oglplus/027_reflected_shape.cpp

Show a how to do texture-based blurry reflection

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/plane.hpp>
#include <oglplus/shapes/twisted_torus.hpp>

#include <oglplus/bound/texture.hpp>
#include <oglplus/bound/framebuffer.hpp>

#include <cmath>

#include "example.hpp"

namespace oglplus {

class ReflectionExample : public Example
{
private:
    // helper object building and storing plane drawing instructions
    shapes::Plane make_plane;
    shapes::DrawingInstructions plane_instr;
    shapes::Plane::IndexArray plane_indices;


    // helper object building and storing shape drawing instructions
    typedef shapes::TwistedTorus Shape;
    Shape make_shape;
    shapes::DrawingInstructions shape_instr;
    Shape::IndexArray shape_indices;

    Context gl;

    VertexShader plane_vs, shape_vs;

    FragmentShader plane_fs, shape_fs;

    Program plane_prog, shape_prog;

    ProgramUniform<Mat4f>
        plane_projection_matrix, plane_camera_matrix, plane_model_matrix,
        shape_projection_matrix, shape_camera_matrix, shape_model_matrix;

    VertexArray plane, shape;

    Buffer plane_verts, plane_texcoords;
    Buffer shape_verts, shape_normals;

    Texture reflect_tex, depth_tex;

    Framebuffer fbo;
    DefaultFramebuffer dfb;

    GLuint width, height;
    const GLuint tex_size_div;
public:
    ReflectionExample(void)
     : make_plane(
        Vec3f(),
        Vec3f(3.0f, 0.0f, 0.0f),
        Vec3f(0.0f, 0.0f, -3.0f),
        15,
        15
    ), plane_instr(make_plane.Instructions())
     , plane_indices(make_plane.Indices())
     , make_shape()
     , shape_instr(make_shape.Instructions())
     , shape_indices(make_shape.Indices())
     , plane_vs(ObjectDesc("Plane vertex"))
     , shape_vs(ObjectDesc("Shape vertex"))
     , plane_fs(ObjectDesc("Plane fragment"))
     , shape_fs(ObjectDesc("Shape fragment"))
     , plane_projection_matrix(plane_prog)
     , plane_camera_matrix(plane_prog)
     , plane_model_matrix(plane_prog)
     , shape_projection_matrix(shape_prog)
     , shape_camera_matrix(shape_prog)
     , shape_model_matrix(shape_prog)
     , width(800)
     , height(600)
     , tex_size_div(2)
    {
        plane_vs.Source(
            "#version 330\n"
            "uniform vec3 LightPosition;"
            "uniform mat4 ProjectionMatrix, CameraMatrix, ModelMatrix;"
            "in vec4 Position;"
            "out vec3 vertLightDir;"
            "out vec4 vertTexCoord;"
            "void main(void)"
            "{"
            "   gl_Position = ModelMatrix*Position;"
            "   vertLightDir = LightPosition - gl_Position.xyz;"
            "   gl_Position = ProjectionMatrix * CameraMatrix * gl_Position;"
            "   vertTexCoord = gl_Position;"
            "}"
        );
        plane_vs.Compile();

        plane_fs.Source(
            "#version 330\n"
            "uniform sampler2DRect ReflectTex;"
            "uniform vec3 Normal;"
            "in vec3 vertLightDir;"
            "in vec4 vertTexCoord;"
            "out vec3 fragColor;"
            "const int n = 5;"
            "const int ns = (n*n);"
            "const float blur = 0.15/n;"
            "void main(void)"
            "{"
            "   float d = dot(Normal, normalize(vertLightDir));"
            "   float intensity = 0.5 + pow(1.4*d, 2.0);"
            "   vec3 color = vec3(0.0, 0.0, 0.0);"
            "   int n = 2;"
            "   float pct = 0.5/vertTexCoord.w;"
            "   for(int y=-n; y!=(n+1); ++y)"
            "   for(int x=-n; x!=(n+1); ++x)"
            "   {"
            "       vec2 coord = vertTexCoord.xy;"
            "       coord += vec2(blur*x, blur*y);"
            "       coord *= pct;"
            "       coord += vec2(0.5, 0.5);"
            "       coord *= textureSize(ReflectTex);"
            "       color += texture(ReflectTex, coord).rgb/ns;"
            "   }"
            "   fragColor = color*intensity;"
            "}"
        );
        plane_fs.Compile();

        plane_prog.AttachShader(plane_vs);
        plane_prog.AttachShader(plane_fs);
        plane_prog.Link();
        plane_prog.Use();

        plane_projection_matrix.BindTo("ProjectionMatrix");
        plane_camera_matrix.BindTo("CameraMatrix");
        plane_model_matrix.BindTo("ModelMatrix");

        Vec3f lightPos(3.0f, 0.5f, 2.0f);
        Uniform<Vec3f>(plane_prog, "LightPosition").Set(lightPos);
        Uniform<Vec3f>(plane_prog, "Normal").Set(make_plane.Normal());

        plane.Bind();

        plane_verts.Bind(Buffer::Target::Array);
        {
            std::vector<GLfloat> data;
            GLuint n_per_vertex = make_plane.Positions(data);
            Buffer::Data(Buffer::Target::Array, data);
            VertexArrayAttrib attr(plane_prog, "Position");
            attr.Setup<GLfloat>(n_per_vertex);
            attr.Enable();
        }
        //
        Texture::Active(1);
        gl.Bound(Texture::Target::Rectangle, depth_tex)
            .MinFilter(TextureMinFilter::Linear)
            .MagFilter(TextureMagFilter::Linear)
            .WrapS(TextureWrap::ClampToEdge)
            .WrapT(TextureWrap::ClampToEdge);

        Texture::Active(0);
        ProgramUniformSampler(plane_prog, "ReflectTex").Set(0);
        gl.Bound(Texture::Target::Rectangle, reflect_tex)
            .MinFilter(TextureMinFilter::Linear)
            .MagFilter(TextureMagFilter::Linear)
            .WrapS(TextureWrap::ClampToEdge)
            .WrapT(TextureWrap::ClampToEdge);

        gl.Bound(Framebuffer::Target::Draw, fbo)
            .AttachTexture(
                FramebufferAttachment::Color,
                reflect_tex,
                0
            ).AttachTexture(
                FramebufferAttachment::Depth,
                depth_tex,
                0
            );

        shape_vs.Source(
            "#version 330\n"
            "uniform vec3 LightPosition;"
            "uniform mat4 ProjectionMatrix, ModelMatrix, CameraMatrix;"
            "in vec4 Position;"
            "in vec3 Normal;"
            "out vec3 vertNormal;"
            "out vec3 vertLightDir;"
            "out vec3 vertLightRefl;"
            "out vec3 vertViewDir;"
            "out vec3 vertColor;"
            "void main(void)"
            "{"
            "   gl_Position = ModelMatrix * Position;"
            "   vertLightDir = LightPosition - gl_Position.xyz;"
            "   vertNormal = mat3(ModelMatrix)*Normal;"
            "   vertLightRefl = reflect("
            "       -normalize(vertLightDir),"
            "       normalize(vertNormal)"
            "   );"
            "   vertViewDir = (vec4(0.0, 0.0, 1.0, 1.0)*CameraMatrix).xyz;"
            "   vertColor = vec3(1, 1, 1) - vertNormal;"
            "   gl_Position = ProjectionMatrix * CameraMatrix * gl_Position;"
            "}"
        );
        shape_vs.Compile();

        shape_fs.Source(
            "#version 330\n"
            "in vec3 vertNormal;"
            "in vec3 vertLightDir;"
            "in vec3 vertLightRefl;"
            "in vec3 vertViewDir;"
            "in vec3 vertColor;"
            "out vec3 fragColor;"

            "void main(void)"
            "{"
            "   float l = length(vertLightDir);"
            "   float d = dot("
            "       normalize(vertNormal), "
            "       normalize(vertLightDir)"
            "   ) / l;"
            "   float s = dot("
            "       normalize(vertLightRefl),"
            "       normalize(vertViewDir)"
            "   );"
            "   vec3 lt = vec3(1.0, 1.0, 1.0);"
            "   fragColor = "
            "       vertColor * 0.4 + "
            "       (lt + vertColor)*pow(max(2.5*d, 0.0), 3) + "
            "       lt * pow(max(s, 0.0), 64);"
            "}"
        );
        shape_fs.Compile();

        shape_prog.AttachShader(shape_vs);
        shape_prog.AttachShader(shape_fs);
        shape_prog.Link();
        shape_prog.Use();

        shape_projection_matrix.BindTo("ProjectionMatrix");
        shape_camera_matrix.BindTo("CameraMatrix");
        shape_model_matrix.BindTo("ModelMatrix");

        Uniform<Vec3f>(shape_prog, "LightPosition").Set(lightPos);

        shape.Bind();

        shape_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(shape_prog, "Position");
            attr.Setup<GLfloat>(n_per_vertex);
            attr.Enable();
        }

        shape_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(shape_prog, "Normal");
            attr.Setup<GLfloat>(n_per_vertex);
            attr.Enable();
        }
        //
        gl.ClearColor(0.5f, 0.5f, 0.4f, 0.0f);
        gl.ClearDepth(1.0f);
        gl.Enable(Capability::DepthTest);
        gl.Enable(Capability::CullFace);
    }

    void Reshape(GLuint vp_width, GLuint vp_height)
    {
        width = vp_width;
        height = vp_height;

        float aspect = float(width)/height;

        auto projection =
            CamMatrixf::PerspectiveX(Degrees(60), aspect, 1, 20);

        plane_projection_matrix.Set(projection);
        shape_projection_matrix.Set(projection);

        gl.Bound(Texture::Target::Rectangle, depth_tex).Image2D(
            0,
            PixelDataInternalFormat::DepthComponent,
            width/tex_size_div, height/tex_size_div,
            0,
            PixelDataFormat::DepthComponent,
            PixelDataType::Float,
            nullptr
        );
        gl.Bound(Texture::Target::Rectangle, reflect_tex).Image2D(
            0,
            PixelDataInternalFormat::RGB,
            width/tex_size_div, height/tex_size_div,
            0,
            PixelDataFormat::RGB,
            PixelDataType::UnsignedByte,
            nullptr
        );
    }

    void Render(double time)
    {
        static const ModelMatrixf reflection =
            ModelMatrixf::Translation(0.0f, -1.0f, 0.0f) *
            ModelMatrixf::Reflection(false, true, false);

        auto camera = CamMatrixf::Orbiting(
            Vec3f(),
            4.5,
            FullCircles(time / 10.0),
            Degrees(45.0 - SineWave(time / 7.0)*35.0)
        );

        shape_prog.Use();
        shape.Bind();
        gl.FrontFace(make_shape.FaceWinding());

        shape_model_matrix =
            ModelMatrixf::Translation(0.0f, 1.1f, 0.0f) *
            ModelMatrixf::RotationX(FullCircles(time / 12.0));


        // render into the off-screen framebuffer
        fbo.Bind(Framebuffer::Target::Draw);
        gl.Viewport(width/tex_size_div, height/tex_size_div);
        gl.Clear().ColorBuffer().DepthBuffer();

        shape_camera_matrix = camera * reflection;

        gl.FrontFace(Inverted(make_shape.FaceWinding()));
        shape_instr.Draw(shape_indices);

        // render into the on-screen framebuffer
        dfb.Bind(Framebuffer::Target::Draw);
        gl.Viewport(width, height);
        gl.Clear().ColorBuffer().DepthBuffer();

        shape_camera_matrix = camera;

        gl.FrontFace(make_shape.FaceWinding());
        shape_instr.Draw(shape_indices);

        // Render the plane
        plane_prog.Use();
        plane.Bind();
        gl.FrontFace(make_plane.FaceWinding());

        plane_camera_matrix = camera;
        plane_model_matrix = ModelMatrixf::Translation(0.0f, -0.5f, 0.0f);

        plane_instr.Draw(plane_indices);
    }

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

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 ReflectionExample);
}

} // namespace oglplus