
// outer
mut xx := outer_radius * ctx.scale * math.sinf(start_angle)
mut yy := outer_radius * ctx.scale * math.cosf(start_angle)
sxx, syy := xx, yy
sgl.v2f(nx + xx, ny + yy)
for i := 0; i < segments; i++ {
xx, yy = xx + yy * tan_factor, yy - xx * tan_factor
xx *= rad_factor
yy *= rad_factor
sgl.v2f(nx + xx, ny + yy)
}
// inner
xx = inner_radius * ctx.scale * math.sinf(end_angle)
yy = inner_radius * ctx.scale * math.cosf(end_angle)
sgl.v2f(nx + xx, ny + yy)
for i := 0; i < segments; i++ {
xx, yy = xx - yy * tan_factor, yy + xx * tan_factor
xx *= rad_factor
yy *= rad_factor
sgl.v2f(nx + xx, ny + yy)
}
sgl.v2f(nx + sxx, ny + syy)
sgl.end()
}
// draw_arc_filled draws a filled arc.
// `x`,`y` defines the central point of the arc (center of the circle that the arc is part of).
// `inner_radius` defines the radius of the arc (length from the center point where the arc is drawn).
// `thickness` defines how wide the arc is drawn.
// `start_angle` is the angle in radians at which the arc starts.
// `end_angle` is the angle in radians at which the arc ends.
// `segments` affects how smooth/round the arc is.
// `c` is the fill color of the arc.
pub fn (ctx &Context) draw_arc_filled(x f32, y f32, inner_radius f32, thickness f32, start_angle f32, end_angle f32, segments int, c gx.Color) {
outer_radius := inner_radius + thickness
if segments <= 0 || outer_radius < 0 {
return
}
if inner_radius <= 0 {
ctx.draw_slice_filled(x, y, outer_radius, start_angle, end_angle, segments, c)
return
}
if inner_radius == outer_radius {
ctx.draw_arc_line(x, y, outer_radius, start_angle, end_angle, segments, c)
return
}
if start_angle == end_angle {
ctx.draw_arc_empty(x, y, inner_radius, thickness, start_angle, end_angle, 1, c)
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
nx := x * ctx.scale
ny := y * ctx.scale
theta := f32(end_angle - start_angle) / f32(segments)
tan_factor := math.tanf(theta)
rad_factor := math.cosf(theta)
mut ix := ctx.scale * math.sinf(start_angle)
mut iy := ctx.scale * math.cosf(start_angle)
mut ox := outer_radius * ix
mut oy := outer_radius * iy
ix *= inner_radius
iy *= inner_radius
sgl.begin_triangle_strip()
sgl.v2f(nx + ix, ny + iy)
sgl.v2f(nx + ox, ny + oy)
for i := 0; i < segments; i++ {
ix, iy = ix + iy * tan_factor, iy - ix * tan_factor
ix *= rad_factor
iy *= rad_factor
sgl.v2f(nx + ix, ny + iy)
ox, oy = ox + oy * tan_factor, oy - ox * tan_factor
ox *= rad_factor
oy *= rad_factor
sgl.v2f(nx + ox, ny + oy)
}
sgl.end()
}
// draw_ellipse_empty draws the outline of an ellipse.
// `x`,`y` defines the center of the ellipse.
// `rw` defines the *width* radius of the ellipse.
// `rh` defines the *height* radius of the ellipse.
// `c` is the color of the outline.
pub fn (ctx &Context) draw_ellipse_empty(x f32, y f32, rw f32, rh f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
for i := 0; i < 360; i += 10 {
sgl.v2f(x + math.sinf(f32(math.radians(i))) * rw, y + math.cosf(f32(math.radians(i))) * rh)
sgl.v2f(x + math.sinf(f32(math.radians(i + 10))) * rw, y + math.cosf(f32(math.radians(i +
10))) * rh)
}
sgl.end()
}
// draw_ellipse_filled draws an opaque elipse.
// `x`,`y` defines the center of the ellipse.
// `rw` defines the *width* radius of the ellipse.
// `rh` defines the *height* radius of the ellipse.
// `c` is the fill color.
pub fn (ctx &Context) draw_ellipse_filled(x f32, y f32, rw f32, rh f32, c gx.Color) {
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_triangle_strip()
for i := 0; i < 360; i += 10 {
sgl.v2f(x, y)
sgl.v2f(x + math.sinf(f32(math.radians(i))) * rw, y + math.cosf(f32(math.radians(i))) * rh)
sgl.v2f(x + math.sinf(f32(math.radians(i + 10))) * rw, y + math.cosf(f32(math.radians(i +
10))) * rh)
}
sgl.end()
}
// draw_cubic_bezier draws a cubic Bézier curve, also known as a spline, from four points.
// The four points is provided as one `points` array which contains a stream of point pairs (x and y coordinates).
// Thus a cubic Bézier could be declared as: `points := [x1, y1, control_x1, control_y1, control_x2, control_y2, x2, y2]`.
// Please see `draw_cubic_bezier_in_steps` to control the amount of steps (segments) used to draw the curve.
pub fn (ctx &Context) draw_cubic_bezier(points []f32, c gx.Color) {
ctx.draw_cubic_bezier_in_steps(points, u32(30 * ctx.scale), c)
}
// draw_cubic_bezier_in_steps draws a cubic Bézier curve, also known as a spline, from four points.
// The smoothness of the curve can be controlled with the `steps` parameter. `steps` determines how many iterations is
// taken to draw the curve.
// The four points is provided as one `points` array which contains a stream of point pairs (x and y coordinates).
// Thus a cubic Bézier could be declared as: `points := [x1, y1, control_x1, control_y1, control_x2, control_y2, x2, y2]`.
pub fn (ctx &Context) draw_cubic_bezier_in_steps(points []f32, steps u32, c gx.Color) {
if steps <= 0 || points.len != 8 {
return
}
if c.a != 255 {
sgl.load_pipeline(ctx.pipeline.alpha)
}
sgl.c4b(c.r, c.g, c.b, c.a)
sgl.begin_line_strip()
p1_x, p1_y := points[0], points[1]
p2_x, p2_y := points[6], points[7]
ctrl_p1_x, ctrl_p1_y := points[2], points[3]
ctrl_p2_x, ctrl_p2_y := points[4], points[5]
// The constant 3 is actually points.len() - 1;
step := f32(1) / steps
sgl.v2f(p1_x * ctx.scale, p1_y * ctx.scale)
for u := f32(0); u <= f32(1); u += step {
pow_2_u := u * u
pow_3_u := pow_2_u * u
x := pow_3_u * (p2_x + 3 * (ctrl_p1_x - ctrl_p2_x) - p1_x) +
3 * pow_2_u * (p1_x - 2 * ctrl_p1_x + ctrl_p2_x) + 3 * u * (ctrl_p1_x - p1_x) + p1_x
y := pow_3_u * (p2_y + 3 * (ctrl_p1_y - ctrl_p2_y) - p1_y) +
3 * pow_2_u * (p1_y - 2 * ctrl_p1_y + ctrl_p2_y) + 3 * u * (ctrl_p1_y - p1_y) + p1_y
sgl.v2f(x * ctx.scale, y * ctx.scale)
}
sgl.v2f(p2_x * ctx.scale, p2_y * ctx.scale)
sgl.end()
}