celestia/src/celengine/boundariesrenderer.cpp

114 lines
3.7 KiB
C++

// boundariesrenderer.cpp
//
// Copyright (C) 2018-2019, the Celestia Development Team
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
#include <cassert>
#include <numeric>
#include <celengine/boundaries.h>
#include <celutil/color.h>
#include "boundariesrenderer.h"
#include "render.h"
#include "vecgl.h"
using namespace Eigen;
using namespace std;
BoundariesRenderer::BoundariesRenderer(const ConstellationBoundaries *boundaries) :
m_boundaries(boundaries)
{
m_shadprop.texUsage = ShaderProperties::VertexColors;
m_shadprop.lightModel = ShaderProperties::UnlitModel;
}
bool BoundariesRenderer::sameBoundaries(const ConstellationBoundaries *boundaries) const
{
return m_boundaries == boundaries;
}
void BoundariesRenderer::render(const Renderer &renderer, const Color &color, const Matrices &mvp)
{
using AttributesType = celgl::VertexObject::AttributesType;
ShaderProperties props = m_shadprop;
bool lineAsTriangles = renderer.shouldDrawLineAsTriangles();
if (lineAsTriangles)
props.texUsage |= ShaderProperties::LineAsTriangles;
auto *prog = renderer.getShaderManager().getShader(props);
if (prog == nullptr)
return;
m_vo.bind(lineAsTriangles ? AttributesType::Default : AttributesType::Alternative1);
if (!m_vo.initialized())
{
std::vector<LineEnds> data;
if (!prepare(data))
{
m_vo.unbind();
return;
}
m_vo.allocate(data.size() * sizeof(LineEnds), data.data());
// Attributes for lines drawn as triangles
m_vo.setVertices(3, GL_FLOAT, false, sizeof(LineEnds), offsetof(LineEnds, point1));
m_vo.setVertexAttribArray(CelestiaGLProgram::NextVCoordAttributeIndex, 3, GL_FLOAT, false, sizeof(LineEnds), offsetof(LineEnds, point2));
m_vo.setVertexAttribArray(CelestiaGLProgram::ScaleFactorAttributeIndex, 1, GL_FLOAT, false, sizeof(LineEnds), offsetof(LineEnds, scale));
// Attributes for lines drawn as lines
m_vo.setVertices(3, GL_FLOAT, false, sizeof(LineEnds) * 3, offsetof(LineEnds, point1), AttributesType::Alternative1);
}
prog->use();
prog->setMVPMatrices(*mvp.projection, *mvp.modelview);
glVertexAttrib(CelestiaGLProgram::ColorAttributeIndex, color);
if (lineAsTriangles)
{
prog->lineWidthX = renderer.getLineWidthX();
prog->lineWidthY = renderer.getLineWidthY();
m_vo.draw(GL_TRIANGLES, m_lineCount * 6, 0);
}
else
{
m_vo.draw(GL_LINES, m_lineCount * 2, 0);
}
m_vo.unbind();
}
bool BoundariesRenderer::prepare(std::vector<LineEnds> &data)
{
auto chains = m_boundaries->getChains();
auto lineCount = accumulate(chains.begin(), chains.end(), 0,
[](int a, ConstellationBoundaries::Chain* b) { return a + b->size() - 1; });
if (lineCount == 0)
return false;
m_lineCount = lineCount;
// we reserve 6 times the space so we can allow to
// draw a line segment with two triangles
data.reserve(m_lineCount * 6);
for (const auto chain : chains)
{
for (unsigned i = 1; i < chain->size(); i++)
{
Eigen::Vector3f prev = (*chain)[i - 1];
Eigen::Vector3f cur = (*chain)[i];
data.emplace_back(prev, cur, -0.5);
data.emplace_back(prev ,cur, 0.5);
data.emplace_back(cur, prev, -0.5);
data.emplace_back(cur, prev, -0.5);
data.emplace_back(cur, prev, 0.5);
data.emplace_back(prev, cur, -0.5);
}
}
return true;
}