typewrite_glow_text.py

import bpy
import os
import sys
from bpy.app.handlers import persistent

# --- Configuration ---
IS_FAST_MODE = True # Set to True for faster rendering, False for detailed rendering

BLINK_SPEED_FRAMES = 10 # How many frames for each blink state (on or off)
PRE_ANIMATION_FRAMES = 24
POST_ANIMATION_FRAMES = 48
CURSOR_OFFSET_X = -.14  # Offset for the cursor position
CURSOR_OFFSET_Y = 0.29  # Offset for the cursor position

# --- Handler Function ---
@persistent
def typewriter_handler(scene, depsgraph):
    text_obj = None
    eval_text_obj = None

    for obj in scene.objects:
        if obj.type == 'FONT' and "full_text" in obj.data:
            text_obj = obj
            eval_text_obj = obj.evaluated_get(depsgraph)
            break

    if not text_obj:
        return

    # --- 1. Typewriter Text Logic ---
    full_text = text_obj.data["full_text"]
    chars_to_show = int(eval_text_obj.data["char_count"])
    visible_text = full_text[:chars_to_show]
    
    if text_obj.data.body != visible_text:
        text_obj.data.body = visible_text

    # --- 2. Cursor Logic (Blinking and Movement) ---
    cursor_obj = scene.objects.get("cursor")
    if cursor_obj:
        text_width = text_obj.dimensions.x
        
        # Get the cursor's own width from its bounding box
        cursor_width = cursor_obj.dimensions.x
        
        # Position the cursor at the end of the text, then shift it by half its own width.
        # This aligns the cursor's left edge with the end of the text.
        cursor_obj.location.x = text_obj.location.x + text_width + (cursor_width) + CURSOR_OFFSET_X
        cursor_obj.location.y = text_obj.location.y + CURSOR_OFFSET_Y
        
        # --- Cursor Blinking ---
        is_hidden = (scene.frame_current // BLINK_SPEED_FRAMES) % 2
        
        cursor_obj.hide_set(bool(is_hidden))
        cursor_obj.hide_render = bool(is_hidden)


# --- Main Script ---

# 1. Get the text string from the command line arguments
try:
    argv = sys.argv
    argv = argv[argv.index("--") + 1:]
    # Add a space at the end so the cursor can blink at the end:
    text_to_animate = argv[0] + " "
except IndexError:
    print("Error: Please provide a string of text to animate.")
    sys.exit(1)

# 2. Get the main objects from the scene
text_object = bpy.data.objects.get("Text")
if not text_object:
    print("Error: A text object named 'Text' was not found in the scene.")
    sys.exit(1)

cursor_object = bpy.data.objects.get("cursor")
if not cursor_object:
    print("Warning: An object named 'cursor' was not found. Skipping cursor animation.")

camera_object = bpy.data.objects.get("Camera")
if not camera_object:
    print("Warning: An object named 'Camera' was not found. Skipping camera tracking.")

print(f"Script found object: {text_object.name}")

# --- Setup Camera Cursor Tracking ---
if camera_object and cursor_object:
    print("Setting up camera constraint...")
    constraint = camera_object.constraints.new(type='COPY_LOCATION')
    constraint.target = cursor_object
    # Only using X axis
    constraint.use_x = True
    constraint.use_y = False
    constraint.use_z = False

# 3. Setup cursor and text initial state
if cursor_object:
    cursor_object.hide_set(False)
    cursor_object.hide_render = False
    cursor_object.location.y = text_object.location.y
    cursor_object.location.z = text_object.location.z

text_object.data["full_text"] = text_to_animate
text_object.data.body = ""

# 4. Setup cursor and text initial state
if cursor_object:
    cursor_object.hide_set(False)
    cursor_object.hide_render = False
    cursor_object.location.y = text_object.location.y
    cursor_object.location.z = text_object.location.z

text_object.data["full_text"] = text_to_animate
text_object.data.body = ""

# 5. Animate the text with padding
full_text_length = len(text_to_animate)
typing_speed_factor = 3

animation_start_frame = 1 + PRE_ANIMATION_FRAMES
typing_duration_frames = full_text_length * typing_speed_factor
if typing_duration_frames < 1:
    typing_duration_frames = 1
animation_end_frame = animation_start_frame + typing_duration_frames

bpy.context.scene.frame_current = animation_start_frame
text_object.data["char_count"] = 0
text_object.data.keyframe_insert(data_path='["char_count"]', frame=animation_start_frame)

bpy.context.scene.frame_current = animation_end_frame
text_object.data["char_count"] = full_text_length
text_object.data.keyframe_insert(data_path='["char_count"]', frame=animation_end_frame)

bpy.context.scene.frame_start = 1
bpy.context.scene.frame_end = animation_end_frame + POST_ANIMATION_FRAMES

# 6. Register the handler function
bpy.app.handlers.frame_change_post.clear()
bpy.app.handlers.frame_change_post.append(typewriter_handler)

# --- Configure Render Settings ---
bpy.context.scene.render.engine = 'BLENDER_EEVEE_NEXT'

# Set render quality based on the flag at the top of the file
if IS_FAST_MODE:
    print("--- Running in FAST TEST mode ---")
    bpy.context.scene.eevee.taa_render_samples = 8
    bpy.context.scene.render.resolution_percentage = 50
else:
    print("--- Running in HIGH QUALITY mode ---")
    bpy.context.scene.eevee.taa_render_samples = 128 # A good default for quality
    bpy.context.scene.render.resolution_percentage = 100

bpy.context.scene.render.image_settings.file_format = 'FFMPEG'
bpy.context.scene.render.ffmpeg.format = 'MPEG4'
bpy.context.scene.render.ffmpeg.codec = 'H264'
bpy.context.scene.render.ffmpeg.video_bitrate = 10000

output_dir = "renders"
if not os.path.exists(output_dir):
    os.makedirs(output_dir)

safe_filename = text_to_animate.replace(" ", "_").replace(":", "").replace("/", "")[:50]
bpy.context.scene.render.filepath = os.path.abspath(f"./{output_dir}/{safe_filename}.mp4")

# --- Render the animation ---
print(f"Rendering text animation for: '{text_to_animate}'...")
bpy.ops.render.render(animation=True)
print("Rendering complete.")

# --- Cleanup and Exit ---
bpy.app.handlers.frame_change_post.remove(typewriter_handler)
bpy.ops.wm.quit_blender()