in ffi, enable GL_DEPTH_TEST and also clear the GL_DEPTH_BUFFER_BIT on each frame; I forgot this before, but it is essential for proper depth testing/layering

fcore/text-builder.sml

@@ -65,13 +65,13 @@ struct
     Rect.lerp
       ( Real32.fromInt (posX - 1)
       , Real32.fromInt posY
-      , 0.01
+      , 0.9
       , scale
       , fw
       , fh
-      , r
-      , g
-      , b
+      , 1.0
+      , 1.0
+      , 1.0
       )
 
   fun makeChr (chr, posX, posY, windowWidth, windowHeight, r, g, b) =
@@ -79,7 +79,7 @@ struct
       ( chr
       , Real32.fromInt posX
       , Real32.fromInt posY
-      , 0.05
+      , 0.1
       , scale
       , windowWidth
       , windowHeight

ffi/gles3-export.c

@@ -13,6 +13,7 @@ unsigned int DYNAMIC_DRAW = GL_DYNAMIC_DRAW;
 // OpenGL functions used below
 void loadGlad() {
   gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
+  glEnable(GL_DEPTH_TEST);
 }
 
 void viewport(int width, int height) {
@@ -24,7 +25,7 @@ void clearColor(float r, float g, float b, float a) {
 }
 
 void clear() {
-  glClear(GL_COLOR_BUFFER_BIT);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 }
 
 unsigned int createBuffer() {