//! Merge all segments triangle's height of which bigger or equal than minTriangleHeight
// http://www.math.ru/dic/276
void Polygon3::MergeFlatPolygonSegments(const Polygon3 &srcPolygon, Polygon3 &destPolygon, float32 minTriangleHeight)
{
float mh2 = minTriangleHeight * minTriangleHeight;
destPolygon.Clear();
for (int i0 = 0; i0 < srcPolygon.pointCount - 2; ++i0)
{
destPolygon.AddPoint(srcPolygon.points[i0]);
Vector3 v0 = srcPolygon.points[i0];
for (int i2 = i0 + 2; i2 < srcPolygon.pointCount; ++i2)
{
Vector3 v2 = srcPolygon.points[i2];
float c = (v2 - v0).Length();
float hc2 = 0.0f;
for (int i1 = i0 + 1; i1 < i2; ++i1)
{
Vector3 v1 = srcPolygon.points[i1];
float a = (v1 - v0).Length();
float b = (v2 - v1).Length();
float p = (a + b + c) / 2.0f;
hc2 = 4.0f * p * (p - a) * (p - b) * (p - c) / (c * c);
if (hc2 >= mh2)
{
break;
}
}
if (hc2 >= mh2)
{
i0 = i2 - 1 - 1;
break;
}
}
}
destPolygon.AddPoint(srcPolygon.points.back());
}
void RenderHelper::DrawCylinder(const Vector3 & center, float32 radius, bool useFilling)
{
Polygon3 pts;
float32 angle = SEGMENT_LENGTH / radius;
int32 ptsCount = (int32)(PI_2 / (DegToRad(angle))) + 1;
Vector<Vector2> vertexes;
for(int32 i = 0; i <= ptsCount; i++)
{
float32 seta = i * 360.0f / (float32)ptsCount;
float32 x = sin(DegToRad(seta)) * radius;
float32 y = cos(DegToRad(seta)) * radius;
vertexes.push_back(Vector2(x, y));
}
for(int32 i = 0; i < ptsCount; ++i)
{
pts.AddPoint((Vector3(vertexes[i].x, vertexes[i].y, 1) * radius) + center);
pts.AddPoint((Vector3(vertexes[i].x, vertexes[i].y, -1) * radius) + center);
pts.AddPoint((Vector3(vertexes[i+1].x, vertexes[i+1].y, -1) * radius) + center);
pts.AddPoint((Vector3(vertexes[i].x, vertexes[i].y, 1) * radius) + center);
pts.AddPoint((Vector3(vertexes[i+1].x, vertexes[i+1].y, 1) * radius) + center);
pts.AddPoint((Vector3(vertexes[i+1].x, vertexes[i+1].y, -1) * radius) + center);
}
if (useFilling)
{
FillPolygon(pts);
}
else
{
DrawPolygon(pts, true);
}
}
void RenderHelper::DrawCircle3D(const Vector3 & center, const Vector3 &emissionVector, float32 radius, bool useFilling)
{
Polygon3 pts;
float32 angle = SEGMENT_LENGTH / radius;
int ptsCount = (int)(PI_2 / (DegToRad(angle))) + 1;
for (int k = 0; k < ptsCount; ++k)
{
float32 angleA = ((float)k / (ptsCount - 1)) * PI_2;
float sinAngle = 0.0f;
float cosAngle = 0.0f;
SinCosFast(angleA, sinAngle, cosAngle);
Vector3 directionVector(radius * cosAngle,
radius * sinAngle,
0.0f);
// Rotate the direction vector according to the current emission vector value.
Vector3 zNormalVector(0.0f, 0.0f, 1.0f);
Vector3 curEmissionVector = emissionVector;
curEmissionVector.Normalize();
// This code rotates the (XY) plane with the particles to the direction vector.
// Taking into account that a normal vector to the (XY) plane is (0,0,1) this
// code is very simplified version of the generic "plane rotation" code.
float32 length = curEmissionVector.Length();
if (FLOAT_EQUAL(length, 0.0f) == false)
{
float32 cosAngleRot = curEmissionVector.z / length;
float32 angleRot = acos(cosAngleRot);
Vector3 axisRot(curEmissionVector.y, -curEmissionVector.x, 0);
Matrix3 planeRotMatrix;
planeRotMatrix.CreateRotation(axisRot, angleRot);
Vector3 rotatedVector = directionVector * planeRotMatrix;
directionVector = rotatedVector;
}
Vector3 pos = center - directionVector;
pts.AddPoint(pos);
}
if (useFilling)
{
FillPolygon(pts);
}
else
{
DrawPolygon(pts, false);
}
}
void RenderHelper::DrawCircle(const Vector3 & center, float32 radius)
{
Polygon3 pts;
float32 angle = SEGMENT_LENGTH / radius;
int ptsCount = (int)(2 * PI / (DegToRad(angle))) + 1;
for (int k = 0; k < ptsCount; ++k)
{
float32 angle = ((float)k / (ptsCount - 1)) * 2 * PI;
float32 sinA = sinf(angle);
float32 cosA = cosf(angle);
Vector3 pos = center - Vector3(sinA * radius, cosA * radius, 0);
pts.AddPoint(pos);
}
DrawPolygon(pts, false);
}
