From fe427689cf1a7db4f769904b201fd220169fbdcb Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Sun, 1 Oct 2023 15:20:59 +0100
Subject: [PATCH] Add support for rendering text with a bitmap font

---
 include/BitmapFont.h | 17 +++++---
 src/BitmapFont.c     | 96 ++++++++++++++++++++++++++++++++++++--------
 2 files changed, 91 insertions(+), 22 deletions(-)

diff --git a/include/BitmapFont.h b/include/BitmapFont.h
index fdea49f..71f666c 100644
--- a/include/BitmapFont.h
+++ b/include/BitmapFont.h
@@ -3,6 +3,7 @@
 
 #include "AssetManager.h"
 #include "Renderer.h"
+#include "SDL_pixels.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -10,13 +11,19 @@ extern "C" {
 
 typedef struct bitmap_font BitmapFont;
 
-BitmapFont *load_bitmap_font(AssetManager *am, const Renderer *renderer,
-                             const char *filepath, u64 tile_width,
-                             u64 tile_height);
+BitmapFont *create_bitmap_font(AssetManager *am, const Renderer *renderer,
+                               const char *filepath, u64 tile_width,
+                               u64 tile_height);
 
-RenderRect get_character_sprite(BitmapFont *font, u64 index);
+TextSize get_text_size_from_bitmap_font(BitmapFont *font, u64 font_size,
+                                        const char *text);
 
-void unload_bitmap_font(AssetManager *am, BitmapFont **font);
+void render_bitmap_font_text(AssetManager *am, Renderer *renderer,
+                             BitmapFont *font, u64 font_size, const char *text,
+                             u64 start_index, RenderRect dst_rect,
+                             SDL_Color text_color);
+
+void destroy_bitmap_font(AssetManager *am, BitmapFont **font);
 
 #ifdef __cplusplus
 }
diff --git a/src/BitmapFont.c b/src/BitmapFont.c
index e89156d..54ffdf1 100644
--- a/src/BitmapFont.c
+++ b/src/BitmapFont.c
@@ -5,6 +5,7 @@
 #include "aliases.h"
 #include "reusable_ids.h"
 #include <stdlib.h>
+#include <string.h>
 
 struct bitmap_font {
   AssetID font_atlas;
@@ -16,9 +17,11 @@ struct bitmap_font {
   u64 cols;
 };
 
-BitmapFont *load_bitmap_font(AssetManager *am, const Renderer *renderer,
-                             const char *filepath, u64 tile_width,
-                             u64 tile_height) {
+RenderRect get_character_sprite(BitmapFont *font, u64 index);
+
+BitmapFont *create_bitmap_font(AssetManager *am, const Renderer *renderer,
+                               const char *filepath, u64 tile_width,
+                               u64 tile_height) {
   BitmapFont *font = (BitmapFont *)malloc(sizeof(BitmapFont));
   if (!font) {
     return NULL;
@@ -28,7 +31,7 @@ BitmapFont *load_bitmap_font(AssetManager *am, const Renderer *renderer,
       load_asset_to_manager(am, filepath, ASSET_TYPE_IMAGE, renderer);
 
   if (font->font_atlas == INVALID_ID) {
-    unload_bitmap_font(am, &font);
+    destroy_bitmap_font(am, &font);
 
     return NULL;
   }
@@ -39,7 +42,7 @@ BitmapFont *load_bitmap_font(AssetManager *am, const Renderer *renderer,
   i32 h;
 
   if (SDL_QueryTexture(texture, NULL, NULL, &w, &h) != 0) {
-    unload_bitmap_font(am, &font);
+    destroy_bitmap_font(am, &font);
 
     return NULL;
   }
@@ -56,7 +59,78 @@ BitmapFont *load_bitmap_font(AssetManager *am, const Renderer *renderer,
   return font;
 }
 
+TextSize get_text_size_from_bitmap_font(BitmapFont *font, u64 font_size,
+                                        const char *text) {
+  u64 length = strlen(text);
+
+  if (!font || font_size == 0 || length == 0) {
+    return (TextSize){0};
+  }
+
+  TextSize size = {.width = 0, .height = font_size};
+
+  f64 ratio = (f64)font_size / font->tile_height;
+
+  size.width = (i32)(font->tile_width * ratio * length);
+
+  return size;
+}
+
+void render_bitmap_font_text(AssetManager *am, Renderer *renderer,
+                             BitmapFont *font, u64 font_size, const char *text,
+                             u64 start_index, RenderRect dst_rect,
+                             SDL_Color text_color) {
+  if (!am || !renderer || !font || font_size == 0) {
+    return;
+  }
+
+  u64 length = strlen(text);
+
+  if (length == 0) {
+    return;
+  }
+
+  SDL_Texture *texture = get_texture(am, font->font_atlas);
+
+  u64 char_index = 0;
+  RenderRect src = {0};
+  RenderRect dst = {
+      .y = dst_rect.y,
+      .width = font->tile_width,
+      .height = font->tile_height,
+  };
+
+  for (u64 i = 0; i < length; ++i) {
+    char_index = (u64)(text[i]) - start_index;
+
+    src = get_character_sprite(font, char_index);
+    dst.x = i * font->tile_width + dst_rect.x;
+
+    set_texture_color_modulation(texture, text_color);
+
+    render_texture(renderer, texture, &src, &dst);
+  }
+}
+
+void destroy_bitmap_font(AssetManager *am, BitmapFont **font) {
+  if (!am || !(*font)) {
+    return;
+  }
+
+  remove_asset_from_manager(am, &((*font)->font_atlas));
+
+  free(*font);
+
+  *font = NULL;
+}
+
 RenderRect get_character_sprite(BitmapFont *font, u64 index) {
+  u64 char_count = font->cols * font->rows;
+
+  if (index >= char_count) {
+    return (RenderRect){0};
+  }
+
   u64 col = index % font->cols;
   u64 row = index / font->cols;
 
@@ -69,15 +143,3 @@ RenderRect get_character_sprite(BitmapFont *font, u64 index) {
 
   return rect;
 }
-
-void unload_bitmap_font(AssetManager *am, BitmapFont **font) {
-  if (!am || !(*font)) {
-    return;
-  }
-
-  remove_asset_from_manager(am, &((*font)->font_atlas));
-
-  free(*font);
-
-  *font = NULL;
-}