From b29e298d55703cc9afa09d1683b7d2c2126b3955 Mon Sep 17 00:00:00 2001
From: tobid7 <tobid7@outlook.de>
Date: Thu, 3 Sep 2026 09:36:41 +0200
Subject: [PATCH] save 75% of font memory

---
 backends/source/gfx_opengl3.cpp | 16 +++++++++++++---
 source/lithium/font.cpp         | 12 ++++--------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/backends/source/gfx_opengl3.cpp b/backends/source/gfx_opengl3.cpp
index 49a8b9b..02a5a06 100644
--- a/backends/source/gfx_opengl3.cpp
+++ b/backends/source/gfx_opengl3.cpp
@@ -80,7 +80,7 @@ void GfxOpenGL3::BindTexture(TextureID id) {
   glUniform1i(pLocTex, 0);
   GLint fmt = 0;
   glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, &fmt);
-  glUniform1i(pLocAlfa, fmt == GL_ALPHA);
+  glUniform1i(pLocAlfa, fmt == GL_R8);
 }
 
 void GfxOpenGL3::SysReset() {
@@ -104,13 +104,23 @@ Li::Texture GfxOpenGL3::LoadTexture(const std::vector<PD::u8>& pixels, int w,
 
   // Set base format (Always using RGBA as base)
   GLenum fmt = GL_RGBA;
+  GLenum ifmt = GL_RGBA8;
   if (type == TextureFormat::RGB24) {
+    ifmt = GL_RGB8;
     fmt = GL_RGB;
   } else if (type == TextureFormat::A8) {
-    fmt = GL_ALPHA;
+    ifmt = GL_R8;
+    fmt = GL_RED;
   }
-  glTexImage2D(GL_TEXTURE_2D, 0, fmt, w, h, 0, fmt, GL_UNSIGNED_BYTE,
+  glTexImage2D(GL_TEXTURE_2D, 0, ifmt, w, h, 0, fmt, GL_UNSIGNED_BYTE,
                pixels.data());
+
+  if (type == TextureFormat::A8) {
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_RED);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_R, GL_ONE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_G, GL_ONE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_B, GL_ONE);
+  }
   if (filter == TextureFilter::Linear) {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
diff --git a/source/lithium/font.cpp b/source/lithium/font.cpp
index 13e76f9..510ccc1 100644
--- a/source/lithium/font.cpp
+++ b/source/lithium/font.cpp
@@ -51,7 +51,7 @@ PD_API void Font::LoadTTF(const std::vector<u8>& data, int px_height) {
   // Cache to not render same codepoint tex twice
   std::map<u32, int> buf_cache;
 
-  std::vector<u8> font_tex(texszs * texszs * 4, 0);
+  std::vector<u8> font_tex(texszs * texszs, 0);
   fvec2 off;
 
   bool empty = true;
@@ -116,12 +116,8 @@ PD_API void Font::LoadTTF(const std::vector<u8>& data, int px_height) {
     for (int y = 0; y < h; ++y) {
       for (int x = 0; x < w; ++x) {
         int map_pos = ((static_cast<int>(off.y) + y) * texszs +
-                       (static_cast<int>(off.x) + x)) *
-                      4;
-        font_tex[map_pos + 0] = 255;
-        font_tex[map_pos + 1] = 255;
-        font_tex[map_pos + 2] = 255;
-        font_tex[map_pos + 3] = bitmap[x + y * w];
+                       (static_cast<int>(off.x) + x));
+        font_tex[map_pos] = bitmap[x + y * w];
       }
     }
 
@@ -286,7 +282,7 @@ PD_API void Font::CleanupTMS() {}
 
 PD_API void Font::BakeAndPush(bool final, std::vector<u8>& font_tex,
                               int texszs) {
-  auto t = PD::Gfx::LoadTexture(font_tex, texszs, texszs);
+  auto t = PD::Gfx::LoadTexture(font_tex, texszs, texszs, TextureFormat::A8);
   PDLOG("Font: Texture backed as 0x{:X} at {}", t.GetID(), pCurrentTex);
   Textures.push_back(t.GetID());
   pCurrentTex = Textures.size();