118 lines
4.3 KiB
GLSL
118 lines
4.3 KiB
GLSL
#version 300 es
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precision mediump float;
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const float smoothing = 10.0;
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const float inf = 1000000.0;
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const float pi = atan(1.0) * 4.0;
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float interpolate(float from, float to, float quotient) {
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float steppedQ = sin(quotient * pi - pi * 0.5) * 0.5 + 0.5;
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return from + (to - from) * clamp(steppedQ, 0.0, 1.0);
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}
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vec2 rotate90deg(in vec2 vector) {
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return vec2(-vector.y, vector.x);
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}
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struct Line {
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vec2 a;
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vec2 b;
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vec2 normal;
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bool isLineEnd;
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}[16] lines;
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float lineDistance(in vec2 position, in Line line, out float h) {
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vec2 pa = position - line.a, ba = line.b - line.a;
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h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0);
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vec2 delta = pa - ba*h;
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// sign can return 0, double sign prevents this
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float side = sign(sign(dot(delta, line.normal)) - 0.5);
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return length(delta) * side;
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}
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Line endDummyLineFromLine(Line line) {
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return Line(line.b, line.b + rotate90deg(line.normal), line.normal, false);
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}
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float getDistance(in vec2 target) {
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float minDistance = inf;
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float leftJoinAcuteness = 0.0;
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vec2 splitterLineNormalStart = vec2(-1.0, 0.0);
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bool skipDistanceToPrevious = true;
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for (int i = 0; i < lines.length(); i++) {
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Line current = lines[i];
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Line next;
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if (current.isLineEnd || i + 1 == lines.length()) {
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next = endDummyLineFromLine(current);
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} else {
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next = lines[i + 1];
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}
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vec2 splitterLineNormalEnd = rotate90deg(normalize(current.normal + next.normal));
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float h;
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float distanceToCurrent = lineDistance(target, current, h);
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float rightJoinAcuteness = dot(next.b - current.a, next.normal - current.normal);
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distanceToCurrent -= interpolate(
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sign(leftJoinAcuteness) * smoothing,
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sign(rightJoinAcuteness) * smoothing, h
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);
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leftJoinAcuteness = rightJoinAcuteness;
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if (
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!(
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dot(target - current.a, splitterLineNormalStart * -sign(dot(current.b - current.a, splitterLineNormalStart))) > 0.0
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|| dot(target - current.b, splitterLineNormalEnd * sign(dot(current.a - current.b, splitterLineNormalEnd))) <= 0.0
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) && abs(distanceToCurrent) < abs(minDistance)
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) {
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minDistance = distanceToCurrent;
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}
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splitterLineNormalStart = splitterLineNormalEnd;
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}
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return minDistance;
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}
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void createWorld() {
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lines[0] = Line(vec2(0.0, 300.0), vec2(550.0, 140.0), vec2(1.0), false);
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lines[1] = Line(vec2(550.0, 140.0), vec2(750.0, 130.0), vec2(1.0), false);
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lines[2] = Line(vec2(750.0, 130.0), vec2(650.0, 230.0), vec2(1.0), false);
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lines[3] = Line(vec2(650.0, 230.0), vec2(850.0, 230.0), vec2(1.0), false);
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lines[4] = Line(vec2(850.0, 230.0), vec2(800.0, 150.0), vec2(1.0), false);
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lines[5] = Line(vec2(800.0, 150.0), vec2(1000.0, 120.0), vec2(1.0), false);
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lines[6] = Line(vec2(1000.0, 120.0), vec2(1150, 120.0), vec2(1.0), false);
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lines[7] = Line(vec2(1150, 120.0), vec2(10200, 350.0), vec2(1.0), true);
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lines[8] = Line(vec2(0.0, 600.0), vec2(550.0, 440.0), vec2(-1.0), false);
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lines[9] = Line(vec2(550.0, 440.0), vec2(750.0, 430.0), vec2(-1.0), false);
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lines[10] = Line(vec2(750.0, 430.0), vec2(650.0, 530.0), vec2(-1.0), false);
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lines[11] = Line(vec2(650.0, 530.0), vec2(850.0, 530.0), vec2(-1.0), false);
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lines[12] = Line(vec2(850.0, 530.0), vec2(820.0, 450.0), vec2(-1.0), false);
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lines[13] = Line(vec2(820.0, 450.0), vec2(1000.0, 420.0), vec2(-1.0), false);
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lines[14] = Line(vec2(1000.0, 420.0), vec2(1150, 420.0), vec2(-1.0), false);
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lines[15] = Line(vec2(1150, 420.0), vec2(10200, 650.0), vec2(-1.0), true);
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for (int i = 0; i < lines.length(); i++) {
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vec2 tangent = lines[i].b - lines[i].a;
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lines[i].normal = normalize(
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vec2(-lines[i].normal.x * tangent.y, lines[i].normal.x * tangent.x)
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);
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}
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}
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uniform vec2 cameraPosition;
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uniform vec2 viewBoxSize;
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uniform vec2 resolution;
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out vec4 fragmentColor;
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void main() {
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createWorld();
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vec2 pixelPosition = gl_FragCoord.xy + vec2(0.5);
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vec2 position = pixelPosition / resolution * viewBoxSize + cameraPosition;
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//fragmentColor = getDistance(position) > 0.0 ? vec4(0.0, 0.0, 0.0, 0.0) : vec4(0.0, 0.0, 0.0, 1.0);
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fragmentColor = vec4(vec3(1.0) * clamp(0.0, 1.0, getDistance(position)), 1.0);
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}
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