standalone/004_bitmap_text_hello.cpp

Shows the usage of OGLplus' text rendering utilitiesCopyright 2008-2012 Matus Chochlik. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include "glut_glew_example.hpp"

#include <oglplus/all.hpp>
#include <oglplus/images/png.hpp>

#include <oglplus/text/bitmap_glyph.hpp>


class BitmapGlyphExample
 : public oglplus::StandaloneExample
{
private:
    oglplus::Context gl;

    typedef oglplus::text::BitmapGlyphRendering TextRendering;

    TextRendering tr;

    TextRendering::Font font;

    TextRendering::Layout layout;

    TextRendering::Renderer rndr;

    oglplus::ProgramUniform<oglplus::Vec3f> rndr_color;
    oglplus::ProgramUniform<GLfloat> rndr_opacity;

    int prev_interval;
    std::size_t current_line;
public:
    BitmapGlyphExample(int argc, const char** argv)
     : gl()
     , tr(0, 1, 2)
     , font(tr.LoadFont((argc>1)?argv[1]:"Sans"))
     , layout(tr.MakeLayout(font, 128))
     , rndr(tr.GetRenderer(
            oglplus::FragmentShader(
                oglplus::ObjectDesc("Pixel color"),
                "#version 330\n"
                "uniform vec3 Color;"
                "uniform float Opacity;"
                "vec4 PixelColor("
                "   vec4 TexelColor,"
                "   vec3 GlyphPosition,"
                "   float GlyphXOffset,"
                "   vec2 GlyphExtent,"
                "   vec2 GlyphCoord,"
                "   float LayoutWidth"
                ")"
                "{"
                "   return vec4(Color, TexelColor.r*Opacity);"
                "}"
            )
        )
    ), rndr_color(rndr.GetUniform<oglplus::Vec3f>("Color"))
     , rndr_opacity(rndr.GetUniform<GLfloat>("Opacity"))
     , prev_interval(-1)
     , current_line(0)
    {
        using namespace oglplus;

        rndr.Use();

        gl.ClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        gl.Enable(Capability::Blend);
        gl.BlendFunc(
            BlendFunction::SrcAlpha,
            BlendFunction::DstAlpha
        );

        rndr.SetAlignment(text::Alignment::Center);
    }

    void LoadNext(void)
    {
        typedef oglplus::text::Direction Dir;
        struct {
            Dir direction;
            const char* text;
        } lines[] = {
            {Dir::LeftToRight, u8"Hello world"},
            {Dir::LeftToRight, u8"Nazdar svet"},
            {Dir::LeftToRight, u8"Γεια σας κόσμο"},
            {Dir::LeftToRight, u8"Привет мир"},
            {Dir::LeftToRight, u8"Witaj świecie"},
            {Dir::LeftToRight, u8"Здравей свят"},
            {Dir::LeftToRight, u8"Ahoj světe"},
            {Dir::LeftToRight, u8"Moi maailma"},
            {Dir::LeftToRight, u8"Bonjour tout le monde"},
            {Dir::LeftToRight, u8"Hallo welt"},
            {Dir::LeftToRight, u8"Բարեւ աշխարհ"},
            {Dir::LeftToRight, u8"Hej världen"},
            {Dir::LeftToRight, u8"Прывітанне свет"},
            {Dir::LeftToRight, u8"Olá mundo"},
            {Dir::LeftToRight, u8"Здраво свете"},
            {Dir::LeftToRight, u8"Zdravo svet"},
            {Dir::LeftToRight, u8"Hola mundo"},
            {Dir::LeftToRight, u8"Merhaba dünya"},
            {Dir::LeftToRight, u8"Привіт світ"},
            {Dir::LeftToRight, u8"Pozdrav svijetu"},
            {Dir::LeftToRight, u8"Hello világ"},
            {Dir::RightToLeft, u8"مرحبا العالم"},
            {Dir::LeftToRight, u8"Ciao mondo"},
            {Dir::LeftToRight, u8"Здраво светот"},
            {Dir::RightToLeft, u8"שלום עולם"},
            {Dir::LeftToRight, u8"Hei verden"}
        };
        const std::size_t line_count = sizeof(lines)/sizeof(lines[0]);

        layout.Set(lines[current_line].text);

        rndr.SetDirection(lines[current_line].direction);
        rndr_color.Set(
            0.1f+GLfloat(0.8f*std::rand())/RAND_MAX,
            0.3f+GLfloat(0.7f*std::rand())/RAND_MAX,
            0.1f+GLfloat(0.8f*std::rand())/RAND_MAX
        );

        if(++current_line >= line_count)
            current_line = 0;
    }

    void Reshape(void)
    {
        using namespace oglplus;

        gl.Viewport(Width(), Height());

        rndr.SetProjection(
            CamMatrixf::PerspectiveX(
                Degrees(60),
                Width()/Height(),
                1, 60
            )
        );
    }

    void Render(void)
    {
        using namespace oglplus;

        GLfloat t = GLfloat(FrameTime());
        GLfloat i = t*0.3f;
        int interval = int(i);
        GLfloat f = i - GLfloat(interval);
        if(prev_interval < interval)
        {
            LoadNext();
            prev_interval = interval;
        }

        gl.Clear().ColorBuffer().DoIt();

        rndr_opacity.Set(SineWave(f*0.5f));

        rndr.SetLayoutTransform(ModelMatrixf::TranslationZ(-20.0f+16.0f*f));
        rndr.Render(layout);
    }
};

int main(int argc, char* argv[])
{
    return oglplus::GlutGlewMain<BitmapGlyphExample>(
        "Example of usage of OGLplus' bitmap glyph text rendering",
        argc, argv
    );
}