Tech ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES - Use vertex attributes and matrices in shaders.

Shader: mm_gouraud

resources/shaders/mm_gouraud_attr.fs

@@ -0,0 +1,63 @@
+#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
+
+const vec3  ZERO    = vec3(0.0, 0.0, 0.0);
+const float EPSILON = 0.0001;
+
+uniform vec4 uniform_color;
+
+uniform bool volume_mirrored;
+
+uniform mat4 view_model_matrix;
+uniform mat3 normal_matrix;
+
+varying vec3 clipping_planes_dots;
+varying vec4 model_pos;
+
+void main()
+{
+    if (any(lessThan(clipping_planes_dots, ZERO)))
+        discard;
+    vec3  color = uniform_color.rgb;
+    float alpha = uniform_color.a;
+
+    vec3 triangle_normal = normalize(cross(dFdx(model_pos.xyz), dFdy(model_pos.xyz)));
+#ifdef FLIP_TRIANGLE_NORMALS
+    triangle_normal = -triangle_normal;
+#endif
+
+    if (volume_mirrored)
+        triangle_normal = -triangle_normal;
+
+    // First transform the normal into camera space and normalize the result.
+    vec3 eye_normal = normalize(normal_matrix * triangle_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);
+
+    // x = diffuse, y = specular;
+    vec2 intensity = vec2(0.0);
+    intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
+    vec3 position = (view_model_matrix * model_pos).xyz;
+    intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(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_FragColor = vec4(vec3(intensity.y) + color * intensity.x, alpha);
+}

resources/shaders/mm_gouraud_attr.vs

@@ -0,0 +1,28 @@
+#version 110
+
+const vec3 ZERO = vec3(0.0, 0.0, 0.0);
+
+attribute vec3 v_position;
+
+uniform mat4 view_model_matrix;
+uniform mat4 projection_matrix;
+
+uniform mat4 volume_world_matrix;
+// Clipping plane, x = min z, y = max z. Used by the FFF and SLA previews to clip with a top / bottom plane.
+uniform vec2 z_range;
+// Clipping plane - general orientation. Used by the SLA gizmo.
+uniform vec4 clipping_plane;
+
+varying vec3 clipping_planes_dots;
+varying vec4 model_pos;
+
+void main()
+{
+    model_pos = vec4(v_position, 1.0);
+    // Point in homogenous coordinates.
+    vec4 world_pos = volume_world_matrix * model_pos;
+
+    gl_Position = projection_matrix * view_model_matrix * model_pos;
+    // Fill in the scalars for fragment shader clipping. Fragments with any of these components lower than zero are discarded.
+    clipping_planes_dots = vec3(dot(world_pos, clipping_plane), world_pos.z - z_range.x, z_range.y - world_pos.z);
+}

src/slic3r/GUI/GLShadersManager.cpp

@@ -109,10 +109,17 @@ std::pair<bool, std::string> GLShadersManager::init()
     // Based on https://stackoverflow.com/a/66206648, the similar behavior was also spotted on some other devices with Arm CPU.
     // Since macOS 12 (Monterey), this issue with the opposite direction on Apple's Arm CPU seems to be fixed, and computed
     // triangle normals inside fragment shader have the right direction.
+#if ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
+    if (platform_flavor() == PlatformFlavor::OSXOnArm && wxPlatformInfo::Get().GetOSMajorVersion() < 12)
+        valid &= append_shader("mm_gouraud_attr", { "mm_gouraud_attr.vs", "mm_gouraud_attr.fs" }, { "FLIP_TRIANGLE_NORMALS"sv });
+    else
+        valid &= append_shader("mm_gouraud_attr", { "mm_gouraud_attr.vs", "mm_gouraud_attr.fs" });
+#else
     if (platform_flavor() == PlatformFlavor::OSXOnArm && wxPlatformInfo::Get().GetOSMajorVersion() < 12)
         valid &= append_shader("mm_gouraud", {"mm_gouraud.vs", "mm_gouraud.fs"}, {"FLIP_TRIANGLE_NORMALS"sv});
     else
         valid &= append_shader("mm_gouraud", {"mm_gouraud.vs", "mm_gouraud.fs"});
+#endif // ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
 
     return { valid, error };
 }

src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp

@@ -170,7 +170,11 @@ void GLGizmoMmuSegmentation::data_changed()
 void GLGizmoMmuSegmentation::render_triangles(const Selection &selection) const
 {
     ClippingPlaneDataWrapper clp_data = this->get_clipping_plane_data();
+#if ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
+    auto* shader = wxGetApp().get_shader("mm_gouraud_attr");
+#else
     auto                    *shader   = wxGetApp().get_shader("mm_gouraud");
+#endif // ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
     if (!shader)
         return;
     shader->start_using();
@@ -192,8 +196,16 @@ void GLGizmoMmuSegmentation::render_triangles(const Selection &selection) const
         if (is_left_handed)
             glsafe(::glFrontFace(GL_CW));
 
+#if ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
+        const Camera& camera = wxGetApp().plater()->get_camera();
+        const Transform3d matrix = camera.get_view_matrix() * trafo_matrix;
+        shader->set_uniform("view_model_matrix", matrix);
+        shader->set_uniform("projection_matrix", camera.get_projection_matrix());
+        shader->set_uniform("normal_matrix", (Matrix3d)matrix.matrix().block(0, 0, 3, 3).inverse().transpose());
+#else
         glsafe(::glPushMatrix());
         glsafe(::glMultMatrixd(trafo_matrix.data()));
+#endif // ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
 
         shader->set_uniform("volume_world_matrix", trafo_matrix);
         shader->set_uniform("volume_mirrored", is_left_handed);
@@ -203,7 +215,9 @@ void GLGizmoMmuSegmentation::render_triangles(const Selection &selection) const
         m_triangle_selectors[mesh_id]->render(m_imgui);
 #endif // ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
 
+#if !ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
         glsafe(::glPopMatrix());
+#endif // !ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
         if (is_left_handed)
             glsafe(::glFrontFace(GL_CCW));
     }
@@ -584,7 +598,11 @@ void TriangleSelectorMmGui::render(ImGuiWrapper *imgui)
     auto *shader = wxGetApp().get_current_shader();
     if (!shader)
         return;
+#if ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
+    assert(shader->get_name() == "mm_gouraud_attr");
+#else
     assert(shader->get_name() == "mm_gouraud");
+#endif // ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES
 
     for (size_t color_idx = 0; color_idx < m_gizmo_scene.triangle_indices.size(); ++color_idx)
         if (m_gizmo_scene.has_VBOs(color_idx)) {