/*
* Descent 3 
* Copyright (C) 2024 Parallax Software
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __IMESH_BUILDER_H__
#define __IMESH_BUILDER_H__

#include "IMeshHandle.h"

namespace RZ {
namespace Renderer {
class IMeshBuilder {
public:
  enum PrimitiveType {
    kTriangle,
    kTriangleFan,
    kTriangleStrip,
  };

  enum VertexType {
    kPosition = 0x01,
    kColor = 0x02,
    kTexture1 = 0x04,
    // kTexture2 = 0x08,
    kNormal = 0x10,
  };

  virtual ~IMeshBuilder() {}

  // Begin
  // Begins the generation of a mesh. You must supply
  // the primitive type, size of the vertex buffer, and
  // the number of primitives.
  // vertexFlags are a combination of VertexType values
  // that represent what data should be stored in the verts.
  virtual void Begin(PrimitiveType type, unsigned int vertexFlags, unsigned int numPrims, unsigned int numVerts,
                     bool autogenNormals) = 0;

  // End
  // Ends the build process which will cause the generation of the mesh data.
  // Returned will be a handle to the mesh
  virtual MeshHandle End(void) = 0;

  // SetStreamData
  // Stores stream data for one or more vertex fields.
  //	streamId: Which field we are setting data for
  //	startVertIndex: Which vertex in vertex buffer are we starting at
  //	numVerts: How many full verts of data are we processing
  //	dataPtr: Incoming data. All data is float based.
  //	elementsPerField: How many floats-per-field for this data.
  //					  NOTE: This is for verification purposes. Positions and
  //					  Normals are 3 elements. Texture UVs are 2 elements. Colors
  //					  are 4 elements.
  //	stride: The number of bytes from the START of one field to the next on the incoming stream.
  virtual void SetStreamData(VertexType streamId, unsigned int startVertIndex, unsigned int numVerts,
                             const float *dataPtr, unsigned int elementsPerField, unsigned int stride) = 0;

  // AddPrimitive
  // Adds another primitive to the buffer.
  virtual void AddPrimitive(unsigned int numVerts, unsigned int *vertexIndices) = 0;
};
} // namespace Renderer
} // namespace RZ

#endif