Initial commit

1 files changed, 124 insertions, 0 deletions

diff --git a/src/main.zig b/src/main.zig
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+++ b/src/main.zig
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+const std = @import("std");
+const testing = std.testing;
+const math = std.math;
+
+const vector = @import("./vector.zig");
+const matrix = @import("./matrix.zig");
+
+pub const Matrix = matrix.Matrix;
+pub const Vector = vector.Vector;
+
+pub const Vec2 = Vector(2);
+pub const Vec3 = Vector(3);
+pub const Vec4 = Vector(4);
+
+pub const Mat2 = Matrix(2);
+pub const Mat3 = Matrix(3);
+pub const Mat4 = Matrix(4);
+
+pub fn translation(v: Vec3) Mat4 {
+  return .{
+    .values = [4][4]f32 {
+      .{ 1, 0, 0, 0 },
+      .{ 0, 1, 0, 0 },
+      .{ 0, 0, 1, 0 },
+      .{ v.values[0], v.values[1], v.values[2], 1 }
+    }
+  };
+}
+
+pub fn rotation(angle: f32, axis: Vec3) Mat4 {
+  const unit = axis.normalize();
+
+  const x = unit.values[0];
+  const y = unit.values[1];
+  const z = unit.values[2];
+
+  const a = math.cos(angle) + x * x * (1 - math.cos(angle));
+  const b = y * x * (1 - math.cos(angle)) + z * math.sin(angle);
+  const c = z * x * (1 - math.cos(angle)) - y * math.sin(angle);
+
+  const d = x * y * (1 - math.cos(angle)) - z * math.sin(angle);
+  const e = math.cos(angle) + y * y * (1 - math.cos(angle));
+  const f = z * y * (1 - math.cos(angle)) + x * math.sin(angle);
+
+  const h = x * z * (1 - math.cos(angle)) + y * math.sin(angle);
+  const i = y * z * (1 - math.cos(angle)) - x * math.sin(angle);
+  const j = math.cos(angle) + z * z * (1 - math.cos(angle));
+
+  return .{
+        .values = [4][4]f32{
+            .{ a, b, c, 0 },
+            .{ d, e, f, 0 },
+            .{ h, i, j, 0 },
+            .{ 0, 0, 0, 1 },
+        },
+    };
+}
+
+pub fn scale(v: Vec3) Mat4 {
+  return .{
+    .values = [4][4]f32 {
+      .{ v.values[0], 0, 0, 0 },
+      .{ 0, v.values[1], 0, 0 },
+      .{ 0, 0, v.values[2], 0 },
+      .{ 0, 0, 0, 1 },
+    }
+  };
+}
+
+pub fn lookAt(eye: Vec3, center: Vec3, up: Vec3) Mat4 {
+  const f = center.sub(eye).normalize();
+  const s = f.cross(up).normalize();
+  const u = s.cross(f);
+
+  return Mat4{
+    .values = [4][4]f32{
+      .{ s.values[0], u.values[0], -f.values[0], 0.0 },
+      .{ s.values[1], u.values[1], -f.values[1], 0.0 },
+      .{ s.values[2], u.values[2], -f.values[2], 0.0 },
+      .{ -s.dot(eye), -u.dot(eye), f.dot(eye), 1.0 },
+    },
+  };
+}
+
+pub fn perspective(fovY: f32, aspectRatio: f32, zNear: f32, zFar: f32) Mat4 {
+  const f = math.tan(fovY / 2.0);
+
+  const a = 1.0 / (aspectRatio * f);
+  const b = 1.0 / f;
+  const c = -(zFar + zNear) / (zFar - zNear);
+  const d = -(2.0 * zFar * zNear) / (zFar - zNear);
+
+  return .{
+    .values = [4][4]f32{
+      .{ a, 0.0, 0.0, 0.0 },
+      .{ 0.0, b, 0.0, 0.0 },
+      .{ 0.0, 0.0, c, -1.0 },
+      .{ 0.0, 0.0, d, 0.0 },
+    },
+  };
+}
+
+pub fn orthogonal(left: f32, right: f32, bottom: f32, top: f32, zNear: f32, zFar: f32) Mat4 {
+  const a = 2.0 / (right - left);
+  const b = 2.0 / (top - bottom);
+  const c = -2.0 / (zFar - zNear);
+  const d = -(right + left) / (right - left);
+  const e = -(top + bottom) / (top - bottom);
+  const f = -(zFar + zNear) / (zFar - zNear);
+
+  return .{
+    .values = [4][4]f32{
+      .{ a, 0.0, 0.0, 0.0 },
+      .{ 0.0, b, 0.0, 0.0 },
+      .{ 0.0, 0.0, c, -1.0 },
+      .{ d, e, f, 0.0 },
+    },
+  };
+}
+
+test "glm" {
+  _ = @import("./vector.zig");
+  _ = @import("./matrix.zig");
+}