From 1949623e5d9cf8bf3f3e9c296138cde2e0ec96c8 Mon Sep 17 00:00:00 2001
From: shylie <shylie@shylie.info>
Date: Thu, 24 Jul 2025 03:02:49 -0400
Subject: [PATCH] Update to use increased range of offsets for shadowing

---
 main.lua | 128 ++++++++++++++++++++++++++++---------------------------
 zprite   |   2 +-
 2 files changed, 67 insertions(+), 63 deletions(-)

diff --git a/main.lua b/main.lua
index 01c73cd..9903e65 100644
--- a/main.lua
+++ b/main.lua
@@ -7,7 +7,32 @@ local gx = 0
 local gy = 0
 local angle = 0
 local scale = 0.35
-local dist = 5
+local dist = 4
+
+local function layered_noise(x, y, layers, persistence)
+	local freq = 1
+	local ampl = 1
+	local maxval = 0
+	local val = 0
+	for _ = 1, layers do
+		val = val + love.math.simplexNoise(x * freq, y * freq) * ampl
+
+		maxval = maxval + ampl
+
+		ampl = ampl * persistence
+		freq = freq * 2
+	end
+
+	return val / maxval
+end
+
+local function ease(n)
+	return math.min((1.1 * n ^ 2 + 1 - math.cos(n * math.pi / 2)) / 2, 1)
+end
+
+local function heightmap(x, y)
+	return ease(layered_noise(x * 0.0005, y * 0.0005, 4, 0.8))
+end
 
 local atlas = {
 	water = love.graphics.newQuad(1, 1, 8, 8, tex),
@@ -18,32 +43,48 @@ local atlas = {
 	snow = love.graphics.newQuad(11, 11, 8, 8, tex),
 }
 
-local alpha = 0.75
-local shadow_alpha = 0.15
+local alpha = 0.8
+local shadow_alpha
 local colors = {}
+local time = 0
+
+local function calculate_shadow_alpha(x, y)
+	local delta = 0.01
+	local dhdx = (heightmap(x + delta / 2, y) - heightmap(x - delta / 2, y)) / delta
+	local dhdy = (heightmap(x, y + delta / 2) - heightmap(x, y - delta / 2)) / delta
+
+	local value = math.max(math.abs(dhdx), math.abs(dhdy)) * 100
+
+	return (1 - 1 / (1 + math.exp(value))) / 8
+end
+
 function colors.water(layer)
 	if layer % 2 == 0 then
 		return 0, 0, 0, shadow_alpha
 	end
+	if layer < 14 then
+		local r, g, b, a = colors.sand(layer)
+		return r, g, b, a * 1.2
+	end
 	layer = layer / 2
-	return 0.1, layer / 16, layer / 8, alpha
+	return layer / 32, layer / 16, layer / 8, alpha
 end
 function colors.sand(layer)
 	if layer % 2 == 0 then
 		return 0, 0, 0, shadow_alpha
 	end
 	layer = layer / 2
-	return layer / 16 + 0.2, layer / 16 + 0.15, 0.4, alpha
+	return layer / 24 + 0.3, layer / 24 + 0.2, layer / 24 + 0.1, alpha
 end
 function colors.dirt(layer)
 	if layer % 2 == 0 then
 		return 0, 0, 0, shadow_alpha
 	end
 	layer = layer / 2
-	if layer < 16 then
-		return layer / 40, layer / 80, 0.1, alpha
+	if layer < 24 then
+		return layer / 32 + 0.1, layer / 48 + 0.05, layer / 64, alpha
 	else
-		return 0.1, layer / 50 + 0.1, 0.1, alpha
+		return layer / 50 - 0.1, layer / 50 + 0.1, 0.1, alpha
 	end
 end
 function colors.stone(layer)
@@ -65,67 +106,19 @@ end
 
 local function offset_map(layer)
 	if layer % 2 == 0 then
-		return 1, 7
+		return math.cos(time) / 16, math.sin(time) / 16 + 0.5
 	else
-		return 0, 7
+		return 0, 0.5
 	end
 end
 
-local z = zprite.zchunk.new(tex, 16 * 8, 80, dist * 2 + 1)
-
-local function layered_noise(x, y, layers, persistence)
-	local freq = 1
-	local ampl = 1
-	local maxval = 0
-	local val = 0
-	for _ = 1, layers do
-		val = val + love.math.simplexNoise(x * freq, y * freq) * ampl
-
-		maxval = maxval + ampl
-
-		ampl = ampl * persistence
-		freq = freq * 2
-	end
-
-	return val / maxval
-end
-
-local function ease(n)
-	return math.min((1.1 * n + 1 - math.cos(n * math.pi / 2)) / 2, 1)
-end
-
-local function heightmap(x, y)
-	return ease(layered_noise(x * 0.0005, y * 0.0005, 4, 0.8))
-end
-
-local function dirtgrass_sprite(layer)
-	if layer < 20 then
-		return atlas.dirt
-	end
-	return atlas.grass
-end
-
-local function pick_from_atlas(height)
-	if height < 0.25 then
-		return atlas.water
-	end
-	if height < 0.3 then
-		return atlas.sand
-	end
-	if height < 0.7 then
-		return dirtgrass_sprite
-	end
-	if height < 0.9 then
-		return atlas.stone
-	end
-	return atlas.snow
-end
+local z = zprite.zchunk.new(tex, 256, 80, dist * 2 + 1)
 
 local function pick_color(height)
 	if height < 0.25 then
 		return colors.water
 	end
-	if height < 0.3 then
+	if height < 0.4 then
 		return colors.sand
 	end
 	if height < 0.67 then
@@ -139,7 +132,8 @@ end
 
 local function generate(x, y)
 	local height = heightmap(x, y)
-	z:put(x, y, atlas.stone, math.ceil(height * 80), pick_color(height), offset_map)
+	shadow_alpha = calculate_shadow_alpha(x, y)
+	z:put(x, y, atlas.stone, math.ceil(height * 64) + 16, pick_color(height), offset_map)
 end
 
 local generated = {}
@@ -161,7 +155,17 @@ local function generate_chunk(cx, cy)
 	end
 end
 
+function love.keyreleased(key)
+	if key == "space" then
+		generated = {}
+	end
+end
+
 function love.update(dt)
+	if love.keyboard.isDown("space") then
+		time = math.fmod(time + dt, 2 * math.pi)
+	end
+
 	local speed = 512
 	if love.keyboard.isDown("d") then
 		local dx = speed * math.cos(-angle)
@@ -224,7 +228,7 @@ end
 local t = love.math.newTransform()
 
 function love.draw()
-	z._height_scale = scale * 1.4
+	z._height_scale = scale * 20
 
 	t:reset()
 	t:translate(love.graphics.getWidth() / 2, love.graphics.getHeight() / 2)
diff --git a/zprite b/zprite
index 0ac6791..5a14f0d 160000
--- a/zprite
+++ b/zprite
@@ -1 +1 @@
-Subproject commit 0ac6791e752f5887cafe38e74e06ee86c76bec44
+Subproject commit 5a14f0da22d2baf1744277c2c3950e57b76aed96