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Merge pull request #333 from ChancellorIkseew/bicubic-interpolation

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add cubic interpolation type
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MihailRis 2024-10-27 22:11:36 +03:00 committed by GitHub
commit 34838f408d
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2 changed files with 70 additions and 2 deletions
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4
src/logic/scripting/lua/usertypes/lua_type_heightmap.cpp
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@ -229,8 +229,10 @@ static int l_resize(lua::State* L) {
uint height = touinteger(L, 3);
auto interpName = tostring(L, 4);
auto interpolation = InterpolationType::NEAREST;
if (!std::strcmp(interpName, "linear")) {
if (std::strcmp(interpName, "linear") == 0) {
interpolation = InterpolationType::LINEAR;
} else if (std::strcmp(interpName, "cubic") == 0) {
interpolation = InterpolationType::CUBIC;
}
heightmap->getHeightmap()->resize(width, height, interpolation);
}

68
src/maths/Heightmap.cpp
View File

@ -50,7 +50,73 @@ static inline float sample_at(
return a00 + a10*tx + a01*ty + a11*tx*ty;
}
// TODO: implement CUBIC (Bicubic) interpolation
case InterpolationType::CUBIC: {
float b1 =
((tx - 1) * (tx - 2) * (tx + 1) * (ty - 1) * (ty - 2) * (ty + 1)) / 4;
float b2 =
(tx * (tx + 1) * (tx - 2) * (ty - 1) * (ty - 2) * (ty + 1)) / -4;
float b3 =
(tx * (tx + 1) * (tx - 2) * (ty - 1) * (ty - 2) * (ty + 1)) / -4;
float b4 =
(tx * (tx + 1) * (tx + 2) * ty * (ty + 1) * (ty - 2)) / 4;
float b5 =
(tx * (tx - 1) * (tx - 2) * (ty - 1) * (ty - 2) * (ty + 1)) / -12;
float b6 =
((tx - 1) * (tx - 2) * (tx + 1) * ty * (ty - 1) * (ty - 2)) / -12;
float b7 =
(tx * (tx - 1) * (tx - 2) * ty * (ty + 1) * (ty - 2)) / 12;
float b8 =
(tx * (tx + 1) * (tx - 2) * ty * (ty - 1) * (ty - 2)) / 12;
float b9 =
(tx * (tx - 1) * (tx + 1) * (ty - 1) * (ty - 2) * (ty + 1)) / 12;
float b10 =
((tx - 1) * (tx - 2) * (tx + 1) * ty * (ty - 1) * (ty + 1)) /12;
float b11 =
(tx * (tx - 1) * (tx - 2) * ty * (ty + 1) * (ty - 2)) / 36;
float b12 =
(tx * (tx - 1) * (tx + 1) * ty * (ty + 1) * (ty - 2)) / -12;
float b13 =
(tx * (tx + 1) * (tx - 2) * ty * (ty - 1) * (ty + 1)) / -12;
float b14 =
(tx * (tx - 1) * (tx + 1) * ty * (ty - 1) * (ty - 2)) / -36;
float b15 =
(tx * (tx - 1) * (tx - 2) * ty * (ty - 1) * (ty + 1)) / -36;
float b16 =
(tx * (tx - 1) * (tx + 1) * ty * (ty - 1) * (ty + 1)) / 36;
float a1 = b1 * val;
float a2 = b2 * sample_at(buffer, width, ix, iy + 1 < height ? iy + 1 : iy);
float a3 = b3 * sample_at(buffer, width, ix + 1 < width ? ix + 1 : ix, iy);
float a4 = b4 * sample_at(buffer, width,
ix + 1 < width ? ix + 1 : ix, iy + 1 < height ? iy + 1 : iy);
float a5 = b5 * sample_at(buffer, width, ix, iy > 1 ? iy - 1 : iy);
float a6 = b6 * sample_at(buffer, width, ix > 1 ? ix - 1 : ix, iy);
float a7 = b7 * sample_at(buffer, width,
ix + 1 < width ? ix + 1 : ix, iy > 1 ? iy - 1 : iy);
float a8 = b8 * sample_at(buffer, width,
ix > 1 ? ix - 1 : ix, iy + 1 < height ? iy + 1 : iy);
float a9 = b9 * sample_at(buffer, width,
ix, iy + 2 < height ? iy + 2 : iy);
float a10 = b10 * sample_at(buffer, width,
ix + 2 < width ? ix + 2 : ix, iy);
float a11 = b11 * sample_at( buffer, width,
ix > 1 ? ix - 1 : ix, iy > 1 ? iy - 1 : iy);
float a12 = b12 * sample_at(buffer, width,
ix + 1 < width ? ix + 1 : ix, iy + 2 < height ? iy + 2 : iy);
float a13 = b13 * sample_at(buffer, width,
ix + 2 < width ? ix + 2 : ix, iy + 1 < height ? iy + 1 : iy);
float a14 = b14 * sample_at(buffer, width,
ix > 1 ? ix - 1 : ix, iy + 2 < height ? iy + 2 : iy);
float a15 = b15 * sample_at(buffer, width,
ix + 2 < width ? ix + 2 : ix, iy > 1 ? iy - 1 : iy);
float a16 = b16 * sample_at(buffer, width,
ix + 2 < width ? ix + 2 : ix, iy + 2 < height ? iy + 2 : iy);
return a1 + a2 + a3 + a4 + a5 + a6 + a7 + a8 +
a9 + a10 + a11 + a12 + a13 + a14 + a15 + a16;
}
default:
throw std::runtime_error("interpolation type is not implemented");
}