[Add] Implement basic UI windowing system.

assets/shaders/shape.frag

@@ -0,0 +1,8 @@
+#version 330 core
+out vec4 FragColor;
+
+uniform vec3 objectColor;
+
+void main() {
+  FragColor = vec4(objectColor, 1.0);
+}

assets/shaders/shape.vert

@@ -0,0 +1,8 @@
+#version 330 core
+layout (location = 0) in vec2 aPos;
+
+uniform mat4 projection;
+
+void main() {
+  gl_Position = projection * vec4(aPos.x, aPos.y, 0.0, 1.0);
+}

client/CMakeLists.txt

@@ -10,3 +10,5 @@ find_package(OpenGL REQUIRED)
 find_package(Freetype REQUIRED)
 
 target_link_libraries(bettolac PRIVATE bettola SDL3::SDL3 GLEW::glew OpenGL::GL Freetype::Freetype)
+
+target_include_directories(bettolac PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/src)

client/src/gfx/shape_renderer.cpp

@@ -0,0 +1,82 @@
+#include <GL/glew.h>
+
+#include "shape_renderer.h"
+
+/* Yep, definately need a math lib, for now, this is just copy form txt_renderer
+ * TODO: Refactor to math lib.
+ */
+void ortho_proj(float* mat, float left, float right, float bottom, float top,
+           float near, float far) {
+
+  mat[0]  = 2.0f / (right - left);
+  mat[4]  = 0.0f;
+  mat[8]  = 0.0f;
+  mat[12] = -(right + left) / (right - left);
+
+  mat[1]  = 0.0f;
+  mat[5]  = 2.0f / (top - bottom);
+  mat[9]  = 0.0f;
+  mat[13] = -(top + bottom) / (top - bottom);
+
+  mat[2]  = 0.0f;
+  mat[6]  = 0.0f;
+  mat[10] = -2.0f / (far - near);
+  mat[14] = -(far + near) / (far - near);
+
+  mat[3]  = 0.0f;
+  mat[7]  = 0.0f;
+  mat[11] = 0.0f;
+  mat[15] = 1.0f;
+}
+
+ShapeRenderer::ShapeRenderer(unsigned int screen_width, unsigned int screen_height) {
+  ortho_proj(_projection, 0.0f, (float)screen_width, 0.0f, (float)screen_height, -1.0f, 1.0f);
+
+  /* Load shader. */
+  _shape_shader = new Shader("assets/shaders/shape.vert",
+                             "assets/shaders/shape.frag");
+  _shape_shader->use();
+  _shape_shader->set_mat4("projection", _projection);
+
+  /* Configure VAO/VBO. */
+  glGenVertexArrays(1, &_vao);
+  glGenBuffers(1, &_vbo);
+  glBindVertexArray(_vao);
+  glBindBuffer(GL_ARRAY_BUFFER, _vbo);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 2, NULL, GL_DYNAMIC_DRAW);
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), 0);
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
+}
+
+ShapeRenderer::~ShapeRenderer(void) {
+  delete _shape_shader;
+}
+
+void ShapeRenderer::draw_rect(int x, int y, int width, int height, float color[3]) {
+  _shape_shader->use();
+  _shape_shader->set_vec3("objectColor", color[0], color[1], color[2]);
+
+  float x_f = (float)x;
+  float y_f = (float)y;
+  float w_f = (float)width;
+  float h_f = (float)height;
+
+  /* This is ugly :) */
+  float vertices[6][2] = {
+    { x_f, y_f + h_f },
+    { x_f, y_f },
+    { x_f + w_f, y_f },
+
+    { x_f, y_f + h_f },
+    { x_f + w_f, y_f },
+    {x_f + w_f, y_f + h_f }
+  };
+
+  glBindVertexArray(_vao);
+  glBindBuffer(GL_ARRAY_BUFFER, _vbo);
+  glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glBindVertexArray(0);
+}

client/src/gfx/shape_renderer.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include "shader.h"
+
+class ShapeRenderer {
+public:
+  ShapeRenderer(unsigned int screen_width, unsigned int screen_height);
+  ~ShapeRenderer(void);
+
+  void draw_rect(int x, int y, int width, int height, float color[3]);
+
+private:
+  Shader* _shape_shader;
+  unsigned int _vao, _vbo;
+  float _projection[16];
+};

client/src/main.cpp

@@ -4,6 +4,8 @@
 #include <SDL3/SDL_keyboard.h>
 
 #include "terminal.h"
+#include "gfx/shape_renderer.h"
+#include "ui/ui_window.h"
 
 const int SCREEN_WIDTH  = 1280;
 const int SCREEN_HEIGHT = 720;
@@ -58,6 +60,12 @@ int main(int argc, char** argv) {
   TextRenderer* txt_render_instance = new TextRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);
   txt_render_instance->load_font("assets/fonts/hack/Hack-Regular.ttf", 14);
 
+  /* Init shape renderer. */
+  ShapeRenderer* shape_renderer_instance = new ShapeRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);
+
+  /* Create UI window. */
+  UIWindow* test_window = new UIWindow("Terminal", 100, 100, 800, 500);
+
   /* Create terminal. */
   Terminal* term = new Terminal();
 
@@ -75,8 +83,7 @@ int main(int argc, char** argv) {
     glClearColor(0.1f, 0.1f, 0.1, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT);
 
-    /* Render text. */
+    test_window->render(shape_renderer_instance, txt_render_instance);
-    float white[] = { 1.0f, 1.0f, 1.0f };
     term->render(txt_render_instance);
 
     /* It's really odd to call it SwapWindow now, rather than SwapBuffer. */
@@ -85,6 +92,8 @@ int main(int argc, char** argv) {
 
   /* Cleanup. */
   delete term;
+  delete test_window;
+  delete shape_renderer_instance;
   delete txt_render_instance;
   SDL_GL_DestroyContext(context);
   SDL_DestroyWindow(window);

client/src/ui/ui_window.cpp

@@ -0,0 +1,32 @@
+#include "ui_window.h"
+#include "gfx/shape_renderer.h"
+#include "gfx/txt_renderer.h"
+
+UIWindow::UIWindow(const char* title, int x, int y, int width, int height) {
+  _title = title;
+  _x = x;
+  _y = y;
+  _width = width;
+  _height = height;
+}
+
+void UIWindow::render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer) {
+  int title_bar_height = 30;
+
+  /* Define colours. */
+  float frame_color[]       = { 0.2f,  0.2f,  0.25f };
+  float title_bar_color[]   = { 0.15f, 0.15f, 0.2f  };
+  float title_text_color[]  = { 0.9f,  0.9f,  0.9f  };
+
+  /* Draw main window frame/background. */
+  shape_renderer->draw_rect(_x, _y, _width, _height, frame_color);
+
+  /* Draw title bar. */
+  shape_renderer->draw_rect(_x, _y+_height-title_bar_height, _width,
+                            title_bar_height, title_bar_color);
+
+  /* Draw title text. */
+  txt_renderer->render_text(_title.c_str(), _x+5, _y+_height-title_bar_height+8,
+                            1.0f, title_text_color);
+}
+

client/src/ui/ui_window.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <string>
+
+#include "gfx/shape_renderer.h"
+#include "gfx/txt_renderer.h"
+
+class UIWindow {
+public:
+  UIWindow(const char* title, int x, int y, int width, int height);
+
+  void render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer);
+
+private:
+  int _x, _y, _width, _height;
+  std::string _title;
+};
+