oglplus/025_multi_viewport.cpp

Shows how to draw into multiple viewport at the same time

Copyright 2008-2014 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/spiral_sphere.hpp>
#include <oglplus/images/newton.hpp>
#include <oglplus/bound/texture.hpp>

#include <cmath>

#include "example.hpp"

namespace oglplus {

class MultiViewportExample : public Example
{
private:
    typedef shapes::SpiralSphere Shape;
    // helper object building shape vertex attributes
    Shape make_shape;
    // helper object encapsulating shape drawing instructions
    shapes::DrawingInstructions shape_instr;
    // indices pointing to shape primitive elements
    Shape::IndexArray shape_indices;

    // wrapper around the current OpenGL context
    Context gl;

    // Program
    Program prog;

    static Program make(void)
    {
        VertexShader vs;
        vs.Source(
            "#version 330\n"
            "uniform mat4 ModelMatrix;"
            "uniform vec3 LightPos;"

            "in vec4 Position;"
            "in vec3 Normal;"

            "out vec3 vertNormal;"
            "out vec3 vertTexCoord;"
            "out vec3 vertLightDir;"
            "out vec3 vertLightRefl;"

            "void main(void)"
            "{"
            "   vertNormal = mat3(ModelMatrix)*Normal;"
            "   vertTexCoord = Normal;"
            "   gl_Position = ModelMatrix * Position;"
            "   vertLightDir = LightPos-gl_Position.xyz;"
            "   vertLightRefl = reflect(-vertLightDir, vertNormal);"
            "}"
        );

        GeometryShader gs;
        gs.Source(
            "#version 330\n"
            "#extension GL_ARB_viewport_array : enable\n"
            "layout(triangles) in;"
            "layout(triangle_strip, max_vertices = 12) out;"

            "uniform mat4 CameraMatrix[4];"
            "uniform vec3 CameraPosition[4];"

            "in vec3 vertNormal[];"
            "in vec3 vertTexCoord[];"
            "in vec3 vertLightDir[];"
            "in vec3 vertLightRefl[];"

            "out vec3 geomNormal;"
            "out vec3 geomTexCoord;"
            "out vec3 geomLightDir;"
            "out vec3 geomLightRefl;"
            "out vec3 geomViewDir;"
            "out vec3 geomViewRefl;"

            "void main(void)"
            "{"
            "   for(int vp=0; vp!=4; ++vp)"
            "   {"
            "       gl_ViewportIndex = vp;"
            "       for(int v=0; v!=3; ++v)"
            "       {"
            "           geomNormal = vertNormal[v];"
            "           geomTexCoord = vertTexCoord[v];"
            "           geomLightDir = vertLightDir[v];"
            "           geomLightRefl = vertLightRefl[v];"
            "           geomViewDir = "
            "               CameraPosition[vp] - "
            "               gl_in[v].gl_Position.xyz;"
            "           geomViewRefl = reflect("
            "               -geomViewDir,"
            "               geomNormal"
            "           );"
            "           gl_Position = "
            "               CameraMatrix[vp] *"
            "               gl_in[v].gl_Position;"
            "           EmitVertex();"
            "       }"
            "       EndPrimitive();"
            "   }"
            "}"
        );

        FragmentShader fs;
        fs.Source(
            "#version 330\n"
            "uniform samplerCube TexUnit;"
            "in vec3 geomNormal;"
            "in vec3 geomTexCoord;"
            "in vec3 geomLightDir;"
            "in vec3 geomLightRefl;"
            "in vec3 geomViewDir;"
            "in vec3 geomViewRefl;"
            "out vec4 fragColor;"
            "void main(void)"
            "{"
            "   float l = length(geomLightDir);"
            "   float d = dot("
            "       normalize(geomNormal), "
            "       normalize(geomLightDir)"
            "   ) / l;"
            "   float s = dot("
            "       normalize(geomLightRefl),"
            "       normalize(geomViewDir)"
            "   );"
            "   vec3 lt = vec3(1.0, 1.0, 1.0);"
            "   vec3 tex = texture(TexUnit, geomTexCoord).rgb;"
            "   fragColor = vec4("
            "       tex * 0.4 + "
            "       (lt + tex) * 1.5 * max(d, 0.0) + "
            "       lt * pow(max(s, 0.0), 64), "
            "       1.0"
            "   );"
            "}"
        );

        Program prog;
        prog.AttachShader(vs);
        prog.AttachShader(gs);
        prog.AttachShader(fs);
        prog.Build();
        prog.Use();
        return prog;
    }

    // Handles for setting uniforms in program
    Uniform<Vec3f> camera_position_3;
    Uniform<Mat4f>
        camera_matrix_0,
        camera_matrix_1,
        camera_matrix_2,
        camera_matrix_3,
        model_matrix;


    // A vertex array object for the rendered shape
    VertexArray shape;

    // VBOs for the shape's vertex attributes
    Buffer verts, normals;

    // The environment cube map
    Texture tex;

    Mat4f projection;
public:
    MultiViewportExample(void)
     : make_shape(1.0, 0.1, 8, 4, 48)
     , shape_instr(make_shape.Instructions())
     , shape_indices(make_shape.Indices())
     , prog(make())
     , camera_position_3(prog, "CameraPosition[3]")
     , camera_matrix_0(prog, "CameraMatrix[0]")
     , camera_matrix_1(prog, "CameraMatrix[1]")
     , camera_matrix_2(prog, "CameraMatrix[2]")
     , camera_matrix_3(prog, "CameraMatrix[3]")
     , model_matrix(prog, "ModelMatrix")
    {
        shape.Bind();

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

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

        // setup the texture
        {
            GLuint tex_side = 512;
            auto image = images::NewtonFractal(
                tex_side, tex_side,
                Vec3f(0.8f, 0.8f, 1.0f),
                Vec3f(0.1f, 0.0f, 0.2f),
                Vec2f(-0.707f, -0.707f),
                Vec2f( 0.707f,  0.707f),
                images::NewtonFractal::X4Minus1(),
                [](double x) -> double
                {
                    return pow(SineWave(pow(x,0.5)), 4.0);
                }
            );

            gl.Bound(Texture::Target::CubeMap, tex)
                .MinFilter(TextureMinFilter::Linear)
                .MagFilter(TextureMagFilter::Linear)
                .WrapS(TextureWrap::ClampToEdge)
                .WrapT(TextureWrap::ClampToEdge)
                .WrapR(TextureWrap::ClampToEdge);

            for(int i=0; i!=6; ++i)
                Texture::ImageCM(i, image);
        }
        //
        UniformSampler(prog, "TexUnit").Set(0);
        Uniform<Vec3f>(prog, "LightPos").Set(Vec3f(3.0f, 5.0f, 4.0f));
        //
        gl.ClearColor(0.1f, 0.05f, 0.2f, 0.0f);
        gl.ClearDepth(1.0f);
        gl.Enable(Capability::DepthTest);

        gl.Enable(Capability::CullFace);
        gl.FrontFace(make_shape.FaceWinding());
        gl.CullFace(Face::Back);

        Uniform<Vec3f> camera_position(prog, "CameraPosition");
        camera_position[0].Set(Vec3f(2, 0, 0));
        camera_position[1].Set(Vec3f(0, 2, 0));
        camera_position[2].Set(Vec3f(0, 0, 2));
    }

    void Reshape(GLuint width, GLuint height)
    {
        GLfloat w_2f = width / 2.0f;
        GLfloat h_2f = height/ 2.0f;
        GLfloat viewports[4*4] = {
            0.0f, 0.0f, w_2f, h_2f,
            w_2f, 0.0f, w_2f, h_2f,
            0.0f, h_2f, w_2f, h_2f,
            w_2f, h_2f, w_2f, h_2f
        };
        gl.ViewportArray(0, 4, viewports);

        projection = CamMatrixf::PerspectiveX(
            Degrees(65),
            double(width)/height,
            1, 30
        );

        camera_matrix_0.Set(
            projection *
            Mat4f(
                 Vec4f(0, 0,-1, 0),
                 Vec4f(0, 1, 0, 0),
                 Vec4f(1, 0, 0,-3),
                 Vec4f(0, 0, 0, 1)
            )
        );
        camera_matrix_1.Set(
            projection *
            Mat4f(
                 Vec4f(1, 0, 0, 0),
                 Vec4f(0, 0,-1, 0),
                 Vec4f(0, 1, 0,-3),
                 Vec4f(0, 0, 0, 1)
            )
        );
        camera_matrix_2.Set(
            projection *
            Mat4f(
                 Vec4f(1, 0, 0, 0),
                 Vec4f(0, 1, 0, 0),
                 Vec4f(0, 0, 1,-3),
                 Vec4f(0, 0, 0, 1)
            )
        );
    }

    void Render(double time)
    {
        gl.Clear().ColorBuffer().DepthBuffer();
        //
        CamMatrixf camera = CamMatrixf::Orbiting(
            Vec3f(),
            4.5 - SineWave(time / 16.0) * 1.5,
            FullCircles(time / 12.0),
            Degrees(SineWave(time / 30.0) * 90)
        );
        // set the matrix for camera orbiting the origin
        camera_matrix_3.Set(projection * camera);
        camera_position_3.Set(camera.Position());

        // set the model matrix
        model_matrix.Set(
            ModelMatrixf::RotationX(FullCircles(time / 10.0))
        );

        shape_instr.Draw(shape_indices);
    }

    bool Continue(double time)
    {
        return time < 60.0;
    }

    double ScreenshotTime(void) const
    {
        return 3.0;
    }
};

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 MultiViewportExample);
}

} // namespace oglplus