library: Allow users to specify model transformation matrices

A manual matrix overrides scale, translation and rotation. It can be
removed to switch back to individual scale, translation and rotation.

include/NEModel.h

@@ -58,6 +58,7 @@ typedef struct {
     int sx;                   ///< X scale of the model (f32)
     int sy;                   ///< Y scale of the model (f32)
     int sz;                   ///< Z scale of the model (f32)
+    m4x3 *mat;                ///< Transformation matrix assigned by the user.
 } NE_Model;
 
 /// Creates a new model object.
@@ -225,6 +226,27 @@ void NE_ModelSetRot(NE_Model *model, int rx, int ry, int rz);
 /// @param rz Rotation by Z axis (0 - 511).
 void NE_ModelRotate(NE_Model *model, int rx, int ry, int rz);
 
+/// Assigns a 4x3 transformation matrix to a model.
+///
+/// When a matrix is assigned, the scale, position and rotation of the model
+/// will be ignored.
+///
+/// Note that the provided matrix is copied to the internal state of the model,
+/// so the caller of the function doesn't need to keep it in memory.
+///
+/// @param model Pointer to the model.
+/// @param mat Matrix to be used.
+/// @return Returns 1 on success, 0 on failure.
+int NE_ModelSetMatrix(NE_Model *model, m4x3 *mat);
+
+/// Clears the 4x3 transformation matrix of a model.
+///
+/// The model will start using the individual scale, translation and rotation
+/// values.
+///
+/// @param model Pointer to the model.
+void NE_ModelClearMatrix(NE_Model *model);
+
 /// Update internal state of the animation of all models.
 void NE_ModelAnimateAll(void);
 

source/NEModel.c

@@ -141,6 +141,8 @@ NE_Model *NE_ModelCreate(NE_ModelType type)
 
     model->sx = model->sy = model->sz = inttof32(1);
 
+    model->mat = NULL;
+
     model->modeltype = type;
     model->meshindex = NE_NO_MESH;
 
@@ -186,6 +188,9 @@ void NE_ModelDelete(NE_Model *model)
             free(model->animinfo[i]);
     }
 
+    if (model->mat != NULL)
+        free(model->mat);
+
     // If there is an asigned mesh
     if (model->meshindex != NE_NO_MESH)
         ne_mesh_delete(model->meshindex);
@@ -271,20 +276,27 @@ void NE_ModelDraw(const NE_Model *model)
 
     MATRIX_PUSH = 0;
 
-    MATRIX_TRANSLATE = model->x;
+    if (model->mat != NULL)
-    MATRIX_TRANSLATE = model->y;
+    {
-    MATRIX_TRANSLATE = model->z;
+        glMultMatrix4x3(model->mat);
+    }
+    else
+    {
+        MATRIX_TRANSLATE = model->x;
+        MATRIX_TRANSLATE = model->y;
+        MATRIX_TRANSLATE = model->z;
 
-    if (model->rx != 0)
+        if (model->rx != 0)
-        glRotateXi(model->rx << 6);
+            glRotateXi(model->rx << 6);
-    if (model->ry != 0)
+        if (model->ry != 0)
-        glRotateYi(model->ry << 6);
+            glRotateYi(model->ry << 6);
-    if (model->rz != 0)
+        if (model->rz != 0)
-        glRotateZi(model->rz << 6);
+            glRotateZi(model->rz << 6);
 
-    MATRIX_SCALE = model->sx;
+        MATRIX_SCALE = model->sx;
-    MATRIX_SCALE = model->sy;
+        MATRIX_SCALE = model->sy;
-    MATRIX_SCALE = model->sz;
+        MATRIX_SCALE = model->sz;
+    }
 
     if (NE_TestTouch)
     {
@@ -404,6 +416,33 @@ void NE_ModelSetRot(NE_Model *model, int rx, int ry, int rz)
     model->rz = rz;
 }
 
+int NE_ModelSetMatrix(NE_Model *model, m4x3 *mat)
+{
+    NE_AssertPointer(model, "NULL model pointer");
+    NE_AssertPointer(mat, "NULL matrix pointer");
+
+    if (model->mat == NULL)
+    {
+        model->mat = malloc(sizeof(m4x3));
+        if (model->mat == NULL)
+            return 0;
+    }
+
+    memcpy(model->mat, mat, sizeof(m4x3));
+
+    return 1;
+}
+
+void NE_ModelClearMatrix(NE_Model *model)
+{
+    NE_AssertPointer(model, "NULL pointer");
+
+    if (model->mat == NULL)
+        return;
+
+    free(model->mat);
+}
+
 void NE_ModelAnimateAll(void)
 {
     if (!ne_model_system_inited)