oglplus/020_icosphere.cpp

Shows a cube-mapped icosphere.

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/subdiv_sphere.hpp>
#include <oglplus/images/load.hpp>

#include <cmath>

#include "example.hpp"

namespace oglplus {

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

    // wrapper around the current OpenGL context
    Context gl;

    VertexShader vs;
    GeometryShader gs;
    FragmentShader fs;

    Program prog;

    // Uniforms
    Lazy<Uniform<Mat4f>> projection_matrix, camera_matrix, model_matrix;

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

    // VBOs for the shape's vertex attributes
    Buffer positions;

    // The environment cube map
    Texture tex;
public:
    CubeMapExample(void)
     : make_shape(4)
     , shape_instr(make_shape.Instructions())
     , shape_indices(make_shape.Indices())
     , projection_matrix(prog, "ProjectionMatrix")
     , camera_matrix(prog, "CameraMatrix")
     , model_matrix(prog, "ModelMatrix")
    {
        vs.Source(
            "#version 330\n"
            "uniform mat4 ProjectionMatrix, CameraMatrix, ModelMatrix;"
            "in vec4 Position;"
            "out vec3 vertNormal;"
            "out vec3 vertTexCoord;"
            "out vec3 vertLightDir;"
            "out vec3 vertViewDir;"
            "uniform vec3 LightPos;"
            "void main(void)"
            "{"
            "   vec3 Normal = Position.xyz;"
            "   gl_Position = ModelMatrix * Position;"
            "   vertNormal = mat3(ModelMatrix)*Normal;"
            "   vertTexCoord = Normal;"
            "   vertLightDir = LightPos - gl_Position.xyz;"
            "   vertViewDir = (vec4(0.0, 0.0, 1.0, 1.0)*CameraMatrix).xyz;"
            "   gl_Position = ProjectionMatrix * CameraMatrix * gl_Position;"
            "}"
        );
        vs.Compile();

        gs.Source(
            "#version 330\n"
            "layout (triangles) in;"
            "layout (triangle_strip, max_vertices = 3) out;"

            "in vec3 vertNormal[3];"
            "in vec3 vertTexCoord[3];"
            "in vec3 vertLightDir[3];"
            "in vec3 vertViewDir[3];"

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

            "void main(void)"
            "{"
            "   vec3 FaceNormal = 0.333333*("
            "       vertNormal[0]+"
            "       vertNormal[1]+"
            "       vertNormal[2] "
            "   );"
            "   for(int v=0; v!=3; ++v)"
            "   {"
            "       gl_Position = gl_in[v].gl_Position;"
            "       geomNormal = 0.5*(vertNormal[v]+FaceNormal);"
            "       geomTexCoord = vertTexCoord[v];"
            "       geomLightDir = vertLightDir[v];"
            "       geomLightRefl = reflect("
            "           -normalize(geomLightDir),"
            "           normalize(FaceNormal)"
            "       );"
            "       geomViewDir = vertViewDir[v];"
            "       EmitVertex();"
            "   }"
            "   EndPrimitive();"
            "}"
        );
        gs.Compile();

        fs.Source(
            "#version 330\n"
            "uniform samplerCube TexUnit;"
            "in vec3 geomNormal;"
            "in vec3 geomTexCoord;"
            "in vec3 geomLightDir;"
            "in vec3 geomLightRefl;"
            "in vec3 geomViewDir;"
            "out vec3 fragColor;"
            "void main(void)"
            "{"
            "   vec3 lt = vec3(1.0, 1.0, 1.0);"
            "   vec3 tex = texture(TexUnit, geomTexCoord).rgb;"
            "   float d = dot("
            "       normalize(geomNormal), "
            "       normalize(geomLightDir)"
            "   );"
            "   float s = dot("
            "       normalize(geomLightRefl),"
            "       normalize(geomViewDir)"
            "   );"
            "   float b = 1.0-sqrt(max(dot("
            "       normalize(geomNormal),"
            "       normalize(geomViewDir)"
            "   ), 0.0));"
            "   float ea = clamp(tex.b*(-d+0.2), 0.0, 1.0);"
            "   float sr = 1.0-tex.b*0.8;"

            "   fragColor = "
            "       tex * (0.3*ea + 0.6*b + 0.8*max(d, 0.0)) + "
            "       (tex+lt) * 0.8*sr*pow(clamp(s+0.05, 0.0, 1.0), 32);"
            "}"
        );
        fs.Compile();

        // attach the shaders to the program
        prog.AttachShader(vs);
        prog.AttachShader(gs);
        prog.AttachShader(fs);
        // link and use it
        prog.Link();
        prog.Use();

        // bind the VAO for the shape
        shape.Bind();

        positions.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();
        }

        // setup the texture
        auto tex_target = Texture::Target::CubeMap;
        tex << tex_target;
        tex_target << TextureMinFilter::Linear;
        tex_target << TextureMagFilter::Linear;
        tex_target << TextureWrap::ClampToEdge;

        const char* tex_name[6] = {
            "cube_0_right",
            "cube_1_left",
            "cube_2_top",
            "cube_3_bottom",
            "cube_4_front",
            "cube_5_back"
        };
        for(GLuint i=0; i!=6; ++i)
        {
            Texture::CubeMapFace(i) <<
                images::LoadTexture(tex_name[i], false, true);
        }

        UniformSampler(prog, "TexUnit").Set(0);
        Uniform<Vec3f>(prog, "LightPos").Set(Vec3f(3.0f, 5.0f, 4.0f));

        gl.ClearColor(0.05f, 0.2f, 0.1f, 0.0f);
        gl.ClearDepth(1.0f);
        gl.Enable(Capability::DepthTest);

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

    void Reshape(GLuint width, GLuint height)
    {
        gl.Viewport(width, height);
        prog.Use();
        projection_matrix.Set(
            CamMatrixf::PerspectiveX(
                Degrees(60),
                double(width)/height,
                1, 100
            )
        );
    }

    void Render(double time)
    {
        gl.Clear().ColorBuffer().DepthBuffer();
        //
        // set the matrix for camera orbiting the origin
        camera_matrix.Set(
            CamMatrixf::Orbiting(
                Vec3f(),
                4.5 - SineWave(time / 16.0) * 2.0,
                FullCircles(time / 12.0),
                Degrees(SineWave(time / 30.0) * 90)
            )
        );

        // set the model matrix
        model_matrix.Set(
            ModelMatrixf::RotationA(
                Vec3f(1.0f, 1.0f, 1.0f),
                FullCircles(time / 10.0)
            )
        );

        shape.Bind();
        shape_instr.Draw(shape_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 CubeMapExample);
}

} // namespace oglplus