standalone/004_any_text_rendering.cpp

Shows the usage of OGLplus' text rendering utilitiesCopyright 2008-2013 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/stb_truetype.hpp>
#include <oglplus/text/any.hpp>

#include <sstream>
#include <iomanip>


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

    typedef oglplus::text::AnyTextRendering TextRendering;

    TextRendering tr;

    TextRendering::Font font;

    TextRendering::Layout oglp_layout;
    TextRendering::Layout desc_layout;

    TextRendering::Layout time_layout;

    std::string time_str;
    std::stringstream text_stream;

    TextRendering::Renderer rndr;

public:
    STBTruetypeExample(int argc, const char** argv)
     : gl()
     , tr(oglplus::text::STBTrueTypeRendering(0, 1, 2))
     , font(tr.LoadFont((argc>1)?argv[1]:"FreeSans"))
     , oglp_layout(tr.MakeLayout(font, "OGLplus"))
     , desc_layout(tr.MakeLayout(font, u8"a C++ wrapper for OpenGL©"))
     , time_layout(tr.MakeLayout(font, 25))
     , rndr(tr.GetRenderer(
            oglplus::FragmentShader(
                oglplus::ObjectDesc("Pixel color"),
                oglplus::StrCRef(
                "#version 330\n"
                "vec4 PixelColor("
                "   vec4 TexelColor,"
                "   vec3 GlyphPosition,"
                "   float GlyphXOffset,"
                "   vec2 GlyphExtent,"
                "   vec2 GlyphCoord,"
                "   float LayoutWidth"
                ")"
                "{"
                "   float g = GlyphXOffset / LayoutWidth;"
                "   float b = GlyphCoord.y;"
                "   vec3 Color = mix("
                "       vec3(1.0, 0.2, 0.2+0.8*b), "
                "       vec3(0.2, 1.0, 0.2+0.8*b), "
                "       g"
                "   );"
                "   return vec4(Color, TexelColor.r);"
                "}")
            )
        )
    )
    {
        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
        );
    }

    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;

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

        GLfloat t = GLfloat(FrameTime());

        rndr.Use();

        text_stream.str(std::string());
        text_stream
            << "Time: "
            << std::fixed
            << std::setw(5)
            << std::setprecision(3)
            << t << " [s]";
        if(time_str != text_stream.str())
        {
            time_str = text_stream.str();
            time_layout.Set(time_str);
        }

        rndr.SetCamera(
            CamMatrixf::Orbiting(
                Vec3f(),
                9.0 + SineWave(t / 7.0)*3.0,
                -FullCircles(t / 17.0),
                Degrees(SineWave(t / 21.0) * 35)
            )
        );

        rndr.SetLayoutTransform(ModelMatrixf::Translation(-3.0f, 0.7f, 1.1f));
        rndr.Render(oglp_layout);

        rndr.SetLayoutTransform(ModelMatrixf::Translation(-6.0f,-0.7f, 0.0f));
        rndr.Render(desc_layout);

        rndr.SetLayoutTransform(
            ModelMatrixf::Translation(-4.0f,-2.0f,-0.5f)*
            ModelMatrixf::Scale(0.7f, 0.7f, 0.5f)
        );
        rndr.Render(time_layout);
    }
};

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