From bc52384ad81bc030f5672d98d0bf4bd92cef884e Mon Sep 17 00:00:00 2001
From: Guillaume Sarthou <gsarthou@laas.fr>
Date: Fri, 16 Aug 2024 18:37:07 +0200
Subject: [PATCH] [TextRenderer] text face camera

---
 .../Engine/Graphics/OpenGL/TextRenderer.h     |  3 ++-
 src/Engine/Graphics/OpenGL/Renderer.cpp       |  3 +--
 src/Engine/Graphics/OpenGL/TextRenderer.cpp   | 25 +++++++++++++------
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/include/overworld/Engine/Graphics/OpenGL/TextRenderer.h b/include/overworld/Engine/Graphics/OpenGL/TextRenderer.h
index b28fceed..ddd47d39 100644
--- a/include/overworld/Engine/Graphics/OpenGL/TextRenderer.h
+++ b/include/overworld/Engine/Graphics/OpenGL/TextRenderer.h
@@ -1,6 +1,7 @@
 #ifndef OWDS_TEXTRENDERER_H
 #define OWDS_TEXTRENDERER_H
 
+#include <glm/matrix.hpp>
 #include <glm/vec2.hpp>
 #include <glm/vec3.hpp>
 #include <map>
@@ -25,7 +26,7 @@ namespace owds {
 
     bool load(const std::string& font, unsigned int font_size);
 
-    void renderText(Shader& shader, const std::string& text, const glm::vec3& position, float height, const glm::vec3& color, bool center = false);
+    void renderText(Shader& shader, const glm::mat4& view_matrix, const std::string& text, const glm::vec3& position, float height, const glm::vec3& color, bool center = false);
 
   private:
     unsigned int vao_;
diff --git a/src/Engine/Graphics/OpenGL/Renderer.cpp b/src/Engine/Graphics/OpenGL/Renderer.cpp
index e856d1eb..fecc1b96 100644
--- a/src/Engine/Graphics/OpenGL/Renderer.cpp
+++ b/src/Engine/Graphics/OpenGL/Renderer.cpp
@@ -412,9 +412,8 @@ namespace owds {
 
     text_shader.use();
     text_shader.setMat4("projection", render_camera_.getProjectionMatrix());
-    text_shader.setMat4("view", render_camera_.getViewMatrix());
 
-    text_renderer_.renderText(text_shader, "tesH", glm::vec3(0, 0, 5), 1, glm::vec3(1.f, 0.f, 1.f), true);
+    text_renderer_.renderText(text_shader, render_camera_.getViewMatrix(), "tesH", glm::vec3(0, 0, 5), 1, glm::vec3(1.f, 0.f, 1.f), true);
 
     // 2. now blit multisampled buffer(s) to normal colorbuffer of intermediate FBO. Image is stored in screenTexture
     glDisable(GL_BLEND);
diff --git a/src/Engine/Graphics/OpenGL/TextRenderer.cpp b/src/Engine/Graphics/OpenGL/TextRenderer.cpp
index d9c42422..a5a147cb 100644
--- a/src/Engine/Graphics/OpenGL/TextRenderer.cpp
+++ b/src/Engine/Graphics/OpenGL/TextRenderer.cpp
@@ -1,6 +1,8 @@
 #include "overworld/Engine/Graphics/OpenGL/TextRenderer.h"
 
 #include <freetype/freetype.h>
+#include <glm/gtc/packing.hpp>
+#include <glm/gtc/type_ptr.hpp>
 #include <string>
 
 #include "glad/glad.h"
@@ -88,7 +90,7 @@ namespace owds {
     return true;
   }
 
-  void TextRenderer::renderText(Shader& shader, const std::string& text, const glm::vec3& position, float height, const glm::vec3& color, bool center)
+  void TextRenderer::renderText(Shader& shader, const glm::mat4& view_matrix, const std::string& text, const glm::vec3& position, float height, const glm::vec3& color, bool center)
   {
     shader.use();
     shader.setVec3("text_color", color);
@@ -102,6 +104,13 @@ namespace owds {
     float y = position.y;
     float z = position.z;
 
+    glm::vec4 center_in_world(x, y, z, 1.);
+    glm::vec4 center_in_cam = view_matrix * center_in_world;
+
+    x = center_in_cam.x;
+    y = center_in_cam.y;
+    z = center_in_cam.z;
+
     if(center)
     {
       float width = 0;
@@ -121,19 +130,19 @@ namespace owds {
       Character_t& ch = characters_[*c];
 
       float xpos = x + ch.bearing.x * height;
-      float zpos = z - (ch.size.y - ch.bearing.y) * height;
+      float ypos = y - (ch.size.y - ch.bearing.y) * height;
 
       float w = ch.size.x * height;
       float h = ch.size.y * height;
 
       float vertices[6 * 5] = {
-        xpos, y, zpos + h, 0.0f, 0.0f,
-        xpos, y, zpos, 0.0f, 1.0f,
-        xpos + w, y, zpos, 1.0f, 1.0f,
+        xpos, ypos + h, z, 0.0f, 0.0f,
+        xpos, ypos, z, 0.0f, 1.0f,
+        xpos + w, ypos, z, 1.0f, 1.0f,
 
-        xpos, y, zpos + h, 0.0f, 0.0f,
-        xpos + w, y, zpos, 1.0f, 1.0f,
-        xpos + w, y, zpos + h, 1.0f, 0.0f};
+        xpos, ypos + h, z, 0.0f, 0.0f,
+        xpos + w, ypos, z, 1.0f, 1.0f,
+        xpos + w, ypos + h, z, 1.0f, 0.0f};
 
       glBindTexture(GL_TEXTURE_2D, ch.texture_id_);
       glBindBuffer(GL_ARRAY_BUFFER, vbo_);