GTAONode: Potentially fix getViewPosition().

[Mugen87]

Related issue: -

Description

When working at SSRNode, I've realized that the current TSL version of getViewPosition() is implemented differently. In the original version, the * 2.0 - 1.0 is applied to all vector components, not just x and y.

Can we please determine which math is correct? If the original is wrong, we should fix the GLSL.

For comparison:

three.js/examples/jsm/shaders/GTAOShader.js

Lines 109 to 113 in 36ae025

	vec3 getViewPosition(const in vec2 screenPosition, const in float depth) {
	vec4 clipSpacePosition = vec4(vec3(screenPosition, depth) * 2.0 - 1.0, 1.0);
	vec4 viewSpacePosition = cameraProjectionMatrixInverse * clipSpacePosition;
	return viewSpacePosition.xyz / viewSpacePosition.w;
	}

[Mugen87]

Ah wait, now I remember: #28844 (comment)