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C cubic curve distance update

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Chlumsky 2025-06-20 17:37:00 +02:00
parent 167be50b5f
commit 05563ad6a8
1 changed files with 20 additions and 21 deletions
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41
c/msdfgen.c
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@ -218,33 +218,32 @@ MSDFGEN_real MSDFGEN_signedDistance(const MSDFGEN_CompiledShape *shapePtr, MSDFG
if (originP1Dist < edgeCache[-1].edgeDistance)
edgeCache[-1].edgeDistance = originP1Dist;
for (start = 0; start <= MSDFGEN_CUBIC_SEARCH_STARTS; ++start) {
MSDFGEN_real t = (MSDFGEN_real) 1/(MSDFGEN_real) MSDFGEN_CUBIC_SEARCH_STARTS*(MSDFGEN_real) start;
MSDFGEN_Vector2 originP = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) 3*t, shapePtr->cubicEdges[i].derivative0)),
MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative1)
), MSDFGEN_Vector2_scale(t*t*t, shapePtr->cubicEdges[i].derivative2)
);
for (step = 0; step < MSDFGEN_CUBIC_SEARCH_STEPS; ++step) {
MSDFGEN_Vector2 derivative0 = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_scale((MSDFGEN_real) 3, shapePtr->cubicEdges[i].derivative0),
MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative1)
), MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative2)
);
MSDFGEN_Vector2 derivative1 = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_scale((MSDFGEN_real) 6, shapePtr->cubicEdges[i].derivative1),
MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative2)
);
t -= MSDFGEN_Vector2_dot(originP, derivative0)/(MSDFGEN_Vector2_squaredLength(derivative0)+MSDFGEN_Vector2_dot(originP, derivative1));
if (t <= (MSDFGEN_real) 0 || t >= (MSDFGEN_real) 1)
break;
int remainingSteps = MSDFGEN_CUBIC_SEARCH_STEPS;
MSDFGEN_real t, improvedT = (MSDFGEN_real) 1/(MSDFGEN_real) MSDFGEN_CUBIC_SEARCH_STARTS*(MSDFGEN_real) start;
MSDFGEN_Vector2 originP, derivative0, derivative1;
do {
t = improvedT;
originP = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) 3*t, shapePtr->cubicEdges[i].derivative0)),
MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative1)
), MSDFGEN_Vector2_scale(t*t*t, shapePtr->cubicEdges[i].derivative2)
);
derivative0 = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_scale((MSDFGEN_real) 3, shapePtr->cubicEdges[i].derivative0),
MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative1)
), MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative2)
);
if (!remainingSteps--)
break;
derivative1 = MSDFGEN_Vector2_sum(
MSDFGEN_Vector2_scale((MSDFGEN_real) 6, shapePtr->cubicEdges[i].derivative1),
MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative2)
);
improvedT = t-MSDFGEN_Vector2_dot(originP, derivative0)/(MSDFGEN_Vector2_squaredLength(derivative0)+MSDFGEN_Vector2_dot(originP, derivative1));
} while (improvedT > (MSDFGEN_real) 0 && improvedT < (MSDFGEN_real) 1);
if (t > (MSDFGEN_real) 0 && t < (MSDFGEN_real) 1) {
MSDFGEN_real originPDist = sqrt(MSDFGEN_Vector2_squaredLength(originP));
if (originPDist < minDistance) {
minDistance = originPDist;