added help overlay

Makefile

@@ -1,7 +1,7 @@
 BIN=cudoku
 CC=gcc
 CFLAGS=-Wall -Wextra -pedantic -O3 -g `pkg-config --cflags freetype2` -I3rdparty/glad/include -I3rdparty/stb
-OBJ=main.o x11.o cudoku.o shader.o font.o 3rdparty/glad/src/gl.o 3rdparty/glad/src/glx.o 3rdparty/stb/stb.o
+OBJ=main.o x11.o cudoku.o shader.o font.o helper.o 3rdparty/glad/src/gl.o 3rdparty/glad/src/glx.o 3rdparty/stb/stb.o
 LDFLAGS=`pkg-config --libs x11 freetype2` -lm
 DEPS=3rdparty/glad/include/glad/gl.h 3rdparty/glad/include/glad/glx.h 3rdparty/stb/stb_image.h
 

cudoku.c

@@ -10,6 +10,9 @@
 #include "cudoku.h"
 #include "font.h"
 #include "shader.h"
+#include "helper.h"
+
+#define help_text_size 12
 
 static const float quad_vertices[] = {
   // positions     // texture coords
@@ -26,6 +29,23 @@ static const int quad_indices[] = {
 
 static const Color mistake_color = {1.f, 0.f, 0.f, 0.5f};
 
+static const char *win_text = "You won!";
+
+static const char *help_texts[help_text_size] = {
+  "F1 - Toggle help",
+  "F11 - Toggle fullscreen",
+  "1-9 - Set number",
+  "0/Del/Backspace - Remove number",
+  "Left/A/H - Move selection left",
+  "Right/D/L - Move selection right",
+  "Up/W/K - Move selection up",
+  "Down/S/J - Move selection down",
+  "Space/Enter - Toggle selection",
+  "N - New board",
+  "C - Check for mistakes",
+  "R - Reset board"
+};
+
 void set_scale_factor(int width, int height, float *x, float *y) {
   if (width > height) {
     float ratio = (float)height / (float)width;
@@ -155,9 +175,8 @@ void draw_win_overlay(Shader win_shader, Shader font_shader, unsigned int vao, u
 
   glBindVertexArray(0);
 
-  const char *text = "You won!";
+  Size text_size = calculate_text_size(win_text, 1.0f);
-  Size text_size = calculate_text_size(text, 1.0f);
+  draw_text(font_shader, win_text, text_size, 1.5f, font_vao, font_vbo, transform);
-  draw_text(font_shader, text, text_size, 1.5f, font_vao, font_vbo, transform);
 }
 
 void prepare_selection_box(unsigned int *vao, unsigned int *vbo) {
@@ -206,7 +225,6 @@ void draw_selection_box(Shader shader, unsigned int vao, unsigned int vbo, int x
 
   glBindBuffer(GL_ARRAY_BUFFER, vbo);
   glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
-
   glBindBuffer(GL_ARRAY_BUFFER, 0);
 
   glDrawArrays(GL_TRIANGLES, 0, 6);
@@ -261,6 +279,7 @@ void reset_state(Cudoku *game) {
   game->should_draw_selection = false;
   game->should_highlight_mistakes = false;
   game->has_won = false;
+  game->should_draw_help = true;
 }
 
 bool check_win(Cudoku *game) {
@@ -274,6 +293,7 @@ bool check_win(Cudoku *game) {
   game->has_won = true;
   game->should_draw_selection = false;
   game->should_highlight_mistakes = false;
+  game->should_draw_help = false;
 
   return true;
 }
@@ -541,4 +561,53 @@ void reset_board(Cudoku *game) {
   }
 }
 
+void toggle_help(Cudoku *game) {
+  if (!game->has_won) {
+    game->should_draw_help = !game->should_draw_help;
+  }
+}
 
+void draw_ui_element_at(Shader shader, unsigned int vao, unsigned int vbo, Matrix4x4 projection, Vec2 pos, Size size, Color color) {
+  use_shader(shader);
+
+  set_mat4f(shader, "transform", (float *)projection.m);
+  set_vec4f(shader, "aColor", color.r, color.g, color.b, color.a);
+
+  glBindVertexArray(vao);
+
+  float vertices[6][2] = {
+     {pos.x,              pos.y + size.height},
+     {pos.x,              pos.y},
+     {pos.x + size.width, pos.y},
+
+     {pos.x,              pos.y + size.height},
+     {pos.x + size.width, pos.y},
+     {pos.x + size.width, pos.y + size.height},
+  };
+
+  glBindBuffer(GL_ARRAY_BUFFER, vbo);
+  glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+
+  glBindVertexArray(0);
+}
+
+void draw_help_overlay(Shader overlay_shader, Shader font_shader, unsigned int overlay_vao, unsigned int overlay_vbo, unsigned int font_vao, unsigned int font_vbo, Matrix4x4 projection, int window_height) {
+  float scale = 0.3f;
+  int total_help_texts_height = 20;
+  int text_padding = 10;
+
+  Size size = {.width = 700, .height = 500};
+  Vec2 pos = {.x = 0, .y = window_height - size.height};
+  Color color = { .r = 0.1f, .g = 0.1f, .b = 0.1f, .a = 0.95f };
+  draw_ui_element_at(overlay_shader, overlay_vao, overlay_vbo, projection, pos, size, color);
+
+  for (int i = 0; i < help_text_size; i++) {
+    Size text_size = calculate_text_size(help_texts[i], scale);
+    Vec2 text_pos = {.x = text_padding, .y = window_height - total_help_texts_height - (text_padding * 2)};
+    total_help_texts_height += text_size.height + text_padding;
+    draw_text_at(font_shader, help_texts[i], text_pos, scale, font_vao, font_vbo, (float *)projection.m);
+  }
+}

cudoku.h

@@ -21,6 +21,7 @@ typedef struct Cudoku {
   Vec2 selection;
   bool should_draw_selection;
   bool should_highlight_mistakes;
+  bool should_draw_help;
 } Cudoku;
 
 typedef struct Color {
@@ -47,3 +48,5 @@ void move_selection(Cudoku *game, int x, int y);
 void toggle_selection(Cudoku *game);
 void generate_random_board(Cudoku *game);
 void reset_board(Cudoku *game);
+void toggle_help(Cudoku *game);
+void draw_help_overlay();

font.c

@@ -223,3 +223,47 @@ void draw_text(Shader shader, const char *text, Size text_size, float scale, uns
   glBindTexture(GL_TEXTURE_2D, 0);
 }
 
+void draw_text_at(Shader shader, const char *text, Vec2 pos, float scale, unsigned int vao, unsigned int vbo, float *projection) {
+  use_shader(shader);
+  set_vec3f(shader, "textColor", 200.f / 255.f, 200.f / 255.f, 200.f / 255.f);
+  set_mat4f(shader, "transform", (float *)projection);
+  glActiveTexture(GL_TEXTURE0);
+  glBindVertexArray(vao);
+
+  int c = 0;
+  while (text[c] != '\0') {
+    Character ch = characters[(int)text[c]];
+
+    float xpos = pos.x + ch.bearing.width * scale;
+    float ypos = pos.y - (ch.size.height - ch.bearing.height) * scale;
+
+    float w = (ch.size.width * scale);
+    float h = (ch.size.height * scale);
+
+    float vertices[6][4] = {
+      // top left tri
+      { xpos,     ypos + h, 0.0f, 0.0f },
+      { xpos,     ypos,     0.0f, 1.0f },
+      { xpos + w, ypos,     1.0f, 1.0f },
+
+      // bottom right tri
+      { xpos,     ypos + h, 0.0f, 0.0f },
+      { xpos + w, ypos,     1.0f, 1.0f },
+      { xpos + w, ypos + h, 1.0f, 0.0f }
+    };
+
+    glBindTexture(GL_TEXTURE_2D, ch.texture_id);
+
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+
+    pos.x += (ch.advance >> 6) * scale; 
+    c++;
+  }
+
+  glBindVertexArray(0);
+  glBindTexture(GL_TEXTURE_2D, 0);
+}

font.h

@@ -20,3 +20,4 @@ void prepare_font(unsigned int *vao, unsigned int *vbo);
 Size calculate_text_size(const char *text, float scale);
 void draw_number(Shader shader, Cell cell, int row, int column, float scale,unsigned int vao, unsigned int vbo, float* transform);
 void draw_text(Shader shader, const char *text, Size text_size, float scale, unsigned int vao, unsigned int vbo, float *transform);
+void draw_text_at(Shader shader, const char *text, Vec2 pos, float scale, unsigned int vao, unsigned int vbo, float *projection);

helper.c

@@ -0,0 +1,21 @@
+#include "helper.h"
+
+Matrix4x4 orthographicProjection2D(float left, float right, float bottom, float top) {
+    Matrix4x4 result;
+
+    // Identity matrix
+    for (int i = 0; i < 4; i++) {
+        for (int j = 0; j < 4; j++) {
+            result.m[i][j] = 0.0f;
+        }
+    }
+
+    result.m[0][0] = 2.0f / (right - left);
+    result.m[3][0] = -(right + left) / (right - left);
+    result.m[1][1] = 2.0f / (top - bottom);
+    result.m[3][1] = -(top + bottom) / (top - bottom);
+    result.m[2][2] = -1.0f;
+    result.m[3][3] = 1.0f;
+
+    return result;
+}

helper.h

@@ -0,0 +1,6 @@
+
+typedef struct {
+    float m[4][4];
+} Matrix4x4;
+
+Matrix4x4 orthographicProjection2D(float left, float right, float bottom, float top);

main.c

@@ -9,6 +9,7 @@
 #include "x11.h"
 #include "cudoku.h"
 #include "font.h"
+#include "helper.h"
 
 Display *display;
 Window window;
@@ -60,8 +61,8 @@ void handle_keypress(XEvent xev, Cudoku *game) {
     toggle_check(game);
   /* } else if (XLookupKeysym(&xev.xkey, 0) == XK_m) { */
   /*   toggle_mute(&game); */
-  /* } else if (XLookupKeysym(&xev.xkey, 0) == XK_F1) { */
+  } else if (XLookupKeysym(&xev.xkey, 0) == XK_F1) {
-  /*   toggle_help(&game); */
+    toggle_help(game);
   }
 }
 
@@ -120,6 +121,7 @@ int main(int argc, char *argv[]) {
   srand(time(NULL));
 
   Cudoku game = {0};
+  game.should_draw_help = true;
   generate_random_board(&game);
 
   for (int i = 0; i < 9; i++) {
@@ -198,6 +200,8 @@ int main(int argc, char *argv[]) {
       {0, 0, 0, 1},
     };
 
+    Matrix4x4 projection = orthographicProjection2D(0.0f, width, 0.0f, height);
+
     if (!use_texture)
       draw_bg_grid_shader(grid_shader, board_vao, (float *)transform, width < height ? width : height);
     else
@@ -218,6 +222,9 @@ int main(int argc, char *argv[]) {
     if (game.should_highlight_mistakes)
       highlight_mistakes(selection_shader, selection_vao, selection_vbo, (float *)transform, &game);
 
+    if (game.should_draw_help)
+      draw_help_overlay(selection_shader, font_shader, selection_vao, selection_vbo, font_vao, font_vbo, projection, height);
+
     if (game.has_won) {
       draw_win_overlay(win_shader, font_shader, win_vao, font_vao, font_vbo, (float *)transform);
     }