From 444227b3c413c544f357f2b8b7e9394a59a7d839 Mon Sep 17 00:00:00 2001
From: "Kartik K. Agaram" <vc@akkartik.com>
Date: Sun, 16 May 2021 15:29:53 -0700
Subject: [PATCH] first bit of animation

---
 509bezier.mu | 21 +++++++++++++++++++++
 hest-life.mu | 27 +++++++++++++++++++++++++--
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/509bezier.mu b/509bezier.mu
index c915bbbb..5cbf23a6 100644
--- a/509bezier.mu
+++ b/509bezier.mu
@@ -293,3 +293,24 @@ fn draw-monotonic-bezier screen: (addr screen), x0: int, y0: int, x1: int, y1: i
   # plot the remaining straight line
   draw-line screen, x y, x2 y2, color
 }
+
+# 0 <= u <= 1
+fn bezier-point u: float, x0: int, x1: int, x2: int -> _/eax: int {
+  var one/eax: int <- copy 1
+  var u-prime/xmm0: float <- convert one
+  u-prime <- subtract u
+  var result/xmm1: float <- convert x0
+  result <- multiply u-prime
+  result <- multiply u-prime
+  var term2/xmm2: float <- convert x1
+  term2 <- multiply u
+  term2 <- multiply u-prime
+  result <- add term2
+  result <- add term2
+  var term3/xmm2: float <- convert x2
+  term3 <- multiply u
+  term3 <- multiply u
+  result <- add term3
+  var result/eax: int <- convert result
+  return result
+}
diff --git a/hest-life.mu b/hest-life.mu
index d3e4cc85..91d2d4cf 100644
--- a/hest-life.mu
+++ b/hest-life.mu
@@ -83,9 +83,32 @@ fn render0 screen: (addr screen), _self: (addr environment) {
   draw-rect screen, 0x1f0/xmin, 0x290/ymin, 0x210/xmax, 0x2b0/ymax, 0xf/alive
   draw-rect screen, 0x310/xmin, 0x170/ymin, 0x330/xmax, 0x190/ymax, 0xf/alive
   # clock
-  var tick/eax: (addr int) <- get self, tick
+  var tick-a/eax: (addr int) <- get self, tick
   set-cursor-position screen, 0x78/x, 0/y
-  draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen screen, *tick, 7/fg 0/bg
+  draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen screen, *tick-a, 7/fg 0/bg
+  # time-variant portion
+  var progress/eax: int <- copy *tick-a
+  progress <- and 7
+  var u/xmm7: float <- convert progress
+  var eight/eax: int <- copy 8
+  var eight-f/xmm0: float <- convert eight
+  u <- divide eight-f
+  # points on conveyers from neighboring cells
+  draw-bezier-point screen, u, 0xa0/x0 0x20/y0, 0x100/x1 0x160/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0xa0/x0 0x180/y0, 0x110/x1 0x160/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0xa0/x0 0x2e0/y0, 0x100/x1 0x160/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0x200/x0 0x20/y0, 0x180/x1 0x90/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0x200/x0 0x2e0/y0, 0x180/x1 0x200/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0x360/x0 0x20/y0, 0x180/x1 0xc0/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0x360/x0 0x180/y0, 0x300/x1 0x160/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+  draw-bezier-point screen, u, 0x360/x0 0x2e0/y0, 0x180/x1 0x200/y1, 0x180/x2 0x160/y2, 7/color, 4/radius
+}
+
+fn draw-bezier-point screen: (addr screen), u: float, x0: int, y0: int, x1: int, y1: int, x2: int, y2: int, color: int, radius: int {
+  var _cy/eax: int <- bezier-point u, y0, y1, y2
+  var cy/ecx: int <- copy _cy
+  var cx/eax: int <- bezier-point u, x0, x1, x2
+  draw-disc screen, cx, cy, radius, color, 0xf/border-color=white
 }
 
 fn edit keyboard: (addr keyboard), _self: (addr environment) {