135 lines
3.3 KiB
GLSL
135 lines
3.3 KiB
GLSL
#version 300 es
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precision mediump float;
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#define INFINITY 1.0 / 0.0
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#define WORLD_SIZE 4
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#define N (20)
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#define CIRCLE 1
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#define LINE 2
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#define TRIANGLE 3
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out vec4 fragmentColor;
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uniform vec2 resolution;
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uniform float time;
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struct Material {
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vec3 color;
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};
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struct Primitive {
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uint type;
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uint index;
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};
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struct Object {
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Material material;
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Primitive[10] primitives;
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};
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struct Circle {
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uint parent;
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vec2 center;
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float radius;
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};
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struct Line {
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uint parent;
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vec2 a;
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vec2 b;
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};
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struct Triangle {
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uint parent;
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vec2 a;
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vec2 b;
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vec2 c;
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};
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// uniform Object[100] objects;
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Circle[3] circles;
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Line[1] lines;
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Triangle[1] triangles;
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float triangleDistance(in vec2 position, in Triangle triangle)
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{
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vec2 e0 = triangle.b - triangle.a, e1 = triangle.c - triangle.b, e2 = triangle.a - triangle.c;
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vec2 v0 = position - triangle.a, v1 = position - triangle.b, v2 = position - triangle.c;
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vec2 pq0 = v0 - e0 * clamp(dot(v0, e0) / dot(e0, e0), 0.0, 1.0);
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vec2 pq1 = v1 - e1 * clamp(dot(v1, e1) / dot(e1, e1), 0.0, 1.0);
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vec2 pq2 = v2 - e2 * clamp(dot(v2, e2) / dot(e2, e2), 0.0, 1.0);
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float s = sign(e0.x*e2.y - e0.y*e2.x);
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vec2 d = min(min(vec2(dot(pq0,pq0), s*(v0.x*e0.y-v0.y*e0.x)),
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vec2(dot(pq1,pq1), s*(v1.x*e1.y-v1.y*e1.x))),
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vec2(dot(pq2,pq2), s*(v2.x*e2.y-v2.y*e2.x)));
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return -sqrt(d.x)*sign(d.y);
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}
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float lineDistance(in vec2 position, in Line line)
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{
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vec2 pa = position - line.a, ba = line.b - line.a;
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float h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0);
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return length(pa - ba*h);
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}
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float circleDistance(in vec2 position, in Circle circle)
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{
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return length(position - circle.center) - circle.radius;
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}
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float getDistance(in vec2 target, out uint nearestParentIndex) {
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float distance = INFINITY;
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for (int i = 0; i < circles.length(); i++) {
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float distanceToCurrent = circleDistance(target, circles[i]);
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if (distanceToCurrent < distance) {
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distance = distanceToCurrent;
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nearestParentIndex = circles[i].parent;
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}
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}
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for (int i = 0; i < lines.length(); i++) {
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float distanceToCurrent = lineDistance(target, lines[i]);
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if (distanceToCurrent < distance) {
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distance = distanceToCurrent;
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nearestParentIndex = lines[i].parent;
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}
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}
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for (int i = 0; i < triangles.length(); i++) {
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float distanceToCurrent = triangleDistance(target, triangles[i]);
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if (distanceToCurrent < distance) {
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distance = distanceToCurrent;
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nearestParentIndex = triangles[i].parent;
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}
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}
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return distance;
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}
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void createWorld() {
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circles[0] = Circle(0u, vec2(250.0, 100.0), 12.5);
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circles[1] = Circle(0u, vec2(150.0, 50.0), 32.5);
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circles[2] = Circle(0u, vec2(300.0, 350.0), 52.5);
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lines[0] = Line(0u, vec2(100.0, 300.0), vec2(550.0, 140.0));
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triangles[0] = Triangle(0u, vec2(400.0, 100.0), vec2(200.0, 240.0), vec2(600.0, 340.0));
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}
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float linearstep(float a, float b, float q) {
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return a + clamp((b - a) * q, 0.0, 1.0);
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}
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void main() {
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createWorld();
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vec2 position = gl_FragCoord.xy + vec2(0.5);
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uint index;
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vec3 color = vec3(1.0) * linearstep(0.0, 1.0, getDistance(position, index));
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fragmentColor = vec4(color, 1.0);
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}
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