add outline support for text

Author: jube

examples/11-text.cc

@@ -31,7 +31,7 @@ int main()
   text_data.character_size = 64;
   text_data.color = gf::darker(gf::Azure, 0.2f);
   // text_data.outline_color = gf::Gray;
-  // text_data.outline_thickness = 2.0f;
+  // text_data.outline_thickness = 0.2f;
 
   gf::TextEntity text_entity(&atlas, &face, text_data, scene_manager.render_manager());
   text_entity.set_location({ 1000.0f, 1000.0f });

include/gf2/core/TextData.h

@@ -26,8 +26,8 @@ namespace gf {
     std::string content;
     float character_size = 0.0f;
     Color color = Black;
-    // float outline_thickness = 0.0f;
-    // Color outline_color = White;
+    Color outline_color = Transparent;
+    float outline_thickness = 0.0f;
     Alignment alignment = Alignment::None;
     float paragraph_width = 0.0f;
     float line_spacing_factor = 1.0f;
@@ -37,7 +37,7 @@ namespace gf {
   template<typename Archive>
   Archive& operator|(Archive& ar, MaybeConst<TextData, Archive>& data)
   {
-    return ar | data.content | data.character_size | data.color | data.alignment | data.paragraph_width | data.line_spacing_factor | data.letter_spacing_factor;
+    return ar | data.content | data.character_size | data.color | data.outline_color | data.outline_thickness | data.alignment | data.paragraph_width | data.line_spacing_factor | data.letter_spacing_factor;
   }
 
   struct GF_CORE_API TextResource {

include/gf2/graphics/RenderRecorder.h

@@ -7,12 +7,14 @@
 
 #include <vector>
 
+#include <gf2/core/Color.h>
 #include <gf2/core/Mat4.h>
 #include <gf2/core/Rect.h>
 
 #include "Buffer.h"
 #include "GraphicsApi.h"
 #include "RenderObject.h"
+#include "TextEffect.h"
 
 namespace gf {
   class RenderManager;
@@ -33,6 +35,7 @@ namespace gf {
 
     void update_view(const Mat3F& view_matrix, const RectF& viewport);
     void update_scissor(const RectI& scissor);
+    void update_text_effect(const TextEffect& effect);
     void record(const RenderObject& object);
 
     void sort();
@@ -44,6 +47,7 @@ namespace gf {
     enum class RecordType : uint8_t {
       View,
       Scissor,
+      Text,
       Object,
     };
 
@@ -61,16 +65,24 @@ namespace gf {
       RectI scissor;
     };
 
+    struct TextRecord {
+      uint32_t text_effect_buffer_index = 0;
+    };
+
     RenderManager* m_render_manager;
 
     std::vector<Record> m_records;
 
     std::vector<ViewRecord> m_views;
     std::vector<ScissorRecord> m_scissors;
+    std::vector<TextRecord> m_texts;
     std::vector<RenderObject> m_objects;
 
     uint32_t m_next_view_matrix_index = 0;
     std::vector<Buffer> m_view_matrix_buffers;
+
+    uint32_t m_next_text_effect_index = 0;
+    std::vector<Buffer> m_text_effect_buffers;
   };
 
 }

include/gf2/graphics/SceneManager.h

@@ -50,8 +50,10 @@ namespace gf {
 
     DescriptorLayout m_camera_descriptor_layout;
     DescriptorLayout m_sampler_descriptor_layout;
+    DescriptorLayout m_text_descriptor_layout;
 
     RenderPipelineLayout m_default_pipeline_layout;
+    RenderPipelineLayout m_text_pipeline_layout;
     RenderPipelineLayout m_fullscreen_pipeline_layout;
 
     RenderPipeline m_default_pipeline;

include/gf2/graphics/Text.h

@@ -12,6 +12,7 @@
 #include "FontAtlas.h"
 #include "GraphicsApi.h"
 #include "RenderObject.h"
+#include "TextEffect.h"
 
 namespace gf {
   class RenderManager;
@@ -31,6 +32,11 @@ namespace gf {
       return m_atlas->texture();
     }
 
+    TextEffect effects()
+    {
+      return m_effects;
+    }
+
     RectF bounds() const
     {
       return m_bounds;
@@ -42,6 +48,7 @@ namespace gf {
     FontFace* m_font = nullptr;
     DynamicBuffer m_vertices;
     DynamicBuffer m_indices;
+    TextEffect m_effects = {};
     RectF m_bounds = {};
   };
 
@@ -59,6 +66,11 @@ namespace gf {
       return m_atlas->texture();
     }
 
+    TextEffect effects()
+    {
+      return m_effects;
+    }
+
     RectF bounds() const
     {
       return m_bounds;
@@ -73,6 +85,7 @@ namespace gf {
     FontFace* m_bold_italic_font = nullptr;
     DynamicBuffer m_vertices;
     DynamicBuffer m_indices;
+    TextEffect m_effects = {};
     RectF m_bounds = {};
   };
 

include/gf2/graphics/TextEffect.h

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: Zlib
+// Copyright (c) 2023-2025 Julien Bernard
+#ifndef GF_TEXT_EFFECT_H
+#define GF_TEXT_EFFECT_H
+
+#include <gf2/core/Color.h>
+
+#include "GraphicsApi.h"
+
+namespace gf {
+
+  struct GF_GRAPHICS_API TextEffect {
+    Color outline_color = Transparent;
+    float outline_thickness = 0.0f;
+  };
+
+}
+
+#endif // GF_TEXT_EFFECT_H

library/graphics/RenderRecorder.cc

@@ -9,6 +9,15 @@
 
 namespace gf {
 
+  namespace {
+
+    std::array<float, 5> compute_raw(const TextEffect& effect)
+    {
+      return { effect.outline_color.r, effect.outline_color.g, effect.outline_color.b, effect.outline_color.a, effect.outline_thickness };
+    }
+
+  }
+
   RenderRecorder::RenderRecorder(RenderManager* render_manager)
   : m_render_manager(render_manager)
   {
@@ -41,6 +50,25 @@ namespace gf {
     m_scissors.push_back({ scissor });
   }
 
+  void RenderRecorder::update_text_effect(const TextEffect& effect)
+  {
+    auto effect_data = compute_raw(effect);
+
+    if (m_next_text_effect_index == m_text_effect_buffers.size()) {
+      Buffer buffer(BufferType::Device, BufferUsage::Uniform, effect_data.size(), sizeof(float), effect_data.data(), m_render_manager);
+      buffer.set_debug_name("[gf2] Text Effect Buffer #" + std::to_string(m_next_text_effect_index));
+      m_text_effect_buffers.push_back(std::move(buffer));
+    } else {
+      m_text_effect_buffers[m_next_text_effect_index].update(effect_data.size(), sizeof(float), effect_data.data(), m_render_manager);
+    }
+
+    const Record record = { RecordType::Text, m_texts.size() };
+    m_records.push_back(record);
+
+    m_texts.push_back({ m_next_text_effect_index });
+    ++m_next_text_effect_index;
+  }
+
   void RenderRecorder::record(const RenderObject& object)
   {
     const Record record = { RecordType::Object, m_objects.size() };
@@ -59,8 +87,10 @@ namespace gf {
     m_records.clear();
     m_views.clear();
     m_scissors.clear();
+    m_texts.clear();
     m_objects.clear();
     m_next_view_matrix_index = 0;
+    m_next_text_effect_index = 0;
   }
 
 }

library/graphics/SceneManager.cc

@@ -15,6 +15,7 @@
 #include <gf2/graphics/RenderRecorder.h>
 #include <gf2/graphics/Scene.h>
 #include <gf2/graphics/Vertex.h>
+#include "gf2/graphics/Descriptor.h"
 
 namespace gf {
 
@@ -115,6 +116,13 @@ namespace gf {
       } else if (record.type == RenderRecorder::RecordType::Scissor) {
         assert(record.index < recorder.m_scissors.size());
         command_buffer.set_scissor(recorder.m_scissors[record.index].scissor);
+      } else if (record.type == RenderRecorder::RecordType::Text) {
+        assert(record.index < recorder.m_texts.size());
+        auto text = recorder.m_texts[record.index];
+
+        auto text_descriptor = m_render_manager.allocate_descriptor_for_layout(&m_text_descriptor_layout);
+        text_descriptor.write(0, &recorder.m_text_effect_buffers[text.text_effect_buffer_index]);
+        command_buffer.bind_descriptor(&m_text_pipeline_layout, 2, text_descriptor);
       } else if (record.type == RenderRecorder::RecordType::Object) {
         assert(record.index < recorder.m_objects.size());
         render_object(command_buffer, recorder.m_objects[record.index]);
@@ -182,6 +190,14 @@ namespace gf {
 
     m_sampler_descriptor_layout = DescriptorLayout(sampler_binding, render_manager());
 
+    // text_descriptor_layout
+
+    const DescriptorBinding text_binding[] = {
+      { 0, DescriptorType::Buffer, ShaderStage::Fragment }
+    };
+
+    m_text_descriptor_layout = DescriptorLayout(text_binding, render_manager());
+
     // default pipeline layout
 
     RenderPipelineLayoutBuilder default_pipeline_layout_builder;
@@ -193,6 +209,18 @@ namespace gf {
     m_default_pipeline_layout = default_pipeline_layout_builder.build(render_manager());
     m_default_pipeline_layout.set_debug_name("[gf2] Default Pipeline Layout");
 
+    // text pipeline layout
+
+    RenderPipelineLayoutBuilder text_pipeline_layout_builder;
+
+    text_pipeline_layout_builder.set_push_constant_parameters(ShaderStage::Vertex, sizeof(float) * 16)
+        .add_descriptor_layout(&m_camera_descriptor_layout)
+        .add_descriptor_layout(&m_sampler_descriptor_layout)
+        .add_descriptor_layout(&m_text_descriptor_layout);
+
+    m_text_pipeline_layout = text_pipeline_layout_builder.build(render_manager());
+    m_text_pipeline_layout.set_debug_name("[gf2] Text Pipeline Layout");
+
     // fullscreen pipeline layout
 
     RenderPipelineLayoutBuilder fullscreen_pipeline_layout_builder;
@@ -219,7 +247,7 @@ namespace gf {
     text_pipeline_builder.set_vertex_input(Vertex::compute_input())
         .add_shader(ShaderStage::Vertex, gf::span(default_vert_shader_code))
         .add_shader(ShaderStage::Fragment, gf::span(text_frag_shader_code))
-        .set_pipeline_layout(&m_default_pipeline_layout);
+        .set_pipeline_layout(&m_text_pipeline_layout);
 
     m_text_pipeline = text_pipeline_builder.build(render_manager());
     m_text_pipeline.set_debug_name("[gf2] Text Pipeline");

library/graphics/Text.cc

@@ -859,6 +859,9 @@ namespace gf {
     m_vertices.update(geometry.vertices.data(), geometry.vertices.size(), render_manager);
     m_indices.update(geometry.indices.data(), geometry.indices.size(), render_manager);
 
+    m_effects.outline_color = data.outline_color;
+    m_effects.outline_thickness = data.outline_thickness;
+
     m_bounds = geometry.compute_bounds();
     fix_bounds(data.alignment, data.paragraph_width, m_bounds);
   }
@@ -922,6 +925,9 @@ namespace gf {
     m_vertices.update(geometry.vertices.data(), geometry.vertices.size(), render_manager);
     m_indices.update(geometry.indices.data(), geometry.indices.size(), render_manager);
 
+    m_effects.outline_color = data.outline_color;
+    m_effects.outline_thickness = data.outline_thickness;
+
     m_bounds = geometry.compute_bounds().shrink_by(static_cast<float>(FontManager::spread()));
     fix_bounds(data.alignment, data.paragraph_width, m_bounds);
   }

library/graphics/TextEffect.cc

@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: Zlib
+// Copyright (c) 2023-2025 Julien Bernard
+
+#include <gf2/graphics/TextEffect.h>