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Minor refactoring of bezier curve evaluation

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- Remove `ValidateFCurve` function because it's small and only used once.
- Remove unnecessary checks in `SolveBezier`, as all of these conditions are already checked before the function is called.
- Remove unnecessary double negation of `InTang` to improve readability.
- Use `double` literals for `double` comparisons instead of `float` literals.
- Fix comments.
This commit is contained in:
Robert Müller 2024-02-25 23:57:18 +01:00
parent 47a8156ca8
commit ecfc18d129
1 changed files with 11 additions and 21 deletions
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30
src/game/client/render_map.cpp
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@ -124,13 +124,6 @@ const CEnvPointBezier *CMapBasedEnvelopePointAccess::GetBezier(int Index) const
return nullptr; return nullptr;
} }
static void ValidateFCurve(const vec2 &p0, vec2 &p1, vec2 &p2, const vec2 &p3)
{
// validate the bezier curve
p1.x = clamp(p1.x, p0.x, p3.x);
p2.x = clamp(p2.x, p0.x, p3.x);
}
static double CubicRoot(double x) static double CubicRoot(double x)
{ {
if(x == 0.0) if(x == 0.0)
@ -143,11 +136,6 @@ static double CubicRoot(double x)
static float SolveBezier(float x, float p0, float p1, float p2, float p3) static float SolveBezier(float x, float p0, float p1, float p2, float p3)
{ {
// check for valid f-curve
// we only take care of monotonic bezier curves, so there has to be exactly 1 real solution
if(!(p0 <= x && x <= p3) || !(p0 <= p1 && p1 <= p3) || !(p0 <= p2 && p2 <= p3))
return 0.0f;
const double x3 = -p0 + 3.0 * p1 - 3.0 * p2 + p3; const double x3 = -p0 + 3.0 * p1 - 3.0 * p2 + p3;
const double x2 = 3.0 * p0 - 6.0 * p1 + 3.0 * p2; const double x2 = 3.0 * p0 - 6.0 * p1 + 3.0 * p2;
const double x1 = -3.0 * p0 + 3.0 * p1; const double x1 = -3.0 * p0 + 3.0 * p1;
@ -179,7 +167,7 @@ static float SolveBezier(float x, float p0, float p1, float p2, float p3)
const double t = (-b + SqrtD) / 2.0; const double t = (-b + SqrtD) / 2.0;
if(0.0 <= t && t <= 1.0001f) if(0.0 <= t && t <= 1.0001)
return t; return t;
return (-b - SqrtD) / 2.0; return (-b - SqrtD) / 2.0;
} }
@ -213,24 +201,24 @@ static float SolveBezier(float x, float p0, float p1, float p2, float p3)
const double s = CubicRoot(-q); const double s = CubicRoot(-q);
const double t = 2.0 * s - sub; const double t = 2.0 * s - sub;
if(0.0 <= t && t <= 1.0001f) if(0.0 <= t && t <= 1.0001)
return t; return t;
return (-s - sub); return (-s - sub);
} }
else else
{ {
// Casus irreductibilis ... ,_, // Casus irreducibilis ... ,_,
const double phi = std::acos(-q / std::sqrt(-(p * p * p))) / 3.0; const double phi = std::acos(-q / std::sqrt(-(p * p * p))) / 3.0;
const double s = 2.0 * std::sqrt(-p); const double s = 2.0 * std::sqrt(-p);
const double t1 = s * std::cos(phi) - sub; const double t1 = s * std::cos(phi) - sub;
if(0.0 <= t1 && t1 <= 1.0001f) if(0.0 <= t1 && t1 <= 1.0001)
return t1; return t1;
const double t2 = -s * std::cos(phi + pi / 3.0) - sub; const double t2 = -s * std::cos(phi + pi / 3.0) - sub;
if(0.0 <= t2 && t2 <= 1.0001f) if(0.0 <= t2 && t2 <= 1.0001)
return t2; return t2;
return -s * std::cos(phi - pi / 3.0) - sub; return -s * std::cos(phi - pi / 3.0) - sub;
} }
@ -304,12 +292,14 @@ void CRenderTools::RenderEvalEnvelope(const IEnvelopePointAccess *pPoints, std::
const vec2 p3 = vec2(pNextPoint->m_Time, fx2f(pNextPoint->m_aValues[c])); const vec2 p3 = vec2(pNextPoint->m_Time, fx2f(pNextPoint->m_aValues[c]));
const vec2 OutTang = vec2(pCurrentPointBezier->m_aOutTangentDeltaX[c], fx2f(pCurrentPointBezier->m_aOutTangentDeltaY[c])); const vec2 OutTang = vec2(pCurrentPointBezier->m_aOutTangentDeltaX[c], fx2f(pCurrentPointBezier->m_aOutTangentDeltaY[c]));
const vec2 InTang = -vec2(pNextPointBezier->m_aInTangentDeltaX[c], fx2f(pNextPointBezier->m_aInTangentDeltaY[c])); const vec2 InTang = vec2(pNextPointBezier->m_aInTangentDeltaX[c], fx2f(pNextPointBezier->m_aInTangentDeltaY[c]));
vec2 p1 = p0 + OutTang; vec2 p1 = p0 + OutTang;
vec2 p2 = p3 - InTang; vec2 p2 = p3 + InTang;
// validate bezier curve // validate bezier curve
ValidateFCurve(p0, p1, p2, p3); p1.x = clamp(p1.x, p0.x, p3.x);
p2.x = clamp(p2.x, p0.x, p3.x);
// solve x(a) = time for a // solve x(a) = time for a
a = clamp(SolveBezier(TimeMillis, p0.x, p1.x, p2.x, p3.x), 0.0f, 1.0f); a = clamp(SolveBezier(TimeMillis, p0.x, p1.x, p2.x, p3.x), 0.0f, 1.0f);