defer.lua

local defaultVert = [[
	vec4 position(mat4 transform_projection, vec4 vertex_position)
	{
	    // The order of operations matters when doing matrix multiplication.
	    return transform_projection * vertex_position;
	}
]]

local gbufferPixel = [[
	uniform Image MainTex;
	extern Image normal;

	void effect()
	{
	    love_Canvases[0] = Texel(MainTex, VaryingTexCoord.xy);
	    love_Canvases[1] = Texel(normal, VaryingTexCoord.xy);
	}
]]

local gbufferShader = love.graphics.newShader(defaultVert, gbufferPixel)

local pointLightShader = love.graphics.newShader(defaultVert, [[
	extern Image normal;

	vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords)
	{
		vec3 lightPos = vec3(400, 300, 100);
		vec3 lightDir = normalize(lightPos - vec3(screen_coords, 0));
		vec3 lightc = vec3(0.5, 0.5, 0.5);

	    vec3 albedo = vec3(Texel(texture, texture_coords));
	    vec3 normal = normalize(Texel(normal, texture_coords).xyz * 2.0 - 1.0) ;

	    vec3 diffuse = max(dot(lightDir, normal), 0.0) * lightc;
	    return vec4(diffuse * albedo, 1);
	}
]])

function love.load()
	local w, h = love.graphics.getDimensions()


	albedo = love.graphics.newCanvas()
	normal = love.graphics.newCanvas()
	albedo:setFilter("nearest", "nearest", 0)
	normal:setFilter("nearest", "nearest", 0)

	amap = love.graphics.newImage("wallalbedo.png")
	nmap = love.graphics.newImage("wallnormal.png")
	amap:setFilter("nearest", "nearest")
	nmap:setFilter("nearest", "nearest")
	amap:setWrap("repeat")
	nmap:setWrap("repeat")

	tiles = love.graphics.newQuad( 0, 0, w, h, amap:getDimensions())
end

function love.draw()
	love.graphics.push()
		love.graphics.scale(2)

		love.graphics.setCanvas(albedo, normal)
			love.graphics.setShader(gbufferShader)
			gbufferShader:send("normal", nmap)
			love.graphics.draw(amap, tiles, 0, 0)
		love.graphics.setCanvas()

		--love.graphics.setShader(pointLightShader)
		--pointLightShader:send("normal", normal)
		love.graphics.draw(normal, 0, 0)
	love.graphics.pop()
end