mapblock_mesh.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include "irrlichttypes.h"
#include "irr_ptr.h"
#include "IMesh.h"
#include "CMeshBuffer.h"
 
#include "util/numeric.h"
#include "client/tile.h"
#include "voxel.h"
#include <map>
 
namespace video {
        class IVideoDriver;
}
 
class Client;
class NodeDefManager;
class IShaderSource;
class ITextureSource;
struct LightPair;
 
/*
        Mesh making stuff
*/
 
 
struct MinimapMapblock;
 
struct MeshMakeData
{
        VoxelManipulator m_vmanip;
 
        // base pos of meshgen area, in blocks
        v3s16 m_blockpos = v3s16(-1337,-1337,-1337);
        // size of meshgen area, in nodes.
        // vmanip will have at least an extra 1 node onion layer.
        // area is expected to fit into mesh grid cell.
        u16 m_side_length;
        // vertex positions will be relative to this grid
        MeshGrid m_mesh_grid;
 
        // relative to blockpos
        v3s16 m_crack_pos_relative = v3s16(-1337,-1337,-1337);
        bool m_generate_minimap = false;
        bool m_smooth_lighting = false;
        bool m_enable_water_reflections = false;
        bool m_enable_waving_water = false;
 
        const NodeDefManager *m_nodedef;
 
        MeshMakeData(const NodeDefManager *ndef, u16 side_lingth, MeshGrid mesh_grid);
 
        /*
                Copy block data manually (to allow optimizations by the caller)
        */
        void fillBlockDataBegin(const v3s16 &blockpos);
 
        /*
                Prepare block data for rendering a single node located at (0,0,0).
        */
        void fillSingleNode(MapNode data, MapNode padding = MapNode(CONTENT_AIR));
 
        /*
                Set the (node) position of a crack
        */
        void setCrack(int crack_level, v3s16 crack_pos);
};
 
// represents a triangle as indexes into the vertex buffer in SMeshBuffer
class MeshTriangle
{
public:
        scene::SMeshBuffer *buffer;
        u16 p1, p2, p3;
        v3f centroid;
        float areaSQ;
 
        void updateAttributes()
        {
                v3f v1 = buffer->getPosition(p1);
                v3f v2 = buffer->getPosition(p2);
                v3f v3 = buffer->getPosition(p3);
 
                centroid = (v1 + v2 + v3) / 3;
                areaSQ = (v2-v1).crossProduct(v3-v1).getLengthSQ() / 4;
        }
 
        v3f getNormal() const {
                v3f v1 = buffer->getPosition(p1);
                v3f v2 = buffer->getPosition(p2);
                v3f v3 = buffer->getPosition(p3);
 
                return (v2-v1).crossProduct(v3-v1);
        }
};

class MapBlockBspTree
{
public:
        MapBlockBspTree() {}
 
        void buildTree(const std::vector<MeshTriangle> *triangles, u16 side_lingth);
 
        void traverse(v3f viewpoint, std::vector<s32> &output) const
        {
                traverse(root, viewpoint, output);
        }
 
private:
        // Tree node definition;
        struct TreeNode
        {
                v3f normal;
                v3f origin;
                std::vector<s32> triangle_refs;
                s32 front_ref;
                s32 back_ref;
 
                TreeNode() = default;
                TreeNode(v3f normal, v3f origin, const std::vector<s32> &triangle_refs, s32 front_ref, s32 back_ref) :
                                normal(normal), origin(origin), triangle_refs(triangle_refs), front_ref(front_ref), back_ref(back_ref)
                {}
        };
 
 
        s32 buildTree(v3f normal, v3f origin, float delta, const std::vector<s32> &list, u32 depth);
        void traverse(s32 node, v3f viewpoint, std::vector<s32> &output) const;
 
        const std::vector<MeshTriangle> *triangles = nullptr; // this reference is managed externally
        std::vector<TreeNode> nodes; // list of nodes
        s32 root = -1; // index of the root node
};
 
/*
 * PartialMeshBuffer
 *
 * Attach alternate `Indices` to an existing mesh buffer, to make it possible to use different
 * indices with the same vertex buffer.
 */
class PartialMeshBuffer
{
public:
        PartialMeshBuffer(scene::SMeshBuffer *buffer, std::vector<u16> &&vertex_indices) :
                        m_buffer(buffer), m_indices(make_irr<scene::SIndexBuffer>())
        {
                m_indices->Data = std::move(vertex_indices);
                m_indices->MappingHint = scene::EHM_STATIC;
        }
 
        auto *getBuffer() const { return m_buffer; }
 
        void draw(video::IVideoDriver *driver) const;
 
private:
        scene::SMeshBuffer *m_buffer;
        irr_ptr<scene::SIndexBuffer> m_indices;
};
 
/*
        Holds a mesh for a mapblock.
 
        Besides the SMesh*, this contains information used fortransparency sorting
        and texture animation.
        For example:
        - cracks
        - day/night transitions
*/
class MapBlockMesh
{
public:
        // Builds the mesh given
        MapBlockMesh(Client *client, MeshMakeData *data);
        ~MapBlockMesh();
 
        // Main animation function, parameters:
        //   faraway: whether the block is far away from the camera (~50 nodes)
        //   time: the global animation time, 0 .. 60 (repeats every minute)
        //   daynight_ratio: 0 .. 1000
        //   crack: -1 .. CRACK_ANIMATION_LENGTH (-1 for off)
        // Returns true if anything has been changed.
        bool animate(bool faraway, float time, int crack, u32 daynight_ratio);

        scene::IMesh *getMesh()
        {
                return m_mesh[0].get();
        }

        scene::IMesh *getMesh(u8 layer)
        {
                assert(layer < MAX_TILE_LAYERS);
                return m_mesh[layer].get();
        }
 
        std::vector<MinimapMapblock*> moveMinimapMapblocks()
        {
                std::vector<MinimapMapblock*> minimap_mapblocks;
                minimap_mapblocks.swap(m_minimap_mapblocks);
                return minimap_mapblocks;
        }

        bool isEmpty() const
        {
                if (!m_transparent_triangles.empty())
                        return false;
                for (auto &mesh : m_mesh) {
                        for (u32 i = 0; i < mesh->getMeshBufferCount(); i++) {
                                if (mesh->getMeshBuffer(i)->getIndexCount() != 0)
                                        return false;
                        }
                }
                return true;
        }
 
        bool isAnimationForced() const
        {
                return m_animation_force_timer == 0;
        }
 
        void decreaseAnimationForceTimer()
        {
                if(m_animation_force_timer > 0)
                        m_animation_force_timer--;
        }

        f32 getBoundingRadius() const { return m_bounding_radius; }

        v3f getBoundingSphereCenter() const { return m_bounding_sphere_center; }

        void updateTransparentBuffers(v3f camera_pos, v3s16 block_pos, bool group_by_buffers);
        void consolidateTransparentBuffers();

        const std::vector<PartialMeshBuffer> &getTransparentBuffers() const
        {
                return m_transparent_buffers;
        }

        static const int TEXTURE_LAYER_CRACK = 1;
 
        static float packCrackMaterialParam(int crack, u8 layer_scale)
        {
                // +1 so that the default MaterialTypeParam = 0 is a no-op,
                // since the shader needs to know when to actually apply the crack.
                u32 n = (layer_scale << 16) | (u16) (crack + 1);
                return n;
        }
        static std::pair<int, u8> unpackCrackMaterialParam(float param)
        {
                u32 n = param;
                return std::make_pair<int, u8>((n & 0xffff) - 1, (n >> 16) & 0xff);
        }
 
private:
 
        typedef std::pair<u8 /* layer index */, u32 /* buffer index */> MeshIndex;
 
        irr_ptr<scene::IMesh> m_mesh[MAX_TILE_LAYERS];
        std::vector<MinimapMapblock*> m_minimap_mapblocks;
        ITextureSource *m_tsrc;
        IShaderSource *m_shdrsrc;
 
        f32 m_bounding_radius;
        v3f m_bounding_sphere_center;
 
        // Must animate() be called before rendering?
        bool m_has_animation;
        int m_animation_force_timer;
 
        // Animation info: cracks
        // Last crack value passed to animate()
        int m_last_crack;
        // Indicates which materials to apply the crack to
        std::vector<MeshIndex> m_crack_materials;
 
        // Animation info: texture animation
        // Maps mesh and mesh buffer indices to TileSpecs
        std::map<MeshIndex, AnimationInfo> m_animation_info;
 
        // list of all semitransparent triangles in the mapblock
        std::vector<MeshTriangle> m_transparent_triangles;
        // Binary Space Partitioning tree for the block
        MapBlockBspTree m_bsp_tree;
        // Ordered list of references to parts of transparent buffers to draw
        std::vector<PartialMeshBuffer> m_transparent_buffers;
        // Is m_transparent_buffers currently in consolidated form?
        bool m_transparent_buffers_consolidated = false;
};

video::SColor encode_light(u16 light, u8 emissive_light);
video::SColor encode_light(LightPair light, u8 emissive_light);
 
// Compute light at node
u16 getInteriorLight(MapNode n, s32 increment, const NodeDefManager *ndef);

void get_sunlight_color(video::SColorf *sunlight, u32 daynight_ratio);

void final_color_blend(video::SColor *result,
                u16 light, u32 daynight_ratio);

void final_color_blend(video::SColor *result,
                const video::SColor &data, const video::SColorf &dayLight);
 
// Retrieves the TileSpec of a face of a node
// Adds MATERIAL_FLAG_CRACK if the node is cracked
// TileSpec should be passed as reference due to the underlying TileFrame and its vector
// TileFrame vector copy cost very much to client
void getNodeTileN(MapNode mn, const v3s16 &p, u8 tileindex, MeshMakeData *data, TileSpec &tile);
void getNodeTile(MapNode mn, const v3s16 &p, const v3s16 &dir, MeshMakeData *data, TileSpec &tile);

u8 get_solid_sides(MeshMakeData *data);