rect.glsl (1499B)
1 /* This Source Code Form is subject to the terms of the Mozilla Public 2 * License, v. 2.0. If a copy of the MPL was not distributed with this 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 4 5 struct RectWithSize { 6 vec2 p0; 7 vec2 size; 8 }; 9 10 struct RectWithEndpoint { 11 vec2 p0; 12 vec2 p1; 13 }; 14 15 float point_inside_rect(vec2 p, vec2 p0, vec2 p1) { 16 vec2 s = step(p0, p) - step(p1, p); 17 return s.x * s.y; 18 } 19 20 vec2 signed_distance_rect_xy(vec2 pos, vec2 p0, vec2 p1) { 21 // Instead of using a true signed distance to rect here, we just use the 22 // simpler approximation of the maximum distance on either axis from the 23 // outside of the rectangle. This avoids expensive use of length() and only 24 // causes mostly imperceptible differences at corner pixels. 25 return max(p0 - pos, pos - p1); 26 } 27 28 float signed_distance_rect(vec2 pos, vec2 p0, vec2 p1) { 29 // Collapse the per-axis distances to edges to a single approximate value. 30 vec2 d = signed_distance_rect_xy(pos, p0, p1); 31 return max(d.x, d.y); 32 } 33 34 vec2 rect_clamp(RectWithEndpoint rect, vec2 pt) { 35 return clamp(pt, rect.p0, rect.p1); 36 } 37 38 vec2 rect_size(RectWithEndpoint rect) { 39 return rect.p1 - rect.p0; 40 } 41 42 // this is similar to rect_clamp but repeats the image for coordinates outside 43 // the rect, used in SVG feTile filter 44 vec2 rect_repeat(vec2 p, vec2 p0, vec2 p1) { 45 vec2 r = p - p0; 46 vec2 s = p1 - p0; 47 vec2 is = 1.0 / max(s, vec2(0.000001)); 48 return p0 + s * fract(is * r); 49 }