Replacing Shader Code for FMA

src/shaders/main.glsl

@@ -194,22 +194,20 @@ vec3 get_normal(vec2 uv, out vec3 tangent, out vec3 binormal) {
 }
 
 vec3 unpack_normal(vec4 rgba) {
-	vec3 n = rgba.xzy * 2.0 - vec3(1.0);
-	n.z *= -1.0;
+	vec3 n = fma(rgba.xzy, vec3(2.0, 2.0, -2.0), vec3(-1.0, -1.0, 1.0));
 	return n;
 }
 
 vec4 pack_normal(vec3 n, float a) {
-	n.z *= -1.0;
-	return vec4((n.xzy + vec3(1.0)) * 0.5, a);
+	return vec4(fma(n.xzy, vec3(0.5, -0.5, 0.5), vec3(0.5)), a);
 }
 
 float random(in vec2 xy) {
 	return fract(sin(dot(xy, vec2(12.9898, 78.233))) * 43758.5453);
 }
 
 vec2 rotate(vec2 v, float cosa, float sina) {
-	return vec2(cosa * v.x - sina * v.y, sina * v.x + cosa * v.y);
+	return vec2(fma(cosa, v.x, - sina * v.y), fma(sina, v.x, cosa * v.y));
 }
 
 // Moves a point around a pivot point.
@@ -224,7 +222,7 @@ vec4 height_blend(vec4 a_value, float a_height, vec4 b_value, float b_height, fl
 		float ma = max(a_height + (1.0 - blend), b_height + blend) - (1.001 - blend_sharpness);
 	    float b1 = max(a_height + (1.0 - blend) - ma, 0.0);
 	    float b2 = max(b_height + blend - ma, 0.0);
-	    return (a_value * b1 + b_value * b2) / (b1 + b2);
+	    return fma(a_value, vec4(b1), b_value * b2) / (b1 + b2);
 	} else {
 		float contrast = 1.0 - blend_sharpness;
 		float factor = (blend - contrast) / contrast;
@@ -235,7 +233,7 @@ vec4 height_blend(vec4 a_value, float a_height, vec4 b_value, float b_height, fl
 vec2 detiling(vec2 uv, vec2 uv_center, int mat_id, inout float normal_rotation){
 	if (_texture_detile_array[mat_id] >= 0.001){
 		uv_center = floor(uv_center) + 0.5;
-		float detile = (random(uv_center) - 0.5) * 2.0 * TAU * _texture_detile_array[mat_id]; // -180deg to 180deg
+		float detile = fma(random(uv_center), 2.0, -1.0) * TAU * _texture_detile_array[mat_id]; // -180deg to 180deg
 		uv = rotate_around(uv, uv_center, detile);
 		// Accumulate total rotation for normal rotation
 		normal_rotation += detile;
@@ -244,9 +242,9 @@ vec2 detiling(vec2 uv, vec2 uv_center, int mat_id, inout float normal_rotation){
 }
 
 vec2 rotate_normal(vec2 normal, float angle) {
-	angle += PI * 0.5;
+	angle = fma(PI, 0.5, angle);
 	float new_y = dot(vec2(cos(angle), sin(angle)), normal);
-	angle -= PI * 0.5;
+	angle = fma(PI, -0.5, angle);
 	float new_x = dot(vec2(cos(angle) ,sin(angle)) ,normal);
 	return vec2(new_x, new_y);
 }
@@ -326,7 +324,7 @@ void get_material(vec2 base_uv, uint control, ivec3 iuv_center, vec3 normal, out
 float blend_weights(float weight, float detail) {
 	weight = smoothstep(0.0, 1.0, weight);
 	weight = sqrt(weight * 0.5);
-	float result = max(0.1 * weight, 10.0 * (weight + detail) + 1.0f - (detail + 10.0));
+	float result = max(0.1 * weight, fma(10.0, (weight + detail), 1.0f - (detail + 10.0)));
 	return result;
 }
 

src/shaders/world_noise.glsl

@@ -40,15 +40,15 @@ float hashf(float f) {
 }
 
 float hashv2(vec2 v) {
-	return fract(1e4 * sin(17.0 * v.x + v.y * 0.1) * (0.1 + abs(sin(v.y * 13.0 + v.x))));
+	return fract(1e4 * sin(fma(17.0, v.x, v.y * 0.1)) * (0.1 + abs(sin(fma(v.y, 13.0, v.x)))));
 }
 
 // https://iquilezles.org/articles/morenoise/
 vec3 noise2D(vec2 x) {
     vec2 f = fract(x);
     // Quintic Hermine Curve.  Similar to SmoothStep()
-    vec2 u = f*f*f*(f*(f*6.0-15.0)+10.0);
-    vec2 du = 30.0*f*f*(f*(f-2.0)+1.0);
+    vec2 u = f * f * f * fma(f, fma(f, vec2(6.0), vec2(-15.0)), vec2(10.0));
+    vec2 du = 30.0 * f * f * fma(f, (f - 2.0), vec2(1.0));
 
     vec2 p = floor(x);
 
@@ -63,8 +63,8 @@ vec3 noise2D(vec2 x) {
     float k1 =   b - a;
     float k2 =   c - a;
     float k3 =   a - b - c + d;
-    return vec3( k0 + k1 * u.x + k2 * u.y + k3 * u.x * u.y,
-                du * ( vec2(k1, k2) + k3 * u.yx) );
+    return vec3( fma(k3, u.x * u.y, fma(u.y, k2, fma(k1, u.x, k0))),
+		du * fma(u.yx, vec2(k3), vec2(k1, k2)) );
 }
 
 float world_noise(vec2 p) {