Cleanup int collision math, which is still wrong

src/const.zig

@@ -38,6 +38,61 @@ pub const sv_per_vx = 4096;
 pub const vx_per_ck = 16;
 pub const sv_per_ck = sv_per_vx * vx_per_ck;
 
-pub inline fn sv(comptime vx: comptime_float) comptime_int {
-    return @intFromFloat(@round(vx * sv_per_vx));
+pub const RoundingMode = enum {
+    border_down,
+    border_up,
+};
+
+/// SV to VX
+pub inline fn subvoxelsToVoxels(comptime rounding_mode: RoundingMode, sv: i32) i32 {
+    return switch (rounding_mode) {
+        .border_down => @divFloor(sv, sv_per_vx - 1),
+        .border_up => @divFloor(sv, sv_per_vx),
+    };
+}
+
+/// SV to CK
+pub inline fn subvoxelsToChunks(comptime rounding_mode: RoundingMode, sv: i32) i32 {
+    return switch (rounding_mode) {
+        .border_down => @divFloor(sv, sv_per_ck - 1),
+        .border_up => @divFloor(sv, sv_per_ck),
+    };
+}
+
+/// SV to CKSV
+pub inline fn subvoxelsToChunkSubvoxels(sv: i32) std.math.IntFittingRange(0, sv_per_ck - 1) {
+    return @intCast(@mod(sv, sv_per_ck));
+}
+
+/// SV to VXSV
+pub inline fn subvoxelsToVoxelSubvoxels(sv: i32) std.math.IntFittingRange(0, sv_per_vx - 1) {
+    return @intCast(@mod(sv, sv_per_vx));
+}
+
+/// VX to SV
+pub inline fn voxelsToSubvoxels(vx: i32) i32 {
+    return vx * sv_per_vx;
+}
+
+/// VX to CK
+pub inline fn voxelsToChunks(comptime rounding_mode: RoundingMode, vx: i32) i32 {
+    return switch (rounding_mode) {
+        .border_down => @divFloor(vx, vx_per_ck - 1),
+        .border_up => @divFloor(vx, vx_per_ck),
+    };
+}
+
+/// VX to CKVX
+pub inline fn voxelsToChunkVoxels(vx: i32) std.math.IntFittingRange(0, vx_per_ck) {
+    return @intCast(@mod(vx, vx_per_ck));
+}
+
+/// CK to SV
+pub inline fn chunksToSubvoxels(ck: i32) i32 {
+    return ck * sv_per_ck;
+}
+
+/// CK to VX
+pub inline fn chunksToVoxels(ck: i32) i32 {
+    return ck * vx_per_ck;
 }