librw/tools/ps2test/vu/setup_persp.vu

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2017-08-12 20:24:19 +01:00
/* This is the the projection matrix we start with:
* 1/2w 0 ox/2w + 1/2 -ox/2w
* 0 -1/2h -oy/2h + 1/2 oy/2h
* 0 0 1 0
* 0 0 1 0
* To get rid of the +1/2 in the combined matrix we
* subtract the z-row/2 from the x- and y-rows.
*
* The z-row is then set to [0 0 0 1] such that multiplication
* by XYZscale gives [0 0 0 zScale]. After perspective division
* and addition of XYZoffset we then get zScale/w + zShift for z.
*
* XYZScale scales xy to the resolution and z by zScale.
* XYZOffset translates xy to the GS coordinate system (where
* [2048, 2048] is the center of the frame buffer) and add zShift to z.
*/
; constant:
; VF28-VF31 transformation matrix
; VF25 XYZ offset
SUB.z VF28, VF28, VF28 LOI 0.5 ; right.z = 0
SUB.z VF29, VF29, VF29 LQ VF28, matrix(VI00) ; up.z = 0 - load matrix
SUB.z VF30, VF30, VF30 LQ VF29, matrix+1(VI00) ; at.z = 0 - load matrix
ADDw.z VF31, VF00, VF00 LQ VF30, matrix+2(VI00) ; at.z = 1 - load matrix
NOP LQ VF31, matrix+3(VI00) ; - load matrix
MULi.w VF20, VF28, I LQ.xyz VF01, XYZScale(VI00) ; fix matrix - load scale
MULi.w VF21, VF29, I NOP ; fix matrix
MULi.w VF22, VF30, I NOP ; fix matrix
MULi.w VF23, VF31, I NOP ; fix matrix
SUBw.xy VF28, VF28, VF20 NOP ; fix matrix
SUBw.xy VF29, VF29, VF21 NOP ; fix matrix
SUBw.xy VF30, VF30, VF22 NOP ; fix matrix
SUBw.xy VF31, VF31, VF23 NOP ; fix matrix
MUL.xy VF28, VF28, VF01 LQ.xyz VF25, XYZOffset(VI00) ; scale matrix
MUL.xy VF29, VF29, VF01 IADDIU VI12, VI00, outBuf1 ; scale matrix
MUL.xy VF30, VF30, VF01 IADDIU VI13, VI00, outBuf2 ; scale matrix
MUL.xyz VF31, VF31, VF01 NOP ; scale matrix