[ISL][workshop] Indigo Shading Language

[Stromberg]

Yeah, that would be great
I have no idea if this is possible either, but i want to think it is... so some of the coders needs to convince us, before we completely take of

[CTZn]

With a delay I must report fused's contribution to the topic:

Code: Select all

<!--Generated by Cindigo 1.1.18-->
<!--Using TinyXml-->
<!--Developed by: Yves Colle aka 'fused'-->
<scenedata>

    <material>
        <name>nullMat</name>
        <null_material />
    </material>
    
    <material>
        <name>mortar</name>
        <oren_nayar>
            <sigma>
                <constant>0.2</constant>
            </sigma>
            <albedo>
                <constant>
                    <rgb>
                        <rgb>0.525 0.404 0.267</rgb>
                        <gamma>2.2</gamma>
                    </rgb>
                </constant>
            </albedo>
        </oren_nayar>
    </material>
    
    <material>
        <name>displace</name>
        <phong>
            <ior>1.141</ior>
            <diffuse_albedo>
                <constant>
                    <rgb>
                        <rgb>0.922 0.949 0.549</rgb>
                        <gamma>2.2</gamma>
                    </rgb>
                </constant>
            </diffuse_albedo>
            <exponent>
                <constant>62.5</constant>
            </exponent>
            <displacement>
                <shader>
                    <shader>
                        <![CDATA[#teh shifter shader
def shift (vec2 uv) vec2:
vec2(
        add(
                doti(uv),
                mul(
                        noise(mul(uv, 8.0)),
                        0.1
                )
        ),
        add(
                dotj(uv),
                mul(
                        noise(mul(uv, 8.0)),
                        0.1
                )
        )
)

#teh vec3 -> real shader
def vec2real (vec3 v) real:
div(
        add(add(doti(v), dotj(v)), dotk(v)), #add all compos together
        3.0
)

#teh vec2 -> real shader
def vec2real (vec2 v) real:
div(
        add(doti(v), dotj(v)), #add all compos together
        2.0
)

def getDisplacementMap () real:
vec2real(sample2DTextureVec3(
        0,
        shift(getTexCoords(0))
))

def getBlendMap (real col) real:
if(
        gt(
                col,
                0.05
        ), 1.0, 0.0
)

#def eval (vec3 pos) vec3: vec3(getBlendMap(getDisplacementMap()))
def eval () real: getDisplacementMap() * 0.4]]>
</shader>
                </shader>
            </displacement>
            <texture>
                <uv_set>default</uv_set>
                <path>mask_map.png</path>
                <exponent>2.20000005</exponent>
                <a>0.00000000</a>
                <b>1.00000000</b>
                <c>0.00000000</c>
            </texture>
        </phong>
    </material>
    <material>
        <name>initialShadingGroup</name>
        <blend>
            <a_name>mortar</a_name>
            <b_name>displace</b_name>
            <blend>
                <shader>
                    <shader>
                        <![CDATA[#teh shifter shader
def shift (vec2 uv) vec2:
vec2(
        add(
                doti(uv),
                mul(
                        noise(mul(uv, 8.0)),
                        0.1
                )
        ),
        add(
                dotj(uv),
                mul(
                        noise(mul(uv, 8.0)),
                        0.1
                )
        )
)

#teh vec3 -> real shader
def vec2real (vec3 v) real:
div(
        add(add(doti(v), dotj(v)), dotk(v)), #add all compos together
        3.0
)

#teh vec2 -> real shader
def vec2real (vec2 v) real:
div(
        add(doti(v), dotj(v)), #add all compos together
        2.0
)

def getDisplacementMap () real:
vec2real(sample2DTextureVec3(
        0,
        shift(getTexCoords(0))
))

def getBlendMap (real col) real:
if(
        gt(
                col,
                0.05
        ), 1.0, 0.0
)

def eval () real: getBlendMap(getDisplacementMap())
#def eval () real: getDisplacementMap() * 0.4]]>
</shader>
                </shader>
            </blend>
            <texture>
                <uv_set>default</uv_set>
                <path>mask_map.png</path>
                <exponent>2.20000005</exponent>
                <a>0.00000000</a>
                <b>1.00000000</b>
                <c>0.00000000</c>
            </texture>
        </blend>
    </material>
    
</scenedata>

the file here (igm)

I'm sorry to drop it without a comment but I took no time for that, also there should be an image linked (will fix). As I could tell from the image, plus what I can see now from the igm I think fused did it all

well done fused !

[OnoSendai]

I added infix operators to ISL ages ago guys,
You can write a + b instead off add(a, b).

[fused]

I added infix operators to ISL ages ago guys,
You can write a + b instead off add(a, b).

yeah, but i really like add(a, b)

[fused]

With a delay I must report fused's contribution to the topic:

Code: Select all

...

the file here (igm)

I'm sorry to drop it without a comment but I took no time for that, also there should be an image linked (will fix). As I could tell from the image, plus what I can see now from the igm I think fused did it all

well done fused !

here are some pics (quite small ). its not even close to CTZn's texture used in his famous rendering, but i think its a start. mabe someone else wants to go on from here?


sorry for double post.

edit: if more people are interested im going to write a small tutorial on ISL (with the code above)

[CTZn]

edit: if more people are interested im going to write a small tutorial on ISL (with the code above)

That would be great if you could expose a bit of the logic behind the code !


Let's use the doc a bit for a start (page 101):

• - The def keyword starts a function definition.
  
  - Next is the name of the function,
  
  - then the list of arguments to the function, where each argument name is preceeded by the argument type.
  
  - Then the return type of the function follows.
  
  - After the colon, the body of the function is defined.

Also the word "cdata" is not exposed in the documentation... like a car with no key

[fused]

Also the word "cdata" is not exposed in the documentation... like a car with no key

CDATA is short for "Character Data".

[CTZn]

yes, and it takes >'s and ['s, how obvious

I was thinking 'Code DATA' rather... but I trust your source !

Nothing new from me, I think people could grab the igm and play with numbers a bit if they want

[OnoSendai]

CData is part of the XML spec. See http://en.wikipedia.org/wiki/CDATA .
I just use CData sections so that XML parsers don't modify the ISL data. Otherwise whitespace will be collapsed etc..

[CTZn]

Aah great, I understand, thanks !

Amazing how a reference on things can change one's perception For some reason it didn't come to my mind it was an XML feature, I was opting for a jit compiler feature, some obscure stuff...

[Stur]

Hey ! ISL Workshop is a geat tool to learn ISL ! Cool.

As far as I understood, "pos" parameter of function "eval()" represents the (x,y,z) coordinates of the pixel being shaded, right ?

Is there a way to get the normal vector of this point ?

Thx.

[fused]

Hey ! ISL Workshop is a geat tool to learn ISL ! Cool.

As far as I understood, "pos" parameter of function "eval()" represents the (x,y,z) coordinates of the pixel being shaded, right ?

Yes, sort of. More precisely its the point on the mesh thats going to be shaded

Is there a way to get the normal vector of this point ?

Thx.

No, not at the moment. Unfortunately...

[Stur]

Ok, another question.

getTexCoords(int texcoord_set_index) vec2

Gets the i-th texture coordinates at the shading point, where i = texcoord_set_index.

What is the unit of the coordinates ? At first I thought coordinates were measured in pixels, but it seems that i & j vary from 0.0 to 1.0

So, am I right if I say that, the texture coordinates are measured in fraction of the texture size ?

Or am I completely wrong ?

Thx.

[fused]

you're right. (0,0) represents the upper left corner of the texture (or lower left? no idea ^^ ) and (1,1) the lower/upper right (depending on what 0,0 was in the first place ).

[Stur]

Ok. Here is my contribution to this topic.

First I must say I'm gratefull to CTZn and Fused to have started and actively contributed to this topic. It gave me the heart to dive into ISL.

I wanted to give a try to this wall, but without bitmap. I was aiming a 100% procedural wall. I do not know if it's wise or not, it has probably a cost in terms of rendering time, but I did it as a challenge to myself, and as a learning exercise.

After many trials, here is what I got.

Code: Select all

	<material>
		<name>Mur</name>
		<diffuse>
			<albedo>
				<shader>
					<shader>
						<![CDATA[
					#
					# pi() : well ... returns Pi.
					#
					def pi() real : 3.14159265358979
					
					#
					# waver() : draws a wave then a flat spacer
					#
					# nb : angle in radians at which the curve is evaluated
					# waveW : width of the wave
					# spacerW : width of the space between waves
					#
					# remark : (waveW + spacerW) should be <= 1.0
					#
					def waver(real nb, real waveW, real spacerW) real :
						if(
							lt(
								mod(nb, waveW + spacerW)
								, waveW
								)
							, sin((mod(nb, waveW + spacerW) / waveW) * pi())
							, 0.0
							)
					
					#
					# getBricks() : draws a brick pattern
					#
					# brickW : brick width
					# brickH : brick height
					# mortarW : mortar width
					# mortarH : mortar height
					#
					# remark : 	(brickW + mortarW) should be <= 1.0
					#			(brickH + mortarH) should be <= 1.0
					#
					def getBricks(real brickW, real brickH, real mortarW, real mortarH) real:
						waver(
							if(
								lt(
									mod(dotj(getTexCoords(0)), (brickH + mortarH) * 2.0)
									, brickH + mortarH
								)
								, doti(getTexCoords(0))
								, doti(getTexCoords(0)) + (brickW + mortarW) / 2.0
								)
							, brickW
							, mortarW
						)
						*
						waver(
							dotj(getTexCoords(0))
							, brickH
						 	, mortarH
						)
					
					#
					# myNoise() : draws a noise map
					#
					# conc : concentration, err, well couldn't find a better word. The biggest the value is, the more concentrated looks the noise
					# f : factor by which is multiplied the noise to control intensity
					#
					def myNoise(real conc, real f) real:
						(
							(
								fbm(getTexCoords(0) * conc, 10) + 1.0
							) / 2.0
						) * f
					
					
					#
					# getStones() : blends the brick wall with the noise map to draw a stones like map
					#
					def getStones() real:
						max(
							min(
								getBricks(0.2, 0.1, 0.01, 0.01)
								* 6.0
								, 1.0
							)
							- myNoise(50.0, 0.5)
							, 0.0
						)
					
					#
					# colMortar : mortar color
					#
					def colMortar() vec3: vec3(0.4)
						
					#
					# colStone() : stone color
					#
					def colStone() vec3: vec3(0.5843, 0.5412, 0.4627)
					
					#
					# eval(vec3) vec3 : called by the albedo shader
					#
					def eval(vec3 pos) vec3:
						if(
							lte(getStones(), 0.2)
							, colMortar()
							, colStone()
						)
											
						]]>
					</shader>
				</shader>
			</albedo>
			<displacement>
				<shader>
					<shader>
						<![CDATA[
					#
					# pi() : well ... returns Pi.
					#
					def pi() real : 3.14159265358979
					
					#
					# waver() : draws a wave then a flat spacer
					#
					# nb : angle in radians at which the curve is evaluated
					# waveW : width of the wave
					# spacerW : width of the space between waves
					#
					# remark : (waveW + spacerW) should be <= 1.0
					#
					def waver(real nb, real waveW, real spacerW) real :
						if(
							lt(
								mod(nb, waveW + spacerW)
								, waveW
								)
							, sin((mod(nb, waveW + spacerW) / waveW) * pi())
							, 0.0
							)
					
					#
					# getBricks() : draws a brick pattern
					#
					# brickW : brick width
					# brickH : brick height
					# mortarW : mortar width
					# mortarH : mortar height
					#
					# remark : 	(brickW + mortarW) should be <= 1.0
					#			(brickH + mortarH) should be <= 1.0
					#
					def getBricks(real brickW, real brickH, real mortarW, real mortarH) real:
						waver(
							if(
								lt(
									mod(dotj(getTexCoords(0)), (brickH + mortarH) * 2.0)
									, brickH + mortarH
								)
								, doti(getTexCoords(0))
								, doti(getTexCoords(0)) + (brickW + mortarW) / 2.0
								)
							, brickW
							, mortarW
						)
						*
						waver(
							dotj(getTexCoords(0))
							, brickH
						 	, mortarH
						)
					
					#
					# myNoise() : draws a noise map
					#
					# conc : concentration, err, well couldn't find a better word. The biggest the value is, the more concentrated looks the noise
					# f : factor by which is multiplied the noise to control intensity
					#
					def myNoise(real conc, real f) real:
						(
							(
								fbm(getTexCoords(0) * conc, 10) + 1.0
							) / 2.0
						) * f
					
					
					#
					# getStones() : blends the brick wall with the noise map to draw a stones like map
					#
					def getStones() real:
						max(
							min(
								getBricks(0.2, 0.1, 0.01, 0.01)
								* 6.0
								, 1.0
							)
							- myNoise(50.0, 0.5)
							, 0.0
						)
										
					#
					# eval() real : called by the displacement shader
					#
					def eval() real:
						getStones() * 0.02
						
						]]>
					</shader>
				</shader>
			</displacement>
		</diffuse>
	</material>

I know my comments are not explicit enough for someone to understand ISL, but it's late here so I will (try to) explain later. I'll also answer questions.
And I'll edit this post to publish more results of small parts of the above code, like Fused did in his topic. It helped me to understand.

Here is the result :
The wall is a simple plane with uv coords in a studio setup.