This repository has no description
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293float getSdfRectangle(in vec2 p, in vec2 xy, in vec2 b){ vec2 d = abs(p - xy) - b; return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0);}
// Based on Inigo Quilez's 2D distance functions article: https://iquilezles.org/articles/distfunctions2d/// Potencially optimized by eliminating conditionals and loops to enhance performance and reduce branching
float seg(in vec2 p, in vec2 a, in vec2 b, inout float s, float d) { vec2 e = b - a; vec2 w = p - a; vec2 proj = a + e * clamp(dot(w, e) / dot(e, e), 0.0, 1.0); float segd = dot(p - proj, p - proj); d = min(d, segd);
float c0 = step(0.0, p.y - a.y); float c1 = 1.0 - step(0.0, p.y - b.y); float c2 = 1.0 - step(0.0, e.x * w.y - e.y * w.x); float allCond = c0 * c1 * c2; float noneCond = (1.0 - c0) * (1.0 - c1) * (1.0 - c2); float flip = mix(1.0, -1.0, step(0.5, allCond + noneCond)); s *= flip; return d;}
float getSdfParallelogram(in vec2 p, in vec2 v0, in vec2 v1, in vec2 v2, in vec2 v3) { float s = 1.0; float d = dot(p - v0, p - v0);
d = seg(p, v0, v3, s, d); d = seg(p, v1, v0, s, d); d = seg(p, v2, v1, s, d); d = seg(p, v3, v2, s, d);
return s * sqrt(d);}
vec2 norm(vec2 value, float isPosition) { return (value * 2.0 - (iResolution.xy * isPosition)) / iResolution.y;}
float determineStartVertexFactor(vec2 a, vec2 b) { // Conditions using step float condition1 = step(b.x, a.x) * step(a.y, b.y); // a.x < b.x && a.y > b.y float condition2 = step(a.x, b.x) * step(b.y, a.y); // a.x > b.x && a.y < b.y
// If neither condition is met, return 1 (else case) return 1.0 - max(condition1, condition2);}
const vec4 CURRENT_COLOR = vec4(0., 1., 1., 1.0);const vec4 PREVIOUS_COLOR = vec4(1., 0., 1., 1.0);const vec4 TRAIL_COLOR = vec4(1., 1., 0., 1.0);const float OPACITY = 0.6;
void mainImage(out vec4 fragColor, in vec2 fragCoord){ fragColor = texture(iChannel0, fragCoord.xy / iResolution.xy); //Normalization for fragCoord to a space of -1 to 1; vec2 vu = norm(fragCoord, 1.); vec2 offsetFactor = vec2(-.5, 0.5);
//Normalization for cursor position and size; //cursor xy has the postion in a space of -1 to 1; //zw has the width and height vec4 currentCursor = vec4(norm(iCurrentCursor.xy, 1.), norm(iCurrentCursor.zw, 0.)); vec4 previousCursor = vec4(norm(iPreviousCursor.xy, 1.), norm(iPreviousCursor.zw, 0.));
//When drawing a parellelogram between cursors for the trail i need to determine where to start at the top-left or top-right vertex of the cursor float vertexFactor = determineStartVertexFactor(currentCursor.xy, previousCursor.xy); float invertedVertexFactor = 1.0 - vertexFactor;
//Set every vertex of my parellogram vec2 v0 = vec2(currentCursor.x + currentCursor.z * vertexFactor, currentCursor.y - currentCursor.w); vec2 v1 = vec2(currentCursor.x + currentCursor.z * invertedVertexFactor, currentCursor.y); vec2 v2 = vec2(previousCursor.x + currentCursor.z * invertedVertexFactor, previousCursor.y); vec2 v3 = vec2(previousCursor.x + currentCursor.z * vertexFactor, previousCursor.y - previousCursor.w);
float sdfPreviousCursor = getSdfRectangle(vu, previousCursor.xy - (previousCursor.zw * offsetFactor), previousCursor.zw * 0.5); float sdfCurrentCursor = getSdfRectangle(vu, currentCursor.xy - (currentCursor.zw * offsetFactor), currentCursor.zw * 0.5); float sdfTrail = getSdfParallelogram(vu, v0, v1, v2, v3);
vec4 newColor = vec4(fragColor); // Draw trail newColor = mix(newColor, TRAIL_COLOR, step(sdfTrail, 0.)); // Draw previous cursor newColor = mix(newColor, PREVIOUS_COLOR, step(sdfPreviousCursor, 0.)); // Draw current cursor newColor = mix(newColor, CURRENT_COLOR, step(sdfCurrentCursor, 0.)); fragColor = mix(fragColor, newColor, OPACITY);}