SAPI/Noise: Add PerlinNoiseMap:getMapSlice() function

This adds the ability to grab 'slices' of noise calculated by PerlinNoiseMap.
Retrieving smaller slices of noise from the computation result as needed
optimizes memory usage while maintaining a reasonable amount of CPU overhead.

1 files changed, 92 insertions, 0 deletions

diff --git a/src/script/common/c_converter.cpp b/src/script/common/c_converter.cpp
index 6fb6f623a..211121552 100644
--- a/src/script/common/c_converter.cpp
+++ b/src/script/common/c_converter.cpp
@@ -510,3 +510,95 @@ void setboolfield(lua_State *L, int table,
 }
 
 
+////
+//// Array table slices
+////
+
+size_t write_array_slice_float(
+	lua_State *L,
+	int table_index,
+	float *data,
+	v3u16 data_size,
+	v3u16 slice_offset,
+	v3u16 slice_size)
+{
+	v3u16 pmin, pmax(data_size);
+
+	if (slice_offset.X > 0) {
+		slice_offset.X--;
+		pmin.X = slice_offset.X;
+		pmax.X = MYMIN(slice_offset.X + slice_size.X, data_size.X);
+	}
+
+	if (slice_offset.Y > 0) {
+		slice_offset.Y--;
+		pmin.Y = slice_offset.Y;
+		pmax.Y = MYMIN(slice_offset.Y + slice_size.Y, data_size.Y);
+	}
+
+	if (slice_offset.Z > 0) {
+		slice_offset.Z--;
+		pmin.Z = slice_offset.Z;
+		pmax.Z = MYMIN(slice_offset.Z + slice_size.Z, data_size.Z);
+	}
+
+	const u32 ystride = data_size.X;
+	const u32 zstride = data_size.X * data_size.Y;
+
+	u32 elem_index = 1;
+	for (u32 z = pmin.Z; z != pmax.Z; z++)
+	for (u32 y = pmin.Y; y != pmax.Y; y++)
+	for (u32 x = pmin.X; x != pmax.X; x++) {
+		u32 i = z * zstride + y * ystride + x;
+		lua_pushnumber(L, data[i]);
+		lua_rawseti(L, table_index, elem_index);
+		elem_index++;
+	}
+
+	return elem_index - 1;
+}
+
+
+size_t write_array_slice_u16(
+	lua_State *L,
+	int table_index,
+	u16 *data,
+	v3u16 data_size,
+	v3u16 slice_offset,
+	v3u16 slice_size)
+{
+	v3u16 pmin, pmax(data_size);
+
+	if (slice_offset.X > 0) {
+		slice_offset.X--;
+		pmin.X = slice_offset.X;
+		pmax.X = MYMIN(slice_offset.X + slice_size.X, data_size.X);
+	}
+
+	if (slice_offset.Y > 0) {
+		slice_offset.Y--;
+		pmin.Y = slice_offset.Y;
+		pmax.Y = MYMIN(slice_offset.Y + slice_size.Y, data_size.Y);
+	}
+
+	if (slice_offset.Z > 0) {
+		slice_offset.Z--;
+		pmin.Z = slice_offset.Z;
+		pmax.Z = MYMIN(slice_offset.Z + slice_size.Z, data_size.Z);
+	}
+
+	const u32 ystride = data_size.X;
+	const u32 zstride = data_size.X * data_size.Y;
+
+	u32 elem_index = 1;
+	for (u32 z = pmin.Z; z != pmax.Z; z++)
+	for (u32 y = pmin.Y; y != pmax.Y; y++)
+	for (u32 x = pmin.X; x != pmax.X; x++) {
+		u32 i = z * zstride + y * ystride + x;
+		lua_pushinteger(L, data[i]);
+		lua_rawseti(L, table_index, elem_index);
+		elem_index++;
+	}
+
+	return elem_index - 1;
+}