oglplus/031_sketch.cpp

Shows how to achieve a hand sketch effect

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/wicker_torus.hpp>

#include <oglplus/images/brushed_metal.hpp>

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

#include <cmath>
#include <functional>

#include "example.hpp"

namespace oglplus {

class TransformProgram : public Program
{
private:
    static Program make(void)
    {
        const GLchar* shader_source =
        "#version 330\n"
        "uniform mat4 CameraMatrix, ModelMatrix;"
        "uniform mat4 LightProjMatrix;"
        "uniform mat2 TextureMatrix;"
        "uniform vec3 CameraPosition, LightPosition;"
        "in vec4 Position;"
        "in vec3 Normal;"
        "in vec2 TexCoord;"

        "out gl_PerVertex {"
        "   vec4 gl_Position;"
        "};"
        "out float vertNoise;"
        "out vec3 vertNormal;"
        "out vec3 vertLightDir, vertViewDir;"
        "out vec2 vertTexCoord;"
        "out vec4 vertLightTexCoord;"
        "void main(void)"
        "{"
        "   gl_Position = "
        "       ModelMatrix *"
        "       Position;"
        "   vertNoise = noise1(Position.x+Position.y+Position.z);"
        "   vertLightDir = LightPosition - gl_Position.xyz;"
        "   vertViewDir = CameraPosition - gl_Position.xyz;"
        "   vertNormal =  (ModelMatrix * vec4(Normal,  0.0)).xyz;"
        "   vertTexCoord = TextureMatrix * TexCoord;"
        "   vertLightTexCoord = LightProjMatrix* gl_Position;"
        "   gl_Position = CameraMatrix * gl_Position;"
        "}";

        return ShaderProgram(
            ShaderType::Vertex,
            shader_source,
            ObjectDesc("Transform")
        );
    }
    const Program& prog(void) const { return *this; }
public:
    ProgramUniform<Mat4f> camera_matrix, model_matrix, light_proj_matrix;
    ProgramUniform<Mat2f> texture_matrix;
    ProgramUniform<Vec3f> camera_position, light_position;

    TransformProgram(void)
     : Program(make())
     , camera_matrix(prog(), "CameraMatrix")
     , model_matrix(prog(), "ModelMatrix")
     , light_proj_matrix(prog(), "LightProjMatrix")
     , texture_matrix(prog(), "TextureMatrix")
     , camera_position(prog(), "CameraPosition")
     , light_position(prog(), "LightPosition")
    { }
};

class ShadowFragShader
 : public FragmentShader
{
public:
    ShadowFragShader(void)
     : FragmentShader(
        ObjectDesc("Shadow fragment shader"),
        "#version 330\n"
        "in float vertNoise;"
        "in vec3 vertNormal;"
        "in vec3 vertLightDir, vertViewDir;"
        "in vec2 vertTexCoord;"
        "in vec4 vertLightTexCoord;"

        "void main(void){ }"
    )
    { }
};

class ShadowProgram : public Program
{
private:
    static Program make(void)
    {
        Program prog(ObjectDesc("Shadow"));
        prog.AttachShader(ShadowFragShader());
        prog.MakeSeparable().Link().Use();
        return prog;
    }
public:
    ShadowProgram(void)
     : Program(make())
    { }
};

class LineGeomShader
 : public GeometryShader
{
public:
    LineGeomShader(void)
     : GeometryShader(
        ObjectDesc("Line geometry shader"),
        "#version 330\n"
        "layout(lines) in;"
        "layout(line_strip, max_vertices=4) out;"

        "in gl_PerVertex {"
        "   vec4 gl_Position;"
        "} gl_in[];"
        "in float vertNoise[];"
        "in vec3 vertNormal[];"
        "in vec3 vertLightDir[], vertViewDir[];"
        "in vec2 vertTexCoord[];"
        "in vec4 vertLightTexCoord[];"

        "out gl_PerVertex {"
        "   vec4 gl_Position;"
        "};"
        "out float geomOpacity;"

        "void main(void)"
        "{"
        "   vec4 p0 = gl_in[0].gl_Position;"
        "   vec4 p1 = gl_in[1].gl_Position;"
        "   vec4 n0 = vec4(vertNormal[0], 0.0);"
        "   vec4 n1 = vec4(vertNormal[1], 0.0);"
        "   float dp = pow(length(p1 - p0), 0.25);"
        "   float l0 = cos(vertNoise[0]*1.618)*dp;"
        "   float l1 = sin(vertNoise[1]*1.618)*dp;"
        "   vec4 v0 = p0 + n0*l0*0.01;"
        "   vec4 v1 = p1 + n1*l1*0.01;"
        "   vec4 v = v1 - v0;"

        "   gl_Position = v0 - v*abs(l1*0.41);"
        "   geomOpacity = 0.0;"
        "   EmitVertex();"

        "   gl_Position = p0;"
        "   geomOpacity = 1.0;"
        "   EmitVertex();"

        "   gl_Position = p1;"
        "   geomOpacity = 1.0;"
        "   EmitVertex();"

        "   gl_Position = v1 + v*abs(l0*0.44);"
        "   geomOpacity = 0.0;"
        "   EmitVertex();"

        "   EndPrimitive();"
        "}"
    )
    { }
};

class LineFragShader
 : public FragmentShader
{
public:
    LineFragShader(void)
     : FragmentShader(
        ObjectDesc("Line fragment shader"),
        "#version 330\n"
        "in float geomOpacity;"

        "out vec4 fragColor;"

        "void main(void)"
        "{"
        "   fragColor = vec4(0.0, 0.0, 0.0, 0.1+0.4*geomOpacity);"
        "}"
    )
    { }
};

class LineProgram : public Program
{
private:
    static Program make(void)
    {
        Program prog(ObjectDesc("Line"));
        prog.AttachShader(LineGeomShader());
        prog.AttachShader(LineFragShader());
        prog.MakeSeparable().Link().Use();
        return prog;
    }
public:
    LineProgram(void)
     : Program(make())
    { }
};

class SketchFragShader
 : public FragmentShader
{
public:
    SketchFragShader(void)
     : FragmentShader(
        ObjectDesc("Sketch fragment shader"),
        "#version 330\n"
        "uniform sampler3D SketchTex;"
        "uniform sampler2DShadow ShadowTex;"

        "in float vertNoise;"
        "in vec3 vertNormal;"
        "in vec3 vertLightDir, vertViewDir;"
        "in vec2 vertTexCoord;"
        "in vec4 vertLightTexCoord;"
        "out vec4 fragColor;"

        "void main(void)"
        "{"
        "   float LightMult = 1.0;"

        "   vec3 LightProjCoord = ("
        "       vertLightTexCoord.xyz /"
        "       vertLightTexCoord.w"
        "   ) * 0.5 + 0.5;"
        "   if("
        "       LightProjCoord.x >= 0.0 && "
        "       LightProjCoord.x <= 1.0 && "
        "       LightProjCoord.y >= 0.0 && "
        "       LightProjCoord.y <= 1.0 && "
        "       LightProjCoord.z <= 1.0"
        "   )"
        "   {"
        "       float Shadow = 0.0;"
        "       const int sn = 12;"
        "       const float o = 1.0/32.0;"
        "       for(int s=0; s!=sn; ++s)"
        "       {"
        "           float r = float(s)/sn;"
        "           float a = 4.0*3.14151*r;"
        "           Shadow += texture("
        "               ShadowTex, "
        "               LightProjCoord+"
        "               vec3(cos(a)*o*r, sin(a)*o*r, 0.0)"
        "           );"
        "       }"
        "       LightMult *= (Shadow / sn);"
        "   }"

        "   vec3 LightRefl = reflect("
        "       -normalize(vertLightDir),"
        "       normalize(vertNormal)"
        "   );"

        "   float Specular = pow(max(dot("
        "       normalize(LightRefl),"
        "       normalize(vertViewDir)"
        "   )+0.02, 0.0)*1.1, 2.0);"

        "   float Diffuse = max(dot("
        "       normalize(vertNormal), "
        "       normalize(vertLightDir)"
        "   ), 0.0)*3.5;"

        "   float Ambient = 0.1;"

        "   float Light = Ambient + (Diffuse + Specular)*LightMult;"
        "   float Shadow = clamp(2.0 - Light, 0.0, 1.0);"
        "   vec3 Sample = texture(SketchTex, vec3(vertTexCoord, Shadow)).rgb;"

        "   fragColor = vec4(0.0, 0.0, 0.0, pow(Sample.b*(0.5 + Shadow*0.5), 0.5));"
        "}"
    )
    { }
};

class SketchProgram : public Program
{
private:
    static Program make(void)
    {
        Program prog(ObjectDesc("Sketch"));
        prog.AttachShader(SketchFragShader());
        prog.MakeSeparable().Link().Use();
        return prog;
    }
    const Program& prog(void) const { return *this; }
public:
    ProgramUniformSampler sketch_tex, shadow_tex;

    SketchProgram(void)
     : Program(make())
     , sketch_tex(prog(), "SketchTex")
     , shadow_tex(prog(), "ShadowTex")
    { }
};


template <typename ShapeBuilder>
class Shape
{
protected:
    // helper object building shape vertex attributes
    ShapeBuilder make_shape;
    // helper object encapsulating shape drawing instructions
    shapes::DrawingInstructions shape_instr, edge_instr;
    // indices pointing to shape primitive elements
    typename ShapeBuilder::IndexArray shape_indices, edge_indices;

    Context gl;

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

    // VBOs for the shape's vertex attributes
    Array<Buffer> vbos;

public:
    Shape(const Program& prog, const ShapeBuilder& builder)
     : make_shape(builder)
     , shape_instr(make_shape.Instructions(shapes::DrawMode::Default()))
     , edge_instr(make_shape.Instructions(shapes::DrawMode::Edges()))
     , shape_indices(make_shape.Indices(shapes::DrawMode::Default()))
     , edge_indices(make_shape.Indices(shapes::DrawMode::Edges()))
     , vbos(3)
    {
        // bind the VAO for the shape
        vao.Bind();

        typename ShapeBuilder::VertexAttribs vert_attr_info;
        const GLuint nva = 3;
        const GLchar* vert_attr_name[nva] = {
            "Position",
            "Normal",
            "TexCoord"
        };
        for(GLuint va=0; va!=nva; ++va)
        {
            const GLchar* name = vert_attr_name[va];
            std::vector<GLfloat> data;
            auto getter = vert_attr_info.VertexAttribGetter(data, name);
            if(getter != nullptr)
            {
                // bind the VBO for the vertex attribute
                vbos[va].Bind(Buffer::Target::Array);
                GLuint n_per_vertex = getter(make_shape, data);
                // upload the data
                Buffer::Data(Buffer::Target::Array, data);
                // setup the vertex attribs array
                VertexArrayAttrib attr(prog, name);
                attr.Setup<GLfloat>(n_per_vertex);
                attr.Enable();
            }
        }
    }

    void Draw(void)
    {
        vao.Bind();
        gl.FrontFace(make_shape.FaceWinding());
        shape_instr.Draw(shape_indices, 1);
    }

    void Draw(const std::function<bool (GLuint)>& drawing_driver)
    {
        vao.Bind();
        gl.FrontFace(make_shape.FaceWinding());
        shape_instr.Draw(shape_indices, 1, 0, drawing_driver);
    }

    void DrawEdges(void)
    {
        vao.Bind();
        edge_instr.Draw(edge_indices);
    }
};

class SketchExample : public Example
{
private:

    // wrapper around the current OpenGL context
    Context gl;

    TransformProgram transf_prog;
    ShadowProgram shadow_prog;
    SketchProgram sketch_prog;
    LineProgram line_prog;

    ProgramPipeline shadow_pp, sketch_pp, line_pp;

    Shape<shapes::Plane> plane;
    Shape<shapes::WickerTorus> torus;

    // The sketch texture
    Texture sketch_texture;

    GLuint width, height;
    const GLuint sketch_tex_layers, shadow_tex_side;

    // The metal frame shadow texture and its framebuffer
    Texture shadow_tex;
    Framebuffer frame_shadow_fbo;

public:
    SketchExample(void)
     : transf_prog()
     , sketch_prog()
     , plane(
        transf_prog,
        shapes::Plane(
            Vec3f(0, 0, 0),
            Vec3f(9, 0, 0),
            Vec3f(0, 0,-9),
            9, 9
        )
    ), torus(transf_prog, shapes::WickerTorus())
     , sketch_tex_layers(8)
     , shadow_tex_side(1024)
    {

        NoProgram().Use();

        shadow_pp.Bind();
        shadow_pp.UseStages(transf_prog).Vertex();
        shadow_pp.UseStages(shadow_prog).Fragment();

        sketch_pp.Bind();
        sketch_pp.UseStages(transf_prog).Vertex();
        sketch_pp.UseStages(sketch_prog).Fragment();

        line_pp.Bind();
        line_pp.UseStages(transf_prog).Vertex();
        line_pp.UseStages(line_prog).Geometry().Fragment();

        Texture::Active(0);
        sketch_prog.sketch_tex.Set(0);
        {
            auto bound_tex = gl.Bound(Texture::Target::_3D, sketch_texture);

            for(GLuint i=0; i!=sketch_tex_layers; ++i)
            {
                auto image = images::BrushedMetalUByte(
                    512, 512,
                    64 + i*128,
                    -(2+i*4), +(2+i*4),
                    64, 256-i*4
                );
                if(i == 0)
                {
                    bound_tex.Image3D(
                        0,
                        PixelDataInternalFormat::RGB,
                        image.Width(),
                        image.Height(),
                        sketch_tex_layers,
                        0,
                        image.Format(),
                        image.Type(),
                        nullptr
                    );
                }
                bound_tex.SubImage3D(
                    0,
                    0, 0, i,
                    image.Width(),
                    image.Height(),
                    1,
                    image.Format(),
                    image.Type(),
                    image.RawData()
                );
            }
            bound_tex.GenerateMipmap();
            bound_tex.MinFilter(TextureMinFilter::LinearMipmapLinear);
            bound_tex.MagFilter(TextureMagFilter::Linear);
            bound_tex.WrapS(TextureWrap::Repeat);
            bound_tex.WrapT(TextureWrap::Repeat);
            bound_tex.WrapR(TextureWrap::ClampToEdge);
        }

        Texture::Active(1);
        sketch_prog.shadow_tex.Set(1);

        gl.Bound(Texture::Target::_2D, shadow_tex)
            .MinFilter(TextureMinFilter::Linear)
            .MagFilter(TextureMagFilter::Linear)
            .WrapS(TextureWrap::ClampToEdge)
            .WrapT(TextureWrap::ClampToEdge)
            .CompareMode(TextureCompareMode::CompareRefToTexture)
            .Image2D(
                0,
                PixelDataInternalFormat::DepthComponent32,
                shadow_tex_side, shadow_tex_side,
                0,
                PixelDataFormat::DepthComponent,
                PixelDataType::Float,
                nullptr
            );

        gl.Bound(Framebuffer::Target::Draw, frame_shadow_fbo)
            .AttachTexture(
                FramebufferAttachment::Depth,
                shadow_tex,
                0
            );

        gl.ClearDepth(1.0f);
        gl.Enable(Capability::DepthTest);
        gl.Enable(Capability::CullFace);

        gl.DepthFunc(CompareFn::LEqual);
        gl.BlendFunc(BlendFn::SrcAlpha, BlendFn::OneMinusSrcAlpha);

        gl.PolygonOffset(1.0, 1.0);
        gl.LineWidth(1.5);

    }

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

    void RenderShadowMap(
        const Vec3f& light_position,
        const Mat4f& torus_matrix,
        const Mat4f& light_proj_matrix
    )
    {
        frame_shadow_fbo.Bind(Framebuffer::Target::Draw);

        gl.Viewport(shadow_tex_side, shadow_tex_side);
        gl.Clear().DepthBuffer();
        gl.CullFace(Face::Back);

        transf_prog.camera_matrix.Set(light_proj_matrix);
        transf_prog.camera_position.Set(light_position);

        // Render the torus' frame
        transf_prog.model_matrix.Set(torus_matrix);

        shadow_pp.Bind();

        gl.Enable(Capability::PolygonOffsetFill);
        torus.Draw();
        gl.Disable(Capability::PolygonOffsetFill);
    }

    void RenderImage(
        double time,
        const Mat4f& torus_matrix,
        const Mat4f& light_proj_matrix
    )
    {
        // this is going into the on-screen framebuffer
        DefaultFramebuffer().Bind(Framebuffer::Target::Draw);

        gl.ClearColor(1.0f, 0.9f, 0.8f, 0.0f);
        gl.Viewport(width, height);
        gl.Clear().ColorBuffer().DepthBuffer();
        gl.CullFace(Face::Back);
        //
        transf_prog.light_proj_matrix.Set(light_proj_matrix);

        Mat4f perspective = CamMatrixf::PerspectiveX(
            Degrees(60),
            double(width)/height,
            1, 60
        );

        // setup the camera
        Vec3f camera_target(0.0, 0.8, 0.0);
        auto camera = CamMatrixf::Orbiting(
            camera_target,
            7.0 - SineWave(time / 14.0)*3.0,
            FullCircles(time / 26.0),
            Degrees(45 + SineWave(time / 17.0) * 40)
        );
        Vec3f camera_position = camera.Position();
        transf_prog.camera_matrix.Set(perspective*camera);
        transf_prog.camera_position.Set(camera_position);

        // render into the depth buffer
        shadow_pp.Bind();

        gl.Enable(Capability::PolygonOffsetFill);
        gl.ColorMask(false, false, false, false);

        transf_prog.model_matrix = ModelMatrixf();
        plane.Draw();

        transf_prog.model_matrix.Set(torus_matrix);
        torus.Draw();

        gl.ColorMask(true, true, true, true);
        gl.Disable(Capability::PolygonOffsetFill);

        gl.Enable(Capability::Blend);
        gl.Disable(Capability::Blend);

        // render into the color buffer
        sketch_pp.Bind();

        gl.Enable(Capability::Blend);

        transf_prog.model_matrix = ModelMatrixf();
        transf_prog.texture_matrix.Set(Mat2f(Vec2f(3.0, 0.0), Vec2f(0.0, 3.0)));
        plane.Draw();

        transf_prog.model_matrix.Set(torus_matrix);
        transf_prog.texture_matrix.Set(Mat2f(Vec2f(8.0, 0.0), Vec2f(0.0, 2.0)));
        torus.Draw([](GLuint phase) -> bool { return phase <  4; });
        transf_prog.texture_matrix.Set(Mat2f(Vec2f(0.0, 2.0), Vec2f(8.0, 0.0)));
        torus.Draw([](GLuint phase) -> bool { return phase >= 4; });

        // render the edges
        line_pp.Bind();

        transf_prog.model_matrix = ModelMatrixf();
        plane.DrawEdges();

        transf_prog.model_matrix.Set(torus_matrix);
        torus.DrawEdges();

        gl.Disable(Capability::Blend);
    }

    void Render(double time)
    {
        const Vec3f light_position(16.0, 10.0, 9.0);
        const Vec3f torus_center(0.0, 1.5, 0.0);

        const Mat4f torus_matrix =
            ModelMatrixf::Translation(torus_center) *
            ModelMatrixf::RotationA(
                Vec3f(1, 2, 1),
                FullCircles(time / 17.0)
            );

        const Mat4f light_proj_matrix =
            CamMatrixf::PerspectiveX(Degrees(10), 1.0, 1, 100) *
            CamMatrixf::LookingAt(light_position, torus_center);

        transf_prog.light_position.Set(light_position);

        RenderShadowMap(
            light_position,
            torus_matrix,
            light_proj_matrix
        );
        RenderImage(
            time,
            torus_matrix,
            light_proj_matrix
        );
    }

    bool Continue(double time)
    {
        return time < 90.0;
    }

    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 SketchExample);
}

} // namespace oglplus