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// 3D model
// Copyright (C) 2002 David Rosen
// Copyright (C) 2023, 2025 Nguyễn Gia Phong
//
// This file is part of Black Shades.
//
// Black Shades is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Black Shades is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Black Shades. If not, see <https://www.gnu.org/licenses/>.
const TokenIterator = std.mem.TokenIterator(u8, .scalar);
const XYZ = geom.XYZ;
const allocator = std.heap.c_allocator;
const assert = std.debug.assert;
const c = @import("cimport.zig");
const crossProduct = geom.crossProduct;
const cwd = std.fs.cwd;
const data_dir = misc.data_dir;
const degreesToRadians = std.math.degreesToRadians;
const endsWith = std.mem.endsWith;
const eql = std.mem.eql;
const floatMax = std.math.floatMax;
const geom = @import("geom.zig");
const misc = @import("misc.zig");
const normalize = geom.normalize;
const parseFloat = std.fmt.parseFloat;
const parseInt = std.fmt.parseInt;
const rotate2d = geom.rotate2d;
const readFile = misc.readFile;
const segCrossSphere = geom.segCrossSphere;
const segCrossTrigon = geom.segCrossTrigon;
const sep = std.fs.path.sep;
const splat = geom.splat;
const sqr = geom.sqr;
const startsWith = std.mem.startsWith;
const std = @import("std");
const tokenizeScalar = std.mem.tokenizeScalar;
const Vertex = extern struct {
position: XYZ,
normal: XYZ,
color: [3]f32,
};
const Face = [3]Vertex;
pub const Model = extern struct {
faces: [*]Face,
face_count: u16,
center: XYZ,
radius: f32,
};
/// Object File Format tokenizer
const OffIterator = struct {
token_iterator: TokenIterator,
pub fn init(buffer: []const u8) OffIterator {
var self = OffIterator{
.token_iterator = tokenizeScalar(u8, buffer, '\n'),
};
if (!endsWith(u8, self.token_iterator.next().?, "OFF"))
self.token_iterator.reset();
return self;
}
pub fn next(self: *OffIterator) ?TokenIterator {
while (self.token_iterator.next()) |line| {
var words = tokenizeScalar(u8, line, ' ');
if (words.next()) |word| { // not empty
if (!startsWith(u8, word, "#")) { // not comment
words.reset();
return words;
}
}
}
return null;
}
};
export fn loadModel(path: [*:0]const u8) Model {
const file = readFile(cwd(), data_dir ++ "models{c}{s}", .{
sep, path,
}) catch unreachable;
defer allocator.free(file);
var lines = OffIterator.init(file);
var counts = lines.next().?;
const vertex_count = parseInt(u16, counts.next().?, 10) catch unreachable;
const face_count = parseInt(u16, counts.next().?, 10) catch unreachable;
const vertices = allocator.alloc(@Vector(3, f32), vertex_count)
catch unreachable;
defer allocator.free(vertices);
for (vertices) |*position| {
var numbers = lines.next().?;
position.* = .{
parseFloat(f32, numbers.next().?) catch unreachable,
parseFloat(f32, numbers.next().?) catch unreachable,
parseFloat(f32, numbers.next().?) catch unreachable,
};
}
const center = blk: {
var sum = @Vector(3, f32){0.0, 0.0, 0.0};
for (vertices) |position|
sum += position;
break :blk sum / splat(3, @as(f32, @floatFromInt(vertex_count)));
};
const faces = allocator.alloc(Face, face_count) catch unreachable;
for (faces) |*face| {
var numbers = lines.next().?;
assert(eql(u8, numbers.next().?, "3"));
const indices = [3]u16{
parseInt(u16, numbers.next().?, 10) catch unreachable,
parseInt(u16, numbers.next().?, 10) catch unreachable,
parseInt(u16, numbers.next().?, 10) catch unreachable,
};
const normal = normalize(crossProduct(
@bitCast(vertices[indices[1]] - vertices[indices[0]]),
@bitCast(vertices[indices[2]] - vertices[indices[0]])));
const color = [3]f32{
parseFloat(f32, numbers.next().?) catch unreachable,
parseFloat(f32, numbers.next().?) catch unreachable,
parseFloat(f32, numbers.next().?) catch unreachable,
};
for (face, indices) |*vertex, index|
vertex.* = .{
.position = @bitCast(vertices[index]),
// OpenGL has no concept of face normal or color.
.normal = normal,
.color = color,
};
}
return .{
.faces = faces.ptr,
.face_count = face_count,
.center = @bitCast(center),
.radius = blk: {
var square: f32 = 0;
for (vertices) |position|
square = @max(square, @reduce(.Add, sqr(position - center)));
break :blk @sqrt(square);
},
};
}
export fn destroyModel(m: *const Model) void {
allocator.free(m.faces[0..m.face_count]);
}
pub export fn drawModel(m: *const Model, color: ?*const [3]f32) void {
c.glEnableClientState(c.GL_VERTEX_ARRAY);
c.glVertexPointer(3, c.GL_FLOAT, @sizeOf(Vertex), &m.faces[0][0].position);
c.glEnableClientState(c.GL_NORMAL_ARRAY);
c.glNormalPointer(c.GL_FLOAT, @sizeOf(Vertex), &m.faces[0][0].normal);
if (color) |ptr| {
c.glDisableClientState(c.GL_COLOR_ARRAY);
c.glColor3fv(ptr);
} else {
c.glEnableClientState(c.GL_COLOR_ARRAY);
c.glColorPointer(3, c.GL_FLOAT, @sizeOf(Vertex), &m.faces[0][0].color);
}
c.glDrawArrays(c.GL_TRIANGLES, 0, @intCast(m.face_count * 3));
}
pub export fn segCrossModel(start: XYZ, end: XYZ, m: *const Model,
intersection: *XYZ) c_int {
if (!segCrossSphere(start, end, m.center, m.radius))
return -1;
const p: @Vector(3, f32) = @bitCast(start);
var result: c_int = -1;
var shortest = floatMax(f32);
for (m.faces[0..m.face_count], 0..) |face, i| {
var v: @Vector(3, f32) = undefined;
if (!segCrossTrigon(start, end, &face[0].position,
&face[1].position, &face[2].position,
&face[0].normal, @ptrCast(&v)))
continue;
const distance = @reduce(.Add, sqr(v - p));
if (distance < shortest or result == -1) {
shortest = distance;
result = @intCast(i);
assert(i < m.face_count);
intersection.* = @bitCast(v);
}
}
return result;
}
pub export fn segCrossModelTrans(start: XYZ, end: XYZ, m: *const Model,
move: XYZ, rot: f32,
intersection: *XYZ) c_int {
const t: @Vector(3, f32) = @bitCast(move);
var p = @as(@Vector(3, f32), @bitCast(start)) - t;
rotate2d(&p[2], &p[0], degreesToRadians(-rot));
var q = @as(@Vector(3, f32), @bitCast(end)) - t;
rotate2d(&q[2], &q[0], degreesToRadians(-rot));
defer {
rotate2d(&intersection.z, &intersection.x, degreesToRadians(rot));
intersection.* = @bitCast(@as(@Vector(3, f32),
@bitCast(intersection.*)) + t);
}
return segCrossModel(@bitCast(p), @bitCast(q), m, intersection);
}
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