X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Fnoise.cpp;h=e6ca8a4951cf669c8312275f2b859fc34d2f1297;hb=b5f7249a7edc25077d84b27b38552228b92ff763;hp=b1b7025383c99ec9550e644d2735a42e187ad119;hpb=d198e420ec54be47fe2285b3205953282ec06742;p=oweals%2Fminetest.git diff --git a/src/noise.cpp b/src/noise.cpp index b1b702538..e6ca8a495 100644 --- a/src/noise.cpp +++ b/src/noise.cpp @@ -47,8 +47,8 @@ typedef float (*Interp3dFxn)( float x, float y, float z); float cos_lookup[16] = { - 1.0, 0.9238, 0.7071, 0.3826, 0, -0.3826, -0.7071, -0.9238, - 1.0, -0.9238, -0.7071, -0.3826, 0, 0.3826, 0.7071, 0.9238 + 1.0f, 0.9238f, 0.7071f, 0.3826f, .0f, -0.3826f, -0.7071f, -0.9238f, + 1.0f, -0.9238f, -0.7071f, -0.3826f, .0f, 0.3826f, 0.7071f, 0.9238f }; FlagDesc flagdesc_noiseparams[] = { @@ -93,23 +93,32 @@ u32 PcgRandom::range(u32 bound) // If the bound is 0, we cover the whole RNG's range if (bound == 0) return next(); + /* - If the bound is not a multiple of the RNG's range, it may cause bias, - e.g. a RNG has a range from 0 to 3 and we take want a number 0 to 2. - Using rand() % 3, the number 0 would be twice as likely to appear. - With a very large RNG range, the effect becomes less prevalent but - still present. This can be solved by modifying the range of the RNG - to become a multiple of bound by dropping values above the a threshhold. - In our example, threshhold == 4 - 3 = 1 % 3 == 1, so reject 0, thus - making the range 3 with no bias. - - This loop looks dangerous, but will always terminate due to the - RNG's property of uniformity. + This is an optimization of the expression: + 0x100000000ull % bound + since 64-bit modulo operations typically much slower than 32. */ - u32 threshhold = -bound % bound; + u32 threshold = -bound % bound; u32 r; - while ((r = next()) < threshhold) + /* + If the bound is not a multiple of the RNG's range, it may cause bias, + e.g. a RNG has a range from 0 to 3 and we take want a number 0 to 2. + Using rand() % 3, the number 0 would be twice as likely to appear. + With a very large RNG range, the effect becomes less prevalent but + still present. + + This can be solved by modifying the range of the RNG to become a + multiple of bound by dropping values above the a threshold. + + In our example, threshold == 4 % 3 == 1, so reject values < 1 + (that is, 0), thus making the range == 3 with no bias. + + This loop may look dangerous, but will always terminate due to the + RNG's property of uniformity. + */ + while ((r = next()) < threshold) ; return r % bound; @@ -121,7 +130,9 @@ s32 PcgRandom::range(s32 min, s32 max) if (max < min) throw PrngException("Invalid range (max < min)"); - u32 bound = max - min + 1; + // We have to cast to s64 because otherwise this could overflow, + // and signed overflow is undefined behavior. + u32 bound = (s64)max - (s64)min + 1; return range(bound) + min; } @@ -156,7 +167,7 @@ s32 PcgRandom::randNormalDist(s32 min, s32 max, int num_trials) /////////////////////////////////////////////////////////////////////////////// -float noise2d(int x, int y, int seed) +float noise2d(int x, int y, s32 seed) { unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_SEED * seed) & 0x7fffffff; @@ -166,7 +177,7 @@ float noise2d(int x, int y, int seed) } -float noise3d(int x, int y, int z, int seed) +float noise3d(int x, int y, int z, s32 seed) { unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z + NOISE_MAGIC_SEED * seed) & 0x7fffffff; @@ -235,7 +246,7 @@ float triLinearInterpolationNoEase( return linearInterpolation(u, v, z); } -float noise2d_gradient(float x, float y, int seed, bool eased) +float noise2d_gradient(float x, float y, s32 seed, bool eased) { // Calculate the integer coordinates int x0 = myfloor(x); @@ -256,7 +267,7 @@ float noise2d_gradient(float x, float y, int seed, bool eased) } -float noise3d_gradient(float x, float y, float z, int seed, bool eased) +float noise3d_gradient(float x, float y, float z, s32 seed, bool eased) { // Calculate the integer coordinates int x0 = myfloor(x); @@ -290,7 +301,7 @@ float noise3d_gradient(float x, float y, float z, int seed, bool eased) } -float noise2d_perlin(float x, float y, int seed, +float noise2d_perlin(float x, float y, s32 seed, int octaves, float persistence, bool eased) { float a = 0; @@ -306,7 +317,7 @@ float noise2d_perlin(float x, float y, int seed, } -float noise2d_perlin_abs(float x, float y, int seed, +float noise2d_perlin_abs(float x, float y, s32 seed, int octaves, float persistence, bool eased) { float a = 0; @@ -321,7 +332,7 @@ float noise2d_perlin_abs(float x, float y, int seed, } -float noise3d_perlin(float x, float y, float z, int seed, +float noise3d_perlin(float x, float y, float z, s32 seed, int octaves, float persistence, bool eased) { float a = 0; @@ -336,7 +347,7 @@ float noise3d_perlin(float x, float y, float z, int seed, } -float noise3d_perlin_abs(float x, float y, float z, int seed, +float noise3d_perlin_abs(float x, float y, float z, s32 seed, int octaves, float persistence, bool eased) { float a = 0; @@ -363,7 +374,7 @@ float contour(float v) ///////////////////////// [ New noise ] //////////////////////////// -float NoisePerlin2D(NoiseParams *np, float x, float y, int seed) +float NoisePerlin2D(NoiseParams *np, float x, float y, s32 seed) { float a = 0; float f = 1.0; @@ -389,7 +400,7 @@ float NoisePerlin2D(NoiseParams *np, float x, float y, int seed) } -float NoisePerlin3D(NoiseParams *np, float x, float y, float z, int seed) +float NoisePerlin3D(NoiseParams *np, float x, float y, float z, s32 seed) { float a = 0; float f = 1.0; @@ -416,7 +427,7 @@ float NoisePerlin3D(NoiseParams *np, float x, float y, float z, int seed) } -Noise::Noise(NoiseParams *np_, int seed, u32 sx, u32 sy, u32 sz) +Noise::Noise(NoiseParams *np_, s32 seed, u32 sx, u32 sy, u32 sz) { memcpy(&np, np_, sizeof(np)); this->seed = seed; @@ -424,10 +435,6 @@ Noise::Noise(NoiseParams *np_, int seed, u32 sx, u32 sy, u32 sz) this->sy = sy; this->sz = sz; - this->persist_buf = NULL; - this->gradient_buf = NULL; - this->result = NULL; - allocBuffers(); } @@ -543,7 +550,7 @@ void Noise::resizeNoiseBuf(bool is3d) void Noise::gradientMap2D( float x, float y, float step_x, float step_y, - int seed) + s32 seed) { float v00, v01, v10, v11, u, v, orig_u; u32 index, i, j, noisex, noisey; @@ -607,7 +614,7 @@ void Noise::gradientMap2D( void Noise::gradientMap3D( float x, float y, float z, float step_x, float step_y, float step_z, - int seed) + s32 seed) { float v000, v010, v100, v110; float v001, v011, v101, v111;