AlphaImage* AlphaImage::CreateMipmap ()
{
if (w == 1 && h == 1)
return 0;
int nw = w/2;
int nh = h/2;
if (!nw) { nw = 1; }
if (!nh) { nh = 1; }
AlphaImage *mipmap = SAFE_NEW AlphaImage;
mipmap->Alloc (nw,nh);
// Scale X&Y
if (w > 1 && h > 1) {
for (int y=0;y<nh;y++)
for (int x=0;x<nw;x++)
mipmap->at (x,y) = (at(x*2,y*2) + at(x*2+1,y*2) + at(x*2, y*2+1) + at(x*2+1,y*2+1)) * 0.25f;
} else if (w == 1 && h > 1) { // Scale Y only
for (int y=0;y<nh;y++)
for (int x=0;x<nw;x++)
mipmap->at (x,y) = (at(x,y*2) + at(x, y*2+1)) * 0.5f;
} else { // if (w > 1 && h == 1) {
for (int y=0;y<nh;y++) // Scale X only
for (int x=0;x<nw;x++)
mipmap->at (x,y) = (at(x*2,y) + at(x*2+1, y)) * 0.5f;
}
return mipmap;
}
void Blendmap::Generate(Heightmap* rootHm, int lodLevel, float hmScale, float hmOffset)
{
const Heightmap* heightmap = rootHm->GetLevel(-lodLevel);
// Allocate the blendmap image
AlphaImage* bm = new AlphaImage;
bm->Alloc(heightmap->w-1, heightmap->h-1); // texture dimensions have to be power-of-two
Blendmap::GeneratorInfo* gi = generatorInfo;
// Calculate blend factors using the function parameters and heightmap input:
for (int y=0;y<bm->h;y++)
{
for (int x=0;x<bm->w;x++)
{
const float h = (heightmap->atSynced(x, y) - hmOffset) / hmScale;
float factor=1.0f;
if(h < gi->minHeight - gi->minHeightFuzzy) {
bm->at(x,y) = 0.0f;
continue;
} else if (gi->minHeightFuzzy > 0.0f && h < gi->minHeight + gi->minHeightFuzzy)
factor = (h - (gi->minHeight - gi->minHeightFuzzy)) / (2.0f * gi->minHeightFuzzy);
if(h > gi->maxHeight + gi->maxHeightFuzzy) {
bm->at (x,y) = 0.0f;
continue;
} else if (gi->maxHeightFuzzy > 0.0f && h > gi->maxHeight - gi->maxHeightFuzzy)
factor *= ((gi->maxHeight + gi->maxHeightFuzzy) - h) / (2.0f * gi->maxHeightFuzzy);
float norm_y = 0.0f;
if (heightmap->normalData) {
const uchar* cnorm = heightmap->GetNormal(x, y);
norm_y = cnorm[1] / 255.0f * 2.0f - 1.0f;
if (norm_y > 1.0f) norm_y = 1.0f;
} else {
Vector3 tangent, binormal;
CalculateTangents(heightmap, x,y,tangent,binormal);
Vector3 normal = tangent.cross(binormal);
normal.ANormalize();
norm_y = normal.y;
}
// flatness=dotproduct of surface normal with up vector
float slope = 1.0f - fabs(norm_y);
if (slope < gi->minSlope - gi->minSlopeFuzzy) {
bm->at(x,y) = 0.0f;
continue;
} else if (gi->minSlopeFuzzy > 0.0f && slope < gi->minSlope + gi->minSlopeFuzzy)
factor *= (h - (gi->minSlope - gi->minSlopeFuzzy)) / ( 2.0f * gi->minSlopeFuzzy);
if (slope > gi->maxSlope + gi->maxSlopeFuzzy) {
bm->at(x,y) = 0.0f;
continue;
} else if (gi->maxSlopeFuzzy > 0.0f && slope > gi->maxSlope - gi->maxSlopeFuzzy)
factor *= ((gi->maxSlope + gi->maxSlopeFuzzy) - h) / (2.0f * gi->maxSlopeFuzzy);
factor *= gi->coverage;
factor *= (rand() < gi->noise * RAND_MAX) ? 0.0f : 1.0f;
bm->at(x,y) = factor;
}
}
BlendmapFilter(bm);
image = bm;
}