/**
* Create "diamonds (4 per each square)" structure by splitting the squares in the middle and
* creating 4 diamond shapes. This is done by setting a value to the middle of each square.
*
* @param iteration The iteration number.
* @param randRange The current random range.
* @param random The random.
* @param modifier The height modifier.
*/
private void diamond(int iteration, float randRange, Random random, HeightModifier modifier) {
final int stepSize = mPatchRowsCols >> iteration;
final int stepSizeH = stepSize / 2;
for (int z = 0; z < mPatchRowsCols; z += stepSize) {
for (int x = 0; x < mPatchRowsCols; x += stepSize) {
final float br = modifier.get(x, z);
final float bl = modifier.get(x + stepSize, z);
final float tr = modifier.get(x, z + stepSize);
final float tl = modifier.get(x + stepSize, z + stepSize);
final float value = getRandomValue(randRange, random) + (br + bl + tr + tl) / 4;
modifier.set(x + stepSizeH, z + stepSizeH, value);
}
}
}
/**
* Create a "square" structure out of each diamond. This is done by adding a new value in the
* middle of the long-side of each diamond.
*
* @param iteration The iteration number.
* @param randRange The current random range.
* @param random The random.
* @param modifier The height modifier.
*/
private void square(int iteration, float randRange, Random random, HeightModifier modifier) {
final int stepSize = mPatchRowsCols >> iteration;
final int stepSizeH = stepSize / 2;
boolean toggle = true;
for (int z = 0; z < mPatchSideVertices; z += stepSizeH) {
final boolean hasTop = z < (mPatchSideVertices - 1);
final boolean hasBottom = z > 0;
int x = toggle ? stepSizeH : 0;
toggle = !toggle;
for (; x < mPatchSideVertices; x += stepSize) {
if (modifier.isModifiable(x, z)) {
final boolean hasRight = x > 0;
final boolean hasLeft = x < (mPatchSideVertices - 1);
int count = 0;
float value = 0;
if (hasRight) {
count++;
value += modifier.get(x - stepSizeH, z);
}
if (hasLeft) {
count++;
value += modifier.get(x + stepSizeH, z);
}
if (hasBottom) {
count++;
value += modifier.get(x, z - stepSizeH);
}
if (hasTop) {
count++;
value += modifier.get(x, z + stepSizeH);
}
modifier.set(x, z, (value / count) + getRandomValue(randRange, random));
} else {
modifier.copyUnModifiable(x, z);
}
}
}
}
/**
* Initialize the 4 corners of the patch.
*
* @param randRange The current random range.
* @param modifier The height modifier.
* @param random The random.
*/
private void initCorners(float randRange, HeightModifier modifier, Random random) {
if (modifier.isModifiable(0, 0)) {
modifier.set(0, 0, getRandomValue(randRange, random));
} else {
modifier.copyUnModifiable(0, 0);
}
if (modifier.isModifiable(0, mPatchRowsCols)) {
modifier.set(0, mPatchRowsCols, getRandomValue(randRange, random));
} else {
modifier.copyUnModifiable(0, mPatchRowsCols);
}
if (modifier.isModifiable(mPatchRowsCols, 0)) {
modifier.set(mPatchRowsCols, 0, getRandomValue(randRange, random));
} else {
modifier.copyUnModifiable(mPatchRowsCols, 0);
}
if (modifier.isModifiable(mPatchRowsCols, mPatchRowsCols)) {
modifier.set(mPatchRowsCols, mPatchRowsCols, getRandomValue(randRange, random));
} else {
modifier.copyUnModifiable(mPatchRowsCols, mPatchRowsCols);
}
}
