31 lines
1.0 KiB
NASM
31 lines
1.0 KiB
NASM
; CONST[0] = {rotate, _, _, _}
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; CONST[1] = {0.159155, 0.5, 6.283185, -3.141593}
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; each instruction is only allowed to use a single unique `const` address
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;
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; instructions may use multiple `temp` addresses, so const[0] is moved to
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; temp[0]:
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;
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temp[0].x = VE_ADD const[1].x___ const[1].0___
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; ME_SIN and ME_COS are clamped to the range -π to +π prior to the sin/cos
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; calculation.
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;
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; This 3-instruction sequence linearly remaps the range [-∞,+∞] to [-π,+π]
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temp[1].x = VE_MAD temp[0].x___ const[0].x___ const[0].y___
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temp[2].x = VE_FRC temp[1].x___
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temp[3].x = VE_MAD temp[2].x___ const[0].z___ const[0].w___
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temp[4].x = ME_SIN temp[3].___x
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temp[4].y = ME_COS temp[3].___x
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; with sin and cos calculated, this now ordinary two-dimensional rotation:
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;
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; x = position.x * cost - position.y * sint
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; y = position.x * sint + position.y * cost
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; z = 0
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; w = 1
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temp[5].xy = VE_MUL input[0].yy__ temp[4].xy__
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out[0].xyzw = VE_MAD input[0].xx01 temp[4].yx01 temp[5].-xy00
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