{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "bf1ae05f",
   "metadata": {
    "lines_to_next_cell": 2
   },
   "source": [
    "# NDC"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3b2580bb",
   "metadata": {
    "lines_to_next_cell": 2
   },
   "outputs": [],
   "source": [
    "\n",
    "# Copyright (c) 2025 William Emerison Six\n",
    "#\n",
    "# This program is free software; you can redistribute it and/or\n",
    "# modify it under the terms of the GNU General Public License\n",
    "# as published by the Free Software Foundation; either version 2\n",
    "# of the License, or (at your option) any later version.\n",
    "#\n",
    "# This program is distributed in the hope that it will be useful,\n",
    "# but WITHOUT ANY WARRANTY; without even the implied warranty of\n",
    "# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n",
    "# GNU General Public License for more details.\n",
    "#\n",
    "# You should have received a copy of the GNU General Public License\n",
    "# along with this program; if not, write to the Free Software\n",
    "# Foundation, Inc., 59 Temple Place - Suite 330,\n",
    "# Boston, MA 02111-1307, USA."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "9dac149c",
   "metadata": {},
   "source": [
    "Drawing in NDC\n",
    "--------------\n",
    "\n",
    "Similar to the Framebuffer code, this is a notebook in which we will\n",
    "only use software to\n",
    "draw pictures of a framebuffer.  We use Normalized Device\n",
    "Coordinates instead of screenspace,\n",
    "and by the end, we will make an animation."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "8278a3d3",
   "metadata": {
    "lines_to_next_cell": 2
   },
   "outputs": [],
   "source": [
    "import warnings\n",
    "\n",
    "import IPython.display\n",
    "import moviepy\n",
    "import numpy as np\n",
    "\n",
    "import modelviewprojection.mathutils2d as mu2d\n",
    "import modelviewprojection.softwarerendering as sr\n",
    "\n",
    "# turn warnings into exceptions\n",
    "warnings.filterwarnings(\"error\", category=RuntimeWarning)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e057b4c3",
   "metadata": {},
   "source": [
    "Make Framebuffer\n",
    "----------------\n",
    "\n",
    "Like in the Framebuffer notebook, we initialize a framebuffer in software."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "73a5f8f8",
   "metadata": {
    "lines_to_next_cell": 2
   },
   "outputs": [],
   "source": [
    "# Show initial random framebuffer\n",
    "fake_fb: sr.FrameBuffer = sr.FrameBuffer(width=400, height=300)\n",
    "fake_fb.show_framebuffer()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a28ea103",
   "metadata": {},
   "source": [
    "Clear Framebuffer\n",
    "-----------------\n",
    "\n",
    "We clear it so that we have a blank slate."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "2ee7e82e",
   "metadata": {
    "lines_to_next_cell": 2
   },
   "outputs": [],
   "source": [
    "# Clear to black and show\n",
    "fake_fb.clear_framebuffer()\n",
    "fake_fb.show_framebuffer()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "99e074b5",
   "metadata": {},
   "source": [
    "Problem 2\n",
    "---------\n",
    "\n",
    "Make a new picture below where the triangle is translated 0.3 units\n",
    "in NDC to the left"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "8ce23dfa",
   "metadata": {},
   "source": [
    "Create function from NDC to screenspace\n",
    "---------------------------------------\n",
    "\n",
    "Create a function to convert from NDC to screen space.  We compose\n",
    "4 functions to achieve this\n",
    "\n",
    "First, translate x to the right one unit, y up on unit, to make\n",
    "the bottom left of the NDC region be at (0,0)\n",
    "\n",
    "Second, since the NDC square is two units wide, scale by 1/2, to\n",
    "make it have a width of 1, and a height of 1.\n",
    "\n",
    "Third, scale by the width and height of the framebuffer.\n",
    "\n",
    "Fourth, translate -1/2 and -1/2, to make (0,0) of NDC map to\n",
    "the center of the pixel at (0,0)\n",
    "\n",
    "Inspired by \"Fundamentals of Computer Graphics, Third Edition\",\n",
    "by Shirley and Marshner, page 60"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "655c4683",
   "metadata": {},
   "outputs": [],
   "source": [
    "ndc_to_screen: mu2d.InvertibleFunction = mu2d.compose(\n",
    "    [\n",
    "        mu2d.translate(mu2d.Vector2D(-0.5, -0.5)),\n",
    "        mu2d.scale(fake_fb.width, fake_fb.height),\n",
    "        mu2d.scale(0.5, 0.5),\n",
    "        mu2d.translate(mu2d.Vector2D(x=1.0, y=1.0)),\n",
    "    ]\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b1079d60",
   "metadata": {},
   "source": [
    "Create NDC data for triangle\n",
    "----------------------------\n",
    "\n",
    "Create a list of Vectors to represent the three vertices of the triangle."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b60c63b3",
   "metadata": {},
   "outputs": [],
   "source": [
    "# Example: draw a white triangle\n",
    "\n",
    "triangle_in_NDC: list[mu2d.Vector] = [\n",
    "    mu2d.Vector2D(0.0, 0.0),\n",
    "    mu2d.Vector2D(0.2, 0.0),\n",
    "    mu2d.Vector2D(0.2, 0.2),\n",
    "]"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f6c531d7",
   "metadata": {},
   "source": [
    "Convert the NDC Vectors to Screenspace\n",
    "--------------------------------------\n",
    "\n",
    "For each vector, apply the function"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "23361557",
   "metadata": {},
   "outputs": [],
   "source": [
    "triangle_in_screen: list[mu2d.Vector] = [\n",
    "    ndc_to_screen(x) for x in triangle_in_NDC\n",
    "]\n",
    "print(triangle_in_screen)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "61f9a481",
   "metadata": {},
   "outputs": [],
   "source": [
    "fake_fb.clear_framebuffer()\n",
    "fake_fb.draw_filled_triangle(\n",
    "    triangle_in_screen[0],\n",
    "    triangle_in_screen[1],\n",
    "    triangle_in_screen[2],\n",
    "    color=(255, 255, 255),\n",
    ")\n",
    "fake_fb.show_framebuffer()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "844562d9",
   "metadata": {},
   "source": [
    "Move the Triangle in NDC\n",
    "------------------------\n",
    "\n",
    "Now, we want to make the triangle move to a different\n",
    "position.  We will use compose to first translate the\n",
    "triangle by 0.5 units of NDC up, and then take the\n",
    "result and convert it from NDC to screenspace"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "7dfd429a",
   "metadata": {},
   "outputs": [],
   "source": [
    "move: mu2d.InvertibleFunction = mu2d.translate(mu2d.Vector2D(0, 0.5))\n",
    "\n",
    "triangle_in_screen = [\n",
    "    mu2d.compose([ndc_to_screen, move])(x) for x in triangle_in_NDC\n",
    "]\n",
    "print(triangle_in_screen)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c91e5b6d",
   "metadata": {},
   "outputs": [],
   "source": [
    "fake_fb.clear_framebuffer()\n",
    "fake_fb.draw_filled_triangle(*triangle_in_screen, color=(255, 255, 255))\n",
    "fake_fb.show_framebuffer()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d24a0fd3",
   "metadata": {},
   "outputs": [],
   "source": [
    "frames = []\n",
    "\n",
    "sixty_fps_times_2_sec = 120\n",
    "\n",
    "# Create 10 frames with simple animation\n",
    "for i in range(sixty_fps_times_2_sec):\n",
    "    fake_fb.clear_framebuffer()\n",
    "    move: mu2d.InvertibleFunction = mu2d.translate(\n",
    "        mu2d.Vector2D(0, 0.5 * (np.sin(np.pi / 60.0 * float(i))))\n",
    "    )\n",
    "\n",
    "    triangle_in_screen = [\n",
    "        mu2d.compose([ndc_to_screen, move])(x) for x in triangle_in_NDC\n",
    "    ]\n",
    "    fake_fb.draw_filled_triangle(*triangle_in_screen, color=(255, 255, 255))\n",
    "\n",
    "    frames.append(fake_fb.framebuffer)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f5306e86",
   "metadata": {},
   "source": [
    "Now that we have the frames, we just need to save them to a\n",
    "video.  The details of how this works is a black box to\n",
    "use, it doesn't really matter for our understanding."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "8cfea01c",
   "metadata": {},
   "outputs": [],
   "source": [
    "np_frames = [np.array(img) for img in frames]\n",
    "\n",
    "frames_np = [np.array(img) for img in frames]\n",
    "clip = moviepy.ImageSequenceClip(frames_np, fps=60)\n",
    "clip.write_videofile(\"animation.mp4\", codec=\"libx264\")\n",
    "\n",
    "IPython.display.Video(\"animation.mp4\", embed=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "10c50618",
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3199cd7f",
   "metadata": {},
   "outputs": [],
   "source": []
  }
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