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text: clean up and update.
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 * Fix blending to avoid ugly dark edges around the text.
 * Document better what the projection / transformation does, have one
   text relative to the window size and the other absolute.
 * Make the window resizable, so the viewport event is actually used.
 * Use color literals, new APIs, in-class initialization etc. Basically
   everything that happened since 2012 when this example was written.
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@mosra
mosra committed Nov 16, 2019
1 parent a3d5472 commit 91faa14
Showing 1 changed file with 64 additions and 40 deletions.
104 changes: 64 additions & 40 deletions src/text/TextExample.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@

namespace Magnum { namespace Examples {

using namespace Magnum::Math::Literals;
using namespace Math::Literals;

class TextExample: public Platform::Application {
public:
Expand All @@ -61,72 +61,96 @@ class TextExample: public Platform::Application {
Containers::Pointer<Text::AbstractFont> _font;

Text::DistanceFieldGlyphCache _cache;
GL::Mesh _text;
GL::Mesh _rotatingText{NoCreate};
GL::Buffer _vertices, _indices;
Containers::Pointer<Text::Renderer2D> _text2;
Containers::Pointer<Text::Renderer2D> _dynamicText;
Shaders::DistanceFieldVector2D _shader;

Matrix3 _transformation;
Matrix3 _projection;
Matrix3 _transformationRotatingText,
_projectionRotatingText,
_transformationProjectionDynamicText;
};

TextExample::TextExample(const Arguments& arguments): Platform::Application{arguments, Configuration{}.setTitle("Magnum Text Example")}, _cache(Vector2i(2048), Vector2i(512), 22), _text{NoCreate} {
/* Load any TrueTypeFont plugin */
_font = _manager.loadAndInstantiate("TrueTypeFont");
if(!_font) std::exit(1);

/* Open the font and fill glyph cache */
TextExample::TextExample(const Arguments& arguments):
Platform::Application{arguments, Configuration{}
.setTitle("Magnum Text Example")
.setWindowFlags(Configuration::WindowFlag::Resizable)},
_cache{Vector2i{2048}, Vector2i{512}, 22}
{
/* Load a TrueTypeFont plugin and open the font */
Utility::Resource rs("fonts");
if(!_font->openData(rs.getRaw("SourceSansPro-Regular.ttf"), 180.0f)) {
Error() << "Cannot open font file";
std::exit(1);
}

_font->fillGlyphCache(_cache, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:-+,.!°ěäЗдравстуймиΓειασουκόμ ");
std::tie(_text, std::ignore) = Text::Renderer2D::render(*_font, _cache, 0.2f,
_font = _manager.loadAndInstantiate("TrueTypeFont");
if(!_font || !_font->openData(rs.getRaw("SourceSansPro-Regular.ttf"), 180.0f))
Fatal{} << "Cannot open font file";

/* Glyphs we need to render everything */
_font->fillGlyphCache(_cache,
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789:-+,.!°ěäЗдравстуймиΓειασουκόμ ");

/* Text that rotates using mouse wheel. Size relative to the window size
(1/10 of it) -- if you resize the window, it gets bigger */
std::tie(_rotatingText, std::ignore) = Text::Renderer2D::render(*_font, _cache, 0.2f,
"Hello, world!\n"
"Ahoj, světe!\n"
"Здравствуй, мир!\n"
"Γεια σου κόσμε!\n"
"Hej Världen!",
_vertices, _indices, GL::BufferUsage::StaticDraw, Text::Alignment::MiddleCenter);

_text2.reset(new Text::Renderer2D(*_font, _cache, 0.05f, Text::Alignment::TopRight));
_text2->reserve(40, GL::BufferUsage::DynamicDraw, GL::BufferUsage::StaticDraw);

_transformationRotatingText = Matrix3::rotation(-10.0_degf);
_projectionRotatingText = Matrix3::projection(
Vector2::xScale(Vector2{windowSize()}.aspectRatio()));

/* Dynamically updated text that shows rotation/zoom of the other. Size in
points that stays the same if you resize the window. Aligned so top
right of the bounding box is at mesh origin, and then transformed so the
origin is at the top right corner of the window. */
_dynamicText.reset(new Text::Renderer2D(*_font, _cache, 32.0f, Text::Alignment::TopRight));
_dynamicText->reserve(40, GL::BufferUsage::DynamicDraw, GL::BufferUsage::StaticDraw);
_transformationProjectionDynamicText =
Matrix3::projection(Vector2{windowSize()})*
Matrix3::translation(Vector2{windowSize()}*0.5f);

/* Set up premultiplied alpha blending to avoid overlapping text characters
to cut into each other */
GL::Renderer::enable(GL::Renderer::Feature::Blending);
GL::Renderer::setBlendFunction(GL::Renderer::BlendFunction::SourceAlpha, GL::Renderer::BlendFunction::OneMinusSourceAlpha);
GL::Renderer::setBlendFunction(GL::Renderer::BlendFunction::One, GL::Renderer::BlendFunction::OneMinusSourceAlpha);
GL::Renderer::setBlendEquation(GL::Renderer::BlendEquation::Add, GL::Renderer::BlendEquation::Add);

_transformation = Matrix3::rotation(-10.0_degf);
_projection = Matrix3::scaling(Vector2::yScale(Vector2(GL::defaultFramebuffer.viewport().size()).aspectRatio()));
updateText();
}

void TextExample::viewportEvent(ViewportEvent& event) {
GL::defaultFramebuffer.setViewport({{}, event.framebufferSize()});

_projection = Matrix3::scaling(Vector2::yScale(Vector2(event.windowSize()).aspectRatio()));
_projectionRotatingText = Matrix3::projection(
Vector2::xScale(Vector2{windowSize()}.aspectRatio()));
_transformationProjectionDynamicText =
Matrix3::projection(Vector2{windowSize()})*
Matrix3::translation(Vector2{windowSize()}*0.5f);
}

void TextExample::drawEvent() {
GL::defaultFramebuffer.clear(GL::FramebufferClear::Color);

_shader.bindVectorTexture(_cache.texture());

_shader.setTransformationProjectionMatrix(_projection * _transformation)
.setColor(Color3::fromHsv({216.0_degf, 0.85f, 1.0f}))
.setOutlineColor(Color3{0.95f})
_shader
.setTransformationProjectionMatrix(
_projectionRotatingText*_transformationRotatingText)
.setColor(0x2f83cc_rgbf)
.setOutlineColor(0xdcdcdc_rgbf)
.setOutlineRange(0.45f, 0.35f)
.setSmoothness(0.025f/ _transformation.uniformScaling());
_text.draw(_shader);
.setSmoothness(0.025f/ _transformationRotatingText.uniformScaling());
_rotatingText.draw(_shader);

_shader.setTransformationProjectionMatrix(_projection*
Matrix3::translation(1.0f/ _projection.rotationScaling().diagonal()))
.setColor(Color3{1.0f})
_shader
.setTransformationProjectionMatrix(_transformationProjectionDynamicText)
.setColor(0xffffff_rgbf)
.setOutlineRange(0.5f, 1.0f)
.setSmoothness(0.075f);
_text2->mesh().draw(_shader);
_dynamicText->mesh().draw(_shader);

swapBuffers();
}
Expand All @@ -135,9 +159,9 @@ void TextExample::mouseScrollEvent(MouseScrollEvent& event) {
if(!event.offset().y()) return;

if(event.offset().y() > 0)
_transformation = Matrix3::rotation(1.0_degf)*Matrix3::scaling(Vector2(1.1f))* _transformation;
_transformationRotatingText = Matrix3::rotation(1.0_degf)*Matrix3::scaling(Vector2{1.1f})* _transformationRotatingText;
else
_transformation = Matrix3::rotation(-1.0_degf)*Matrix3::scaling(Vector2(1.0f/1.1f))* _transformation;
_transformationRotatingText = Matrix3::rotation(-1.0_degf)*Matrix3::scaling(Vector2{1.0f/1.1f})* _transformationRotatingText;

updateText();

Expand All @@ -146,9 +170,9 @@ void TextExample::mouseScrollEvent(MouseScrollEvent& event) {
}

void TextExample::updateText() {
_text2->render(Utility::formatString("Rotation: {:.2}°\nScale: {:.2}",
Float(Deg(Complex::fromMatrix(_transformation.rotation()).angle())),
_transformation.uniformScaling()));
_dynamicText->render(Utility::formatString("Rotation: {:.2}°\nScale: {:.2}",
Float(Deg(Complex::fromMatrix(_transformationRotatingText.rotation()).angle())),
_transformationRotatingText.uniformScaling()));
}

}}
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