oglplus/015_obj_mesh.cpp

Shows how to use the obj file mesh loader

Copyright 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 <oglplus/gl.hpp>
#include <oglplus/all.hpp>
#include <oglplus/shapes/obj_mesh.hpp>
#include <oglplus/opt/resources.hpp>

#include <cmath>

#include "example.hpp"

namespace oglplus {

struct MeshInputFile
{
    std::ifstream stream;

    MeshInputFile(void)
    {
        OpenResourceFile(stream, "models", "suzanne", ".obj");
    }
};

class MeshExample : public Example
{
private:
    MeshInputFile mesh_input;
    shapes::ObjMesh load_mesh;
    shapes::DrawingInstructions mesh_instr;
    shapes::ObjMesh::IndexArray mesh_indices;

    Context gl;

    Program prog;

    Uniform<Mat4f> camera_matrix, projection_matrix, stretch_matrix;

    VertexArray mesh;
    Spheref mesh_bs;

    Buffer positions;
    Buffer normals;
    Buffer texcoords;
public:
    MeshExample(void)
     : load_mesh(mesh_input.stream)
     , mesh_instr(load_mesh.Instructions())
     , mesh_indices(load_mesh.Indices())
     , camera_matrix(prog)
     , projection_matrix(prog)
     , stretch_matrix(prog)
    {
        load_mesh.BoundingSphere(mesh_bs);

        VertexShader vs;
        vs.Source(
            "#version 330\n"
            "uniform mat4 StretchMatrix, ProjectionMatrix, CameraMatrix;"
            "in vec4 Position;"
            "in vec3 Normal;"

            "out vec3 vertNormal;"
            "void main(void)"
            "{"
            "   vertNormal = Normal;"
            "   gl_Position = "
            "       StretchMatrix *"
            "       ProjectionMatrix *"
            "       CameraMatrix *"
            "       Position;"
            "}"
        ).Compile();

        FragmentShader fs;
        fs.Source(
            "#version 330\n"
            "in vec3 vertNormal;"
            "out vec3 fragColor;"
            "void main(void)"
            "{"
            "   vec3 c = normalize(vec3(1, 1, 1) - vertNormal);"
            "   fragColor = c;"
            "}"
        ).Compile();

        prog.AttachShader(vs).AttachShader(fs);
        prog.Link().Use();

        camera_matrix.BindTo("CameraMatrix");
        projection_matrix.BindTo("ProjectionMatrix");
        stretch_matrix.BindTo("StretchMatrix");

        mesh.Bind();

        positions.Bind(Buffer::Target::Array);
        {
            std::vector<GLfloat> data;
            GLuint n_per_vertex = load_mesh.Positions(data);
            Buffer::Data(Buffer::Target::Array, data);
            (prog|"Position").Setup<GLfloat>(n_per_vertex).Enable();
        }

        normals.Bind(Buffer::Target::Array);
        {
            std::vector<GLfloat> data;
            GLuint n_per_vertex = load_mesh.Normals(data);
            Buffer::Data(Buffer::Target::Array, data);
            (prog|"Normal").Setup<GLfloat>(n_per_vertex).Enable();
        }

        //
        gl.ClearColor(0.8f, 0.8f, 0.7f, 0.0f);
        gl.ClearDepth(1.0f);
        gl.Enable(Capability::DepthTest);
    }

    void Reshape(GLuint width, GLuint height)
    {
        gl.Viewport(width, height);
        projection_matrix.Set(
            CamMatrixf::PerspectiveX(
                Degrees(70),
                double(width)/height,
                1, 20
            )
        );
    }

    void Render(double time)
    {
        gl.Clear().ColorBuffer().DepthBuffer();
        //
        int x=0, y=0, nx=1, ny=1;
        switch(int(time / 3.0) % 5)
        {
            case 1: x=1; y=1; nx=4; ny=4; break;
            case 2: x=2; y=1; nx=4; ny=4; break;
            case 3: x=1; y=2; nx=4; ny=4; break;
            case 4: x=2; y=2; nx=4; ny=4; break;
            default:;
        }
        stretch_matrix.Set(CamMatrixf::ScreenTile(x, y, nx, ny));

        camera_matrix.Set(
            CamMatrixf::Orbiting(
                mesh_bs.Center(),
                mesh_bs.Radius()*1.4+1.0,
                FullCircles(-time / 13.0),
                Degrees(SineWave(time / 17.0) * 80)
            )
        );

        mesh_instr.Draw(mesh_indices);
    }

    bool Continue(double time)
    {
        return time < 30.0;
    }

    double ScreenshotTime(void) const
    {
        return 2.5;
    }
};

void setupExample(ExampleParams& /*params*/){ }

std::unique_ptr<ExampleThread> makeExampleThread(
    Example& /*example*/,
    unsigned /*thread_id*/,
    const ExampleParams& /*params*/
){ return std::unique_ptr<ExampleThread>(); }

std::unique_ptr<Example> makeExample(const ExampleParams& /*params*/)
{
    return std::unique_ptr<Example>(new MeshExample);
}

} // namespace oglplus