src/gl/vertexprogram.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 196
6bcb284679d4
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 "vertexprogram.h"
#include "document.h"

static const char vertexShaderSource[] = R"(
#version 330 core
const int FRAGSTYLE_Normal = 0;
const int FRAGSTYLE_Id = 1;
layout (location = 0) in vec3 in_position;
layout (location = 1) in vec3 in_color;
uniform mat4 view;
uniform mat4 projection;
uniform mat4 model;
smooth out vec3 ex_color;

void main()
{
	gl_Position = projection * view * model * vec4(in_position, 1.0);
	ex_color = in_color;
}
)";

static const char fragmentShaderSource[] = R"(
#version 330 core

out vec4 color;
smooth in vec3 ex_color;

void main(void)
{
	color = vec4(ex_color, 1);
}
)";

std::vector<glm::vec3> sphere(const int d2)
{
	std::vector<glm::vec3> result;
	result.reserve(12 * d2 * d2);
	for (int i = 0; i < d2; ++i)
	{
		const float alpha = i * pi<> / d2;
		const float alpha_2 = (i + 1) * pi<> / d2;
		for (int j = -d2; j < d2; ++j)
		{
			const float beta = j * pi<> / d2;
			const float beta_2 = (j + 1) * pi<> / d2;
			const float x1 = cos(beta) * sin(alpha);
			const float x2 = cos(beta) * sin(alpha_2);
			const float x3 = cos(beta_2) * sin(alpha_2);
			const float x4 = cos(beta_2) * sin(alpha);
			const float z1 = sin(beta) * sin(alpha);
			const float z2 = sin(beta) * sin(alpha_2);
			const float z3 = sin(beta_2) * sin(alpha_2);
			const float z4 = sin(beta_2) * sin(alpha);
			const float y1 = cos(alpha);
			const float y2 = cos(alpha_2);
			result.push_back({x1, y1, z1});
			result.push_back({x2, y2, z2});
			result.push_back({x3, y2, z3});
			result.push_back({x1, y1, z1});
			result.push_back({x3, y2, z3});
			result.push_back({x4, y1, z4});
		}
	}
	return result;
}

VertexProgram::VertexProgram(QObject *parent) :
	AbstractBasicShaderProgram{parent}
{
}

const char *VertexProgram::vertexShaderSource() const
{
	return ::vertexShaderSource;
}

const char *VertexProgram::fragmentShaderSource() const
{
	return ::fragmentShaderSource;
}

const void *VertexProgram::vertexData() const
{
	return this->data.data();
}

int VertexProgram::vertexSize() const
{
	return sizeof(Vertex);
}

int VertexProgram::vertexCount() const
{
	return this->data.size();
}

void VertexProgram::setupVertexArrays()
{
	for (int i : {0, 1})
	{
		this->program->enableAttributeArray(i);
	}
	const int stride = this->vertexSize();
	this->program->setAttributeBuffer(0, GL_FLOAT, offsetof(Vertex, position), 3, stride);
	this->program->setAttributeBuffer(1, GL_FLOAT, offsetof(Vertex, color), 3, stride);
}

GLenum VertexProgram::drawMode() const
{
	return GL_TRIANGLES;
}

QOpenGLBuffer::UsagePattern VertexProgram::usagePattern() const
{
	return QOpenGLBuffer::DynamicDraw;
}

void VertexProgram::setFragmentStyle(const FragmentStyle newFragmentStyle)
{
	this->fragmentStyle = newFragmentStyle;
}

void VertexProgram::build(const Document *document)
{
	constexpr glm::vec3 color = {0.0, 1.0, 1.0};
	this->data.clear();
	const std::vector<glm::vec3> sphere = ::sphere(8 / 2);
	document->applyToVertices([&](const glm::vec3&, const VertexMap::VertexInfo& info)
	{
		reserveMore(this->data, sphere.size());
		for (const glm::vec3& point : sphere)
		{
			const glm::vec3 transformed = glm::scale(info.transform, glm::vec3{0.5, 0.5, 0.5}) * glm::vec4{point, 1};
			this->data.push_back({transformed, color});
		}
	});
	this->buffer.bind();
	this->buffer.allocate(this->vertexData(), this->vertexCount() * this->vertexSize());
	this->buffer.release();
}

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