Math fixes, SSR enhancements, improved precision and image sharpness, moved envmap into its own shader to improve SSR realism. Various improvements.

leenkx/Shaders/std/environment_sample.glsl

@@ -0,0 +1,28 @@
+#ifndef _ENVIRONMENT_SAMPLE_GLSL_
+#define _ENVIRONMENT_SAMPLE_GLSL_
+
+// Sample diffuse ambient environment lighting (irradiance)
+vec3 sampleDiffuseEnvironment(vec3 normal) {
+#ifdef _Irr
+    vec3 envl = shIrradiance(normal, shirr);
+
+    #ifdef _EnvTex
+    envl /= PI;
+    #endif
+
+    return envl;
+#else
+    return vec3(0.0);
+#endif
+}
+
+// Sample specular environment reflection (skybox or cubemap)
+vec3 sampleSpecularEnvironment(vec3 viewDir, float roughness) {
+#ifdef _EnvTex
+    return textureLod(texEnvironment, viewDir, roughness * 8.0).rgb;
+#else
+    return vec3(0.0);
+#endif
+}
+
+#endif

leenkx/Shaders/std/gbuffer.glsl

@@ -109,8 +109,10 @@ vec2 encode_oct(vec3 v) {
 
 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);
+    if (v.z < 0.0) {
+        v.xy = (1.0 - abs(v.yx)) * (vec2(v.x >= 0.0 ? 1.0 : -1.0, v.y >= 0.0 ? 1.0 : -1.0));
+    }
+    return normalize(v);
 }
 
 uint encNor(vec3 n) {

leenkx/Shaders/std/math.glsl

@@ -7,6 +7,12 @@ float hash(const vec2 p) {
 	return fract(sin(h) * 43758.5453123);
 }
 
+float hash12(vec2 p) {
+    vec3 p3  = fract(vec3(p.xyx) * 0.1031);
+    p3 += dot(p3, p3.yzx + 33.33);
+    return fract((p3.x + p3.y) * p3.z);
+}
+
 vec2 envMapEquirect(const vec3 normal) {
 	const float PI = 3.1415926535;
 	const float PI2 = PI * 2.0;
@@ -27,9 +33,9 @@ vec2 rand2(const vec2 coord) {
 	return vec2(noiseX, noiseY);
 }
 
-float linearize(const float depth, vec2 cameraProj) {
-	// to viewz
-	return cameraProj.y / (depth - cameraProj.x);
+float linearize(float depth, vec2 cameraProj) {
+    depth = depth * 2.0 - 1.0;
+    return cameraProj.y / (cameraProj.x - depth);
 }
 
 float attenuate(const float dist) {