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

2 files changed, 17 insertions, 13 deletions

diff --git a/draw/floor.cpp b/draw/floor.cpp
index 5e645b0f..5b5a515f 100644
--- a/draw/floor.cpp
+++ b/draw/floor.cpp
@@ -13,30 +13,32 @@ floor_mesh::floor_mesh() = default;
 
 void floor_mesh::draw(tile_shader& shader, chunk& c)
 {
-    constexpr auto quad_index_count = 6;
-    auto [mesh_, ids] = c.ensure_ground_mesh();
+    constexpr int quad_index_count = 6;
+    const auto [mesh_, ids, size] = c.ensure_ground_mesh();
     struct { tile_atlas* atlas = nullptr; std::size_t pos = 0; } last;
     GL::MeshView mesh{mesh_};
 
     [[maybe_unused]] std::size_t draw_count = 0;
 
-    const auto do_draw = [&](std::size_t i, tile_atlas* atlas) {
+    const auto do_draw = [&](std::size_t i, tile_atlas* atlas, std::uint32_t max_index) {
         if (atlas == last.atlas)
             return;
         if (auto len = i - last.pos; last.atlas && len > 0)
         {
             last.atlas->texture().bind(0);
             mesh.setCount((int)(quad_index_count * len));
-            mesh.setIndexRange((int)(last.pos*quad_index_count), 0, quad_index_count*TILE_COUNT - 1);
+            mesh.setIndexRange((int)(last.pos*quad_index_count), 0, max_index);
             shader.draw(mesh);
             draw_count++;
         }
         last = { atlas, i };
     };
 
-    for (std::size_t k = 0; k < TILE_COUNT; k++)
-        do_draw(k, c.ground_atlas_at(ids[k]));
-    do_draw(TILE_COUNT, nullptr);
+    const auto max_index = std::uint32_t(size*quad_index_count - 1);
+    std::size_t k;
+    for (k = 0; k < size; k++)
+        do_draw(k, c.ground_atlas_at(ids[k]), max_index);
+    do_draw(size, nullptr, max_index);
 
 #ifdef FM_DEBUG_DRAW_COUNT
     if (draw_count)
diff --git a/draw/wall.cpp b/draw/wall.cpp
index dbc9c2ad..85365844 100644
--- a/draw/wall.cpp
+++ b/draw/wall.cpp
@@ -17,28 +17,30 @@ wall_mesh::wall_mesh() = default;
 
 void wall_mesh::draw(tile_shader& shader, chunk& c)
 {
-    auto [mesh_, ids] = c.ensure_wall_mesh();
+    const auto [mesh_, ids, size] = c.ensure_wall_mesh();
     struct { tile_atlas* atlas = nullptr; std::size_t pos = 0; } last;
     GL::MeshView mesh{mesh_};
     [[maybe_unused]] std::size_t draw_count = 0;
 
-    const auto do_draw = [&](std::size_t i, tile_atlas* atlas) {
+    const auto do_draw = [&](std::size_t i, tile_atlas* atlas, std::uint32_t max_index) {
         if (atlas == last.atlas)
             return;
         if (auto len = i - last.pos; last.atlas && len > 0)
         {
             last.atlas->texture().bind(0);
             mesh.setCount((int)(quad_index_count * len));
-            mesh.setIndexRange((int)(last.pos*quad_index_count), 0, quad_index_count*TILE_COUNT*2 - 1);
+            mesh.setIndexRange((int)(last.pos*quad_index_count), 0, max_index);
             shader.draw(mesh);
             draw_count++;
         }
         last = { atlas, i };
     };
 
-    for (std::size_t k = 0; k < TILE_COUNT*2; k++)
-        do_draw(k, c.wall_atlas_at(ids[k]));
-    do_draw(TILE_COUNT*2, nullptr);
+    const auto max_index = std::uint32_t(size*quad_index_count - 1);
+    std::size_t k;
+    for (k = 0; k < size; k++)
+        do_draw(k, c.wall_atlas_at(ids[k]), max_index);
+    do_draw(size, nullptr, max_index);
 
 #ifdef FM_DEBUG_DRAW_COUNT
     if (draw_count)