loader/lottie: minimum support for 3D transform

It lacks perspective projection information,
so it transforms 3D axes with orthogonal projection.

src/examples/Lottie.cpp

@@ -30,7 +30,7 @@
 /************************************************************************/
 
 #define NUM_PER_ROW 10
-#define NUM_PER_COL 10
+#define NUM_PER_COL 9
 #define SIZE (WIDTH/NUM_PER_ROW)
 
 static int counter = 0;

src/loaders/lottie/tvgLottieBuilder.cpp

@@ -64,6 +64,32 @@ static void _updateLayer(LottieLayer* root, LottieLayer* layer, int32_t frameNo)
 static bool _buildPrecomp(LottieComposition* comp, LottieGroup* parent);
 
 
+static void _rotateY(Matrix* m, float degree)
+{
+    if (degree == 0.0f) return;
+
+    auto radian = degree / 180.0f * M_PI;
+    auto cosVal = cosf(radian);
+    auto sinVal = sinf(radian);
+
+    m->e11 = cosVal;
+    m->e31 = -sinVal;
+}
+
+
+static void _rotateX(Matrix* m, float degree)
+{
+    if (degree == 0.0f) return;
+
+    auto radian = degree / 180.0f * M_PI;
+    auto cosVal = cosf(radian);
+    auto sinVal = sinf(radian);
+
+    m->e22 = cosVal;
+    m->e32 = -sinVal;
+}
+
+
 static bool _updateTransform(LottieTransform* transform, int32_t frameNo, bool autoOrient, Matrix& matrix, uint8_t& opacity)
 {
     mathIdentity(&matrix);
@@ -84,6 +110,11 @@ static bool _updateTransform(LottieTransform* transform, int32_t frameNo, bool a
     if (autoOrient) angle = transform->position.angle(frameNo);
     mathRotate(&matrix, transform->rotation(frameNo) + angle);
 
+    if (transform->rotationEx) {
+        _rotateY(&matrix, transform->rotationEx->y(frameNo));
+        _rotateX(&matrix, transform->rotationEx->x(frameNo));
+    }
+
     auto scale = transform->scale(frameNo);
     mathScaleR(&matrix, scale.x * 0.01f, scale.y * 0.01f);
 

src/loaders/lottie/tvgLottieModel.h

@@ -253,9 +253,16 @@ struct LottieTransform : LottieObject
         LottieFloat y = 0.0f;
     };
 
+    struct RotationEx
+    {
+        LottieFloat x = 0.0f;
+        LottieFloat y = 0.0f;
+    };
+
     ~LottieTransform()
     {
         delete(coords);
+        delete(rotationEx);
     }
 
     void prepare()
@@ -263,16 +270,17 @@ struct LottieTransform : LottieObject
         LottieObject::type = LottieObject::Transform;
         if (position.frames || rotation.frames || scale.frames || anchor.frames || opacity.frames) statical = false;
         else if (coords && (coords->x.frames || coords->y.frames)) statical = false;
+        else if (rotationEx && (rotationEx->x.frames || rotationEx->y.frames)) statical = false;
     }
 
     LottiePosition position = Point{0.0f, 0.0f};
-    LottieFloat rotation = 0.0f;
+    LottieFloat rotation = 0.0f;           //z rotation
     LottiePoint scale = Point{100.0f, 100.0f};
     LottiePoint anchor = Point{0.0f, 0.0f};
     LottieOpacity opacity = 255;
 
-    //either a position or separate coordinates
+    SeparateCoord* coords = nullptr;       //either a position or separate coordinates
-    SeparateCoord* coords = nullptr;
+    RotationEx* rotationEx = nullptr;      //extension for 3d rotation
 };
 
 

src/loaders/lottie/tvgLottieParser.cpp

@@ -502,7 +502,10 @@ LottieTransform* LottieParser::parseTransform(bool ddd)
     auto transform = new LottieTransform;
     if (!transform) return nullptr;
 
-    if (ddd) TVGERR("LOTTIE", "3d transform(ddd) is not supported");
+    if (ddd) {
+        transform->rotationEx = new LottieTransform::RotationEx;
+        TVGLOG("LOTTIE", "3D transform(ddd) is not 100% compatible.");
+    }
 
     while (auto key = nextObjectKey()) {
         if (!strcmp(key, "p"))
@@ -524,12 +527,12 @@ LottieTransform* LottieParser::parseTransform(bool ddd)
         else if (!strcmp(key, "s")) parseProperty(transform->scale);
         else if (!strcmp(key, "r")) parseProperty(transform->rotation);
         else if (!strcmp(key, "o")) parseProperty(transform->opacity);
-        //else if (!strcmp(key, "sk")) //skew
+        else if (transform->rotationEx && !strcmp(key, "rx")) parseProperty(transform->rotationEx->x);
-        //else if (!strcmp(key, "sa")) //skew axis
+        else if (transform->rotationEx && !strcmp(key, "ry")) parseProperty(transform->rotationEx->y);
-        //else if (!strcmp(key, "rx")  //3d rotation
+        else if (transform->rotationEx && !strcmp(key, "rz")) parseProperty(transform->rotation);
-        //else if (!strcmp(key, "ry")  //3d rotation
-        else if (!strcmp(key, "rz")) parseProperty(transform->rotation);
         else if (!strcmp(key, "nm")) transform->name = getStringCopy();
+        //else if (!strcmp(key, "sk")) //TODO: skew
+        //else if (!strcmp(key, "sa")) //TODO: skew axis
         else skip(key);
     }
     transform->prepare();