src/vertexmap.cpp

Wed, 25 May 2022 20:36:34 +0300

author
Teemu Piippo <teemu@hecknology.net>
date
Wed, 25 May 2022 20:36:34 +0300
changeset 199
6988973515d2
parent 151
e628fc2e0c72
child 200
ca23936b455b
permissions
-rw-r--r--

Fix pick() picking from weird places on the screen with high DPI scaling

glReadPixels reads data from the frame buffer, which contains data after
high DPI scaling, so any reads to that need to take this scaling into account

#include "vertexmap.h"
#include "linetypes/polygonobject.h"

unsigned int hashVertex(const glm::vec3& vec)
{
	return qHash(glm::ivec3{
		int(vec.x * 10000),
		int(vec.y * 10000),
		int(vec.z * 10000),
	});
}

VertexMap::VertexMap(const Model *model) :
	model{model}
{
	connect(
		model,
		&Model::dataChanged,
		this,
		&VertexMap::build
	);
	connect(
		model,
		&Model::rowsInserted,
		this,
		&VertexMap::build
	);
	connect(
		model,
		&Model::rowsRemoved,
		this,
		&VertexMap::build
	);
	this->build();
}

struct Edge
{
	const glm::vec3& a;
	const glm::vec3& b;
};

inline void edges(const ldraw::Object* object, std::function<void(Edge&&)> fn)
{
	for (int i = 0; i < object->numPoints() - 1; i += 1)
	{
		const glm::vec3 p1 = object->getPoint(i);
		const glm::vec3 p2 = object->getPoint((i + 1) % object->numPoints());
		fn(Edge{p1, p2});
	}
}

void VertexMap::build()
{
	this->map.clear();
	this->vertices.clear();
	this->vertexHashes.clear();
	applyToModel<ldraw::Object>(*this->model, [&](const ldraw::Object* object)
	{
		glm::mat4 matrix;
		if (object->numPoints() > 2)
		{
			const auto& p0 = object->getPoint(0);
			const auto& p1 = object->getPoint(1);
			const auto& p2 = object->getPoint(2);
			const glm::vec3 a = glm::normalize(p1 - p0);
			const glm::vec3 b = glm::normalize(p2 - p0);
			const glm::vec3 c = glm::normalize(glm::cross(a, b));
			const glm::vec3 d = glm::normalize(glm::cross(a, c));
			matrix = glm::mat4{{a, 0}, {-c, 0}, {d, 0}, {}};
		}
		for (int i = 0; i < object->numPoints(); i += 1)
		{
			const glm::vec3& point = object->getPoint(i);
			const unsigned int hash = hashVertex(point);
			VertexInfo& info = this->map[hash];
			info.point = point;
			info.objects.insert(object->id);
			if (object->numPoints() > 2 and not info.transformSet)
			{
				info.transform = matrix;
				info.transform[3] = {point, 1};
				info.transformSet = true;
			}
			if (not this->vertexHashes.contains(hash))
			{
				this->vertexHashes.insert(hash);
				this->vertices.push_back(point);
			}
		}
	});
	for (auto& pair : this->map)
	{
		auto& info = pair.second;
		// If there's no transformation calculated yet, make up a simple one that at least
		// contains translation.
		if (not info.transformSet)
		{
			info.transform = glm::translate(glm::identity<glm::mat4>(), info.point);
			info.transformSet = true;
		}
		float scale = 1.0f;
		for (const ldraw::id_t objectId : info.objects)
		{
			edges(model->get(objectId), [&](Edge&& edge)
			{
				if (hashVertex(edge.a) == pair.first or hashVertex(edge.b) == pair.first)
				{
					scale = std::min(scale, glm::length(edge.b - edge.a) / 3);
				}
			});
		}
		info.transform = glm::scale(info.transform, glm::vec3{scale, scale, scale});
	}
	Q_EMIT this->verticesChanged();
}

/**
 * @brief Apply \c fn for all vertices in the map.
 * @param fn
 */
void VertexMap::apply(ApplyFunction fn) const
{
	for (unsigned int i = 0; i < this->vertices.size(); i += 1)
	{
		const glm::vec3& point = this->vertices[i];
		fn(point, this->map.at(hashVertex(point)));
	}
}

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