src, draw: don't overallocate ground & wall vbo's

2 files changed, 62 insertions, 55 deletions

diff --git a/src/chunk-render.cpp b/src/chunk-render.cpp
index 37440af9..cfd10307 100644
--- a/src/chunk-render.cpp
+++ b/src/chunk-render.cpp
@@ -1,16 +1,18 @@
 #include "chunk.hpp"
 #include "tile-atlas.hpp"
+#include "anim-atlas.hpp"
 #include "shaders/tile.hpp"
 #include <algorithm>
-#include <Magnum/GL/Buffer.h>
 #include <Corrade/Containers/ArrayViewStl.h>
+#include <Magnum/GL/Buffer.h>
 
 namespace floormat {
 
-static auto make_index_array(std::size_t offset)
+template<std::size_t N = 1>
+static auto make_index_array(std::size_t offset, std::size_t max)
 {
-    std::array<std::array<UnsignedShort, 6>, TILE_COUNT> array; // NOLINT(cppcoreguidelines-pro-type-member-init)
-    for (std::size_t i = 0; i < TILE_COUNT; i++)
+    std::array<std::array<UnsignedShort, 6>, N*TILE_COUNT> array; // NOLINT(cppcoreguidelines-pro-type-member-init)
+    for (std::size_t i = 0; i < max; i++)
         array[i] = tile_atlas::indices(i + offset);
     return array;
 }
@@ -24,84 +26,87 @@ struct vertex {
 auto chunk::ensure_ground_mesh() noexcept -> ground_mesh_tuple
 {
     if (!_ground_modified)
-        return { ground_mesh, ground_indexes };
+        return { ground_mesh, ground_indexes, std::size_t(ground_mesh.count()/6) };
     _ground_modified = false;
 
+    std::size_t count = 0;
     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();
-    });
+        if (_ground_atlases[i])
+            ground_indexes[count++] = std::uint8_t(i);
+
+    std::sort(ground_indexes.begin(), ground_indexes.begin() + count,
+              [this](std::uint8_t a, std::uint8_t b) {
+                  return _ground_atlases[a] < _ground_atlases[b];
+              });
 
     std::array<std::array<vertex, 4>, TILE_COUNT> vertexes;
-    for (std::size_t k = 0; k < TILE_COUNT; k++)
+    for (std::size_t k = 0; k < count; k++)
     {
         const std::uint8_t i = ground_indexes[k];
-        if (auto atlas = _ground_atlases[i]; !atlas)
-            vertexes[k] = {};
-        else
-        {
-            const local_coords pos{i};
-            const auto quad = atlas->floor_quad(Vector3(pos.x, pos.y, 0) * TILE_SIZE, TILE_SIZE2);
-            const auto texcoords = atlas->texcoords_for_id(_ground_variants[i]);
-            const float depth = tile_shader::depth_value(pos);
-            auto& v = vertexes[k];
-            for (std::size_t j = 0; j < 4; j++)
-                v[j] = { quad[j], texcoords[j], depth };
-        }
+        const auto& atlas = _ground_atlases[i];
+        const local_coords pos{i};
+        const auto quad = atlas->floor_quad(Vector3(pos.x, pos.y, 0) * TILE_SIZE, TILE_SIZE2);
+        const auto texcoords = atlas->texcoords_for_id(_ground_variants[i]);
+        const float depth = tile_shader::depth_value(pos);
+        auto& v = vertexes[k];
+        for (std::size_t j = 0; j < 4; j++)
+            v[j] = { quad[j], texcoords[j], depth };
     }
-    const auto indexes = make_index_array(0);
+
+    const auto indexes = make_index_array(0, count);
+    const auto vertex_view = ArrayView{vertexes.data(), count};
+    const auto vert_index_view = ArrayView{indexes.data(), count};
 
     GL::Mesh mesh{GL::MeshPrimitive::Triangles};
-    mesh.addVertexBuffer(GL::Buffer{vertexes}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
-        .setIndexBuffer(GL::Buffer{indexes}, 0, GL::MeshIndexType::UnsignedShort)
-        .setCount(6 * TILE_COUNT);
+    mesh.addVertexBuffer(GL::Buffer{vertex_view}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
+        .setIndexBuffer(GL::Buffer{vert_index_view}, 0, GL::MeshIndexType::UnsignedShort)
+        .setCount(std::int32_t(6 * count));
     ground_mesh = Utility::move(mesh);
-    return { ground_mesh, ground_indexes };
+    return { ground_mesh, ground_indexes, count };
 }
 
 auto chunk::ensure_wall_mesh() noexcept -> wall_mesh_tuple
 {
     if (!_walls_modified)
-        return { wall_mesh, wall_indexes };
+        return { wall_mesh, wall_indexes, std::size_t(wall_mesh.count()/6) };
     _walls_modified = false;
 
+    std::size_t count = 0;
     for (std::size_t i = 0; i < TILE_COUNT*2; i++)
-        wall_indexes[i] = std::uint16_t(i);
+        if (_wall_atlases[i])
+            wall_indexes[count++] = std::uint16_t(i);
 
-    std::sort(wall_indexes.begin(), wall_indexes.end(), [this](std::uint16_t a, std::uint16_t b) {
-        return _wall_atlases[a] < _wall_atlases[b];
-    });
+    std::sort(wall_indexes.begin(), wall_indexes.begin() + count,
+              [this](std::uint16_t a, std::uint16_t b) {
+                  return _wall_atlases[a] < _wall_atlases[b];
+              });
 
     std::array<std::array<vertex, 4>, TILE_COUNT*2> vertexes;
-    for (std::size_t k = 0; k < TILE_COUNT*2; k++)
+    for (std::size_t k = 0; k < count; k++)
     {
         const std::uint16_t i = wall_indexes[k];
-        if (const auto& atlas = _wall_atlases[i]; !atlas)
-            vertexes[k] = {};
-        else
-        {
-            const auto& variant = _wall_variants[i];
-            const local_coords pos{i / 2u};
-            const auto center = Vector3(pos.x, pos.y, 0) * TILE_SIZE;
-            const auto quad = i & 1 ? atlas->wall_quad_W(center, TILE_SIZE) : atlas->wall_quad_N(center, TILE_SIZE);
-            const float depth = tile_shader::depth_value(pos);
-            const auto texcoords = atlas->texcoords_for_id(variant);
-            auto& v = vertexes[k];
-            for (std::size_t j = 0; j < 4; j++)
-                v[j] = { quad[j], texcoords[j], depth, };
-        }
+        const auto& atlas = _wall_atlases[i];
+        const auto& variant = _wall_variants[i];
+        const local_coords pos{i / 2u};
+        const auto center = Vector3(pos.x, pos.y, 0) * TILE_SIZE;
+        const auto quad = i & 1 ? atlas->wall_quad_W(center, TILE_SIZE) : atlas->wall_quad_N(center, TILE_SIZE);
+        const float depth = tile_shader::depth_value(pos);
+        const auto texcoords = atlas->texcoords_for_id(variant);
+        auto& v = vertexes[k];
+        for (std::size_t j = 0; j < 4; j++)
+            v[j] = { quad[j], texcoords[j], depth, };
     }
 
-    using index_t = std::array<std::array<UnsignedShort, 6>, TILE_COUNT>;
-    const index_t indexes[2] = { make_index_array(0), make_index_array(TILE_COUNT) };
+    auto indexes = make_index_array<2>(0, count);
+    const auto vertex_view = ArrayView{vertexes.data(), count};
+    const auto vert_index_view = ArrayView{indexes.data(), count};
 
     GL::Mesh mesh{GL::MeshPrimitive::Triangles};
-    mesh.addVertexBuffer(GL::Buffer{vertexes}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
-        .setIndexBuffer(GL::Buffer{indexes}, 0, GL::MeshIndexType::UnsignedShort)
-        .setCount(6 * TILE_COUNT);
+    mesh.addVertexBuffer(GL::Buffer{vertex_view}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
+        .setIndexBuffer(GL::Buffer{vert_index_view}, 0, GL::MeshIndexType::UnsignedShort)
+        .setCount(std::int32_t(6 * count));
     wall_mesh = Utility::move(mesh);
-    return { wall_mesh, wall_indexes };
+    return { wall_mesh, wall_indexes, count };
 }
 
 } // namespace floormat
diff --git a/src/chunk.hpp b/src/chunk.hpp
index 3a6ea3df..c061d070 100644
--- a/src/chunk.hpp
+++ b/src/chunk.hpp
@@ -63,11 +63,13 @@ struct chunk final
 
     struct ground_mesh_tuple final {
         GL::Mesh& mesh;                                     // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
-        const std::array<std::uint8_t, TILE_COUNT>& ids;    // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
+        const ArrayView<const std::uint8_t> ids;            // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
+        const std::size_t size;
     };
     struct wall_mesh_tuple final {
         GL::Mesh& mesh;                                     // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
-        const std::array<std::uint16_t, TILE_COUNT*2>& ids; // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
+        const ArrayView<const std::uint16_t> ids;           // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)
+        const std::size_t size;
     };
 
     ground_mesh_tuple ensure_ground_mesh() noexcept;