engine/tools/asset_compiler.zig

82 lines
2.5 KiB
Zig

const std = @import("std");
const formats = @import("formats");
const Vector3 = formats.Vector3;
const c = @cImport({
@cInclude("assimp/cimport.h");
@cInclude("assimp/scene.h");
@cInclude("assimp/mesh.h");
@cInclude("assimp/postprocess.h");
});
pub fn main() !void {
const allocator = std.heap.c_allocator;
const argv = std.os.argv;
if (argv.len < 3) {
return error.MissingArgs;
}
const input = std.os.argv[argv.len - 2];
const output = std.mem.span(std.os.argv[argv.len - 1]);
std.log.debug("input: {s}\n", .{input});
const maybe_scene: ?*const c.aiScene = @ptrCast(c.aiImportFile(
input,
c.aiProcess_CalcTangentSpace | c.aiProcess_Triangulate | c.aiProcess_JoinIdenticalVertices | c.aiProcess_SortByPType | c.aiProcess_GenNormals,
));
if (maybe_scene == null) {
std.log.err("assimp import error: {s}\n", .{c.aiGetErrorString()});
return error.ImportFailed;
}
const scene = maybe_scene.?;
defer c.aiReleaseImport(scene);
if (scene.mNumMeshes == 0) return error.NoMeshes;
if (scene.mNumMeshes > 1) return error.TooManyMeshes;
const mesh: *c.aiMesh = @ptrCast(scene.mMeshes[0]);
if (mesh.mNormals == null) return error.MissingNormals;
var vertices = try allocator.alloc(Vector3, @intCast(mesh.mNumVertices));
var normals = try allocator.alloc(Vector3, @intCast(mesh.mNumVertices));
var indices = try allocator.alloc(u16, @intCast(mesh.mNumFaces * 3)); // triangles
for (0..mesh.mNumVertices) |i| {
vertices[i] = .{
.x = mesh.mVertices[i].x,
.y = mesh.mVertices[i].y,
.z = mesh.mVertices[i].z,
};
normals[i] = .{
.x = mesh.mNormals[i].x,
.y = mesh.mNormals[i].y,
.z = mesh.mNormals[i].z,
};
}
for (0..mesh.mNumFaces) |i| {
std.debug.assert(mesh.mFaces[i].mNumIndices == 3);
for (0..3) |j| {
indices[i * 3 + j] = @intCast(mesh.mFaces[i].mIndices[j]);
}
}
const out_mesh = formats.Mesh{
.vertices = vertices,
.normals = normals,
.indices = indices,
};
const out_file = try std.fs.createFileAbsolute(output, .{});
defer out_file.close();
var buf_writer = std.io.bufferedWriter(out_file.writer());
try formats.writeMesh(
buf_writer.writer(),
out_mesh,
formats.native_endian, // TODO: use target endiannes
);
try buf_writer.flush();
}