tile.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 <ITexture.h>
#include <vector>
#include <SMaterial.h>
 
enum MaterialType : u8 {
        TILE_MATERIAL_BASIC,
        TILE_MATERIAL_ALPHA,
        TILE_MATERIAL_LIQUID_TRANSPARENT,
        TILE_MATERIAL_LIQUID_OPAQUE,
        TILE_MATERIAL_WAVING_LEAVES,
        TILE_MATERIAL_WAVING_PLANTS,
        TILE_MATERIAL_OPAQUE,
        TILE_MATERIAL_WAVING_LIQUID_BASIC,
        TILE_MATERIAL_WAVING_LIQUID_TRANSPARENT,
        TILE_MATERIAL_WAVING_LIQUID_OPAQUE,
        // Note: PLAIN isn't a material actually used by tiles, rather just entities.
        TILE_MATERIAL_PLAIN,
        TILE_MATERIAL_PLAIN_ALPHA
};
 
static inline MaterialType material_type_with_alpha(MaterialType type)
{
        switch (type) {
                case TILE_MATERIAL_OPAQUE:
                        return TILE_MATERIAL_BASIC;
                case TILE_MATERIAL_WAVING_LIQUID_OPAQUE:
                        return TILE_MATERIAL_WAVING_LIQUID_BASIC;
                default:
                        return type;
        }
}
 
// Material flags
// Should backface culling be enabled?
#define MATERIAL_FLAG_BACKFACE_CULLING 0x01
// Should a crack be drawn?
#define MATERIAL_FLAG_CRACK 0x02
// Does this layer have texture animation?
#define MATERIAL_FLAG_ANIMATION 0x08
#define MATERIAL_FLAG_TILEABLE_HORIZONTAL 0x20
#define MATERIAL_FLAG_TILEABLE_VERTICAL 0x40
 
/*
        This fully defines the looks of a tile.
        The SMaterial of a tile is constructed according to this.
*/
 
struct FrameSpec
{
        FrameSpec() = default;
 
        u32 texture_id = 0;
        video::ITexture *texture = nullptr;
};
 
#define MAX_TILE_LAYERS 2
 
struct TileLayer
{
        TileLayer() = default;
 
        bool operator==(const TileLayer &other) const
        {
                return
                        texture_id == other.texture_id &&
                        shader_id == other.shader_id &&
                        material_flags == other.material_flags &&
                        has_color == other.has_color &&
                        color == other.color &&
                        need_polygon_offset == other.need_polygon_offset;
                // texture_layer_idx and scale are notably part of the vertex data
        }
 
        bool operator!=(const TileLayer &other) const
        {
                return !(*this == other);
        }
 
        void applyMaterialOptions(video::SMaterial &material, int layer) const;
 
        bool empty() const
        {
                return !shader_id && !texture_id;
        }
 
        bool isTransparent() const
        {
                // see also: the mapping in ShaderSource::generateShader()
                switch (material_type) {
                case TILE_MATERIAL_ALPHA:
                case TILE_MATERIAL_PLAIN_ALPHA:
                case TILE_MATERIAL_LIQUID_TRANSPARENT:
                case TILE_MATERIAL_WAVING_LIQUID_TRANSPARENT:
                        return true;
                default:
                        return false;
                }
        }
 
        // Ordered for size, please do not reorder
 
        video::ITexture *texture = nullptr;
 
        u32 shader_id = 0;
 
        u32 texture_id = 0;
 
        u16 animation_frame_length_ms = 0;
        u16 animation_frame_count = 1;
 
        u16 texture_layer_idx = 0;
 
        MaterialType material_type = TILE_MATERIAL_BASIC;
        u8 material_flags =
                MATERIAL_FLAG_BACKFACE_CULLING |
                MATERIAL_FLAG_TILEABLE_HORIZONTAL|
                MATERIAL_FLAG_TILEABLE_VERTICAL;
 
        u8 scale = 1;
 
        bool need_polygon_offset = false;
 
        std::vector<FrameSpec> *frames = nullptr;
 
        video::SColor color;
 
        bool has_color = false;
};
 
template<>
struct std::hash<TileLayer>
{
        // All layers equal according to TileLayer::operator== will have the same
        // hash value according to this function.
        std::size_t operator()(const TileLayer &l) const noexcept
        {
                std::size_t ret = 0;
                for (auto h : { l.texture_id, l.shader_id, (u32)l.material_flags }) {
                        ret += h;
                        ret ^= (ret << 6) + (ret >> 2); // distribute bits
                }
                return ret;
        }
};
 
 
// Stores information for drawing an animated tile
struct AnimationInfo {
 
        AnimationInfo() = default;
 
        AnimationInfo(const TileLayer &tile) :
                        m_frame_length_ms(tile.animation_frame_length_ms),
                        m_frame_count(tile.animation_frame_count),
                        m_frames(tile.frames)
        {}
 
        AnimationInfo(std::vector<FrameSpec> *frames, u16 frame_length_ms) :
                        m_frame_length_ms(frame_length_ms),
                        m_frame_count(frames->size()),
                        m_frames(frames)
        {}
 
        size_t getFrameCount() const
        {
                return m_frames ? m_frame_count : 0;
        }
 
        void updateTexture(video::SMaterial &material, float animation_time);
 
        // Returns nullptr if texture did not change since last time
        video::ITexture *getTexture(float animation_time) const;
 
private:
        u16 m_frame_length_ms = 0;
        u16 m_frame_count = 1;
 
        std::vector<FrameSpec> *m_frames = nullptr;
};
 
enum class TileRotation: u8 {
        None,
        R90,
        R180,
        R270,
};
 
struct TileSpec
{
        TileSpec() = default;
 
        bool world_aligned = false;
        TileRotation rotation = TileRotation::None;
        TileLayer layers[MAX_TILE_LAYERS];
};