src/gl/vertexprogram.cpp

#include "vertexprogram.h"
#include "document.h"

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

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);
}
)";

static constexpr int VERTICES_PER_OBJECT = 16;


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_LINES;
}

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

void VertexProgram::build(const Document *document)
{
	constexpr float size = 1;
	constexpr glm::vec3 color = {0.0, 1.0, 1.0};
	this->data.clear();
	document->applyToVertices([&](const glm::vec3& vertex, const std::set<ldraw::id_t>&)
	{
		reserveMore(this->data, VERTICES_PER_OBJECT);
		this->data.push_back({vertex, color});
		this->data.push_back({vertex + glm::vec3{size, -size, size}, color});
		this->data.push_back({vertex, color});
		this->data.push_back({vertex + glm::vec3{size, -size, -size}, color});
		this->data.push_back({vertex, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, -size}, color});
		this->data.push_back({vertex, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, size}, color});
		this->data.push_back({vertex + glm::vec3{size, -size, size}, color});
		this->data.push_back({vertex + glm::vec3{size, -size, -size}, color});
		this->data.push_back({vertex + glm::vec3{size, -size, -size}, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, -size}, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, -size}, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, size}, color});
		this->data.push_back({vertex + glm::vec3{-size, -size, size}, color});
		this->data.push_back({vertex + glm::vec3{size, -size, size}, color});
	});
	this->buffer.bind();
	this->buffer.allocate(this->vertexData(), this->vertexCount() * this->vertexSize());
	this->buffer.release();
}