Update mesh collector and move it to a separate file (#6904)

* Update MeshCollector

* Simplify MeshCollector

2 files changed, 169 insertions, 0 deletions

diff --git a/src/client/meshgen/collector.cpp b/src/client/meshgen/collector.cpp
new file mode 100644
index 000000000..c317a0772
--- /dev/null
+++ b/src/client/meshgen/collector.cpp
@@ -0,0 +1,104 @@
+/*
+Minetest
+Copyright (C) 2018 numzero, Lobachevskiy Vitaliy <numzer0@yandex.ru>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "collector.h"
+#include <stdexcept>
+#include "log.h"
+#include "mesh.h"
+
+void MeshCollector::append(const TileSpec &tile, const video::S3DVertex *vertices,
+		u32 numVertices, const u16 *indices, u32 numIndices)
+{
+	for (int layernum = 0; layernum < MAX_TILE_LAYERS; layernum++) {
+		const TileLayer *layer = &tile.layers[layernum];
+		if (layer->texture_id == 0)
+			continue;
+		append(*layer, vertices, numVertices, indices, numIndices, layernum,
+				tile.world_aligned);
+	}
+}
+
+void MeshCollector::append(const TileLayer &layer, const video::S3DVertex *vertices,
+		u32 numVertices, const u16 *indices, u32 numIndices, u8 layernum,
+		bool use_scale)
+{
+	PreMeshBuffer &p = findBuffer(layer, layernum, numVertices);
+
+	f32 scale = 1.0f;
+	if (use_scale)
+		scale = 1.0f / layer.scale;
+
+	u32 vertex_count = p.vertices.size();
+	for (u32 i = 0; i < numVertices; i++)
+		p.vertices.emplace_back(vertices[i].Pos, vertices[i].Normal,
+				vertices[i].Color, scale * vertices[i].TCoords);
+
+	for (u32 i = 0; i < numIndices; i++)
+		p.indices.push_back(indices[i] + vertex_count);
+}
+
+void MeshCollector::append(const TileSpec &tile, const video::S3DVertex *vertices,
+		u32 numVertices, const u16 *indices, u32 numIndices, v3f pos,
+		video::SColor c, u8 light_source)
+{
+	for (int layernum = 0; layernum < MAX_TILE_LAYERS; layernum++) {
+		const TileLayer *layer = &tile.layers[layernum];
+		if (layer->texture_id == 0)
+			continue;
+		append(*layer, vertices, numVertices, indices, numIndices, pos, c,
+				light_source, layernum, tile.world_aligned);
+	}
+}
+
+void MeshCollector::append(const TileLayer &layer, const video::S3DVertex *vertices,
+		u32 numVertices, const u16 *indices, u32 numIndices, v3f pos,
+		video::SColor c, u8 light_source, u8 layernum, bool use_scale)
+{
+	PreMeshBuffer &p = findBuffer(layer, layernum, numVertices);
+
+	f32 scale = 1.0f;
+	if (use_scale)
+		scale = 1.0f / layer.scale;
+
+	u32 vertex_count = p.vertices.size();
+	for (u32 i = 0; i < numVertices; i++) {
+		video::SColor color = c;
+		if (!light_source)
+			applyFacesShading(color, vertices[i].Normal);
+		p.vertices.emplace_back(vertices[i].Pos + pos, vertices[i].Normal, color,
+				scale * vertices[i].TCoords);
+	}
+
+	for (u32 i = 0; i < numIndices; i++)
+		p.indices.push_back(indices[i] + vertex_count);
+}
+
+PreMeshBuffer &MeshCollector::findBuffer(
+		const TileLayer &layer, u8 layernum, u32 numVertices)
+{
+	if (numVertices > U16_MAX)
+		throw std::invalid_argument(
+				"Mesh can't contain more than 65536 vertices");
+	std::vector<PreMeshBuffer> &buffers = prebuffers[layernum];
+	for (PreMeshBuffer &p : buffers)
+		if (p.layer == layer && p.vertices.size() + numVertices <= U16_MAX)
+			return p;
+	buffers.emplace_back(layer);
+	return buffers.back();
+}
diff --git a/src/client/meshgen/collector.h b/src/client/meshgen/collector.h
new file mode 100644
index 000000000..e4189088e
--- /dev/null
+++ b/src/client/meshgen/collector.h
@@ -0,0 +1,65 @@
+/*
+Minetest
+Copyright (C) 2018 numzero, Lobachevskiy Vitaliy <numzer0@yandex.ru>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+#include <array>
+#include <vector>
+#include "irrlichttypes.h"
+#include <S3DVertex.h>
+#include "client/tile.h"
+
+struct PreMeshBuffer
+{
+	TileLayer layer;
+	std::vector<u16> indices;
+	std::vector<video::S3DVertex> vertices;
+
+	PreMeshBuffer() = default;
+	explicit PreMeshBuffer(const TileLayer &layer) : layer(layer) {}
+};
+
+struct MeshCollector
+{
+	std::array<std::vector<PreMeshBuffer>, MAX_TILE_LAYERS> prebuffers;
+
+	// clang-format off
+	void append(const TileSpec &material,
+			const video::S3DVertex *vertices, u32 numVertices,
+			const u16 *indices, u32 numIndices);
+	void append(const TileSpec &material,
+			const video::S3DVertex *vertices, u32 numVertices,
+			const u16 *indices, u32 numIndices,
+			v3f pos, video::SColor c, u8 light_source);
+	// clang-format on
+
+private:
+	// clang-format off
+	void append(const TileLayer &material,
+			const video::S3DVertex *vertices, u32 numVertices,
+			const u16 *indices, u32 numIndices,
+			u8 layernum, bool use_scale = false);
+	void append(const TileLayer &material,
+			const video::S3DVertex *vertices, u32 numVertices,
+			const u16 *indices, u32 numIndices,
+			v3f pos, video::SColor c, u8 light_source,
+			u8 layernum, bool use_scale = false);
+	// clang-format on
+
+	PreMeshBuffer &findBuffer(const TileLayer &layer, u8 layernum, u32 numVertices);
+};