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Normal Map Rotation #51

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Normal Map Rotation #51

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ecd29fb
add new shader to rotate normal map vectors to the rotation of the sp…
connershoop Nov 19, 2025
f73b364
add contrib
connershoop Nov 19, 2025
e1a8f3b
add import for normal rotate shader
connershoop Nov 21, 2025
e1d8531
add normal map rotation to normal map example
connershoop Dec 24, 2025
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1 change: 1 addition & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -53,3 +53,4 @@ end
- @Buckle2000
- Benoit Giannangeli @giann
- Ivory @tiwe0
- Conner @connershoop
30 changes: 24 additions & 6 deletions examples/normalMap.lua
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@@ -1,34 +1,52 @@
-- Example: Normal map Example
local LightWorld = require "lib"
local image, image_normal
local lightWorld, lightMouse
local lightWorld, lightMouse, imageBody, font
local rotation = 0

local function load()
-- load images
image = love.graphics.newImage("examples/img/normalMap/rock.png")
image_normal = love.graphics.newImage("examples/img/normalMap/normal.png")
-- load font
font = love.graphics.newImageFont("examples/img/complex/font.png", " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.,!?-+/():;%&`'*#=[]\"")
love.graphics.setFont(font)
-- create light world
lightWorld = LightWorld({ambient = {0.21,0.21,0.21}})
-- create light
lightMouse = lightWorld:newLight(0, 0, 160, 160, 160, 300)
lightMouse.normalInvert = true
lightMouse.normalInvert = true
-- create shadow bodys
local w, h = love.graphics.getWidth(), love.graphics.getHeight()
lightWorld:newImage(image, w/2, h/2):setNormalMap(image_normal)
local w, h = love.graphics.getWidth(), love.graphics.getHeight()
imageBody = lightWorld:newImage(image, w/2, h/2)
imageBody:setNormalMap(image_normal)
end

local function update(dt)
love.window.setTitle("Light vs. Shadow Engine (FPS:" .. love.timer.getFPS() .. ")")
lightWorld:update(dt)
lightWorld:update(dt)
lightMouse:setPosition(love.mouse.getX(), love.mouse.getY())

-- Handle arrow key rotation
if love.keyboard.isDown("left") then
rotation = rotation - 2 * dt
end
if love.keyboard.isDown("right") then
rotation = rotation + 2 * dt
end
imageBody:setRotation(rotation)
end

local function draw()
love.graphics.clear(0.21,0.21,0.21)
lightWorld:draw(function(l, t, w, h, s)
love.graphics.setColor(1, 1, 1)
love.graphics.draw(image, w/2-(image:getWidth()/2), h/2-(image:getHeight()/2))
love.graphics.rectangle("fill", 0, 0, love.graphics.getWidth(), love.graphics.getHeight())
love.graphics.draw(image, w/2, h/2, rotation, 1, 1, image:getWidth()/2, image:getHeight()/2)
end)
love.graphics.setBlendMode("alpha")
love.graphics.setColor(0, 0.5, 1)
love.graphics.print("Arrow Keys: Rotate Object", 4, love.graphics.getHeight() - 20 * 1)
end

return {
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7 changes: 7 additions & 0 deletions lib/body.lua
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Expand Up @@ -9,6 +9,7 @@ body.__index = body

body.glowShader = love.graphics.newShader(_PACKAGE.."/shaders/glow.glsl")
body.materialShader = love.graphics.newShader(_PACKAGE.."/shaders/material.glsl")
body.normalRotateShader = love.graphics.newShader(_PACKAGE .. "/shaders/normal_rotate.glsl")

local function new(id, type, ...)
local args = {...}
Expand Down Expand Up @@ -575,11 +576,17 @@ end
function body:drawNormal()
if not self.refraction and not self.reflection and self.normalMesh then
love.graphics.setColor(1, 1, 1)

love.graphics.setShader(body.normalRotateShader)
body.normalRotateShader:send("rotation", self.rotation)

if self.type == 'animation' then
self.animation:draw(self.normal, self.x, self.y, self.rotation, self.scalex, self.scaley, self.nx, self.ny)
else
love.graphics.draw(self.normalMesh, self.x, self.y, self.rotation, self.scalex, self.scaley, self.nx, self.ny)
end

love.graphics.setShader()
end
end

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22 changes: 22 additions & 0 deletions lib/shaders/normal_rotate.glsl
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@@ -0,0 +1,22 @@
extern float rotation;

vec4 effect(vec4 color, Image normalTex, vec2 uv, vec2 pixel_coords) {
vec4 tex = Texel(normalTex, uv);

vec3 normal = tex.rgb * 2.0 - 1.0;

// Z-axis rotation (rotates in XY plane)
float c = cos(rotation);
float s = sin(rotation);
vec3 rotated = vec3(
c * normal.x - s * normal.y, // X'
s * normal.x + c * normal.y, // Y'
normal.z // Z'
);

rotated = normalize(rotated);

vec3 encoded = rotated * 0.5 + 0.5;

return vec4(encoded, tex.a);
}