;;; Register usage:
;; vf20		light color
;; vf21		light direction
;; vf23		surfaceProps

Lighting:
	nop				iaddiu vi08,vi00,light
	nop				lq vf23,surfaceProps(vi00)
LightLoop:
	nop				ilw.w vi15,0(vi08)		; load light type
	nop				lqi.xyz vf20,(vi08++)		; light color
	nop				ibeq vi15,vi00,PostLighting
	nop				nop
	nop				iaddiu vi15,vi15,LightSwitch
	nop				jr vi15
LightSwitch:
	;; Light type dispatch table
	nop				nop
	nop				b AmbientLight
	nop				nop
	nop				b DirectLight
	nop				lqi.xyz vf21,(vi08++)		; light direction

;; Apply Ambient light
AmbientLight:
	mulx.xyz vf20,vf20,vf23		xtop vi02			; multiply color by surfProps - input pointer
	nop				xitop vi01			; vertex count
AmbientLoop:
	nop				lq vf02,2(vi02)			; load rgba
	nop				nop
	nop				nop
	nop				nop
	add.xyz vf02,vf02,vf20		nop
	nop				isubiu vi01,vi01,1
	nop				nop
	nop				nop
	nop				sq vf02,2(vi02)			; store rgba
	nop				ibne vi01,vi00,AmbientLoop
	nop				iaddiu vi02,vi02,numInAttribs
	nop				b LightLoop
	nop				nop

;; Apply Directional light
DirectLight:
	mulz.xyz vf20,vf20,vf23		xtop vi02			; multiply color by surfProps - input pointer
	nop				xitop vi01			; vertex count
	nop				nop
	sub.xyz vf21,vf00,vf21		nop				; flip light direction
DirectLoop:
	nop				lq.xyz vf03,3(vi02)		; load normal
	nop				lq vf02,2(vi02)			; load rgba
	nop				nop
	nop				nop
	mul.xyz vf01,vf03,vf21		nop				; normal*direction
	nop				nop
	nop				nop
	nop				nop
	addy.x vf01,vf01,vf01		nop
	nop				nop
	nop				nop
	nop				nop
	addz.x vf01,vf01,vf01		nop
	nop				nop
	nop				nop
	nop				nop
	maxx vf01,vf01,vf00		nop				; clamp light factor
	nop				nop
	nop				nop
	addax acc,vf02,vf00		nop
	maddx vf02,vf20,vf01		nop				; accumulate
	nop				isubiu vi01,vi01,1
	nop				nop
	nop				nop
	nop				sq vf02,2(vi02)			; store rgba
	nop				ibne vi01,vi00,DirectLoop
	nop				iaddiu vi02,vi02,numInAttribs
	nop				b LightLoop
	nop				nop

;;; Clamp lighting and multiply by material color
PostLighting:
	nop				xtop vi02			; input pointer
	nop				xitop vi01			; vertex count
PostLightLoop:
	nop				lq vf02,2(vi02)			; load rgba
	nop				nop
	nop				nop
	nop				loi 255.0
	minii vf02,vf02,i		nop
	nop				nop
	nop				nop
	nop				nop
	mul vf02,vf02,vf25		nop				; scale color
	nop				isubiu vi01,vi01,1
	nop				nop
	nop				nop
	nop				sq vf02,2(vi02)			; store rgba
	nop				ibne vi01,vi00,PostLightLoop
	nop				iaddiu vi02,vi02,numInAttribs