77 lines
1.8 KiB
Zig
77 lines
1.8 KiB
Zig
const std = @import("std");
|
|
|
|
pub fn Matrix(comptime n: usize, comptime Element: type) type {
|
|
return [n]@Vector(n, Element);
|
|
}
|
|
|
|
pub const ProjectionMatrix = Matrix(4, f32);
|
|
|
|
pub const Rect = struct {
|
|
left: f32,
|
|
top: f32,
|
|
right: f32,
|
|
bottom: f32,
|
|
};
|
|
|
|
pub fn cross(v1: anytype, v2: anytype) @typeInfo(@TypeOf(v1, v2)).Vector.child {
|
|
const multipled = v1 * v2;
|
|
const vector_info = @typeInfo(@TypeOf(v1)).Vector;
|
|
var result = multipled[0];
|
|
comptime var index = @as(usize, 1);
|
|
|
|
inline while (index < vector_info.len) : (index += 1) {
|
|
result -= multipled[index];
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
pub fn distance(v1: anytype, v2: anytype) @typeInfo(@TypeOf(v1, v2)).Vector.child {
|
|
return length(v1 - v2);
|
|
}
|
|
|
|
pub fn dot(v1: anytype, v2: anytype) @typeInfo(@TypeOf(v1, v2)).Vector.child {
|
|
const multipled = v1 * v2;
|
|
const vector_info = @typeInfo(@TypeOf(v1)).Vector;
|
|
var result = multipled[0];
|
|
comptime var index = @as(usize, 1);
|
|
|
|
inline while (index < vector_info.len) : (index += 1) {
|
|
result += multipled[index];
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
pub fn length(v: anytype) @typeInfo(@TypeOf(v)).Vector.child {
|
|
return @sqrt(length_squared(v));
|
|
}
|
|
|
|
pub fn length_squared(v: anytype) @typeInfo(@TypeOf(v)).Vector.child {
|
|
return dot(v, v);
|
|
}
|
|
|
|
pub fn normal(v: anytype) @TypeOf(v) {
|
|
const ls = length_squared(v);
|
|
const Vector = @TypeOf(v);
|
|
|
|
if (ls > std.math.floatEps(@typeInfo(Vector).Vector.child)) {
|
|
return v / @as(Vector, @splat(@sqrt(ls)));
|
|
}
|
|
|
|
return v;
|
|
}
|
|
|
|
pub fn orthographic_projection(near: f32, far: f32, viewport: Rect) Matrix(4, f32) {
|
|
const width = viewport.right - viewport.left;
|
|
const height = viewport.bottom - viewport.top;
|
|
|
|
return .{
|
|
.{2 / width, 0, 0, 0},
|
|
.{0, 2 / height, 0, 0},
|
|
.{0, 0, 1 / (far - near), 0},
|
|
.{-((viewport.left + viewport.right) / width), -((viewport.top + viewport.bottom) / height), near / (near - far), 1},
|
|
};
|
|
}
|
|
|