mtgodot-poc/extension/src/static_object.cpp

#include "static_object.h"

#include "asset_io.h"
#include "dxt.h"
#include "gr2_bridge.h"
#include "texture_util.h"

#include <godot_cpp/classes/image.hpp>
#include <godot_cpp/classes/image_texture.hpp>
#include <godot_cpp/classes/standard_material3d.hpp>
#include <godot_cpp/variant/packed_byte_array.hpp>
#include <godot_cpp/variant/utility_functions.hpp>

#include <asset_resolver.h>
#include <gr2/gr2.h>

#include <unordered_map>

using namespace godot;

namespace mtgodot {

namespace {

std::unordered_map<std::string, Ref<ImageTexture>> g_dds_cache;

// Building albedo (sRGB colour) -> mobile-ASTC-eligible via make_color_texture
// (no-op on desktop). mipmaps=false keeps the desktop result byte-identical to
// the old path (buildings had no mip chain). §F4.
Ref<ImageTexture> decode_dds_cached(const std::string &real_path) {
	auto &cache = g_dds_cache;
	auto it = cache.find(real_path);
	if (it != cache.end())
		return it->second;
	Ref<ImageTexture> tex;
	mtgodot::Image d = mtgodot::dds_from_file(godot::String(real_path.c_str()));
	if (d.ok()) {
		tex = mtgodot::make_color_texture(d.w, d.h, d.rgba.data(), d.rgba.size(),
				/*mipmaps=*/false);
	}
	cache.emplace(real_path, tex);
	return tex;
}

Ref<StandardMaterial3D> material_for(const std::string &tex_name, bool alpha_blend, bool two_sided,
		const fmt::AssetResolver &res) {
	Ref<StandardMaterial3D> mat;
	mat.instantiate();
	mat->set_albedo(Color(0.7f, 0.7f, 0.7f));
	mat->set_roughness(1.0f);
	mat->set_texture_filter(StandardMaterial3D::TEXTURE_FILTER_LINEAR_WITH_MIPMAPS_ANISOTROPIC);
	mat->set_cull_mode(StandardMaterial3D::CULL_DISABLED);
	mat->set_diffuse_mode(StandardMaterial3D::DIFFUSE_LAMBERT_WRAP);
	mat->set_specular_mode(StandardMaterial3D::SPECULAR_DISABLED);
	mat->set_feature(StandardMaterial3D::FEATURE_BACKLIGHT, true);
	mat->set_backlight(Color(0.2f, 0.2f, 0.2f));

	String t = String(tex_name.c_str()).to_lower();
	bool kw_alpha = t.find("leaf") != -1 || t.find("grass") != -1 || t.find("fence") != -1 ||
			t.find("net") != -1 || t.find("ivy") != -1 || t.find("tree") != -1 ||
			t.find("branch") != -1;
	if (alpha_blend) {
		// EterGrnLib TYPE_BLEND_PNT：真 alpha 混合（第 2 map 作 opacity）
		mat->set_transparency(StandardMaterial3D::TRANSPARENCY_ALPHA);
		mat->set_cull_mode(StandardMaterial3D::CULL_DISABLED);
	} else if (kw_alpha) {
		mat->set_transparency(StandardMaterial3D::TRANSPARENCY_ALPHA_SCISSOR);
		mat->set_alpha_scissor_threshold(0.5f);
		mat->set_cull_mode(StandardMaterial3D::CULL_DISABLED);
	}
	if (two_sided)
		mat->set_cull_mode(StandardMaterial3D::CULL_DISABLED);

	if (tex_name.empty())
		return mat;
	std::string rp = res.resolve(tex_name, nullptr);
	if (rp.empty()) {
		// gr2 里常是 .dds；有时资产用别的大小写 / 扩展。先只试原名。
		return mat;
	}
	Ref<ImageTexture> tex = decode_dds_cached(rp);
	if (tex.is_valid()) {
		mat->set_texture(StandardMaterial3D::TEXTURE_ALBEDO, tex);
		mat->set_albedo(Color(1, 1, 1));
		mat->set_feature(StandardMaterial3D::FEATURE_EMISSION, true);
		mat->set_texture(StandardMaterial3D::TEXTURE_EMISSION, tex);
		mat->set_emission(Color(1.0f, 1.0f, 1.0f));
		mat->set_emission_energy_multiplier(0.18f);
	}
	return mat;
}

} // namespace

Ref<godot::ArrayMesh> get_static_mesh(const std::string &real_gr2_path,
		const fmt::AssetResolver &res, StaticMeshCache &cache) {
	auto it = cache.by_path.find(real_gr2_path);
	if (it != cache.by_path.end())
		return it->second;

	Ref<godot::ArrayMesh> result; // invalid until success

	gr2::LoadError err;
	auto loaded = mtgodot::gr2_from_file(godot::String(real_gr2_path.c_str()), &err);
	if (!loaded) {
		++cache.failed;
		UtilityFunctions::push_warning(String("[static] gr2 load failed: ") +
				real_gr2_path.c_str() + " (" + err.message.c_str() + ")");
		cache.by_path.emplace(real_gr2_path, result);
		return result;
	}
	const gr2::FileInfo &fi = loaded->file_info();

	// 贴图名 -> 渲染态（来自 libgr2 dump_materials 的名字/map 推断）
	std::vector<gr2::MaterialInfo> mats = gr2::dump_materials(*loaded);
	std::map<std::string, std::pair<bool, bool>> tex_state; // lower(tex) -> {alpha, two_sided}
	for (const auto &m : mats) {
		std::string k;
		for (char c : m.diffuse_texture)
			k += (char)std::tolower((unsigned char)c);
		if (!k.empty())
			tex_state[k] = {m.alpha_blend, m.two_sided};
	}

	std::vector<mtgodot::RenderPart> parts = mtgodot::build_parts(fi);
	AABB bounds;
	Ref<godot::ArrayMesh> mesh = mtgodot::build_mesh(fi, parts, /*flip_winding=*/false, bounds);
	if (mesh.is_valid() && mesh->get_surface_count() > 0) {
		for (int s = 0; s < mesh->get_surface_count() && s < (int)parts.size(); ++s) {
			const mtgodot::RenderPart &rp = parts[s];
			std::string tex;
			if (rp.mesh >= 0 && rp.mesh < (int)fi.meshes.size()) {
				const auto &mt = fi.meshes[rp.mesh].material_textures;
				if (rp.mat_index >= 0 && rp.mat_index < (int)mt.size())
					tex = mt[rp.mat_index];
				else if (!mt.empty())
					tex = mt[0];
			}
			bool alpha = false, two = false;
			{
				std::string k;
				for (char c : tex)
					k += (char)std::tolower((unsigned char)c);
				auto f = tex_state.find(k);
				if (f != tex_state.end()) {
					alpha = f->second.first;
					two = f->second.second;
				}
			}
			mesh->surface_set_material(s, material_for(tex, alpha, two, res));
		}
		result = mesh;
		++cache.loaded;
	} else {
		++cache.failed;
	}
	cache.by_path.emplace(real_gr2_path, result);
	return result;
}

void cleanup_static_object_cache() { g_dds_cache.clear(); }

} // namespace mtgodot