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Spoiler:Here's a water warping shader from ShaderToy which I converted for use in GZDoom... it looks amazing and I really like how it looks, but its execution time is absolutely murderous (almost 10 ms!!! Even the heaviest pass, the SSAO, is only 0.9 ms by comparison). What can be done to make this faster, while still retaining this look?Code: Select all
// https://www.shadertoy.com/view/XtsSzN vec3 mod289(vec3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } vec4 mod289(vec4 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } vec4 permute(vec4 x) { return mod289(((x * 34.0) + 1.0) * x); } vec4 taylorInvSqrt(vec4 r) { return 1.79284291400159 - 0.85373472095314 * r; } float snoise(vec3 v) { const vec2 C = vec2(1.0 / 6.0, 1.0 / 3.0) ; const vec4 D = vec4(0.0, 0.5, 1.0, 2.0); // First corner vec3 i = floor(v + dot(v, C.yyy)); vec3 x0 = v - i + dot(i, C.xxx); // Other corners vec3 g = step(x0.yzx, x0.xyz); vec3 l = 1.0 - g; vec3 i1 = min( g.xyz, l.zxy ); vec3 i2 = max( g.xyz, l.zxy ); // x0 = x0 - 0.0 + 0.0 * C.xxx; // x1 = x0 - i1 + 1.0 * C.xxx; // x2 = x0 - i2 + 2.0 * C.xxx; // x3 = x0 - 1.0 + 3.0 * C.xxx; vec3 x1 = x0 - i1 + C.xxx; vec3 x2 = x0 - i2 + C.yyy; // 2.0 * C.x = 1/3 = C.y vec3 x3 = x0 - D.yyy; // -1.0 + 3.0 * C.x = -0.5 = -D.y // Permutations i = mod289(i); vec4 p = permute(permute(permute( i.z + vec4(0.0, i1.z, i2.z, 1.0)) + i.y + vec4(0.0, i1.y, i2.y, 1.0)) + i.x + vec4(0.0, i1.x, i2.x, 1.0)); // Gradients: 7x7 points over a square, mapped onto an octahedron. // The ring size 17 * 17 = 289 is close to a multiple of 49 (49 * 6 = 294) float n_ = 0.142857142857; // 1.0 / 7.0 vec3 ns = n_ * D.wyz - D.xzx; vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p, 7 * 7) vec4 x_ = floor(j * ns.z); vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N) vec4 x = x_ * ns.x + ns.yyyy; vec4 y = y_ * ns.x + ns.yyyy; vec4 h = 1.0 - abs(x) - abs(y); vec4 b0 = vec4(x.xy, y.xy); vec4 b1 = vec4(x.zw, y.zw); //vec4 s0 = vec4(lessThan(b0, 0.0)) * 2.0 - 1.0; //vec4 s1 = vec4(lessThan(b1, 0.0)) * 2.0 - 1.0; vec4 s0 = floor(b0) * 2.0 + 1.0; vec4 s1 = floor(b1) * 2.0 + 1.0; vec4 sh = -step(h, vec4(0.0)); vec4 a0 = b0.xzyw + s0.xzyw * sh.xxyy; vec4 a1 = b1.xzyw + s1.xzyw * sh.zzww; vec3 p0 = vec3(a0.xy, h.x); vec3 p1 = vec3(a0.zw, h.y); vec3 p2 = vec3(a1.xy, h.z); vec3 p3 = vec3(a1.zw, h.w); // Normalise gradients vec4 norm = taylorInvSqrt(vec4(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3))); p0 *= norm.x; p1 *= norm.y; p2 *= norm.z; p3 *= norm.w; // Mix final noise value vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), 0.0); m = m * m; return 42.0 * dot(m * m, vec4(dot(p0,x0), dot(p1,x1), dot(p2,x2), dot(p3,x3))); } float fBm(vec3 coords) { const int octaves = 2; float smoothness = 2.0; // should be between 0.0 and 1.0? float lacunarity = 2.0; float result = 0.0; float totalAmplitude = 0.0; for (int o = 0; o != octaves; ++o) { float amplitude = pow(lacunarity, -smoothness * float(o)); result += snoise(coords) * amplitude; totalAmplitude += amplitude; coords *= lacunarity; } return result / totalAmplitude; } float turbulence(vec3 coords) { const float f_low = 1.0; const int octaves = 8; float t = 0.0; for (int o = 0; o != octaves; ++o) { float f = f_low * pow(2.0, float(o)); t += abs(snoise(coords)) / f; coords *= 2.0; } return t; // - 0.3; } void main() { vec2 texSize = textureSize(InputTexture, 0); float time_scale = 0.0035; float time = timer * time_scale; vec2 uv = TexCoord; vec2 fbm_scale = vec2(1.0); vec2 t_scale = vec2(5.0); vec2 x_offset = vec2(123.456, 0.0); vec2 y_offset = vec2(349.234, 1704.2); vec2 x_coords = (uv + x_offset) * fbm_scale; float xo = fBm(vec3(x_coords, time)); vec2 tx_coords = (uv + x_offset) * t_scale; float xt = turbulence(vec3(tx_coords, time)); vec2 y_coords = (uv + y_offset) * fbm_scale; float yo = fBm(vec3(y_coords, time)); vec2 ty_coords = (uv + y_offset) * t_scale; float yt = turbulence(vec3(ty_coords, time)); vec2 pixel = 1.0 / texSize.xy; float max_po = 30.0; vec2 po = max_po * vec2(xo + xt, yo + yt) * pixel; vec3 bg = texture(InputTexture, uv + po).rgb; FragColor = vec4(vec3(bg), 1.0); }
EDIT: I suspect the "vec3 bg" line is the slowest because of the way it's getting the input pixel sample but I don't know...
