83 lines
2.2 KiB
Markdown
83 lines
2.2 KiB
Markdown
# obj_loader - a zig obj file loader
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This was very rapidly written to provide a simple interface for loading `.obj` files in zig.
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At this time I make no garauntees on correctness or performance, will eventually support all .obj and .mtl
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directives.
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To load an obj,
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```zig
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const obj_loader = @import("path/to/obj_loader.zig");
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var contents: ObjContents = obj_loader.loadObj("suzanne.obj", your.favorite.allocator);
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defer contents.deinit();
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```
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Transforming a mesh into your vertex/model format should be quite easy.
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```zig
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const mesh = fileContents.meshes.items[0];
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try vertices.ensureTotalCapacity(mesh.v_faces.items.len * 4);
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for (mesh.v_faces.items) |face| {
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var i: u32 = 0;
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while (i < face.count) : (i += 1) {
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const p = mesh.v_positions.items[face.vertex[i] - 1];
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const n = mesh.v_normals.items[face.normal[i] - 1];
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const v = Vertex{
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.position = .{ .x = p.x, .y = p.y, .z = p.z },
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.normal = .{ .x = n.x, .y = n.y, .z = n.z },
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.color = .{ .r = n.x, .g = n.y, .b = n.z, .a = 1.0 },
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};
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try vertices.append(v);
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}
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}
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```
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## Details
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The ObjContents contains a list of ObjMesh objects.
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```zig
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std.debug.print("obj: {s}, Vertices count = {d} Normals count = {d}, faces = {d}\n", .{
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contents.meshes.items[0].object_name,
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contents.meshes.items[0].v_positions.items.len,
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contents.meshes.items[0].v_normals.items.len,
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contents.meshes.items[0].v_faces.items.len,
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});
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```
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```zig
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pub const ObjMesh = struct {
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object_name: []u8,
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v_positions: ArrayListUnmanaged(ObjVec) = .{},
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v_colors: ArrayListUnmanaged(ObjColor) = .{},
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v_normals: ArrayListUnmanaged(ObjVec) = .{},
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v_textures: ArrayListUnmanaged(ObjVec2) = .{},
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v_faces: ArrayListUnmanaged(ObjFace) = .{},
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...
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}
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```
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## Faces
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The faces produced by this library are currently coded to a maximum of 4. If you want more advanced
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n-gon triangulation, give [`zmesh`](https://github.com/michal-z/zig-gamedev/tree/main/libs/zmesh) a try.
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```zig
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pub const ObjFace = struct {
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vertex: [4]u32,
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texture: [4]u32,
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normal: [4]u32,
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count: u32,
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};
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```
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