cellular sim deterministic work

.vscode/settings.json

@@ -36,6 +36,8 @@
         "dispatcher.h": "c",
         "cellular.h": "c",
         "limits": "c",
-        "boundsolver.h": "c"
+        "boundsolver.h": "c",
+        "randutils.h": "c",
+        "mathutils.h": "c"
     }
 }

docs/src/progress/renderertodo.md

@@ -1265,6 +1265,8 @@ Add hard walls to bounds solver
 Cellular bounds transfer properly
 Fluid chunk terrain bounds transfer
 Cellular transfer behavior work
+Native math utils
+Frame tracking on native side
 
 
 # TODO

src/main/c/includes/fluid/env/environment.h

@@ -71,7 +71,8 @@ typedef struct {
     double existingDensity;
     double newDensity;
     float normalizationRatio;
-} FluidDensityTracking;
+    int frame;
+} FluidSimState;
 
 /**
  * Stores data about the simulation environment
@@ -80,7 +81,7 @@ typedef struct {
     JNILookupTable lookupTable;
     FluidSimQueue queue;
     FluidSimConsts consts;
-    FluidDensityTracking densityTracking;
+    FluidSimState state;
 } Environment;
 
 /**

src/main/c/includes/math/mathutils.h

@@ -0,0 +1,23 @@
+#ifndef MATHUTILS_H
+#define MATHUTILS_H
+
+#include "public.h"
+
+
+/**
+ * Calculates the fractional component of a float
+ */
+LIBRARY_API float fract(float x);
+
+/**
+ * Calculates the dot product of 2D vectors
+ */
+LIBRARY_API float dot2(float x1, float y1, float x2, float y2);
+
+/**
+ * Calculates the dot product of 3D vectors
+ */
+LIBRARY_API float dot3(float x1, float y1, float z1, float x2, float y2, float z2);
+
+
+#endif

src/main/c/includes/math/randutils.h

@@ -0,0 +1,28 @@
+#ifndef RANDUTILS_H
+#define RANDUTILS_H
+
+#include "public.h"
+
+
+/**
+ * Generates a random number given a seed value
+ */
+LIBRARY_API float randutils_rand1(float x);
+
+/**
+ * Generates a random number given two seed values
+ */
+LIBRARY_API float randutils_rand2(float x, float y);
+
+/**
+ * Generates a random number given three seed values
+ */
+LIBRARY_API float randutils_rand3(float x, float y, float z);
+
+/**
+ * Maps a float of range [0,1] to an integer range
+ */
+LIBRARY_API float randutils_map(float x, int min, int max);
+
+
+#endif

src/main/c/src/fluid/queue/javainterface.c

@@ -100,9 +100,10 @@ JNIEXPORT void JNICALL Java_electrosphere_server_fluid_simulator_FluidAccelerate
 
     //store variables from java side
     environment->consts.gravity = gravity;
-    environment->densityTracking.existingDensity = 0;
-    environment->densityTracking.newDensity = 0;
-    environment->densityTracking.normalizationRatio = 0;
+    environment->state.existingDensity = 0;
+    environment->state.newDensity = 0;
+    environment->state.normalizationRatio = 0;
+    environment->state.frame = 0;
 
     //store jni lookup tables
     jclass listClass = (*env)->FindClass(env,"java/util/List");

src/main/c/src/fluid/queue/metadatacalc.c

@@ -89,7 +89,11 @@ void updateMetadata(JNIEnv * env, int numChunks, Chunk ** passedInChunks, Enviro
     }
 
     //alert java side to updated static values
-    float normalizationRatio = environment->densityTracking.normalizationRatio;
+    float normalizationRatio = environment->state.normalizationRatio;
     (*env)->SetStaticFloatField(env,environment->lookupTable.serverFluidChunkClass,environment->lookupTable.serverFluidChunkTable.normalizationRatioId,normalizationRatio);
+
+
+    //update frame state
+    environment->state.frame += 1;
 }
 

src/main/c/src/fluid/sim/cellular/cellular.c

@@ -4,6 +4,7 @@
 #include "fluid/sim/cellular/cellular.h"
 #include "fluid/queue/chunkmask.h"
 #include "fluid/env/utilities.h"
+#include "math/randutils.h"
 
 
 #define FLUID_CELLULAR_DIFFUSE_RATE 0.001
@@ -43,8 +44,10 @@ LIBRARY_API void fluid_cellular_simulate(Environment * environment){
         int transferred = 0;
 
         // printf("%f %f %f %d %d %d\n",bounds[IX(0,1,1)],bounds[IX(1,0,1)],bounds[IX(1,1,0)],currentChunk->x,currentChunk->y,currentChunk->z);
-        for(int x = 0; x < DIM; x++){
         for(int y = 0; y < DIM; y++){
+            int shift = randutils_map(randutils_rand2(environment->state.frame,y),0,FLUID_CELLULAR_KERNEL_PERMUTATIONS - 1);
+            int permutation = randutils_map(randutils_rand2(environment->state.frame,y + 1),0,FLUID_CELLULAR_KERNEL_PERMUTATIONS - 1);
+            for(int x = 0; x < DIM; x++){
                 for(int z = 0; z < DIM; z++){
 
                     //diffuse density
@@ -116,10 +119,10 @@ LIBRARY_API void fluid_cellular_simulate(Environment * environment){
                             }
                         }
                         //transfer laterally
-                        int permutation = (z % (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2)) + ((x % (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2)) * (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2));
-                        for(int j = 0; j < FLUID_CELLULAR_KERNEL_SIZE; j++){
-                            int nX = x + fluid_cellular_kernel_x[permutation][j];
-                            int nZ = z + fluid_cellular_kernel_z[permutation][j];
+                        // int permutation = (z % (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2)) + ((x % (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2)) * (FLUID_CELLULAR_KERNEL_PERMUTATIONS / 2));
+                        // for(int j = 0; j < FLUID_CELLULAR_KERNEL_SIZE; j++){
+                            int nX = x + fluid_cellular_kernel_x[permutation][shift];
+                            int nZ = z + fluid_cellular_kernel_z[permutation][shift];
                             if(nX < 0 || nX >= DIM || nZ < 0 || nZ >= DIM){
                                 continue;
                             }
@@ -130,7 +133,7 @@ LIBRARY_API void fluid_cellular_simulate(Environment * environment){
                                     break;
                                 }
                             }
-                        }
+                        // }
                     }
                 }
             }

src/main/c/src/fluid/sim/grid/densitystep.c

@@ -26,8 +26,8 @@ void addDensity(
     float * x = GET_ARR_RAW(d,CENTER_LOC);
     float * s = GET_ARR_RAW(d0,CENTER_LOC);
     for(i=0; i<size; i++){
-        environment->densityTracking.newDensity = environment->densityTracking.newDensity + dt * s[i];
-        environment->densityTracking.existingDensity = environment->densityTracking.existingDensity + x[i];
+        environment->state.newDensity = environment->state.newDensity + dt * s[i];
+        environment->state.existingDensity = environment->state.existingDensity + x[i];
         x[i] += dt*s[i];
         if(x[i] < MIN_FLUID_VALUE){
             x[i] = MIN_FLUID_VALUE;

src/main/c/src/fluid/sim/grid/fluidsim.c

@@ -445,8 +445,8 @@ void fluid_grid_simulate(
     //add density
     {
         double deltaDensity = 0;
-        environment->densityTracking.existingDensity = 0;
-        environment->densityTracking.newDensity = 0;
+        environment->state.existingDensity = 0;
+        environment->state.newDensity = 0;
         for(int i = 0; i < numChunks; i++){
             Chunk * currentChunk = chunks[i];
             addDensity(environment,DIM,currentChunk->chunkMask,currentChunk->d,currentChunk->d0,timestep);
@@ -525,8 +525,8 @@ void fluid_grid_simulate(
         }
         float normalizationRatio = 0;
         if(transformedDensity != 0){
-            normalizationRatio = (environment->densityTracking.existingDensity + environment->densityTracking.newDensity) / transformedDensity;
-            environment->densityTracking.normalizationRatio = normalizationRatio;
+            normalizationRatio = (environment->state.existingDensity + environment->state.newDensity) / transformedDensity;
+            environment->state.normalizationRatio = normalizationRatio;
         }
         for(int i = 0; i < numChunks; i++){
             Chunk * currentChunk = chunks[i];

src/main/c/src/math/mathutils.c

@@ -0,0 +1,27 @@
+#include <math.h>
+
+
+#include "math/mathutils.h"
+
+
+/**
+ * Calculates the fractional component of a float
+ */
+LIBRARY_API float fract(float x){
+    return x - floor(x);
+}
+
+/**
+ * Calculates the dot product of 2D vectors
+ */
+LIBRARY_API float dot2(float x1, float y1, float x2, float y2){
+    return (x1 * x2) + (y1 * y2);
+}
+
+/**
+ * Calculates the dot product of 3D vectors
+ */
+LIBRARY_API float dot3(float x1, float y1, float z1, float x2, float y2, float z2){
+    return (x1 * x2) + (y1 * y2) + (z1 * z2);
+}
+

src/main/c/src/math/randutils.c

@@ -0,0 +1,46 @@
+#include <math.h>
+
+#include "math/mathutils.h"
+#include "math/randutils.h"
+
+/**
+ * The magnitude of the random oscillator
+ */
+#define MATHUTILS_RAND_MAG 100000.0f
+
+/**
+ * Vectors used for prng generation
+ */
+#define MATHUTILS_RAND_VEC_X 111.154315f
+#define MATHUTILS_RAND_VEC_Y 123.631631f
+#define MATHUTILS_RAND_VEC_Z 117.724545f
+
+/**
+ * Generates a random number given a seed value
+ */
+LIBRARY_API float randutils_rand1(float x){
+    return fract(sin(x) * MATHUTILS_RAND_MAG);
+}
+
+/**
+ * Generates a random number given two seed values
+ */
+LIBRARY_API float randutils_rand2(float x, float y){
+    return fract(sin(dot2(x,y,MATHUTILS_RAND_VEC_X,MATHUTILS_RAND_VEC_Y)) * MATHUTILS_RAND_MAG);
+}
+
+/**
+ * Generates a random number given three seed values
+ */
+LIBRARY_API float randutils_rand3(float x, float y, float z){
+    return fract(sin(dot3(x,y,z,MATHUTILS_RAND_VEC_X,MATHUTILS_RAND_VEC_Y,MATHUTILS_RAND_VEC_Z)) * MATHUTILS_RAND_MAG);
+}
+
+/**
+ * Maps a float of range [0,1] to an integer range
+ */
+LIBRARY_API float randutils_map(float x, int min, int max){
+    return (int)(x * (max - min) + min);
+}
+
+

src/test/c/math/mathutils_tests.c

@@ -0,0 +1,26 @@
+
+#include "math/mathutils.h"
+#include "../util/test.h"
+
+
+int math_mathutils_tests(){
+    int rVal = 0;
+
+    //test fract()
+    rVal += assertEqualsFloat(0.5,fract(1.5),"Fract failed to calculate correctly! %f %f \n");
+    rVal += assertEqualsFloat(0.0,fract(1.0),"Fract failed to calculate correctly! %f %f \n");
+
+    //test dot2()
+    rVal += assertEqualsFloat(1,dot2(1,0,1,0),"dot2 should be 1! %f %f \n");
+    rVal += assertEqualsFloat(-1,dot2(1,0,-1,0),"dot2 should be -1! %f %f \n");
+    rVal += assertEqualsFloat(0,dot2(1,0,0,1),"dot2 should be 0! %f %f \n");
+
+
+    //test dot3()
+    rVal += assertEqualsFloat(1,dot3(1,0,0,1,0,0),"dot3 should be 1! %f %f \n");
+    rVal += assertEqualsFloat(-1,dot3(1,0,0,-1,0,0),"dot3 should be -1! %f %f \n");
+    rVal += assertEqualsFloat(0,dot3(1,0,0,0,1,0),"dot3 should be 0! %f %f \n");
+    
+
+    return rVal;
+}

src/test/c/math/randutils_tests.c

@@ -0,0 +1,15 @@
+
+#include "math/mathutils.h"
+#include "math/randutils.h"
+#include "../util/test.h"
+
+
+int math_randutils_tests(){
+    int rVal = 0;
+
+    randutils_rand1(1);
+    randutils_rand2(1,2);
+    randutils_rand3(1,2,3);
+
+    return rVal;
+}