// -----------------------------------------------------------------------------
// CAknPhysicsRestrictor::PositionToViewTop()
// -----------------------------------------------------------------------------
//
void CAknPhysicsRestrictor::PositionToViewTop( TPoint& aPosition ) const
{
TInt topPos( ViewTopPosition() );
if ( iLandscape )
{
aPosition.iX = topPos;
}
else
{
aPosition.iY = topPos;
}
}
// Interpolating between the 4 vertices of the square
float HeightNode::evalHeight(Vertex2D & pos,
int effMapSize,
Biome* biomeMap) {
// Getting the required informations
Vertex2D tlPos = topLeftData.getPosition();
Vertex2D brPos = bottomRightData.getPosition();
Biome tlBiome = topLeftData.getBiome();
Biome trBiome = topRightData.getBiome();
Biome blBiome = bottomLeftData.getBiome();
Biome brBiome = bottomRightData.getBiome();
float tlHeight = topLeftData.getHeight();
float trHeight = topRightData.getHeight();
float blHeight = bottomLeftData.getHeight();
float brHeight = bottomRightData.getHeight();
// Computing the local coordinates to interpolate
float x = pos.first - tlPos.first;
float xMax = brPos.first - tlPos.first;
float y = pos.second - brPos.second;
float yMax = tlPos.second - brPos.second;
// Interpolation coefficients to compute
float u, uTop, uBottom, v, vLeft, vRight;
/*
* We do here a kind of distorted bilinear interpolation to compute
* the height of a point given the height of the four vertices
* of the square the point is in.
*
* Indeed, unlike the classical bilinear interpolation where the
* four vertices have a symetric role, there, the four vertices are
* charaterized by their nature (ie their biome).
* Whereas a beach or a plain can be extended, thus affect the whole
* square, a mountain must have a very local influence ie it must
* not turn the surrounding plains into green mountains.
*
* Thus we compute the interpolation using the following strategy
* that consider the four biomes.
*
* TL----uTop-------TR
* | |
* vLeft X vRight
* | | ^ y
* | | |
* BL----uBot-------BR |__> x
*
* 1) The four coefficients on the previous schema are computed
* ie an interpolation is done on each edge according to the rules
* explained in MapUtils
* 2) We use these coefficients to interpolate a height on each edge
* 3) Then we interpolate on each axis :
* heightVertical(heightTop, heightBottom)
* heightHorizontal(heightLeft, heightRight)
* 4) Finally we interpolate between the two heights
*/
// Interpolating on each edge
// Left side
vLeft = computeInterpolationCoefficient(m_mapParameters, blBiome, tlBiome, y, yMax);
float leftHeight = vLeft * (blHeight) + (1 - vLeft) * (tlHeight);
// Right side
vRight = computeInterpolationCoefficient(m_mapParameters, brBiome, trBiome, y, yMax);
float rightHeight = vRight * (brHeight) + (1 - vRight) * (trHeight);
// Top side
uTop = computeInterpolationCoefficient(m_mapParameters, tlBiome, trBiome, x, xMax);
float topHeight = uTop * (tlHeight) + (1 - uTop) * (trHeight);
// Bottom side
uBottom = computeInterpolationCoefficient(m_mapParameters, blBiome, brBiome, x, xMax);
float botHeight = uBottom * (blHeight) + (1 - uBottom) * (brHeight);
// Interpolating on each axis
// Vertical axis
Vertex2D botPos(pos.first, brPos.second);
Biome botBiome = findApproximativeBiome(botPos, effMapSize, biomeMap, m_mapParameters.getHeightmapScaling());
Vertex2D topPos(pos.first, tlPos.second);
Biome topBiome = findApproximativeBiome(topPos, effMapSize, biomeMap, m_mapParameters.getHeightmapScaling());
u = computeInterpolationCoefficient(m_mapParameters, botBiome, topBiome, y, yMax);
float vertHeight = u * botHeight + (1 - u) * topHeight;
// Horizontal axis
Vertex2D leftPos(tlPos.first, pos.second);
Biome leftBiome = findApproximativeBiome(leftPos, effMapSize, biomeMap, m_mapParameters.getHeightmapScaling());
Vertex2D rightPos(brPos.first, pos.second);
Biome rightBiome = findApproximativeBiome(rightPos, effMapSize, biomeMap, m_mapParameters.getHeightmapScaling());
v = computeInterpolationCoefficient(m_mapParameters, leftBiome, rightBiome, x, xMax);
float horiHeight = v * leftHeight + (1 - v) * rightHeight;
return 0.5f*(vertHeight + horiHeight);
}