ENABLE_SEAMS_USING_INSTANCED_MODELS -> WIP: Render models using glDrawElementsInstanced

2021-08-26 12:37:55 +02:00 · 2021-08-26 12:37:55 +02:00 · 2980418706
commit 2980418706
parent 34da899c66
8 changed files with 229 additions and 31 deletions
--- a/resources/shaders/gouraud_light_instanced.fs
+++ b/resources/shaders/gouraud_light_instanced.fs
@ -0,0 +1,12 @@
+#version 110
+
+uniform vec4 uniform_color;
+uniform float emission_factor;
+
+// x = tainted, y = specular;
+varying vec2 intensity;
+
+void main()
+{
+    gl_FragColor = vec4(vec3(intensity.y) + uniform_color.rgb * (intensity.x + emission_factor), uniform_color.a);
+}
--- a/resources/shaders/gouraud_light_instanced.vs
+++ b/resources/shaders/gouraud_light_instanced.vs
@ -0,0 +1,57 @@
+#version 110
+
+#define INTENSITY_CORRECTION 0.6
+
+// normalized values for (-0.6/1.31, 0.6/1.31, 1./1.31)
+const vec3 LIGHT_TOP_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
+#define LIGHT_TOP_DIFFUSE    (0.8 * INTENSITY_CORRECTION)
+#define LIGHT_TOP_SPECULAR   (0.125 * INTENSITY_CORRECTION)
+#define LIGHT_TOP_SHININESS  20.0
+
+// normalized values for (1./1.43, 0.2/1.43, 1./1.43)
+const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
+#define LIGHT_FRONT_DIFFUSE  (0.3 * INTENSITY_CORRECTION)
+
+#define INTENSITY_AMBIENT    0.3
+
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+// vertex attributes
+in vec3 v_position;
+in vec3 v_normal;
+// instance attributes
+in vec3 i_offset;
+in vec2 i_scales;
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
+// x = tainted, y = specular;
+varying vec2 intensity;
+
+void main()
+{
+    // First transform the normal into camera space and normalize the result.
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    vec3 eye_normal = normalize(gl_NormalMatrix * v_normal);
+//    vec3 eye_normal = normalize(gl_NormalMatrix * gl_Normal);
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    
+    // Compute the cos of the angle between the normal and lights direction. The light is directional so the direction is constant for every vertex.
+    // Since these two are normalized the cosine is the dot product. We also need to clamp the result to the [0,1] range.
+    float NdotL = max(dot(eye_normal, LIGHT_TOP_DIR), 0.0);
+
+    intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    vec4 world_position = vec4(v_position * vec3(vec2(i_scales.x), i_scales.y) + i_offset, 1.0);
+    vec3 eye_position = (gl_ModelViewMatrix * world_position).xyz;
+//    vec3 eye_position = (gl_ModelViewMatrix * gl_Vertex).xyz;
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_TOP_DIR, eye_normal)), 0.0), LIGHT_TOP_SHININESS);
+
+    // Perform the same lighting calculation for the 2nd light source (no specular applied).
+    NdotL = max(dot(eye_normal, LIGHT_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
+
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    gl_Position = gl_ProjectionMatrix * vec4(eye_position, 1.0);
+//    gl_Position = ftransform();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+}
--- a/src/libslic3r/Technologies.hpp
+++ b/src/libslic3r/Technologies.hpp
@ -50,10 +50,6 @@
 // Enable rendering seams (and other options) in preview using models
 #define ENABLE_SEAMS_USING_MODELS (1 && ENABLE_2_4_0_ALPHA0)
 // Enable rendering seams (and other options) in preview using instanced models
-// references:
-// https://ogldev.org/www/tutorial33/tutorial33.html
-// https://docs.gl/gl3/glDrawElementsInstanced
-// https://www.khronos.org/opengl/wiki/Vertex_Rendering#Instancing
 #define ENABLE_SEAMS_USING_INSTANCED_MODELS (1 && ENABLE_SEAMS_USING_MODELS)


--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@ -102,7 +102,8 @@ void GCodeViewer::InstanceVBuffer::reset()
    if (vbo > 0)
        glsafe(::glDeleteBuffers(1, &vbo));
    s_ids.clear();
-    render_range = { 0, 0 };
+    buffer.clear();
+    render_ranges.clear();
 }
 #endif // ENABLE_SEAMS_USING_INSTANCED_MODELS

@ -803,7 +804,11 @@ void GCodeViewer::render()
 #if ENABLE_SEAMS_USING_MODELS
                if (wxGetApp().is_gl_version_greater_or_equal_to(3, 1)) {
                    buffer.render_primitive_type = TBuffer::ERenderPrimitiveType::Model;
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+                    buffer.shader = "gouraud_light_instanced";
+#else
                    buffer.shader = "gouraud_light";
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
                    buffer.model.model.init_from(diamond(16));
                    buffer.model.color = option_color(type);
                }
@ -1764,7 +1769,6 @@ void GCodeViewer::load_toolpaths(const GCodeProcessor::Result& gcode_result)

 #if ENABLE_GCODE_VIEWER_STATISTICS
                m_statistics.total_instances_gpu_size += static_cast<int64_t>(size_bytes);
-                m_statistics.max_instance_vbuffer_gpu_size = std::max(m_statistics.max_instance_vbuffer_gpu_size, static_cast<int64_t>(size_bytes));
 #endif // ENABLE_GCODE_VIEWER_STATISTICS

                GLuint id = 0;
@ -1774,6 +1778,7 @@ void GCodeViewer::load_toolpaths(const GCodeProcessor::Result& gcode_result)
                glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));

                t_buffer.model.instances2.vbo = id;
+                t_buffer.model.instances2.buffer = inst_buffer;
                t_buffer.model.instances2.s_ids = instances_ids[i];
            }
        }
@ -2467,22 +2472,37 @@ void GCodeViewer::refresh_render_paths(bool keep_sequential_current_first, bool
        if (buffer.render_primitive_type != TBuffer::ERenderPrimitiveType::Model)
            continue;

-        buffer.model.instances2.render_range = { 0, 0 };
+        buffer.model.instances2.render_ranges.clear();

        if (!buffer.visible)
            continue;

+        buffer.model.instances2.render_ranges.push_back({ 0, 0, buffer.model.color });
+        bool has_second_range = top_layer_only && m_sequential_view.current.last != m_sequential_view.global.last;
+        if (has_second_range)
+            buffer.model.instances2.render_ranges.push_back({ 0, 0, Neutral_Color });
+
        if (m_sequential_view.current.first <= buffer.model.instances2.s_ids.back() && buffer.model.instances2.s_ids.front() <= m_sequential_view.current.last) {
            for (size_t id : buffer.model.instances2.s_ids) {
-                if (id <= m_sequential_view.current.first) {
-                    buffer.model.instances2.render_range.offset += buffer.model.instances2.instance_size_bytes();
-                    buffer.model.instances2.render_range.count = 0;
+                if (has_second_range) {
+                    if (id <= m_sequential_view.endpoints.first) {
+                        buffer.model.instances2.render_ranges.front().offset += buffer.model.instances2.instance_size_bytes();
+                        ++buffer.model.instances2.render_ranges.back().count;
                    }
                    else if (id <= m_sequential_view.current.last)
-                    ++buffer.model.instances2.render_range.count;
+                        ++buffer.model.instances2.render_ranges.front().count;
                    else
                        break;
                }
+                else {
+                    if (id <= m_sequential_view.current.first)
+                        buffer.model.instances2.render_ranges.front().offset += buffer.model.instances2.instance_size_bytes();
+                    else if (id <= m_sequential_view.current.last)
+                        ++buffer.model.instances2.render_ranges.front().count;
+                    else
+                        break;
+                }
+            }
        }
    }
 #endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
@ -2616,7 +2636,9 @@ void GCodeViewer::refresh_render_paths(bool keep_sequential_current_first, bool
        }
 #if ENABLE_SEAMS_USING_MODELS
 #if ENABLE_SEAMS_USING_INSTANCED_MODELS
+        statistics->models_instances_size += SLIC3R_STDVEC_MEMSIZE(buffer.model.instances2.buffer, float);
        statistics->models_instances_size += SLIC3R_STDVEC_MEMSIZE(buffer.model.instances2.s_ids, size_t);
+        statistics->models_instances_size += SLIC3R_STDVEC_MEMSIZE(buffer.model.instances2.render_ranges, InstanceVBuffer::RenderRange);
 #else
        statistics->models_instances_size += SLIC3R_STDVEC_MEMSIZE(buffer.model.instances, TBuffer::Model::Instance);
 #endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
@ -2711,7 +2733,18 @@ void GCodeViewer::render_toolpaths()

 #if ENABLE_SEAMS_USING_MODELS
    auto render_as_instanced_model = [this]
-        (TBuffer & buffer, GLShaderProgram & shader) {
+        (TBuffer& buffer, GLShaderProgram & shader) {
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+        if (buffer.model.instances2.vbo > 0) {
+            for (const InstanceVBuffer::RenderRange& range : buffer.model.instances2.render_ranges) {
+                buffer.model.model.set_color(-1, range.color);
+                buffer.model.model.render_instanced(buffer.model.instances2.vbo, range.count);
+#if ENABLE_GCODE_VIEWER_STATISTICS
+                ++m_statistics.gl_instanced_models_calls_count;
+#endif // ENABLE_GCODE_VIEWER_STATISTICS
+            }
+        }
+#else
        for (const TBuffer::Model::Instance& inst : buffer.model.instances) {
            bool top_layer_only = get_app_config()->get("seq_top_layer_only") == "1";
            bool visible = top_layer_only ?
@ -2732,6 +2765,7 @@ void GCodeViewer::render_toolpaths()
 #endif // ENABLE_GCODE_VIEWER_STATISTICS
            }
        }
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
    };
 #endif // ENABLE_SEAMS_USING_MODELS

@ -3800,7 +3834,11 @@ void GCodeViewer::render_statistics()
        add_counter(std::string("Multi GL_TRIANGLES:"), m_statistics.gl_multi_triangles_calls_count);
        add_counter(std::string("GL_TRIANGLES:"), m_statistics.gl_triangles_calls_count);
 #if ENABLE_SEAMS_USING_MODELS
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+        add_counter(std::string("Instanced models:"), m_statistics.gl_instanced_models_calls_count);
+#else
        add_counter(std::string("Models:"), m_statistics.gl_models_calls_count);
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
 #endif // ENABLE_SEAMS_USING_MODELS
    }

@ -3824,9 +3862,6 @@ void GCodeViewer::render_statistics()
        ImGui::Separator();
        add_memory(std::string("Max VBuffer:"), m_statistics.max_vbuffer_gpu_size);
        add_memory(std::string("Max IBuffer:"), m_statistics.max_ibuffer_gpu_size);
-#if ENABLE_SEAMS_USING_INSTANCED_MODELS
-        add_memory(std::string("Max instance VBuffer:"), m_statistics.max_instance_vbuffer_gpu_size);
-#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
    }

    if (ImGui::CollapsingHeader("Other")) {
--- a/src/slic3r/GUI/GCodeViewer.hpp
+++ b/src/slic3r/GUI/GCodeViewer.hpp
@ -105,8 +105,9 @@ class GCodeViewer
    };

 #if ENABLE_SEAMS_USING_INSTANCED_MODELS
-    // vbo buffer containing instances data used to render a toolpaths using instanced models
-    // record format: 5 floats -> position.x|position.y|position.z|width|height
+    // buffer containing instances data used to render a toolpaths using instanced models
+    // instance record format: 5 floats -> position.x|position.y|position.z|width|height
+    // which is sent to the shader as -> vec3 (offset) + vec2 (scales) in GLModel::render_instanced()
    struct InstanceVBuffer
    {
        struct RenderRange
@ -115,13 +116,18 @@ class GCodeViewer
            unsigned int offset;
            // count of instances to render
            unsigned int count;
+            // Color to apply to the instances
+            Color color;
        };

        // vbo id
        unsigned int vbo{ 0 };
-        // move ids
+        // cpu-side buffer containing all instances data
+        InstanceBuffer buffer;
+        // indices of the moves for all instances
        std::vector<size_t> s_ids;
-        RenderRange render_range;
+        // ranges used to render only subparts of the intances
+        std::vector<RenderRange> render_ranges;

        size_t data_size_bytes() const { return s_ids.size() * instance_size_bytes(); }

@ -518,7 +524,11 @@ class GCodeViewer
        int64_t gl_multi_triangles_calls_count{ 0 };
        int64_t gl_triangles_calls_count{ 0 };
 #if ENABLE_SEAMS_USING_MODELS
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+        int64_t gl_instanced_models_calls_count{ 0 };
+#else
        int64_t gl_models_calls_count{ 0 };
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
 #endif // ENABLE_SEAMS_USING_MODELS
        // memory
        int64_t results_size{ 0 };
@ -529,9 +539,6 @@ class GCodeViewer
 #endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
        int64_t max_vbuffer_gpu_size{ 0 };
        int64_t max_ibuffer_gpu_size{ 0 };
-#if ENABLE_SEAMS_USING_INSTANCED_MODELS
-        int64_t max_instance_vbuffer_gpu_size{ 0 };
-#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
        int64_t paths_size{ 0 };
        int64_t render_paths_size{ 0 };
 #if ENABLE_SEAMS_USING_MODELS
@ -570,7 +577,11 @@ class GCodeViewer
            gl_multi_triangles_calls_count = 0;
            gl_triangles_calls_count = 0;
 #if ENABLE_SEAMS_USING_MODELS
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+            gl_instanced_models_calls_count = 0;
+#else
            gl_models_calls_count = 0;
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
 #endif // ENABLE_SEAMS_USING_MODELS
        }

@ -583,9 +594,6 @@ class GCodeViewer
 #endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
            max_vbuffer_gpu_size = 0;
            max_ibuffer_gpu_size = 0;
-#if ENABLE_SEAMS_USING_INSTANCED_MODELS
-            max_instance_vbuffer_gpu_size = 0;
-#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
            paths_size = 0;
            render_paths_size = 0;
 #if ENABLE_SEAMS_USING_MODELS
--- a/src/slic3r/GUI/GLModel.cpp
+++ b/src/slic3r/GUI/GLModel.cpp
@ -207,6 +207,85 @@ void GLModel::render() const
    }
 }

+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+void GLModel::render_instanced(unsigned int instances_vbo, unsigned int instances_count) const
+{
+    if (instances_vbo == 0)
+        return;
+
+    GLShaderProgram* shader = wxGetApp().get_current_shader();
+    assert(shader == nullptr || boost::algorithm::iends_with(shader->get_name(), "_instanced"));
+
+    // vertex attributes
+    GLint position_id = (shader != nullptr) ? shader->get_attrib_location("v_position") : -1;
+    GLint normal_id = (shader != nullptr) ? shader->get_attrib_location("v_normal") : -1;
+    assert(position_id != -1 && normal_id != -1);
+
+    // instance attributes
+    GLint offset_id = (shader != nullptr) ? shader->get_attrib_location("i_offset") : -1;
+    GLint scales_id = (shader != nullptr) ? shader->get_attrib_location("i_scales") : -1;
+    assert(offset_id != -1 && scales_id != -1);
+
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, instances_vbo));
+    if (offset_id != -1) {
+        glsafe(::glVertexAttribPointer(offset_id, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (GLvoid*)0));
+        glsafe(::glEnableVertexAttribArray(offset_id));
+        glsafe(::glVertexAttribDivisor(offset_id, 1));
+    }
+    if (scales_id != -1) {
+        glsafe(::glVertexAttribPointer(scales_id, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (GLvoid*)(3 * sizeof(float))));
+        glsafe(::glEnableVertexAttribArray(scales_id));
+        glsafe(::glVertexAttribDivisor(scales_id, 1));
+    }
+
+    for (const RenderData& data : m_render_data) {
+        if (data.vbo_id == 0 || data.ibo_id == 0)
+            continue;
+
+        GLenum mode;
+        switch (data.type)
+        {
+        default:
+        case PrimitiveType::Triangles: { mode = GL_TRIANGLES; break; }
+        case PrimitiveType::Lines:     { mode = GL_LINES; break; }
+        case PrimitiveType::LineStrip: { mode = GL_LINE_STRIP; break; }
+        case PrimitiveType::LineLoop:  { mode = GL_LINE_LOOP; break; }
+        }
+
+        if (shader != nullptr)
+            shader->set_uniform("uniform_color", data.color);
+        else
+            glsafe(::glColor4fv(data.color.data()));
+
+        glsafe(::glBindBuffer(GL_ARRAY_BUFFER, data.vbo_id));
+        if (position_id != -1) {
+            glsafe(::glVertexAttribPointer(position_id, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (GLvoid*)0));
+            glsafe(::glEnableVertexAttribArray(position_id));
+        }
+        if (normal_id != -1) {
+            glsafe(::glVertexAttribPointer(normal_id, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (GLvoid*)(3 * sizeof(float))));
+            glsafe(::glEnableVertexAttribArray(normal_id));
+        }
+
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, data.ibo_id));
+        glsafe(::glDrawElementsInstanced(mode, static_cast<GLsizei>(data.indices_count), GL_UNSIGNED_INT, (const void*)0, instances_count));
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
+
+        if (normal_id != -1)
+            glsafe(::glDisableVertexAttribArray(normal_id));
+        if (position_id != -1)
+            glsafe(::glDisableVertexAttribArray(position_id));
+    }
+
+    if (scales_id != -1)
+        glsafe(::glDisableVertexAttribArray(scales_id));
+    if (offset_id != -1)
+        glsafe(::glDisableVertexAttribArray(offset_id));
+
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));
+}
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
+
 void GLModel::send_to_gpu(RenderData& data, const std::vector<float>& vertices, const std::vector<unsigned int>& indices)
 {
    assert(data.vbo_id == 0);
--- a/src/slic3r/GUI/GLModel.hpp
+++ b/src/slic3r/GUI/GLModel.hpp
@ -72,6 +72,9 @@ namespace GUI {

        void reset();
        void render() const;
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+        void render_instanced(unsigned int instances_vbo, unsigned int instances_count) const;
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS

        bool is_initialized() const { return !m_render_data.empty(); }

--- a/src/slic3r/GUI/GLShadersManager.cpp
+++ b/src/slic3r/GUI/GLShadersManager.cpp
@ -38,9 +38,17 @@ std::pair<bool, std::string> GLShadersManager::init()
    // used to render printbed
    valid &= append_shader("printbed", { "printbed.vs", "printbed.fs" });
    // used to render options in gcode preview
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+    if (GUI::wxGetApp().is_gl_version_greater_or_equal_to(3, 1))
+        valid &= append_shader("gouraud_light_instanced", { "gouraud_light_instanced.vs", "gouraud_light_instanced.fs" });
+    else {
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
        valid &= append_shader("options_110", { "options_110.vs", "options_110.fs" });
        if (GUI::wxGetApp().is_glsl_version_greater_or_equal_to(1, 20))
            valid &= append_shader("options_120", { "options_120.vs", "options_120.fs" });
+#if ENABLE_SEAMS_USING_INSTANCED_MODELS
+    }
+#endif // ENABLE_SEAMS_USING_INSTANCED_MODELS
    // used to render extrusion and travel paths as lines in gcode preview
    valid &= append_shader("toolpaths_lines", { "toolpaths_lines.vs", "toolpaths_lines.fs" });
    // used to render objects in 3d editor