commit 1e1a77b4ca78a098b8f054754a6eb4562e4f47fa
parent dd09b4131dced5f702ba7c26bbe413a1f6316fb3
Author: Christian Ermann <christianermann@gmail.com>
Date: Sun, 8 Dec 2024 13:42:58 -0800
Move 'tangentsAndBitangents' from 'load_obj.zig' to 'mesh.zig'
Diffstat:
| M | src/load_obj.zig | | | 68 | +------------------------------------------------------------------- |
| M | src/mesh.zig | | | 72 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- |
2 files changed, 70 insertions(+), 70 deletions(-)
diff --git a/src/load_obj.zig b/src/load_obj.zig
@@ -192,73 +192,7 @@ pub fn loadFile(options: LoadFileOptions) !Mesh {
.bitangents = try allocator.alloc(f32x3, pslice.len),
};
mesh.bbox = mesh.axisAlignedBoundingBox();
- try tangentsAndBitangents(&mesh, allocator);
+ try mesh.tangentsAndBitangents(allocator);
return mesh;
}
-
-fn tangentsAndBitangents(
- mesh: *const Mesh,
- allocator: std.mem.Allocator,
-) !void {
- const positions = mesh.positions;
- const tex_coords = mesh.tex_coords;
- const indices = mesh.indices;
- const tangents = mesh.tangents;
- const bitangents = mesh.bitangents;
-
- @memset(std.mem.asBytes(tangents), 0);
- @memset(std.mem.asBytes(bitangents), 0);
- if (tex_coords.len <= 0) {
- return;
- }
-
- var references = try allocator.alloc(u32, positions.len);
- defer allocator.free(references);
- @memset(references, 0);
-
- var i: u32 = 0;
- while (i < indices.len) : (i += 3) {
- const idx_0 = indices[i + 0];
- const idx_1 = indices[i + 1];
- const idx_2 = indices[i + 2];
-
- const p0: f32x3 = @as([4]f32, positions[idx_0])[0..3].*;
- const p1: f32x3 = @as([4]f32, positions[idx_1])[0..3].*;
- const p2: f32x3 = @as([4]f32, positions[idx_2])[0..3].*;
- const delta_p1 = p1 - p0;
- const delta_p2 = p2 - p0;
-
- const t0 = tex_coords[idx_0];
- const t1 = tex_coords[idx_1];
- const t2 = tex_coords[idx_2];
- const delta_t1 = t1 - t0;
- const delta_t2 = t2 - t0;
-
- const r = 1.0 / (delta_t1[0] * delta_t2[1] - delta_t1[1] * delta_t2[0]);
-
- const tangent_a = delta_p1 * @as(f32x3, @splat(delta_t2[1]));
- const tangent_b = delta_p2 * @as(f32x3, @splat(delta_t1[1]));
- const tangent = (tangent_a - tangent_b) * @as(f32x3, @splat(r));
- tangents[idx_0] += tangent;
- tangents[idx_1] += tangent;
- tangents[idx_2] += tangent;
-
- const bitangent_a = delta_p2 * @as(f32x3, @splat(delta_t1[0]));
- const bitangent_b = delta_p1 * @as(f32x3, @splat(delta_t2[0]));
- const bitangent = (bitangent_a - bitangent_b) * @as(f32x3, @splat(-r));
- bitangents[idx_0] += bitangent;
- bitangents[idx_1] += bitangent;
- bitangents[idx_2] += bitangent;
-
- references[idx_0] += 1;
- references[idx_1] += 1;
- references[idx_2] += 1;
- }
-
- for (references, 0..references.len) |ref_count, idx| {
- const scale = @as(f32x3, @splat(1 / @as(f32, @floatFromInt(ref_count))));
- tangents[idx] *= scale;
- bitangents[idx] *= scale;
- }
-}
diff --git a/src/mesh.zig b/src/mesh.zig
@@ -3,7 +3,7 @@ const std = @import("std");
const f32x3 = @Vector(3, f32);
const f32x4 = @Vector(4, f32);
-const Self = @This();
+const Mesh = @This();
positions: []f32x4,
normals: []f32x3,
@@ -20,7 +20,73 @@ pub const MeshletDescriptor = struct {
num_triangles: u32,
};
-pub fn axisAlignedBoundingBox(self: *const Self) [6]f32 {
+pub fn tangentsAndBitangents(
+ mesh: *const Mesh,
+ allocator: std.mem.Allocator,
+) !void {
+ const positions = mesh.positions;
+ const tex_coords = mesh.tex_coords;
+ const indices = mesh.indices;
+ const tangents = mesh.tangents;
+ const bitangents = mesh.bitangents;
+
+ @memset(std.mem.asBytes(tangents), 0);
+ @memset(std.mem.asBytes(bitangents), 0);
+ if (tex_coords.len <= 0) {
+ return;
+ }
+
+ var references = try allocator.alloc(u32, positions.len);
+ defer allocator.free(references);
+ @memset(references, 0);
+
+ var i: u32 = 0;
+ while (i < indices.len) : (i += 3) {
+ const idx_0 = indices[i + 0];
+ const idx_1 = indices[i + 1];
+ const idx_2 = indices[i + 2];
+
+ const p0: f32x3 = @as([4]f32, positions[idx_0])[0..3].*;
+ const p1: f32x3 = @as([4]f32, positions[idx_1])[0..3].*;
+ const p2: f32x3 = @as([4]f32, positions[idx_2])[0..3].*;
+ const delta_p1 = p1 - p0;
+ const delta_p2 = p2 - p0;
+
+ const t0 = tex_coords[idx_0];
+ const t1 = tex_coords[idx_1];
+ const t2 = tex_coords[idx_2];
+ const delta_t1 = t1 - t0;
+ const delta_t2 = t2 - t0;
+
+ const r = 1.0 / (delta_t1[0] * delta_t2[1] - delta_t1[1] * delta_t2[0]);
+
+ const tangent_a = delta_p1 * @as(f32x3, @splat(delta_t2[1]));
+ const tangent_b = delta_p2 * @as(f32x3, @splat(delta_t1[1]));
+ const tangent = (tangent_a - tangent_b) * @as(f32x3, @splat(r));
+ tangents[idx_0] += tangent;
+ tangents[idx_1] += tangent;
+ tangents[idx_2] += tangent;
+
+ const bitangent_a = delta_p2 * @as(f32x3, @splat(delta_t1[0]));
+ const bitangent_b = delta_p1 * @as(f32x3, @splat(delta_t2[0]));
+ const bitangent = (bitangent_a - bitangent_b) * @as(f32x3, @splat(-r));
+ bitangents[idx_0] += bitangent;
+ bitangents[idx_1] += bitangent;
+ bitangents[idx_2] += bitangent;
+
+ references[idx_0] += 1;
+ references[idx_1] += 1;
+ references[idx_2] += 1;
+ }
+
+ for (references, 0..references.len) |ref_count, idx| {
+ const scale = @as(f32x3, @splat(1 / @as(f32, @floatFromInt(ref_count))));
+ tangents[idx] *= scale;
+ bitangents[idx] *= scale;
+ }
+}
+
+pub fn axisAlignedBoundingBox(self: *const Mesh) [6]f32 {
var min_x: f32 = self.positions[0][0];
var max_x: f32 = self.positions[0][0];
var min_y: f32 = self.positions[0][1];
@@ -55,7 +121,7 @@ pub fn axisAlignedBoundingBox(self: *const Self) [6]f32 {
return .{ min_x, min_y, min_z, max_x, max_y, max_z };
}
-pub fn bboxVertices(self: *const Self) [8]f32x4 {
+pub fn bboxVertices(self: *const Mesh) [8]f32x4 {
const min_x = self.bbox[0];
const min_y = self.bbox[1];
const min_z = self.bbox[2];
