a

1 files changed, 15 insertions, 0 deletions

diff --git a/shaders/tile-shader.hpp b/shaders/tile-shader.hpp
index c53dfff5..0dd2b631 100644
--- a/shaders/tile-shader.hpp
+++ b/shaders/tile-shader.hpp
@@ -20,6 +20,9 @@ struct tile_shader : GL::AbstractShaderProgram
     Vector4 tint() const { return tint_; }
     tile_shader& set_tint(const Vector4& tint);
 
+    static constexpr Vector2 project(Vector3 pt);
+    static constexpr Vector2 unproject(Vector2 px);
+
 private:
     Vector2 scale_, camera_offset_;
     Vector4 tint_;
@@ -27,4 +30,16 @@ private:
     enum { ScaleUniform = 0, OffsetUniform = 1, TintUniform = 2, };
 };
 
+constexpr Vector2 tile_shader::project(const Vector3 pt)
+{
+    const float x = -pt[1], y = -pt[0], z = pt[2];
+    return { x-y, (x+y+z*2)*.59f };
+}
+
+constexpr Vector2 tile_shader::unproject(const Vector2 px)
+{
+    const float X = px[0], Y = px[1];
+    return { X/2 + 50.f * Y / 59, 50 * Y / 59 - X/2 };
+}
+
 } // namespace floormat