LNXSDK/leenkx/Shaders/std/gbuffer.glsl

#ifndef _GBUFFER_GLSL_
#define _GBUFFER_GLSL_

vec2 octahedronWrap(const vec2 v) {
	return (1.0 - abs(v.yx)) * (vec2(v.x >= 0.0 ? 1.0 : -1.0, v.y >= 0.0 ? 1.0 : -1.0));
}

vec3 getNor(const vec2 enc) {
	vec3 n;
	n.z = 1.0 - abs(enc.x) - abs(enc.y);
	n.xy = n.z >= 0.0 ? enc.xy : octahedronWrap(enc.xy);
	n = normalize(n);
	return n;
}

vec3 getPosView(const vec3 viewRay, const float depth, const vec2 cameraProj) {
	float linearDepth = cameraProj.y / (cameraProj.x - depth);
	//float linearDepth = cameraProj.y / ((depth * 0.5 + 0.5) - cameraProj.x);
	return viewRay * linearDepth;
}

vec3 getPos(const vec3 eye, const vec3 eyeLook, const vec3 viewRay, const float depth, const vec2 cameraProj) {
	// eyeLook, viewRay should be normalized
	float linearDepth = cameraProj.y / ((depth * 0.5 + 0.5) - cameraProj.x);
	float viewZDist = dot(eyeLook, viewRay);
	vec3 wposition = eye + viewRay * (linearDepth / viewZDist);
	return wposition;
}

vec3 getPosNoEye(const vec3 eyeLook, const vec3 viewRay, const float depth, const vec2 cameraProj) {
	// eyeLook, viewRay should be normalized
	float linearDepth = cameraProj.y / ((depth * 0.5 + 0.5) - cameraProj.x);
	float viewZDist = dot(eyeLook, viewRay);
	vec3 wposition = viewRay * (linearDepth / viewZDist);
	return wposition;
}

#if defined(HLSL) || defined(METAL)
vec3 getPos2(const mat4 invVP, const float depth, vec2 coord) {
	coord.y = 1.0 - coord.y;
#else
vec3 getPos2(const mat4 invVP, const float depth, const vec2 coord) {
#endif
	vec4 pos = vec4(coord * 2.0 - 1.0, depth, 1.0);
	pos = invVP * pos;
	pos.xyz /= pos.w;
	return pos.xyz;
}

#if defined(HLSL) || defined(METAL)
vec3 getPosView2(const mat4 invP, const float depth, vec2 coord) {
	coord.y = 1.0 - coord.y;
#else
vec3 getPosView2(const mat4 invP, const float depth, const vec2 coord) {
#endif
	vec4 pos = vec4(coord * 2.0 - 1.0, depth, 1.0);
	pos = invP * pos;
	pos.xyz /= pos.w;
	return pos.xyz;
}

#if defined(HLSL) || defined(METAL)
vec3 getPos2NoEye(const vec3 eye, const mat4 invVP, const float depth, vec2 coord) {
	coord.y = 1.0 - coord.y;
#else
vec3 getPos2NoEye(const vec3 eye, const mat4 invVP, const float depth, const vec2 coord) {
#endif
	vec4 pos = vec4(coord * 2.0 - 1.0, depth, 1.0);
	pos = invVP * pos;
	pos.xyz /= pos.w;
	return pos.xyz - eye;
}

float packFloat(const float f1, const float f2) {
	return floor(f1 * 100.0) + min(f2, 1.0 - 1.0 / 100.0);
}

vec2 unpackFloat(const float f) {
	return vec2(floor(f) / 100.0, fract(f));
}

float packFloat2(const float f1, const float f2) {
	// Higher f1 = less precise f2
	return floor(f1 * 255.0) + min(f2, 1.0 - 1.0 / 100.0);
}

vec2 unpackFloat2(const float f) {
	return vec2(floor(f) / 255.0, fract(f));
}

vec4 encodeRGBM(const vec3 rgb) {
	const float maxRange = 6.0;
	float maxRGB = max(rgb.x, max(rgb.g, rgb.b));
	float m = maxRGB / maxRange;
	m = ceil(m * 255.0) / 255.0;
	return vec4(rgb / (m * maxRange), m);
}

vec3 decodeRGBM(const vec4 rgbm) {
	const float maxRange = 6.0;
	return rgbm.rgb * rgbm.a * maxRange;
}

vec2 signNotZero(vec2 v)
{
	return vec2((v.x >= 0.0) ? +1.0 : -1.0, (v.y >= 0.0) ? +1.0 : -1.0);
}

vec2 encode_oct(vec3 v)
{
	// Project the sphere onto the octahedron, and then onto the xy plane
	vec2 p = v.xy * (1.0 / (abs(v.x) + abs(v.y) + abs(v.z)));
	// Reflect the folds of the lower hemisphere over the diagonals
	return (v.z <= 0.0) ? ((1.0 - abs(p.yx)) * signNotZero(p)) : p;
}

vec3 decode_oct(vec2 e)
{
	vec3 v = vec3(e.xy, 1.0 - abs(e.x) - abs(e.y));
	if (v.z < 0) v.xy = (1.0 - abs(v.yx)) * signNotZero(v.xy);
	return normalize(v);
}

uint encNor(vec3 n) {
	ivec3 nor = ivec3(n * 255.0f);
	uvec3 norSigns;
	norSigns.x = (nor.x >> 5) & 0x04000000;
	norSigns.y = (nor.y >> 14) & 0x00020000;
	norSigns.z = (nor.z >> 23) & 0x00000100;
	nor = abs(nor);
	uint val = norSigns.x | (nor.x << 18) | norSigns.y | (nor.y << 9) | norSigns.z | nor.z;
	return val;
}

vec3 decNor(uint val) {
	uvec3 nor;
	nor.x = (val >> 18) & 0x000000ff;
	nor.y = (val >> 9) & 0x000000ff;
	nor.z = val & 0x000000ff;
	uvec3 norSigns;
	norSigns.x = (val >> 25) & 0x00000002;
	norSigns.y = (val >> 16) & 0x00000002;
	norSigns.z = (val >> 7) & 0x00000002;
	norSigns = 1 - norSigns;
	vec3 normal = vec3(nor) / 255.0f;
	normal *= norSigns;
	return normal;
}

/**
	Packs a float in [0, 1] and an integer in [0..15] into a single 16 bit float value.
**/
float packFloatInt16(const float f, const uint i) {
	const uint numBitFloat = 12;
	const float maxValFloat = float((1 << numBitFloat) - 1);

	const uint bitsInt = i << numBitFloat;
	const uint bitsFloat = uint(f * maxValFloat);

	return float(bitsInt | bitsFloat);
}

void unpackFloatInt16(const float val, out float f, out uint i) {
	const uint numBitFloat = 12;
	const float maxValFloat = float((1 << numBitFloat) - 1);

	const uint bitsValue = uint(val);

	i = bitsValue >> numBitFloat;
	f = (bitsValue & ~(0xF << numBitFloat)) / maxValFloat;
}

#endif