love-android-sdl2 shader test

main.lua

local function firePalette()
	local c = love.graphics.newCanvas(512,512)
	love.graphics.setCanvas(c)
		c:clear()
		local i = 0
		for y = 0, 31 do
			for x = 0, 31 do
				local r = 255*(math.sin(i * math.pi / 128.0)/2.0 + 0.5)
				local g = 0
				local s = math.sin(i * math.pi / 128.0)
				if s > 0.5 then
					s = s - 0.5
					g = (192*s*2.0);
				end
				local b = 128*(math.cos(i * math.pi / 96.0)/2.0 + 0.5)
				local mf = math.floor
				love.graphics.setColor(mf(r),mf(g),mf(b),255)
				love.graphics.point(x+0.5,y+0.5)
				i = i + 1
			end
		end
	love.graphics.setCanvas()
	return c
end

function love.load()
	balls = {{128,128}, {128,128}, {128,128}}
	pal = firePalette()

	love.graphics.setBackgroundColor(0,60,0)
	love.graphics.setColor(255,255,255,255)

	effect = love.graphics.newShader(([[
		extern vec2 ball1, ball2, ball3;
		float dist(vec2 x)
		{
			return sqrt(dot(x, x) + .00001);
		}
		vec4 effect(vec4 color, Image tex, vec2 tc, vec2 pc)
		{
			float p = 0.0;
			float r = 0.0;
			p += sin(dist(pc - ball1) / 129.0);
			p += sin(dist(pc - ball2) / 149.0);
			p += sin(dist(pc - ball3) / 139.0);
			p += 3.0;
			p /= 2.0 * 3.0;
			p = p * 1024.0;
			r = p - 32.0 * floor(p / 32.0);
			return vec4(Texel(tex, vec2(r/(32.0*512.0), 1.0 - p/(32.0*512.0))).rgb, 1.0);
		}
	]]))

	effect:send('ball1', balls[1])
	effect:send('ball2', balls[2])
	effect:send('ball3', balls[3])

end

function love.keypressed(k)
	if k == "q" or k == "escape" then
		love.event.quit()
	end
end

function love.draw()
	love.graphics.setShader(effect)
	love.graphics.draw(pal, 0, 0)
end

t = 0
function love.update(dt)
	t = t + dt
	local midx = pal:getWidth()/2
	local midy = pal:getHeight()/2
	balls[1] = {math.sin(t/5) * 128 + midx, math.cos(t/5) * 128 + midy}
	balls[2] = {math.sin(t) * 128 + midx, math.cos(t/3) * 128 + midy}
	balls[3] = {
		math.sin(t) * (110 + math.sin(.01*t) * 110)  + midx,
		math.cos(t) * (110 + math.sin(.01*t) * 110)  + midy,
	}
	effect:send('ball1', balls[1])
	effect:send('ball2', balls[2])
	effect:send('ball3', balls[3])
end