add floor mesh to struct chunk

1 files changed, 74 insertions, 1 deletions

diff --git a/src/chunk.cpp b/src/chunk.cpp
index ea3fd8d7..973a1a5d 100644
--- a/src/chunk.cpp
+++ b/src/chunk.cpp
@@ -1,4 +1,9 @@
 #include "chunk.hpp"
+#include "tile-atlas.hpp"
+#include "shaders/tile.hpp"
+#include <algorithm>
+#include <Corrade/Containers/ArrayViewStl.h>
+#include <Magnum/GL/Buffer.h>
 
 namespace floormat {
 
@@ -19,7 +24,65 @@ bool chunk::empty(bool force) const noexcept
     return true;
 }
 
-chunk::chunk() noexcept = default;
+tile_atlas* chunk::ground_atlas_at(std::size_t i) const noexcept
+{
+    return _ground_atlases[i].get();
+}
+
+static constexpr auto make_index_array()
+{
+    std::array<std::array<UnsignedShort, 6>, TILE_COUNT> array;
+    for (std::size_t i = 0; i < TILE_COUNT; i++)
+        array[i] = tile_atlas::indices(i);
+    return array;
+}
+
+auto chunk::ensure_ground_mesh() noexcept -> mesh_tuple
+{
+    if (!_ground_modified)
+        return { ground_mesh, ground_indexes };
+    _ground_modified = false;
+
+    for (std::size_t i = 0; i < TILE_COUNT; i++)
+        ground_indexes[i] = std::uint8_t(i);
+    std::sort(ground_indexes.begin(), ground_indexes.end(), [this](std::uint8_t a, std::uint8_t b) {
+        return _ground_atlases[a].get() < _ground_atlases[b].get();
+    });
+
+    struct vertex {
+        Vector3 position;
+        Vector2 texcoords;
+    };
+    std::array<std::array<vertex, 4>, TILE_COUNT> vertexes;
+    for (std::size_t k = 0; k < TILE_COUNT; k++)
+    {
+        const std::uint8_t i = ground_indexes[k];
+        if (auto atlas = _ground_atlases[i]; !atlas)
+            vertexes[k] = {};
+        else
+        {
+            const std::uint8_t x = i % TILE_MAX_DIM, y = i / TILE_MAX_DIM;
+            auto quad = atlas->floor_quad(Vector3(x, y, 0) * TILE_SIZE, TILE_SIZE2);
+            auto texcoords = atlas->texcoords_for_id(_ground_variants[i] % atlas->num_tiles());
+            auto& v = vertexes[k];
+            for (std::size_t j = 0; j < 4; j++)
+                v[j] = { quad[j], texcoords[j] };
+        }
+    }
+    constexpr auto indexes = make_index_array();
+
+    GL::Mesh mesh{GL::MeshPrimitive::Triangles};
+    mesh.addVertexBuffer(GL::Buffer{vertexes}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{})
+        .setIndexBuffer(GL::Buffer{indexes}, 0, GL::MeshIndexType::UnsignedShort)
+        .setCount(6 * TILE_COUNT);
+    ground_mesh = Utility::move(mesh);
+    return { ground_mesh, ground_indexes };
+}
+
+chunk::chunk() noexcept // NOLINT(modernize-use-equals-default)
+{
+    //fm_debug("chunk ctor");
+}
 
 tile_ref chunk::operator[](std::size_t idx) noexcept { return { *this, std::uint8_t(idx) }; }
 tile_proto chunk::operator[](std::size_t idx) const noexcept { return tile_proto(tile_ref { *const_cast<chunk*>(this), std::uint8_t(idx) }); }
@@ -36,4 +99,14 @@ auto chunk::end() const noexcept -> const_iterator { return cend(); }
 chunk::chunk(chunk&&) noexcept = default;
 chunk& chunk::operator=(chunk&&) noexcept = default;
 
+void chunk::mark_modified() noexcept
+{
+    _ground_modified = true;
+}
+
+bool chunk::is_modified() const noexcept
+{
+    return _ground_modified;
+}
+
 } // namespace floormat