Grab rotation flags (#58)

* introduced "enum GrabRotationFlags" for type-based grab behavior and added grab_rotation.c/.h to offload grabRotation code from player.c

* grab_rotation snap cube normals fix

* grab_rotation: some cleanup

* grab_rotation.c: simplify grabRotationInitBase + some cleanup

src/player/grab_rotation.c

@@ -0,0 +1,101 @@
+#include "grab_rotation.h"
+#include "../player/player.h"
+
+
+struct Vector3 gCubeSurfaceNormals[6] = {
+    {  1.0f,  0.0f,  0.0f },
+    { -1.0f,  0.0f,  0.0f },
+    {  0.0f,  1.0f,  0.0f },
+    {  0.0f, -1.0f,  0.0f },
+    {  0.0f,  0.0f,  1.0f },
+    {  0.0f,  0.0f, -1.0f }
+};
+
+
+enum GrabRotationFlags grabRotationFlagsForDecorId(const int decorId) {
+    enum GrabRotationFlags flags = 0;
+    // object specific flags
+    if (decorId == DECOR_TYPE_RADIO) {
+        flags |= GrabRotationTurnTowardsPlayer | GrabRotationUseZLookDirection;
+    }
+    else // default flags
+    {
+        flags |= GrabRotationSnapToCubeNormals;
+    }
+    return flags;
+}
+
+enum GrabRotationFlags grabRotationFlagsForDecorObjectDef(struct DecorObjectDefinition* decorObjectDef) {
+    return grabRotationFlagsForDecorId(decorIdForObjectDefinition(decorObjectDef));
+}
+
+enum GrabRotationFlags grabRotationFlagsForCollisionObject(struct CollisionObject* collisionObject) {
+    return grabRotationFlagsForDecorId(decorIdForCollisionObject(collisionObject)); // this will probably need to be replaced in the future
+}
+
+
+void grabRotationApplyTurnTowardsPlayer(struct Quaternion* grabRotationBaseOut) {
+    quatIdent(grabRotationBaseOut);
+}
+
+void grabRotationApplySnapToCubeNormals(struct Quaternion* forwardRotationIn, struct Quaternion* objectRotationIn, struct Quaternion* grabRotationBaseOut) {
+    struct Vector3 forward, up;
+    quatMultVector(forwardRotationIn, &gForward, &forward);
+    quatMultVector(forwardRotationIn, &gUp, &up);
+
+    int closestNormalTowards = 0, closestNormalUp = 0;
+    float closestNormalTowardsDot = 1.0f, closestNormalUpDot = -1.0f;
+    for (int i = 0; i < 6; ++i) {
+        struct Vector3 surfaceNormal;
+        quatMultVector(objectRotationIn, &gCubeSurfaceNormals[i], &surfaceNormal);
+
+        float dot = vector3Dot(&surfaceNormal, &forward);
+        if (dot < closestNormalTowardsDot) {
+            closestNormalTowardsDot = dot;
+            closestNormalTowards = i;
+        }
+        dot = vector3Dot(&surfaceNormal, &up);
+        if (dot > closestNormalUpDot) {
+            closestNormalUpDot = dot;
+            closestNormalUp = i;
+        }
+    }
+    struct Quaternion normalRotation;
+    quatLook(&gCubeSurfaceNormals[closestNormalTowards], &gCubeSurfaceNormals[closestNormalUp], &normalRotation);
+    quatConjugate(&normalRotation, grabRotationBaseOut);
+}
+
+void grabRotationApplyNoRotation(struct Quaternion* forwardRotationIn, struct Quaternion* objectRotationIn, struct Quaternion* grabRotationBaseOut) {
+    struct Quaternion forwardRotationInverted;
+    quatConjugate(forwardRotationIn, &forwardRotationInverted);
+    quatMultiply(&forwardRotationInverted, objectRotationIn, grabRotationBaseOut);
+}
+
+void grabRotationInitBase(const enum GrabRotationFlags flags, struct Quaternion* forwardRotationIn, struct Quaternion* objectRotationIn, struct Quaternion* grabRotationBaseOut) {
+    // modify object rotation according to flags
+    if (flags & GrabRotationTurnTowardsPlayer) {
+        grabRotationApplyTurnTowardsPlayer(grabRotationBaseOut);
+    } else if (flags & GrabRotationSnapToCubeNormals) {
+        grabRotationApplySnapToCubeNormals(forwardRotationIn, objectRotationIn, grabRotationBaseOut);
+    } else { // with no rotation modifier, object is not rotated on grab
+        grabRotationApplyNoRotation(forwardRotationIn, objectRotationIn, grabRotationBaseOut);
+    }
+}
+
+
+void grabRotationApplyUseZLookDirection(struct Quaternion* lookRotationDeltaIn, struct Quaternion* grabRotationBaseInOut) {
+    struct Quaternion tmp;
+    quatMultiply(lookRotationDeltaIn, grabRotationBaseInOut, &tmp);
+    *grabRotationBaseInOut = tmp;
+}
+
+void grabRotationUpdate(const enum GrabRotationFlags flags, struct Quaternion* lookRotationDeltaIn, struct Quaternion* forwardRotationIn, struct Quaternion* grabRotationBaseIn, struct Quaternion* grabRotationOut) {
+    // modify target object rotation in object-space
+    struct Quaternion grabRotationBase = *grabRotationBaseIn;
+    if (flags & GrabRotationUseZLookDirection) {
+        grabRotationApplyUseZLookDirection(lookRotationDeltaIn, &grabRotationBase);
+    }
+
+    // maintain object's relative rotation
+    quatMultiply(forwardRotationIn, &grabRotationBase, grabRotationOut);
+}

src/player/grab_rotation.h

@@ -0,0 +1,21 @@
+#ifndef __GRAB_ROTATION_H__
+#define __GRAB_ROTATION_H__
+
+#include "../decor/decor_object_list.h"
+#include "../physics/collision_object.h"
+#include "../math/transform.h"
+
+enum GrabRotationFlags {
+    GrabRotationSnapToCubeNormals = (1 << 0),
+    GrabRotationTurnTowardsPlayer = (1 << 1),
+    GrabRotationUseZLookDirection = (1 << 2),
+};
+
+enum GrabRotationFlags grabRotationFlagsForDecorId(const int decorId);
+enum GrabRotationFlags grabRotationFlagsForDecorObjectDef(struct DecorObjectDefinition* decorObjectDef);
+enum GrabRotationFlags grabRotationFlagsForCollisionObject(struct CollisionObject* collisionObject);
+
+void grabRotationInitBase(const enum GrabRotationFlags flags, struct Quaternion* forwardRotationIn, struct Quaternion* objectRotationIn, struct Quaternion* grabRotationBaseOut);
+void grabRotationUpdate(const enum GrabRotationFlags flags, struct Quaternion* lookRotationDeltaIn, struct Quaternion* forwardRotationIn, struct Quaternion* grabRotationBaseIn, struct Quaternion* grabRotationOut);
+
+#endif

src/player/player.c

@@ -17,14 +17,15 @@
 #include "../physics/contact_insertion.h"
 #include "../scene/ball.h"
 #include "../savefile/savefile.h"
+#include "../player/grab_rotation.h"
 
 #include "../build/assets/models/player/chell.h"
 #include "../build/assets/materials/static.h"
 #include "../build/assets/models/portal_gun/w_portalgun.h"
 
 #define GRAB_RAYCAST_DISTANCE   2.5f
-#define GRAB_MIN_OFFSET_Y     -1.1f
-#define GRAB_MAX_OFFSET_Y      1.25f
+#define GRAB_MIN_OFFSET_Y      -1.1f
+#define GRAB_MAX_OFFSET_Y       1.25f
 
 #define DROWN_TIME              2.0f
 #define STEP_TIME               0.35f
@@ -79,15 +80,6 @@ struct ColliderTypeData gPlayerColliderData = {
     &gCollisionCapsuleCallbacks,
 };
 
-struct Vector3 gCubeNormals[6] = {
-    {  1.0f,  0.0f,  0.0f },
-    { -1.0f,  0.0f,  0.0f },
-    {  0.0f,  1.0f,  0.0f },
-    {  0.0f, -1.0f,  0.0f },
-    {  0.0f,  0.0f,  1.0f },
-    {  0.0f,  0.0f, -1.0f }
-};
-
 void playerRender(void* data, struct DynamicRenderDataList* renderList, struct RenderState* renderState) {
     struct Player* player = (struct Player*)data;
 
@@ -284,36 +276,14 @@ void playerInitGrabRotationBase(struct Player* player) {
         return;
     }
     struct Quaternion forwardRotation = player->lookTransform.rotation;
-    struct Vector3 forward, tmpVec, up;
+    struct Vector3 forward, tmpVec;
     playerGetMoveBasis(&forwardRotation, &forward, &tmpVec);
-    vector3Negate(&forward, &tmpVec);
-    quatLook(&tmpVec, &gUp, &forwardRotation);
+    vector3Negate(&forward, &forward);
+    quatLook(&forward, &gUp, &forwardRotation);
     playerPortalGrabTransform(player, NULL, &forwardRotation);
-    quatMultVector(&forwardRotation, &gForward, &forward);
-    quatMultVector(&forwardRotation, &gUp, &up);
-
-    struct Quaternion objectRotation = player->grabConstraint.object->body->transform.rotation;
 
-    // snap target rotation to nearest cube normals
-    int closestNormalUp = 0, closestNormalTowards = 0;
-    float closestNormalTowardsDot = 1.0f, closestNormalUpDot = -1.0f;
-    for (int i = 0; i < 6; ++i) {
-        struct Vector3 surfaceNormal;
-        quatMultVector(&objectRotation, &gCubeNormals[i], &surfaceNormal);
-
-        float dot = vector3Dot(&surfaceNormal, &forward);
-        if (dot < closestNormalTowardsDot) {
-            closestNormalTowardsDot = dot;
-            closestNormalTowards = i;
-        }
-        dot = vector3Dot(&surfaceNormal, &up);
-        if (dot > closestNormalUpDot) {
-            closestNormalUpDot = dot;
-            closestNormalUp = i;
-        }
-    }
-    quatLook(&gCubeNormals[closestNormalTowards], &gCubeNormals[closestNormalUp], &objectRotation);
-    quatConjugate(&objectRotation, &player->grabRotationBase);
+    enum GrabRotationFlags grabRotationFlags = grabRotationFlagsForCollisionObject(player->grabConstraint.object);
+    grabRotationInitBase(grabRotationFlags, &forwardRotation, &player->grabConstraint.object->body->transform.rotation, &player->grabRotationBase);
 }
 
 void playerShakeUpdate(struct Player* player) {
@@ -488,7 +458,10 @@ void playerUpdateGrabbedObject(struct Player* player) {
         vector3Add(&player->lookTransform.position, &grabPoint, &grabPoint);
         grabPoint.y += grabY;
 
-        struct Quaternion grabRotation;
+        // remember delta between forwardRotation and lookTransform.rotation
+        struct Quaternion lookRotationDelta, forwardRotationInv;
+        quatConjugate(&forwardRotation, &forwardRotationInv);
+        quatMultiply(&forwardRotationInv, &player->lookTransform.rotation, &lookRotationDelta);
 
         if (player->grabbingThroughPortal != PLAYER_GRABBING_THROUGH_NOTHING) {
             if (!collisionSceneIsPortalOpen()) {
@@ -500,9 +473,10 @@ void playerUpdateGrabbedObject(struct Player* player) {
             playerPortalGrabTransform(player, &grabPoint, &forwardRotation);
         }
 
-        // maintain object's relative rotation
-        quatMultiply(&forwardRotation, &player->grabRotationBase, &grabRotation);
-
+        struct Quaternion grabRotation;
+        enum GrabRotationFlags grabRotationFlags = grabRotationFlagsForCollisionObject(player->grabConstraint.object);
+        grabRotationUpdate(grabRotationFlags, &lookRotationDelta, &forwardRotation, &player->grabRotationBase, &grabRotation);
+
         pointConstraintUpdateTarget(&player->grabConstraint, &grabPoint, &grabRotation);
     }
 }