aibohphobia
My entry shouldn’t win cos it’s just a tweak of an old particle effect shader I did yonks ago.
Run it and touch the screen. Can stutter with a lot of simultaneous touches, but smooth if touched gently.
--# Main
-- Particle Effect
-- Use this function to perform your initial setup
function setup()
displayMode(FULLSCREEN)
--to get ghost trails
backingMode(RETAINED)
--b=Backup("Particle Effect Ver 007")
--sprite("Tyrian Remastered:Explosion Huge")
particles = Particles(readImage("Tyrian Remastered:Explosion Huge"), 100)
end
function touched(touch)
if touch.state == BEGAN then
x,y = touch.x,touch.y
for i=1,100 do
particles:addParticle(x, y, math.random(WIDTH)-x, math.random(HEIGHT)-y, math.random(10), 0, math.random(4000)-2000, math.random(50)+70, math.random(200)-100, 1, -1, 2^(math.random(5)-1) + (math.random(2)-1) * 32, 2^(math.random(5)-1), 2^(math.random(5)-1), 2^(math.random(5)-1), color(255,255,255, 255))
end
end
end
-- This function gets called once every frame
function draw()
output.clear()
--debug info
print(1/DeltaTime)
print(particles.numParticles)
--background(0, 0, 0, 5)
fill(0, 0, 0, 20)
--fade to black
rect(0, 0 , WIDTH, HEIGHT)
--draw the particles
particles:draw()
end
--# Particles
Particles = class()
function Particles:init(particleImage, gravity)
self.particleMesh = mesh()
self.particleMesh.shader = shader(ParticleShader.vertexShader, ParticleShader.fragmentShader)
self.particleMesh.texture = particleImage
self.particleMesh.shader.gravity = gravity
self.particleBuffers = {}
--x,y is the start location z,w is the movement to the end location
self.particleBuffers["startAndEnd"] = self.particleMesh:buffer("startAndEnd")
--x,y is the start time and time to live z,w is the start rotation and delta rotation
self.particleBuffers["timeAndRotation"] = self.particleMesh:buffer("timeAndRotation")
--x,y is the start size and delta size, z,w is the start alpha and alpha delta
self.particleBuffers["sizeAndAlpha"] = self.particleMesh:buffer("sizeAndAlpha")
--easing mode x is position, y is rotation, z is size, w is alpha
--modes
--type 1 linear, 2 quadin, 4 quadout, 8 expoin, 16 expoout
--apply gravity (only applies to position) add 32
self.particleBuffers["easing"] = self.particleMesh:buffer("easing")
self.particleDeath = {}
self.numParticles = 0
end
function Particles:draw()
self.particleMesh.shader.time = ElapsedTime
self.particleMesh:draw()
end
function Particles:addParticle(startX,startY,endDeltaX, endDeltaY, timeToLive, startAngle, deltaAngle, startSize, deltaSize, startAlpha, deltaAlpha, easePos, easeSize, easeRot, easeAlpha, particleColor)
etime = ElapsedTime
firstVertex = 0
for i=1,self.numParticles do
if self.particleDeath[i] < etime then
firstVertex = i*6-5
break
end
end
if firstVertex == 0 then
firstVertex = self.particleMesh.size + 1
self.particleMesh:addRect(0,0,1,1)
self.particleBuffers["startAndEnd"]:resize(firstVertex + 5)
self.particleBuffers["timeAndRotation"]:resize(firstVertex + 5)
self.particleBuffers["sizeAndAlpha"]:resize(firstVertex + 5)
self.particleBuffers["easing"]:resize(firstVertex + 5)
self.numParticles = self.numParticles + 1
end
self.particleMesh:setRectColor((firstVertex+5)/6, particleColor)
self.particleDeath[(firstVertex+5)/6] = etime+timeToLive
for i=firstVertex,firstVertex+5 do
self.particleBuffers["startAndEnd"][i] = vec4(startX,startY,endDeltaX, endDeltaY)
self.particleBuffers["timeAndRotation"][i] = vec4(etime, timeToLive, math.rad(startAngle), math.rad(deltaAngle))
self.particleBuffers["sizeAndAlpha"][i] = vec4(startSize, deltaSize, startAlpha, deltaAlpha)
self.particleBuffers["easing"][i] = vec4(easePos, easeSize, easeRot, easeAlpha)
end
end
ParticleShader = {
vertexShader = [[
//
// A basic vertex shader
//
//This is the current model * view * projection matrix
// Codea sets it automatically
uniform mat4 modelViewProjection;
uniform float time;
uniform float gravity;
//This is the current mesh vertex position, color and tex coord
// Set automatically
attribute vec4 color;
attribute vec4 position;
attribute vec2 texCoord;
attribute vec4 startAndEnd;
attribute vec4 timeAndRotation;
attribute vec4 sizeAndAlpha;
attribute vec4 easing;
//This is an output variable that will be passed to the fragment shader
varying lowp vec4 vColor;
varying highp vec2 vTexCoord;
void main()
{
//Pass the mesh color to the fragment shader
vColor = easing;
vColor = color;
vTexCoord = texCoord;
vec4 lPosition = position;
if (time < (timeAndRotation.x + timeAndRotation.y)) {
//type 1 linear, 2 quadin, 4 quadout, 8 expoin, 16 expoout
float timeDelta = (time - timeAndRotation.x)/timeAndRotation.y;
float positionDelta = timeDelta;
float rotationDelta = timeDelta;
float sizeDelta = timeDelta;
float alphaDelta = timeDelta;
if (mod(easing.x, 4.0) > 1.5) {
positionDelta = pow(timeDelta, 2.0);
}
if (mod(easing.x, 8.0) > 3.5) {
positionDelta = 1.0 - pow((1.0-timeDelta),2.0);
}
if (mod(easing.x, 16.0) > 7.5) {
positionDelta = pow(2.0, 10.0 * (timeDelta - 1.0)) - 0.001;
}
if (mod(easing.x, 32.0) > 15.5) {
positionDelta = 1.001 * (-pow(2.0, -10.0 * timeDelta) + 1.0);
}
if (mod(easing.y, 4.0) > 1.5) {
rotationDelta = pow(timeDelta, 2.0);
}
if (mod(easing.y, 8.0) > 3.5) {
rotationDelta = 1.0 - pow((1.0-timeDelta),2.0);
}
if (mod(easing.y, 16.0) > 7.5) {
rotationDelta = pow(2.0, 10.0 * (timeDelta - 1.0)) - 0.001;
}
if (mod(easing.y, 32.0) > 15.5) {
rotationDelta = 1.001 * (-pow(2.0, -10.0 * timeDelta) + 1.0);
}
if (mod(easing.z, 4.0) > 1.5) {
sizeDelta = pow(timeDelta, 2.0);
}
if (mod(easing.z, 8.0) > 3.5) {
sizeDelta = 1.0 - pow((1.0-timeDelta),2.0);
}
if (mod(easing.z, 16.0) > 7.5) {
sizeDelta = pow(2.0, 10.0 * (timeDelta - 1.0)) - 0.001;
}
if (mod(easing.z, 32.0) > 15.5) {
sizeDelta = 1.001 * (-pow(2.0, -10.0 * timeDelta) + 1.0);
}
if (mod(easing.w, 4.0) > 1.5) {
alphaDelta = pow(timeDelta, 2.0);
}
if (mod(easing.w, 8.0) > 3.5) {
alphaDelta = 1.0 - pow((1.0-timeDelta),2.0);
}
if (mod(easing.w, 16.0) > 7.5) {
alphaDelta = pow(2.0, 10.0 * (timeDelta - 1.0)) - 0.001;
}
if (mod(easing.w, 32.0) > 15.5) {
alphaDelta = 1.001 * (-pow(2.0, -10.0 * timeDelta) + 1.0);
}
float sinAngle = sin(timeAndRotation.z + rotationDelta * timeAndRotation.w);
float cosAngle = cos(timeAndRotation.z + rotationDelta * timeAndRotation.w);
lPosition.xy = vec2(dot(lPosition.xy, vec2(cosAngle, -sinAngle)),
dot(lPosition.xy, vec2(sinAngle, cosAngle)));
lPosition.xy = lPosition.xy * (sizeAndAlpha.x + sizeDelta * sizeAndAlpha.y);
lPosition.xy = lPosition.xy + startAndEnd.xy + (startAndEnd.zw * positionDelta);
if (mod(easing.x,64.0) > 31.5) {
//adjust position by gravity
lPosition.y = lPosition.y - (0.5 * gravity * pow((time - timeAndRotation.x), 2.0));
}
//not sure why just alpha channel isn't working...
//vColor.a = sizeAndAlpha.z + (alphaDelta * sizeAndAlpha.w);
vColor = vColor * sizeAndAlpha.z + (alphaDelta * sizeAndAlpha.w);
}
else {
lPosition = vec4(-1000.0,-1000.0, -1000.0, -1000.0);
}
//Multiply the vertex position by our combined transform
gl_Position = modelViewProjection * lPosition;
}
]],
fragmentShader = [[
//
// A basic fragment shader
//
//Default precision qualifier
precision highp float;
//This represents the current texture on the mesh
uniform lowp sampler2D texture;
//The interpolated vertex color for this fragment
varying lowp vec4 vColor;
//The interpolated texture coordinate for this fragment
varying highp vec2 vTexCoord;
void main()
{
//Sample the texture at the interpolated coordinate
lowp vec4 col = texture2D( texture, vTexCoord ) * vColor;
//Set the output color to the texture color
gl_FragColor = col;
}
]]
}
