From 1a884666eccef1d8a199038342f07b818e4ad25a Mon Sep 17 00:00:00 2001
From: Dethrace Engineering Department
 <78985374+dethrace-labs@users.noreply.github.com>
Date: Thu, 5 May 2022 05:05:52 +1200
Subject: [PATCH] Offroad effects (#128)

* dust and bumpiness
---
 src/DETHRACE/common/car.c   | 28 ++++++++++++++++++---
 src/DETHRACE/common/spark.c | 50 +++++++++++++++++++++++++++++++++++--
 2 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/src/DETHRACE/common/car.c b/src/DETHRACE/common/car.c
index 5a3c1099..338062e9 100644
--- a/src/DETHRACE/common/car.c
+++ b/src/DETHRACE/common/car.c
@@ -999,9 +999,9 @@ void FinishCars(tU32 pLast_frame_time, tU32 pTime) {
             car->lf_sus_position = (car->ride_height - car->oldd[2]) / WORLD_SCALE;
             car->rf_sus_position = (car->ride_height - car->oldd[3]) / WORLD_SCALE;
             for (wheel = 0; wheel < 4; wheel++) {
-                if (car->oldd[wheel] < car->susp_height[wheel >> 1] && gCurrent_race.material_modifiers[car->material_index[wheel]].smoke_type >= 2
-                    && !car->doing_nothing_flag)
+                if (car->oldd[wheel] < car->susp_height[wheel >> 1] && gCurrent_race.material_modifiers[car->material_index[wheel]].smoke_type >= 2 && !car->doing_nothing_flag) {
                     GenerateContinuousSmoke(car, wheel, pTime);
+                }
             }
         }
     }
@@ -1698,7 +1698,29 @@ void DoBumpiness(tCar_spec* c, br_vector3* wheel_pos, br_vector3* norm, br_scala
     tMaterial_modifiers* mat_list;
     LOG_TRACE("(%p, %p, %p, %p, %d)", c, wheel_pos, norm, d, n);
 
-    STUB_ONCE();
+    tv.v[0] = c->nor[n].v[0] * d[n] + wheel_pos[n].v[0];
+    tv.v[2] = c->nor[n].v[2] * d[n] + wheel_pos[n].v[2];
+
+    x = abs((int)(512.0f * tv.v[0])) % 2048;
+    y = abs((int)(512.0f * tv.v[2])) % 2048;
+
+    if (x > 1024) {
+        x = 2048 - x;
+    }
+    if (y > 1024) {
+        y = 2048 - y;
+    }
+    if (x + y <= 1024) {
+        delta = x + y;
+    } else {
+        delta = 2048 - x - y;
+    }
+    delta -= 400;
+    if (delta < 0) {
+        delta = 0;
+    }
+    mat_list = gCurrent_race.material_modifiers;
+    d[n] = delta * mat_list[c->material_index[n]].bumpiness / 42400.0f * norm[n].v[1] + d[n];
 }
 
 // IDA: void __usercall CalcForce(tCar_spec *c@<EAX>, br_scalar dt)
diff --git a/src/DETHRACE/common/spark.c b/src/DETHRACE/common/spark.c
index 5a1b6b9f..26990f41 100644
--- a/src/DETHRACE/common/spark.c
+++ b/src/DETHRACE/common/spark.c
@@ -1106,7 +1106,53 @@ void GenerateContinuousSmoke(tCar_spec* pCar, int wheel, tU32 pTime) {
     int colour;
     LOG_TRACE("(%p, %d, %d)", pCar, wheel, pTime);
 
-    STUB_ONCE();
+    if (pCar->dust_time[wheel] > pTime) {
+        pCar->dust_time[wheel] -= pTime;
+        return;
+    }
+    pCar->dust_time[wheel] += IRandomBetween(200, 400) - pTime;
+    if (pCar->dust_time[wheel] < 0) {
+        pCar->dust_time[wheel] = 0;
+    }
+    BrVector3Cross(&tv, &pCar->omega, &pCar->wpos[wheel]);
+    BrVector3Scale(&vcs, &pCar->velocity_car_space, WORLD_SCALE * 1000.0f);
+    BrVector3Accumulate(&vcs, &tv);
+    ts = BrVector3LengthSquared(&vcs);
+    if (ts < 25.0f) {
+        return;
+    }
+    decay_factor = sqrtf(ts) / 25.0f;
+    if (decay_factor > 1.0f) {
+        decay_factor = 1.0f;
+    }
+    BrVector3InvScale(&tv, &pCar->wpos[wheel], WORLD_SCALE);
+    tv.v[1] -= pCar->oldd[wheel] / WORLD_SCALE;
+
+    alpha = -1000.0f;
+    if (vcs.v[2] > 0.0f) {
+        alpha = (pCar->bounds[0].min.v[2] - tv.v[2]) / vcs.v[2];
+    } else if (vcs.v[2] < 0.0f) {
+        alpha = (pCar->bounds[0].max.v[2] - tv.v[2]) / vcs.v[2];
+    }
+
+    beta = -1000.0f;
+    if (vcs.v[0] > 0.0f) {
+        beta = (pCar->bounds[0].min.v[0] - tv.v[0]) / vcs.v[0];
+    } else if (vcs.v[0] < 0.0f) {
+        beta = (pCar->bounds[0].max.v[0] - tv.v[0]) / vcs.v[0];
+    }
+
+    ts = MAX(alpha, beta);
+    BrVector3Scale(&pos, &vcs, ts);
+    BrVector3Accumulate(&tv, &pos);
+    BrMatrix34ApplyP(&pos, &tv, &pCar->car_master_actor->t.t.mat);
+    BrMatrix34ApplyV(&v, &vcs, &pCar->car_master_actor->t.t.mat);
+
+    colour = gDust_rotate + gCurrent_race.material_modifiers[pCar->material_index[wheel]].smoke_type - 2;
+    while (colour >= gNum_dust_tables) {
+        colour -= gNum_dust_tables;
+    }
+    CreatePuffOfSmoke(&pos, &v, decay_factor, decay_factor * 2, colour + 8, pCar);
 }
 
 // IDA: void __cdecl DustRotate()
@@ -1234,7 +1280,7 @@ void CreatePuffOfSmoke(br_vector3* pos, br_vector3* v, br_scalar strength, br_sc
     }
 
     BrVector3InvScale(&gSmoke[gSmoke_num].v, v, WORLD_SCALE);
-    gSmoke[gSmoke_num].v.v[1] = gSmoke[gSmoke_num].v.v[1] + 0.1449275362318841;
+    gSmoke[gSmoke_num].v.v[1] = gSmoke[gSmoke_num].v.v[1] + (1.0f / WORLD_SCALE);
     gSmoke[gSmoke_num].pos = *pos;
     gSmoke[gSmoke_num].radius = 0.05;
     if ((pType & 0xF) == 7) {