SDF font rendering

Editor/resources/Shaders/sdf_text.shader

@@ -0,0 +1,52 @@
+#shader vertex
+#version 460 core
+layout(location = 0) in vec3 Position;
+layout(location = 1) in vec2 UV;
+
+uniform mat4 model;
+uniform mat4 projection;
+
+out vec2 a_UV;
+
+void main()
+{
+    a_UV = UV;
+    gl_Position = projection * model * vec4(Position, 1.0);
+}
+
+#shader fragment
+#version 460 core
+out vec4 FragColor;
+
+in vec2 a_UV;
+
+uniform vec2 texPos;
+uniform vec2 texScale;
+uniform sampler2D msdf;
+uniform vec4 bgColor;
+uniform vec4 fgColor;
+
+uniform float pxRange; // set to distance field's pixel range
+
+float screenPxRange(vec2 coord) {
+    vec2 unitRange = vec2(pxRange) / vec2(textureSize(msdf, 0));
+    vec2 screenTexSize = vec2(1.0) / fwidth(coord);
+    return max(0.5 * dot(unitRange, screenTexSize), 1.0);
+}
+
+float median(float r, float g, float b) {
+    return max(min(r, g), min(max(r, g), b));
+}
+
+void main() {
+    vec2 textSize = textureSize(msdf, 0);
+
+    vec2 uv = vec2(mix(texPos.x / textSize.x,texScale.x / textSize.x, a_UV.x),
+        mix(texScale.y / textSize.y, texPos.y / textSize.y,  a_UV.y));
+
+    vec3 msd = texture(msdf, uv).rgb;
+    float sd = median(msd.r, msd.g, msd.b);
+    float screenPxDistance = screenPxRange(uv) * (sd - 0.5);
+    float alpha = smoothstep(0.5 - 1/16.0, 0.5 + 1 / 16.0, sd);
+    FragColor = mix(bgColor, fgColor, alpha);
+}

Editor/src/EditorInterface.cpp

@@ -19,7 +19,7 @@
 #include "src/Resource/Project.h"
 #include <src/Scene/Entities/Components/LuaScriptComponent.h>
 #include <src/Core/Logger.h>
-
+Ref<UI::UserInterface> userInterface;
 ImFont* normalFont;
 ImFont* EditorInterface::bigIconFont;
 void EditorInterface::Init()
@@ -56,6 +56,19 @@ void EditorInterface::DrawViewport()
         }
         
     }
+
+   ImGui::End();
+   if (ImGui::Begin("SDF FONT"))
+   {
+       ImVec2 regionAvail = ImGui::GetContentRegionAvail();
+       if (userInterface)
+       {
+           auto id = userInterface->font->FontAtlas->GetID();
+           ImGui::Image((void*)id, regionAvail, ImVec2(0, 1), ImVec2(1, 0));
+
+       }
+
+   }
    ImGui::End();
     if(ImGui::Begin("Viewport"))
     {
@@ -222,7 +235,6 @@ void EditorInterface::DrawSceneTree()
         // Buttons to add and remove entity.
         ImGui::BeginChild("Buttons", ImVec2(300, 20), false);
         {
-
             // Add entity.
             if (ImGui::Button("Add"))
                 Engine::GetCurrentScene()->CreateEntity("Entity");
@@ -895,7 +907,7 @@ void OpenProject()
     Engine::LoadProject(project);
 
     // Create new interface named test.
-    Ref<UI::UserInterface> userInterface = UI::UserInterface::New("test");
+    userInterface = UI::UserInterface::New("test");
 
    
     // Set current interface running.