1 files changed, 155 insertions, 0 deletions
diff --git a/tests/java_api/Balls/src/com/example/android/rs/balls/ball_physics.rscript b/tests/java_api/Balls/src/com/example/android/rs/balls/ball_physics.rscript
new file mode 100644
index 00000000..a8c781d2
--- /dev/null
+++ b/tests/java_api/Balls/src/com/example/android/rs/balls/ball_physics.rscript
@@ -0,0 +1,155 @@
+#pragma version(1)
+#pragma rs java_package_name(com.example.android.rs.balls)
+
+#include "balls.rsh"
+
+float2 gGravityVector = {0.f, 9.8f};
+
+float2 gMinPos = {0.f, 0.f};
+float2 gMaxPos = {1280.f, 700.f};
+
+static float2 touchPos[10];
+static float touchPressure[10];
+static const float gDT = 1.f / 30.f;
+
+rs_allocation gGrid;
+rs_allocation gGridCache;
+rs_allocation gBalls;
+
+float gScale = 1.f;
+
+void touch(float x, float y, float pressure, int id) {
+    if (id >= 10) {
+        return;
+    }
+
+    touchPos[id].x = x;
+    touchPos[id].y = y;
+    touchPressure[id] = pressure;
+}
+
+void root(Ball_t *ball, uint32_t x) {
+    float2 fv = 0;
+    float pressure = 0;
+    float2 pos = ball->position;
+    int2 gridPos[9];
+
+    gridPos[0] = convert_int2((ball->position / 100.f) /*- 0.4999f*/);
+    gridPos[1] = (int2){gridPos[0].x - 1, gridPos[0].y - 1};
+    gridPos[2] = (int2){gridPos[0].x + 0, gridPos[0].y - 1};
+    gridPos[3] = (int2){gridPos[0].x + 1, gridPos[0].y - 1};
+    gridPos[4] = (int2){gridPos[0].x - 1, gridPos[0].y};
+    gridPos[5] = (int2){gridPos[0].x + 1, gridPos[0].y};
+    gridPos[6] = (int2){gridPos[0].x - 1, gridPos[0].y + 1};
+    gridPos[7] = (int2){gridPos[0].x + 0, gridPos[0].y + 1};
+    gridPos[8] = (int2){gridPos[0].x + 1, gridPos[0].y + 1};
+
+    for (int gct=0; gct < 9; gct++) {
+        if ((gridPos[gct].x >= rsAllocationGetDimX(gGrid)) ||
+            (gridPos[gct].x < 0) ||
+            (gridPos[gct].y >= rsAllocationGetDimY(gGrid)) ||
+            (gridPos[gct].y < 0)) {
+            continue;
+        }
+        //rsDebug("grid ", gridPos[gct]);
+        const BallGrid_t *bg = (const BallGrid_t *)rsGetElementAt(gGrid, gridPos[gct].x, gridPos[gct].y);
+
+        for (int cidx = 0; cidx < bg->count; cidx++) {
+            float2 bcptr = rsGetElementAt_float2(gGridCache, bg->cacheIdx + cidx);
+            float2 vec = bcptr - pos;
+            float2 vec2 = vec * vec;
+            float len2 = vec2.x + vec2.y;
+
+            if ((len2 < 10000.f) && (len2 > 0.001f)) {
+                float len = rsqrt(len2 + 4.f);
+                float f = (len * len * len) * 20000.f;
+                fv -= vec * f;
+                pressure += f;
+            }
+        }
+    }
+
+    //fv /= ball->size * ball->size * ball->size;
+    fv -= gGravityVector * 4.f * gScale;
+    fv *= gDT;
+
+    for (int i=0; i < 10; i++) {
+        if (touchPressure[i] > 0.1f) {
+            float2 vec = touchPos[i] - ball->position;
+            float2 vec2 = vec * vec;
+            float len2 = max(2.f, vec2.x + vec2.y);
+            float2 pfv = (vec / len2) * touchPressure[i] * 500.f * gScale;
+            pressure += length(pfv);
+            fv -= pfv;
+        }
+    }
+
+    ball->delta = (ball->delta * (1.f - 0.008f)) + fv;
+    ball->position = ball->position + (ball->delta * gDT);
+
+    const float wallForce = 400.f * gScale;
+    if (ball->position.x > (gMaxPos.x - 20.f)) {
+        float d = gMaxPos.x - ball->position.x;
+        if (d < 0.f) {
+            if (ball->delta.x > 0) {
+                ball->delta.x *= -0.7f;
+            }
+            ball->position.x = gMaxPos.x - 1.f;
+        } else {
+            ball->delta.x -= min(wallForce / (d * d), 10.f);
+        }
+    }
+
+    if (ball->position.x < (gMinPos.x + 20.f)) {
+        float d = ball->position.x - gMinPos.x;
+        if (d < 0.f) {
+            if (ball->delta.x < 0) {
+                ball->delta.x *= -0.7f;
+            }
+            ball->position.x = gMinPos.x + 1.f;
+        } else {
+            ball->delta.x += min(wallForce / (d * d), 10.f);
+        }
+    }
+
+    if (ball->position.y > (gMaxPos.y - 20.f)) {
+        float d = gMaxPos.y - ball->position.y;
+        if (d < 0.f) {
+            if (ball->delta.y > 0) {
+                ball->delta.y *= -0.7f;
+            }
+            ball->position.y = gMaxPos.y - 1.f;
+        } else {
+            ball->delta.y -= min(wallForce / (d * d), 10.f);
+        }
+    }
+
+    if (ball->position.y < (gMinPos.y + 20.f)) {
+        float d = ball->position.y - gMinPos.y;
+        if (d < 0.f) {
+            if (ball->delta.y < 0) {
+                ball->delta.y *= -0.7f;
+            }
+            ball->position.y = gMinPos.y + 1.f;
+        } else {
+            ball->delta.y += min(wallForce / (d * d * d), 10.f);
+        }
+    }
+
+    // low pressure ~500, high ~2500
+    pressure *= 12.f;
+    ball->pressure = pressure;
+
+    //rsDebug("p ", pressure);
+
+    float4 color = 1.f;
+    color.r = pow(pressure, 0.25f) / 12.f;
+    color.b = 1.f - color.r;
+    color.g = sin(pressure / 1500.f * 3.14f);
+    color.rgb = max(color.rgb, (float3)0);
+    color.rgb = normalize(color.rgb);
+    ball->color = rsPackColorTo8888(color);
+
+    //rsDebug("physics pos out", ball->position);
+}
+