예제 #1
0
void ShadingEngine::shade_environment(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const ShadingPoint&     shading_point,
    ShadingResult&          shading_result) const
{
    // Retrieve the environment shader of the scene.
    const EnvironmentShader* environment_shader =
        shading_point.get_scene().get_environment()->get_environment_shader();

    if (environment_shader)
    {
        // There is an environment shader: execute it.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        const ShadingRay& ray = shading_point.get_ray();
        const Vector3d direction = normalize(ray.m_dir);
        environment_shader->evaluate(
            input_evaluator,
            direction,
            shading_result);

        // Set environment shader AOV.
        shading_result.set_entity_aov(*environment_shader);
    }
    else
    {
        // No environment shader: shade as transparent black.
        shading_result.set_main_to_transparent_black_linear_rgba();
        shading_result.set_aovs_to_transparent_black_linear_rgba();
    }
}
예제 #2
0
        void apply_aerial_perspective(
            const InputValues&      values,
            const ShadingContext&   shading_context,
            const PixelContext&     pixel_context,
            const ShadingPoint&     shading_point,
            ShadingResult&          shading_result) const
        {
            Spectrum sky_color;

            if (m_aerial_persp_mode == AerialPerspSkyColor)
                sky_color = values.m_aerial_persp_sky_color;
            else
            {
                // Retrieve the environment shader of the scene.
                const Scene& scene = shading_point.get_scene();
                const EnvironmentShader* environment_shader =
                    scene.get_environment()->get_environment_shader();

                if (environment_shader)
                {
                    // Execute the environment shader to obtain the sky color in the direction of the ray.
                    InputEvaluator input_evaluator(shading_context.get_texture_cache());
                    const ShadingRay& ray = shading_point.get_ray();
                    const Vector3d direction = normalize(ray.m_dir);
                    ShadingResult sky;
                    environment_shader->evaluate(
                        shading_context,
                        pixel_context,
                        input_evaluator,
                        direction,
                        sky);
                    sky_color = sky.m_main.m_color;
                }
                else sky_color.set(0.0f);
            }

            // Compute the blend factor.
            const double d = shading_point.get_distance() * m_aerial_persp_rcp_distance;
            const double k = m_aerial_persp_intensity * exp(d);
            const double blend = min(k, 1.0);

            // Blend the shading result and the sky color.
            sky_color *= static_cast<float>(blend);
            shading_result.m_main.m_color *= static_cast<float>(1.0 - blend);
            shading_result.m_main.m_color += sky_color;
        }
예제 #3
0
void compute_ibl_bsdf_sampling(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const EnvironmentEDF&   environment_edf,
    const ShadingPoint&     shading_point,
    const Vector3d&         outgoing,
    const BSDF&             bsdf,
    const void*             bsdf_data,
    const int               bsdf_sampling_modes,
    const size_t            bsdf_sample_count,
    const size_t            env_sample_count,
    Spectrum&               radiance)
{
    assert(is_normalized(outgoing));

    const Vector3d& geometric_normal = shading_point.get_geometric_normal();
    const Basis3d& shading_basis = shading_point.get_shading_basis();

    radiance.set(0.0f);

    for (size_t i = 0; i < bsdf_sample_count; ++i)
    {
        // Sample the BSDF.
        // todo: rendering will be incorrect if the BSDF value returned by the sample() method
        // includes the contribution of a specular component since these are explicitly rejected
        // afterward. We need a mechanism to indicate that we want the contribution of some of
        // the components only.
        Vector3d incoming;
        Spectrum bsdf_value;
        double bsdf_prob;
        const BSDF::Mode bsdf_mode =
            bsdf.sample(
                sampling_context,
                bsdf_data,
                false,              // not adjoint
                true,               // multiply by |cos(incoming, normal)|
                geometric_normal,
                shading_basis,
                outgoing,
                incoming,
                bsdf_value,
                bsdf_prob);

        // Filter scattering modes.
        if (!(bsdf_sampling_modes & bsdf_mode))
            return;

        // Discard occluded samples.
        const double transmission =
            shading_context.get_tracer().trace(
                shading_point,
                incoming,
                ShadingRay::ShadowRay);
        if (transmission == 0.0)
            continue;

        // Evaluate the environment's EDF.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        Spectrum env_value;
        double env_prob;
        environment_edf.evaluate(
            input_evaluator,
            incoming,
            env_value,
            env_prob);

        // Apply all weights, including MIS weight.
        if (bsdf_mode == BSDF::Specular)
            env_value *= static_cast<float>(transmission);
        else
        {
            const double mis_weight =
                mis_power2(
                    bsdf_sample_count * bsdf_prob,
                    env_sample_count * env_prob);
            env_value *= static_cast<float>(transmission / bsdf_prob * mis_weight);
        }

        // Add the contribution of this sample to the illumination.
        env_value *= bsdf_value;
        radiance += env_value;
    }

    if (bsdf_sample_count > 1)
        radiance /= static_cast<float>(bsdf_sample_count);
}
예제 #4
0
void compute_ibl_environment_sampling(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const EnvironmentEDF&   environment_edf,
    const ShadingPoint&     shading_point,
    const Vector3d&         outgoing,
    const BSDF&             bsdf,
    const void*             bsdf_data,
    const int               env_sampling_modes,
    const size_t            bsdf_sample_count,
    const size_t            env_sample_count,
    Spectrum&               radiance)
{
    assert(is_normalized(outgoing));

    const Vector3d& geometric_normal = shading_point.get_geometric_normal();
    const Basis3d& shading_basis = shading_point.get_shading_basis();

    radiance.set(0.0f);

    // todo: if we had a way to know that a BSDF is purely specular, we could
    // immediately return black here since there will be no contribution from
    // such a BSDF.

    sampling_context.split_in_place(2, env_sample_count);

    for (size_t i = 0; i < env_sample_count; ++i)
    {
        // Generate a uniform sample in [0,1)^2.
        const Vector2d s = sampling_context.next_vector2<2>();

        // Sample the environment.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        Vector3d incoming;
        Spectrum env_value;
        double env_prob;
        environment_edf.sample(
            input_evaluator,
            s,
            incoming,
            env_value,
            env_prob);

        // Cull samples behind the shading surface.
        assert(is_normalized(incoming));
        const double cos_in = dot(incoming, shading_basis.get_normal());
        if (cos_in < 0.0)
            continue;

        // Discard occluded samples.
        const double transmission =
            shading_context.get_tracer().trace(
                shading_point,
                incoming,
                ShadingRay::ShadowRay);
        if (transmission == 0.0)
            continue;

        // Evaluate the BSDF.
        Spectrum bsdf_value;
        const double bsdf_prob =
            bsdf.evaluate(
                bsdf_data,
                false,                          // not adjoint
                true,                           // multiply by |cos(incoming, normal)|
                geometric_normal,
                shading_basis,
                outgoing,
                incoming,
                env_sampling_modes,
                bsdf_value);
        if (bsdf_prob == 0.0)
            continue;

        // Compute MIS weight.
        const double mis_weight =
            mis_power2(
                env_sample_count * env_prob,
                bsdf_sample_count * bsdf_prob);

        // Add the contribution of this sample to the illumination.
        env_value *= static_cast<float>(transmission / env_prob * mis_weight);
        env_value *= bsdf_value;
        radiance += env_value;
    }

    if (env_sample_count > 1)
        radiance /= static_cast<float>(env_sample_count);
}
예제 #5
0
void compute_ibl_environment_sampling(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const EnvironmentEDF&   environment_edf,
    const BSSRDF&           bssrdf,
    const void*             bssrdf_data,
    const ShadingPoint&     incoming_point,
    const ShadingPoint&     outgoing_point,
    const Dual3d&           outgoing,
    const size_t            bssrdf_sample_count,
    const size_t            env_sample_count,
    Spectrum&               radiance)
{
    assert(is_normalized(outgoing.get_value()));

    const Basis3d& shading_basis = incoming_point.get_shading_basis();

    radiance.set(0.0f);

    sampling_context.split_in_place(2, env_sample_count);

    for (size_t i = 0; i < env_sample_count; ++i)
    {
        // Generate a uniform sample in [0,1)^2.
        const Vector2d s = sampling_context.next_vector2<2>();

        // Sample the environment.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        Vector3d incoming;
        Spectrum env_value;
        double env_prob;
        environment_edf.sample(
            shading_context,
            input_evaluator,
            s,
            incoming,
            env_value,
            env_prob);

        // Cull samples behind the shading surface.
        assert(is_normalized(incoming));
        const double cos_in = dot(incoming, shading_basis.get_normal());
        if (cos_in <= 0.0)
            continue;

        // Discard occluded samples.
        const double transmission =
            shading_context.get_tracer().trace(
                incoming_point,
                incoming,
                VisibilityFlags::ShadowRay);
        if (transmission == 0.0)
            continue;

        // Evaluate the BSSRDF.
        Spectrum bssrdf_value;
        bssrdf.evaluate(
            bssrdf_data,
            outgoing_point,
            outgoing.get_value(),
            incoming_point,
            incoming,
            bssrdf_value);

        // Compute MIS weight.
        const double bssrdf_prob = cos_in * RcpPi;
        const double mis_weight =
            mis_power2(
                env_sample_count * env_prob,
                bssrdf_sample_count * bssrdf_prob);

        // Add the contribution of this sample to the illumination.
        env_value *= static_cast<float>(transmission * cos_in / env_prob * mis_weight);
        env_value *= bssrdf_value;
        radiance += env_value;
    }

    if (env_sample_count > 1)
        radiance /= static_cast<float>(env_sample_count);
}
예제 #6
0
void compute_ibl_bssrdf_sampling(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const EnvironmentEDF&   environment_edf,
    const BSSRDF&           bssrdf,
    const void*             bssrdf_data,
    const ShadingPoint&     incoming_point,
    const ShadingPoint&     outgoing_point,
    const Dual3d&           outgoing,
    const size_t            bssrdf_sample_count,
    const size_t            env_sample_count,
    Spectrum&               radiance)
{
    assert(is_normalized(outgoing.get_value()));

    radiance.set(0.0f);

    sampling_context.split_in_place(2, bssrdf_sample_count);

    for (size_t i = 0; i < bssrdf_sample_count; ++i)
    {
        // Generate a uniform sample in [0,1)^2.
        const Vector2d s = sampling_context.next_vector2<2>();

        // Sample the BSSRDF (hemisphere cosine).
        Vector3d incoming = sample_hemisphere_cosine(s);
        const double cos_in = incoming.y;
        const double bssrdf_prob = cos_in * RcpPi;
        incoming = incoming_point.get_shading_basis().transform_to_parent(incoming);
        if (incoming_point.get_side() == ObjectInstance::BackSide)
            incoming = -incoming;
        assert(is_normalized(incoming));

        // Discard occluded samples.
        const double transmission =
            shading_context.get_tracer().trace(
                incoming_point,
                incoming,
                VisibilityFlags::ShadowRay);
        if (transmission == 0.0)
            continue;

        // Evaluate the BSSRDF.
        Spectrum bssrdf_value;
        bssrdf.evaluate(
            bssrdf_data,
            outgoing_point,
            outgoing.get_value(),
            incoming_point,
            incoming,
            bssrdf_value);

        // Evaluate the environment's EDF.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        Spectrum env_value;
        double env_prob;
        environment_edf.evaluate(
            shading_context,
            input_evaluator,
            incoming,
            env_value,
            env_prob);

        // Compute MIS weight.
        const double mis_weight =
            mis_power2(
                bssrdf_sample_count * bssrdf_prob,
                env_sample_count * env_prob);

        // Add the contribution of this sample to the illumination.
        env_value *= static_cast<float>(transmission * cos_in / bssrdf_prob * mis_weight);
        env_value *= bssrdf_value;
        radiance += env_value;
    }

    if (bssrdf_sample_count > 1)
        radiance /= static_cast<float>(bssrdf_sample_count);
}
예제 #7
0
void ShadingEngine::shade_hit_point(
    SamplingContext&        sampling_context,
    const PixelContext&     pixel_context,
    const ShadingContext&   shading_context,
    const ShadingPoint&     shading_point,
    ShadingResult&          shading_result) const
{
    // Retrieve the material of the intersected surface.
    const Material* material = shading_point.get_material();

    // Compute the alpha channel of the main output.
    if (material && material->get_alpha_map())
    {
        // There is an alpha map: evaluate it.
        material->get_alpha_map()->evaluate(
            shading_context.get_texture_cache(),
            shading_point.get_uv(0),
            shading_result.m_main.m_alpha);
    }
    else
    {
        // No alpha map: solid sample.
        shading_result.m_main.m_alpha = Alpha(1.0f);
    }

#ifdef WITH_OSL
    if (material && material->get_osl_surface() && material->get_osl_surface()->has_transparency())
    {
        Alpha a;
        shading_context.execute_osl_transparency(
            *material->get_osl_surface(),
            shading_point,
            a);

        shading_result.m_main.m_alpha *= a;
    }
#endif

    if (shading_result.m_main.m_alpha[0] > 0.0f || material->shade_alpha_cutouts())
    {
        // Use the diagnostic surface shader if there is one.
        const SurfaceShader* surface_shader = m_diagnostic_surface_shader.get();

        if (surface_shader == 0)
        {
            if (material == 0)
            {
                // The intersected surface has no material: return solid pink.
                shading_result.set_main_to_opaque_pink_linear_rgba();
                shading_result.set_aovs_to_transparent_black_linear_rgba();
                return;
            }

            // Use the surface shader of the intersected surface.
            surface_shader = material->get_surface_shader();

            if (surface_shader == 0)
            {
                // The intersected surface has no surface shader: return solid pink.
                shading_result.set_main_to_opaque_pink_linear_rgba();
                shading_result.set_aovs_to_transparent_black_linear_rgba();
                return;
            }
        }

        // Execute the surface shader.
        surface_shader->evaluate(
            sampling_context,
            pixel_context,
            shading_context,
            shading_point,
            shading_result);

        // Set AOVs.
        shading_result.set_entity_aov(shading_point.get_assembly());
        shading_result.set_entity_aov(shading_point.get_assembly_instance());
        shading_result.set_entity_aov(shading_point.get_object());
        shading_result.set_entity_aov(shading_point.get_object_instance());
        if (material)
            shading_result.set_entity_aov(*material);
        shading_result.set_entity_aov(*surface_shader);
    }
    else
    {
        // Alpha is zero: shade as transparent black.
        shading_result.set_main_to_transparent_black_linear_rgba();
        shading_result.set_aovs_to_transparent_black_linear_rgba();
    }
}
void DiagnosticSurfaceShader::evaluate(
    SamplingContext&        sampling_context,
    const PixelContext&     pixel_context,
    const ShadingContext&   shading_context,
    const ShadingPoint&     shading_point,
    ShadingResult&          shading_result) const
{
    switch (m_shading_mode)
    {
      case Color:
        {
            shading_result.set_main_to_opaque_pink_linear_rgba();

            const Material* material = shading_point.get_material();
            if (material)
            {
                const Material::RenderData& material_data = material->get_render_data();

#ifdef APPLESEED_WITH_OSL
                // Execute the OSL shader if there is one.
                if (material_data.m_shader_group)
                {
                    shading_context.execute_osl_shading(
                        *material_data.m_shader_group,
                        shading_point);
                }
#endif

                if (material_data.m_bsdf)
                {
                    InputEvaluator input_evaluator(shading_context.get_texture_cache());
                    material_data.m_bsdf->evaluate_inputs(
                        shading_context,
                        input_evaluator,
                        shading_point);

                    const Vector3d direction = -normalize(shading_point.get_ray().m_dir);
                    material_data.m_bsdf->evaluate(
                        input_evaluator.data(),
                        false,
                        false,
                        shading_point.get_geometric_normal(),
                        shading_point.get_shading_basis(),
                        direction,
                        direction,
                        ScatteringMode::All,
                        shading_result.m_main.m_color);

                    shading_result.m_color_space = ColorSpaceSpectral;
                }
            }
        }
        break;

      case Coverage:
        shading_result.set_main_to_linear_rgb(Color3f(1.0f));
        break;

      case Barycentric:
        shading_result.set_main_to_linear_rgb(
            vector2_to_color(shading_point.get_bary()));
        break;

      case UV:
        shading_result.set_main_to_linear_rgb(
            uvs_to_color(shading_point.get_uv(0)));
        break;

      case Tangent:
      case Bitangent:
      case ShadingNormal:
        {
#ifdef APPLESEED_WITH_OSL
            const Material* material = shading_point.get_material();
            if (material)
            {
                const Material::RenderData& material_data = material->get_render_data();

                // Execute the OSL shader if there is one.
                if (material_data.m_shader_group)
                {
                    sampling_context.split_in_place(2, 1);
                    shading_context.execute_osl_bump(
                        *material_data.m_shader_group,
                        shading_point,
                        sampling_context.next_vector2<2>());
                }
            }
#endif

            const Vector3d v =
                m_shading_mode == ShadingNormal ? shading_point.get_shading_basis().get_normal() :
                m_shading_mode == Tangent ? shading_point.get_shading_basis().get_tangent_u() :
                shading_point.get_shading_basis().get_tangent_v();

            shading_result.set_main_to_linear_rgb(vector3_to_color(v));
        }
        break;

      case GeometricNormal:
        shading_result.set_main_to_linear_rgb(
            vector3_to_color(shading_point.get_geometric_normal()));
        break;

      case OriginalShadingNormal:
        shading_result.set_main_to_linear_rgb(
            vector3_to_color(shading_point.get_original_shading_normal()));
        break;

      case WorldSpacePosition:
        {
            const Vector3d& p = shading_point.get_point();
            shading_result.set_main_to_linear_rgb(
                Color3f(Color3d(p.x, p.y, p.z)));
        }
        break;

      case Sides:
        shading_result.set_main_to_linear_rgb(
            shading_point.get_side() == ObjectInstance::FrontSide
                ? Color3f(0.0f, 0.0f, 1.0f)
                : Color3f(1.0f, 0.0f, 0.0f));
        break;

      case Depth:
        shading_result.set_main_to_linear_rgb(
            Color3f(static_cast<float>(shading_point.get_distance())));
        break;

      case ScreenSpaceWireframe:
        {
            // Initialize the shading result to the background color.
            shading_result.set_main_to_linear_rgba(Color4f(0.0f, 0.0f, 0.8f, 0.5f));

            if (shading_point.is_triangle_primitive())
            {
                // Film space thickness of the wires.
                const double SquareWireThickness = square(0.00025);

                // Retrieve the time, the scene and the camera.
                const double time = shading_point.get_time().m_absolute;
                const Scene& scene = shading_point.get_scene();
                const Camera& camera = *scene.get_camera();

                // Compute the film space coordinates of the intersection point.
                Vector2d point_ndc;
                camera.project_point(time, shading_point.get_point(), point_ndc);

                // Loop over the triangle edges.
                for (size_t i = 0; i < 3; ++i)
                {
                    // Retrieve the end points of this edge.
                    const size_t j = (i + 1) % 3;
                    const Vector3d vi = shading_point.get_vertex(i);
                    const Vector3d vj = shading_point.get_vertex(j);

                    // Compute the film space coordinates of the edge's end points.
                    Vector2d vi_ndc, vj_ndc;
                    if (!camera.project_segment(time, vi, vj, vi_ndc, vj_ndc))
                        continue;

                    // Compute the film space distance from the intersection point to the edge.
                    const double d = square_distance_point_segment(point_ndc, vi_ndc, vj_ndc);

                    // Shade with the wire's color if the hit point is close enough to the edge.
                    if (d < SquareWireThickness)
                    {
                        shading_result.set_main_to_linear_rgba(Color4f(1.0f));
                        break;
                    }
                }
            }
            else
            {
                assert(shading_point.is_curve_primitive());

                // todo: implement.
            }
        }
        break;

      case WorldSpaceWireframe:
        {
            // Initialize the shading result to the background color.
            shading_result.set_main_to_linear_rgba(Color4f(0.0f, 0.0f, 0.8f, 0.5f));

            if (shading_point.is_triangle_primitive())
            {
                // World space thickness of the wires.
                const double SquareWireThickness = square(0.0015);

                // Retrieve the world space intersection point.
                const Vector3d& point = shading_point.get_point();

                // Loop over the triangle edges.
                for (size_t i = 0; i < 3; ++i)
                {
                    // Retrieve the end points of this edge.
                    const size_t j = (i + 1) % 3;
                    const Vector3d& vi = shading_point.get_vertex(i);
                    const Vector3d& vj = shading_point.get_vertex(j);

                    // Compute the world space distance from the intersection point to the edge.
                    const double d = square_distance_point_segment(point, vi, vj);

                    // Shade with the wire's color if the hit point is close enough to the edge.
                    if (d < SquareWireThickness)
                    {
                        shading_result.set_main_to_linear_rgba(Color4f(1.0f));
                        break;
                    }
                }
            }
            else
            {
                assert(shading_point.is_curve_primitive());

                // todo: implement.
            }
        }
        break;

      case AmbientOcclusion:
        {
            // Compute the occlusion.
            const double occlusion =
                compute_ambient_occlusion(
                    sampling_context,
                    sample_hemisphere_uniform<double>,
                    shading_context.get_intersector(),
                    shading_point,
                    m_ao_max_distance,
                    m_ao_samples);

            // Return a gray scale value proportional to the accessibility.
            const float accessibility = static_cast<float>(1.0 - occlusion);
            shading_result.set_main_to_linear_rgb(Color3f(accessibility));
        }
        break;

      case AssemblyInstances:
        shading_result.set_main_to_linear_rgb(
            integer_to_color(shading_point.get_assembly_instance().get_uid()));
        break;

      case ObjectInstances:
        shading_result.set_main_to_linear_rgb(
            integer_to_color(shading_point.get_object_instance().get_uid()));
        break;

      case Regions:
        {
            const uint32 h =
                mix_uint32(
                    static_cast<uint32>(shading_point.get_object_instance().get_uid()),
                    static_cast<uint32>(shading_point.get_region_index()));
            shading_result.set_main_to_linear_rgb(integer_to_color(h));
        }
        break;

      case Primitives:
        {
            const uint32 h =
                mix_uint32(
                    static_cast<uint32>(shading_point.get_object_instance().get_uid()),
                    static_cast<uint32>(shading_point.get_region_index()),
                    static_cast<uint32>(shading_point.get_primitive_index()));
            shading_result.set_main_to_linear_rgb(integer_to_color(h));
        }
        break;

      case Materials:
        {
            const Material* material = shading_point.get_material();
            if (material)
                shading_result.set_main_to_linear_rgb(integer_to_color(material->get_uid()));
            else shading_result.set_main_to_opaque_pink_linear_rgba();
        }
        break;

      case RaySpread:
        {
            const ShadingRay& ray = shading_point.get_ray();
            if (!ray.m_has_differentials)
                break;

            const Material* material = shading_point.get_material();
            if (material)
            {
                const Material::RenderData& material_data = material->get_render_data();

#ifdef APPLESEED_WITH_OSL
                // Execute the OSL shader if there is one.
                if (material_data.m_shader_group)
                {
                    shading_context.execute_osl_shading(
                        *material_data.m_shader_group,
                        shading_point);
                }
#endif

                if (material_data.m_bsdf)
                {
                    const Dual3d outgoing(
                        -ray.m_dir,
                        ray.m_dir - ray.m_rx.m_dir,
                        ray.m_dir - ray.m_ry.m_dir);

                    InputEvaluator input_evaluator(shading_context.get_texture_cache());
                    material_data.m_bsdf->evaluate_inputs(
                        shading_context,
                        input_evaluator,
                        shading_point);
                    const void* bsdf_data = input_evaluator.data();

                    BSDFSample sample(shading_point, outgoing);
                    material_data.m_bsdf->sample(
                        sampling_context,
                        bsdf_data,
                        false,
                        false,
                        sample);

                    if (!sample.m_incoming.has_derivatives())
                        break;

                    // The 3.0 factor is chosen so that ray spread from Lambertian BRDFs is approximately 1.
                    const double spread =
                        max(
                            norm(sample.m_incoming.get_dx()),
                            norm(sample.m_incoming.get_dy())) * 3.0;

                    shading_result.set_main_to_linear_rgb(
                        Color3f(static_cast<float>(spread)));
                }
            }
        }
        break;

      case FacingRatio:
        {
            const Vector3d& normal = shading_point.get_shading_normal();
            const Vector3d& view   = shading_point.get_ray().m_dir;

            const double facing = abs(dot(normal, view));

            shading_result.set_main_to_linear_rgb(
                Color3f(static_cast<float>(facing)));
        }
        break;

      default:
        assert(false);
        shading_result.set_main_to_transparent_black_linear_rgba();
        break;
    }
}
예제 #9
0
void compute_ibl_bsdf_sampling(
    SamplingContext&        sampling_context,
    const ShadingContext&   shading_context,
    const EnvironmentEDF&   environment_edf,
    const ShadingPoint&     shading_point,
    const Dual3d&           outgoing,
    const BSDF&             bsdf,
    const void*             bsdf_data,
    const int               bsdf_sampling_modes,
    const size_t            bsdf_sample_count,
    const size_t            env_sample_count,
    Spectrum&               radiance)
{
    assert(is_normalized(outgoing.get_value()));

    radiance.set(0.0f);

    for (size_t i = 0; i < bsdf_sample_count; ++i)
    {
        // Sample the BSDF.
        // todo: rendering will be incorrect if the BSDF value returned by the sample() method
        // includes the contribution of a specular component since these are explicitly rejected
        // afterward. We need a mechanism to indicate that we want the contribution of some of
        // the components only.
        BSDFSample sample(shading_point, outgoing);
        bsdf.sample(
            sampling_context,
            bsdf_data,
            false,              // not adjoint
            true,               // multiply by |cos(incoming, normal)|
            sample);

        // Filter scattering modes.
        if (!(bsdf_sampling_modes & sample.m_mode))
            continue;

        // Discard occluded samples.
        const float transmission =
            shading_context.get_tracer().trace(
                shading_point,
                Vector3d(sample.m_incoming.get_value()),
                VisibilityFlags::ShadowRay);
        if (transmission == 0.0f)
            continue;

        // Evaluate the environment's EDF.
        InputEvaluator input_evaluator(shading_context.get_texture_cache());
        Spectrum env_value;
        float env_prob;
        environment_edf.evaluate(
            shading_context,
            input_evaluator,
            sample.m_incoming.get_value(),
            env_value,
            env_prob);

        // Apply all weights, including MIS weight.
        if (sample.m_mode == ScatteringMode::Specular)
            env_value *= transmission;
        else
        {
            const float mis_weight =
                mis_power2(
                    bsdf_sample_count * sample.m_probability,
                    env_sample_count * env_prob);
            env_value *= transmission / sample.m_probability * mis_weight;
        }

        // Add the contribution of this sample to the illumination.
        env_value *= sample.m_value;
        radiance += env_value;
    }

    if (bsdf_sample_count > 1)
        radiance /= static_cast<float>(bsdf_sample_count);
}