235 lines
4.4 KiB
Plaintext
235 lines
4.4 KiB
Plaintext
.constf myconst(0.0, 1.0, 0.01, 1000.0)
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.constf myconst2(0.5, 999.0, 0.0, 0.0)
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.alias zeros myconst.xxxx
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.alias halfs myconst2.xxxx
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.alias ones myconst.yyyy
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.alias near myconst.zzzz
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.alias far myconst.wwww
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.alias noHit myconst2.yyyy
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.consti bounceLoopParams(9, 0, 1, 0)
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.consti calcSphereLoopParams(3, 0, 1, 0)
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.setb b0 true
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.alias true b0
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; xyz center (in world space)
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; w radius (in world space)
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.fvec spheres[4]
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; material albedo
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.fvec sphereColors[4]
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; material emitted light
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.fvec sphereLights[4]
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; random numbers
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.fvec rand[10]
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.in inOrigin v0
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.in inLowerLeftCorner v1
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.in inHorizontal v2
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.in inVertical v3
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.in inST v4
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.in inPos v5
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.in inUV v6
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.out outPos position
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.out outUV texcoord0
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.out outColor color
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.proc main
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; outPos = inPos
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mov outPos, inPos
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; outUV = inUV
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mov outUV, inUV
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; r1 = inOrigin
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mov r1, inOrigin
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; r2 = inDirection
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mov r2.xyz, inLowerLeftCorner
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mov r3.xy, inST.xy
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mad r2.xyz, inHorizontal, r3.x, r2.xyz
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mad r2.xyz, inVertical, r3.y, r2.xyz
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; set initial color multiplier to (1, 1, 1)
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mov r4.xyz, ones
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; set initial color to (0, 0, 0)
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mov r13.xyz, zeros
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; calculate light bounces
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for bounceLoopParams
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; setup random numbers for this iteration
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mov r11, rand[aL]
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; reset max ray distance
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mov r4.w, far
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; set albedo to a large number for sphere hit check
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mov r10.xyz, far
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; for each sphere
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for calcSphereLoopParams
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; r3 = spheres[i]
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mov r3, spheres[aL]
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; do calculation
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call calcSphere
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.end
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; check if noHit < albedo
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; and exit early if true
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; as albedo has not been set
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; after the initial set
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; which only happens when
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; a ray does not hit any spheres
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cmp noHit.xyz, lt, lt, r10.xyz
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breakc cmp.x
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; multiply color by albedo
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mul r4.xyz, r4.xyz, r10.xyz
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; add emitted light
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mad r13.xyz, r4.xyz, r12.xyz, r13.xyz
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; set r1 to new ray origin
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mov r1.xyz, r5.xyz
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; set r2 to new ray direction
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call diffuse
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.end
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; copy final color to output
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mov outColor.xyz, r13.xyz
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; set alpha to 1
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mov outColor.w, ones
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end
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.end
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; Calculate Sphere Intersection
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; -----------------------------
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;
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; Inputs
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; ------
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; r1.xyz: ray origin
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; r2.xyz: ray direction
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; r3.xyz: sphere origin
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; r3.w: sphere radius
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; r4.w: min distance
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; r11.xyz: random unit vector
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; r11.w: random number
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;
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; Outputs
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; -------
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; r4.w: new min distance
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; r10.xyz: albedo
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; r12.xyz: light emitted
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;
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; Temporaries
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; -----------
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; r5.xyz: new origin
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; r6.xyz: new direction
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; r7.xyz: hit normal
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; r8.xyzw: used for calculations
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; r9.xyzw: used for calculations
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.proc calcSphere
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; vec3 oc = origin - center
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add r8.xyz, r1.xyz, -r3.xyz
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; float a = dot(direction, direction)
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dp3 r9.x, r2.xyz, r2.xyz
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; float halfB = dot(oc, direction)
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dp3 r9.y, r8.xyz, r2.xyz
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; float radiusSquared = radius * radius
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mul r8.w, r3.w, r3.w
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; float c = dot(oc, oc) - radius * radius
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dp3 r9.z, r8.xyz, r8.xyz
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add r9.z, r9.z, -r8.w
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; float halfBSquared = halfB * halfB;
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mul r8.w, r9.y, r9.y
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; float ac = a * c;
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mul r9.w, r9.x, r9.z
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; float discriminant = bSquared - ac
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add r8.w, r8.w, -r9.w
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; if discriminant < 0, exit procedure early
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cmp zeros, gt, gt, r8.w
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jmpc cmp.x, calcSphereExit
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; calculate t
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; float sqrtDiscriminant = sqrt(discriminant)
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rsq r8.w, r8.w
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rcp r8.w, r8.w
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; a = 1 / a
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rcp r9.x, r9.x
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; float root = (-halfB - sqrtDiscriminant) / a
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add r9.z, -r9.y, -r8.w
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mul r9.z, r9.z, r9.x
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; if root < min distance, check other root
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cmp near, gt, gt, r9.z
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jmpc cmp.x, calcSphereCheckOtherRoot
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; if root > max distance, check other root
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cmp r9.z, gt, gt, r4.w
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jmpc cmp.x, calcSphereCheckOtherRoot
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; if root is in range, finalize calculations
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jmpu true, calcSphereFin
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calcSphereCheckOtherRoot:
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; float root = (-halfB + sqrtDiscriminant) / a
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add r9.z, -r9.y, r8.w
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mul r9.z, r9.z, r9.x
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; if root < min distance, check other root
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cmp near, gt, gt, r9.z
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jmpc cmp.x, calcSphereExit
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; if root > max distance, check other root
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cmp r9.z, gt, gt, r4.w
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jmpc cmp.x, calcSphereExit
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calcSphereFin:
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; change max distance to closest hit
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mov r4.w, r9.z
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; calculate new origin
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mul r5.xyz, r2.xyz, r9.zzz
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add r5.xyz, r5.xyz, r1.xyz
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; calculate normal
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add r7.xyz, r5.xyz, -r3.xyz
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rcp r3.w, r3.w
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mul r7.xyz, r7.xyz, r3.w
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; set albedo
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mov r10.xyz, sphereColors[aL].xyz
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; set light emitted
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mov r12.xyz, sphereLights[aL].xyz
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; early exit label
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calcSphereExit:
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nop
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.end
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.proc diffuse
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add r2.xyz, r7.xyz, r11.xyz
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.end |