src/gl/vertexprogram.cpp

#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 VertexMap* vertexMap)
{
	constexpr glm::vec3 color = {0.0, 1.0, 1.0};
	this->data.clear();
	const std::vector<glm::vec3> sphere = ::sphere(8 / 2);
	vertexMap->apply([&](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();
}