new light path drawing using antialisased billboarded quads

src/appleseed.studio/mainwindow/rendering/lightpathslayer.h

@@ -77,6 +77,7 @@ class LightPathsLayer: public QObject
         const size_t                        width,
         const size_t                        height);
 
+    void resize(const size_t width, const size_t height);
 
     void update_render_camera_transform();
 
@@ -120,15 +121,26 @@ class LightPathsLayer: public QObject
 
     renderer::LightPathArray                m_light_paths;
     int                                     m_selected_light_path_index;    // -1 == display all paths
+    float                                   m_max_luminance;
+    float                                   m_max_thickness;
+    float                                   m_min_thickness;
+    size_t                                  m_width;
+    size_t                                  m_height;
 
     QOpenGLFunctions_3_3_Core*              m_gl;
 
-    GLuint                                  m_light_paths_vbo;
-    std::vector<GLsizei>                    m_light_paths_index_offsets;
+    GLuint                                  m_positions_vbo;
+    GLuint                                  m_others_vbo;
+    GLuint                                  m_indices_ebo;
+    std::vector<GLsizei>                    m_index_offsets;
     GLuint                                  m_light_paths_vao;
-    GLuint                                  m_light_paths_shader_program;
-    GLint                                   m_light_paths_view_mat_location;
-    GLint                                   m_light_paths_proj_mat_location;
+    GLuint                                  m_shader_program;
+    GLint                                   m_view_mat_loc;
+    GLint                                   m_proj_mat_loc;
+    GLint                                   m_res_loc;
+    GLint                                   m_max_luminance_loc;
+    GLint                                   m_min_thickness_loc;
+    GLint                                   m_max_thickness_loc;
     foundation::Matrix4f                    m_gl_render_view_matrix;
     foundation::Matrix4f                    m_gl_view_matrix;
     foundation::Matrix4f                    m_gl_proj_matrix;

src/appleseed.studio/mainwindow/rendering/viewportwidget.cpp

@@ -174,10 +174,18 @@ void ViewportWidget::initializeGL() {
 }
 
 void ViewportWidget::resize(
-    const size_t    width,
-    const size_t    height)
+    const size_t width,
+    const size_t height)
 {
     m_render_layer->resize(width, height);
+    m_light_paths_layer->resize(width, height);
+}
+
+void ViewportWidget::resizeGL(
+    int width,
+    int height)
+{
+    m_light_paths_layer->resize(width, height);
 }
 
 void ViewportWidget::set_draw_light_paths_enabled(const bool enabled)

src/appleseed.studio/mainwindow/rendering/viewportwidget.h

@@ -138,6 +138,7 @@ class ViewportWidget
     void create_render_layer(OCIO::ConstConfigRcPtr  ocio_config);
 
     void initializeGL() override;
+    void resizeGL(int width, int height) override;
     void paintGL() override;
     void dragEnterEvent(QDragEnterEvent* event) override;
     void dragMoveEvent(QDragMoveEvent* event) override;

src/appleseed.studio/resources/shaders/lightpaths.frag

@@ -28,11 +28,20 @@
 #version 330
 #extension GL_ARB_separate_shader_objects : enable
 
-layout(location = 0) in vec3 v_color;
+flat in vec3 f_color;
+in float f_aa_norm;
+flat in float f_thickness;
+flat in float f_total_thickness;
+flat in float f_aspect_expansion_len;
+
+uniform vec2 u_res;
 
 out vec4 Target0;
 
 void main()
 {
-    Target0 = vec4(v_color, 1.0);
+    float dist = abs(f_aa_norm) * f_total_thickness - 0.5 / f_aspect_expansion_len;
+    float eps = fwidth(dist);
+    float a = 1.0 - smoothstep(f_thickness - eps, f_thickness + eps, dist);
+    Target0 = vec4(f_color, a);
 }

src/appleseed.studio/resources/shaders/lightpaths.vert

@@ -26,18 +26,84 @@
 //
 
 #version 330
-#extension GL_ARB_separate_shader_objects : enable
 
-layout(location = 0) in vec3 a_pos;
-layout(location = 1) in vec3 a_color;
+const float AA_BUFFER_SIZE = 1.0;
+
+layout(location = 0) in vec3 v_previous;
+layout(location = 1) in vec3 v_position;
+layout(location = 2) in vec3 v_next;
+layout(location = 3) in float v_luminance;
+layout(location = 4) in int v_direction_start_end;
+layout(location = 5) in vec3 v_color;
+layout(location = 6) in vec3 v_surface_normal;
 
-uniform mat4 u_view;
 uniform mat4 u_proj;
+uniform mat4 u_view;
+uniform vec2 u_res;
+uniform float u_max_luminance;
+uniform float u_max_thickness;
+uniform float u_min_thickness;
+
+flat out vec3 f_color;
+out float f_aa_norm;
+flat out float f_thickness;
+flat out float f_total_thickness;
+flat out float f_aspect_expansion_len;
+
+void main() {
+    float aspect = u_res.x / u_res.y;
+    vec2 aspect_vec = vec2(aspect, 1.0);
+    mat4 vp = u_proj * u_view;
+    vec4 prev_proj = vp * vec4(v_previous, 1.0);
+    vec4 curr_proj = vp * vec4(v_position, 1.0);
+    vec4 next_proj = vp * vec4(v_next, 1.0);
+
+    //get 2D screen space with W divide and aspect correction
+    vec2 curr_screen = curr_proj.xy / curr_proj.w * aspect_vec;
+    vec2 prev_screen = prev_proj.xy / prev_proj.w * aspect_vec;
+    vec2 next_screen = next_proj.xy / next_proj.w * aspect_vec;
+
+    float orientation = 1.0;
+    if ((v_direction_start_end & 1) == 1)
+    {
+        orientation = -1.0;
+    }
+
+    vec2 dir = vec2(0.0);
+    if ((v_direction_start_end & 2) == 2)
+    {
+        //starting point uses (next - current)
+        dir = normalize(next_screen - curr_screen);
+    } 
+    else if ((v_direction_start_end & 4) == 4)
+    {
+        //ending point uses (current - v_previous)
+        dir = normalize(curr_screen - prev_screen);
+    }
+    vec2 perp_dir = vec2(-dir.y, dir.x);
+
+    vec4 normal_clip = vp * vec4(v_surface_normal, 0.0);
+    normal_clip.xy *= aspect_vec;
+    normal_clip = normalize(normal_clip);
+    vec2 tang_clip = vec2(-normal_clip.y, normal_clip.x);
+
+    float tdp = dot(tang_clip, perp_dir);
+    vec2 expansion = perp_dir;
+    if (tdp > 0.05)
+        expansion = tang_clip / tdp;
+
+    vec2 norm_exp = normalize(expansion);
+    vec2 res_exp_dir = vec2(norm_exp.x * u_res.x, norm_exp.y * u_res.y);
+    f_aspect_expansion_len = length(res_exp_dir);
+
+    f_thickness = (max(max(min(v_luminance / u_max_luminance, 1.0), 0.0) * u_max_thickness, u_min_thickness) / 2.0) / f_aspect_expansion_len;
+
+    f_total_thickness = f_thickness + AA_BUFFER_SIZE / f_aspect_expansion_len;
 
-layout(location = 0) out vec3 v_color;
+    expansion *= f_total_thickness;
+    expansion *= orientation;
 
-void main()
-{
-    v_color = a_color;
-    gl_Position = u_proj * u_view * vec4(a_pos, 1.0);
+    gl_Position = vec4((curr_screen + expansion) / aspect_vec, curr_proj.z / curr_proj.w, 1.0);
+    f_aa_norm = orientation;
+    f_color = v_color;
 }

src/appleseed/renderer/kernel/lighting/directlightingintegrator.cpp

@@ -466,6 +466,7 @@ void DirectLightingIntegrator::add_emitting_shape_sample_contribution(
         light_path_stream->sampled_emitting_shape(
             *sample.m_shape,
             sample.m_point,
+            sample.m_geometric_normal,
             material_value.m_beauty,
             edf_value);
     }
@@ -541,6 +542,7 @@ void DirectLightingIntegrator::add_non_physical_light_sample_contribution(
         light_path_stream->sampled_non_physical_light(
             *light,
             emission_position,
+            m_material_sampler.get_shading_point().get_geometric_normal(),
             material_value.m_beauty,
             light_value);
     }

src/appleseed/renderer/kernel/lighting/lightpathrecorder.cpp

@@ -276,6 +276,10 @@ void LightPathRecorder::get_light_path_vertex(
     result.m_radiance[0] = source_vertex.m_radiance[0];
     result.m_radiance[1] = source_vertex.m_radiance[1];
     result.m_radiance[2] = source_vertex.m_radiance[2];
+
+    result.m_surface_normal[0] = source_vertex.m_surface_normal[0];
+    result.m_surface_normal[1] = source_vertex.m_surface_normal[1];
+    result.m_surface_normal[2] = source_vertex.m_surface_normal[2];
 }
 
 bool LightPathRecorder::write(const char* filename) const

src/appleseed/renderer/kernel/lighting/lightpathrecorder.h

@@ -68,6 +68,7 @@ struct LightPathVertex
     const Entity*   m_entity;
     float           m_position[3];
     float           m_radiance[3];
+    float           m_surface_normal[3];
 };
 
 

src/appleseed/renderer/kernel/lighting/lightpathstream.cpp

@@ -77,7 +77,8 @@ void LightPathStream::clear()
 void LightPathStream::begin_path(
     const PixelContext&     pixel_context,
     const Camera*           camera,
-    const Vector3d&         camera_vertex_position)
+    const Vector3d&         camera_vertex_position,
+    const Vector3d&         camera_vertex_normal)
 {
     assert(m_events.empty());
     assert(m_hit_reflector_data.empty());
@@ -90,6 +91,7 @@ void LightPathStream::begin_path(
 
     m_camera = camera;
     m_camera_vertex_position = Vector3f(camera_vertex_position);
+    m_camera_vertex_normal = Vector3f(camera_vertex_normal);
     m_pixel_coords = pixel_context.get_pixel_coords();
     m_sample_position = Vector2f(pixel_context.get_sample_position());
 }
@@ -107,6 +109,7 @@ void LightPathStream::hit_reflector(const PathVertex& vertex)
     HitReflectorData data;
     data.m_object_instance = &vertex.m_shading_point->get_object_instance();
     data.m_vertex_position = Vector3f(vertex.get_point());
+    data.m_surface_normal = Vector3f(vertex.get_geometric_normal());
     data.m_path_throughput = vertex.m_throughput.to_rgb(g_std_lighting_conditions);
     m_hit_reflector_data.push_back(data);
 }
@@ -126,6 +129,7 @@ void LightPathStream::hit_emitter(
     HitEmitterData data;
     data.m_object_instance = &vertex.m_shading_point->get_object_instance();
     data.m_vertex_position = Vector3f(vertex.get_point());
+    data.m_surface_normal = Vector3f(vertex.get_geometric_normal());
     data.m_path_throughput = vertex.m_throughput.to_rgb(g_std_lighting_conditions);
     data.m_emitted_radiance = emitted_radiance.to_rgb(g_std_lighting_conditions);
     m_hit_emitter_data.push_back(data);
@@ -134,6 +138,7 @@ void LightPathStream::hit_emitter(
 void LightPathStream::sampled_emitting_shape(
     const EmittingShape&    shape,
     const Vector3d&         emission_position,
+    const Vector3d&         emission_normal,
     const Spectrum&         material_value,
     const Spectrum&         emitted_radiance)
 {
@@ -147,6 +152,7 @@ void LightPathStream::sampled_emitting_shape(
         shape.get_assembly_instance()->get_assembly().object_instances().get_by_index(
             shape.get_object_instance_index());
     data.m_vertex_position = Vector3f(emission_position);
+    data.m_surface_normal = Vector3f(emission_normal);
     data.m_material_value = material_value.to_rgb(g_std_lighting_conditions);
     data.m_emitted_radiance = emitted_radiance.to_rgb(g_std_lighting_conditions);
     m_sampled_emitter_data.push_back(data);
@@ -155,6 +161,7 @@ void LightPathStream::sampled_emitting_shape(
 void LightPathStream::sampled_non_physical_light(
     const Light&            light,
     const Vector3d&         emission_position,
+    const Vector3d&         emission_normal,
     const Spectrum&         material_value,
     const Spectrum&         emitted_radiance)
 {
@@ -166,6 +173,7 @@ void LightPathStream::sampled_non_physical_light(
     SampledEmitterData data;
     data.m_entity = &light;
     data.m_vertex_position = Vector3f(emission_position);
+    data.m_surface_normal = Vector3f(emission_normal);
     data.m_material_value = material_value.to_rgb(g_std_lighting_conditions);
     data.m_emitted_radiance = emitted_radiance.to_rgb(g_std_lighting_conditions);
     m_sampled_emitter_data.push_back(data);
@@ -244,6 +252,7 @@ void LightPathStream::create_path_from_hit_emitter(const size_t emitter_event_in
     StoredPathVertex emitter_vertex;
     emitter_vertex.m_entity = hit_emitter_data.m_object_instance;
     emitter_vertex.m_position = hit_emitter_data.m_vertex_position;
+    emitter_vertex.m_surface_normal = hit_emitter_data.m_surface_normal;
     emitter_vertex.m_radiance = hit_emitter_data.m_emitted_radiance;
     m_vertices.push_back(emitter_vertex);
 
@@ -264,6 +273,7 @@ void LightPathStream::create_path_from_hit_emitter(const size_t emitter_event_in
             StoredPathVertex reflector_vertex;
             reflector_vertex.m_entity = event_data.m_object_instance;
             reflector_vertex.m_position = event_data.m_vertex_position;
+            reflector_vertex.m_surface_normal = event_data.m_surface_normal;
             reflector_vertex.m_radiance = current_radiance;
             m_vertices.push_back(reflector_vertex);
 
@@ -288,6 +298,7 @@ void LightPathStream::create_path_from_hit_emitter(const size_t emitter_event_in
     StoredPathVertex camera_vertex;
     camera_vertex.m_entity = m_camera;
     camera_vertex.m_position = m_camera_vertex_position;
+    camera_vertex.m_surface_normal = m_camera_vertex_normal;
     camera_vertex.m_radiance = current_radiance;
     m_vertices.push_back(camera_vertex);
 
@@ -319,6 +330,7 @@ void LightPathStream::create_path_from_sampled_emitter(const size_t emitter_even
     StoredPathVertex emitter_vertex;
     emitter_vertex.m_entity = sampled_emitter_data.m_entity;
     emitter_vertex.m_position = sampled_emitter_data.m_vertex_position;
+    emitter_vertex.m_surface_normal = sampled_emitter_data.m_surface_normal;
     emitter_vertex.m_radiance = sampled_emitter_data.m_emitted_radiance;
     m_vertices.push_back(emitter_vertex);
 
@@ -339,6 +351,7 @@ void LightPathStream::create_path_from_sampled_emitter(const size_t emitter_even
             StoredPathVertex reflector_vertex;
             reflector_vertex.m_entity = event_data.m_object_instance;
             reflector_vertex.m_position = event_data.m_vertex_position;
+            reflector_vertex.m_surface_normal = event_data.m_surface_normal;
             reflector_vertex.m_radiance = current_radiance;
             m_vertices.push_back(reflector_vertex);
 
@@ -363,6 +376,7 @@ void LightPathStream::create_path_from_sampled_emitter(const size_t emitter_even
     StoredPathVertex camera_vertex;
     camera_vertex.m_entity = m_camera;
     camera_vertex.m_position = m_camera_vertex_position;
+    camera_vertex.m_surface_normal = m_camera_vertex_normal;
     camera_vertex.m_radiance = current_radiance;
     m_vertices.push_back(camera_vertex);
 
@@ -394,6 +408,7 @@ void LightPathStream::create_path_from_sampled_environment(const size_t env_even
     StoredPathVertex emitter_vertex;
     emitter_vertex.m_entity = sampled_env_data.m_environment_edf;
     emitter_vertex.m_position = last_reflector_data.m_vertex_position + m_scene_diameter * sampled_env_data.m_emission_direction;
+    emitter_vertex.m_surface_normal = -sampled_env_data.m_emission_direction;
     emitter_vertex.m_radiance = sampled_env_data.m_emitted_radiance;
     m_vertices.push_back(emitter_vertex);
 
@@ -414,6 +429,7 @@ void LightPathStream::create_path_from_sampled_environment(const size_t env_even
             StoredPathVertex reflector_vertex;
             reflector_vertex.m_entity = event_data.m_object_instance;
             reflector_vertex.m_position = event_data.m_vertex_position;
+            reflector_vertex.m_surface_normal = event_data.m_surface_normal;
             reflector_vertex.m_radiance = current_radiance;
             m_vertices.push_back(reflector_vertex);
 
@@ -438,6 +454,7 @@ void LightPathStream::create_path_from_sampled_environment(const size_t env_even
     StoredPathVertex camera_vertex;
     camera_vertex.m_entity = m_camera;
     camera_vertex.m_position = m_camera_vertex_position;
+    camera_vertex.m_surface_normal = m_camera_vertex_normal;
     camera_vertex.m_radiance = current_radiance;
     m_vertices.push_back(camera_vertex);