1 files changed, 78 insertions, 0 deletions
diff --git a/shaders/shader.hpp b/shaders/shader.hpp
new file mode 100644
index 00000000..280850b9
--- /dev/null
+++ b/shaders/shader.hpp
@@ -0,0 +1,78 @@
+#pragma once
+#include "compat/defs.hpp"
+#include "tile-defs.hpp"
+#include <Magnum/GL/AbstractShaderProgram.h>
+#include <Magnum/Math/Vector2.h>
+#include <Magnum/Math/Vector3.h>
+#include <Magnum/Math/Vector4.h>
+
+namespace floormat {
+
+struct local_coords;
+
+struct tile_shader : GL::AbstractShaderProgram
+{
+    using Position           = GL::Attribute<0, Vector3>;
+    using TextureCoordinates = GL::Attribute<1, Vector2>;
+    using Depth              = GL::Attribute<2, float>;
+
+    fm_DECLARE_DEFAULT_MOVE_ASSIGNMENT_(tile_shader);
+    fm_DECLARE_DELETED_COPY_ASSIGNMENT(tile_shader);
+
+    explicit tile_shader();
+    ~tile_shader() override;
+
+    Vector2 scale() const { return _scale; }
+    tile_shader& set_scale(const Vector2& scale);
+    Vector2d camera_offset() const { return _camera_offset; }
+    tile_shader& set_camera_offset(const Vector2d& camera_offset, float depth_offset);
+    Vector4 tint() const { return _tint; }
+    tile_shader& set_tint(const Vector4& tint);
+    float depth_offset() const { return _depth_offset; }
+    static float depth_value(const local_coords& xy, float offset = 0) noexcept;
+
+    template<typename T = float> static constexpr Math::Vector2<T> project(const Math::Vector3<T>& pt);
+    template<typename T = float> static constexpr Math::Vector2<T> unproject(const Math::Vector2<T>& px);
+
+    template<typename T, typename... Xs>
+    decltype(auto) draw(T&& mesh, Xs&&... xs);
+
+    static const Vector2s max_screen_tiles;
+    static const float depth_tile_size;
+    static const float character_depth_offset, scenery_depth_offset, wall_depth_offset, z_depth_offset;
+
+private:
+    void _draw();
+
+    Vector2d _camera_offset;
+    Vector4 _tint, _real_tint;
+    Vector2 _scale;
+    Vector3 _real_camera_offset;
+    float _depth_offset = 0;
+
+    enum { ScaleUniform = 0, OffsetUniform = 1, TintUniform = 2, };
+};
+
+template<typename T, typename... Xs>
+decltype(auto) tile_shader::draw(T&& mesh, Xs&&... xs)
+{
+    _draw();
+    return GL::AbstractShaderProgram::draw(std::forward<T>(mesh), std::forward<Xs>(xs)...);
+}
+
+template<typename T>
+constexpr Math::Vector2<T> tile_shader::project(const Math::Vector3<T>& pt)
+{
+    static_assert(std::is_floating_point_v<T>);
+    const auto x = pt[0], y = pt[1], z = -pt[2];
+    return { x-y, (x+y+z*2)*T(.59) };
+}
+
+template<typename T>
+constexpr Math::Vector2<T> tile_shader::unproject(const Math::Vector2<T>& px)
+{
+    const auto X = px[0], Y = px[1];
+    return { X + 100 * Y / 59, 100 * Y / 59 - X };
+}
+
+} // namespace floormat