using UnityEngine;
using UnityEngine.TerrainTools;

namespace UnityEditor.TerrainTools
{
    /// <summary>
    /// An interface that represent all of the functionality required to render a
    /// terrain-brush at a particular UV co-ordinate on a particular terrain.
    /// </summary>
    public interface IBrushRenderWithTerrain : IPaintContextRender
    {
        /// <summary>
        /// Calculates the brush-transform on the specified terrain at the specified UV co-ordinates (taking into account scattering).
        /// </summary>
        /// <param name="terrain">The terrain to calculate the brush-transform for.</param>
        /// <param name="uv">The UV co-ordinate on that terrain.</param>
        /// <returns>The brush-transform on the terrain at the specified UV co-ordinates.</returns>
        /// <param name="size">The size of the brush.</param>
        /// <param name="rotation">The rotation about the Y axis of the brush.</param>
        /// <param name="brushTransform">The brush-transform on the terrain at the specified UV co-ordinates.</param>
        /// <returns>Returns <c>true</c> if calculated successfully, <c>false</c> otherwise.</returns>
        bool CalculateBrushTransform(Terrain terrain, Vector2 uv, float size, float rotation, out BrushTransform brushTransform);

        /// <summary>
        /// Calculates the brush-transform on the specified terrain at the specified UV co-ordinates (taking into account scattering).
        /// </summary>
        /// <param name="terrain">The terrain to calculate the brush-transform for.</param>
        /// <param name="uv">The UV co-ordinate on that terrain.</param>
        /// <param name="size">The size of the brush.</param>
        /// <param name="brushTransform">The brush-transform on the terrain at the specified UV co-ordinates.</param>
        /// <returns>Returns "true" if calculated successfully, "false" otherwise.</returns>
        bool CalculateBrushTransform(Terrain terrain, Vector2 uv, float size, out BrushTransform brushTransform);

        /// <summary>
        /// Calculates the brush-transform on the specified terrain at the specified UV co-ordinates (taking into account scattering).
        /// </summary>
        /// <param name="terrain">The terrain to calculate the brush-transform for.</param>
        /// <param name="uv">The UV co-ordinate on that terrain.</param>
        /// <param name="brushTransform">The brush-transform on the terrain at the specified UV co-ordinates.</param>
        /// <returns>Returns "true" if calculated successfully, "false" otherwise.</returns>
        bool CalculateBrushTransform(Terrain terrain, Vector2 uv, out BrushTransform brushTransform);

        /// <summary>
        /// Gets the PaintContext for the height-map at the bounds specified,
        /// you need to say whether this is to be writable upon acquisition.
        /// </summary>
        /// <param name="writable">Determines if we wish to allow writing to the height-map.</param>
        /// <param name="terrain">The initial terrain to acquire the height-map.</param>
        /// <param name="boundsInTerrainSpace">The bounds of the height-map to use (in pixels).</param>
        /// <param name="extraBorderPixels">Extra padding on the bounds specified.</param>
        /// <returns>Returns the paint context created.</returns>
        PaintContext AcquireHeightmap(bool writable, Terrain terrain, Rect boundsInTerrainSpace, int extraBorderPixels = 0);

        /// <summary>
        /// Gets the PaintContext for the texture-map at the bounds specified,
        /// you need to say whether this is to be writable upon acquisition.
        /// </summary>
        /// <param name="writable">Determines if we wish to allow writing to the texture-map.</param>
        /// <param name="terrain">The initial terrain to acquire the texture-map.</param>
        /// <param name="boundsInTerrainSpace">The bounds of the texture-map to use (in pixels).</param>
        /// <param name="layer">The terrain layer to acquire the texture-map for.</param>
        /// <param name="extraBorderPixels">Extra padding on the bounds specified.</param>
        /// <returns>Returns the paint context created.</returns>
        PaintContext AcquireTexture(bool writable, Terrain terrain, Rect boundsInTerrainSpace, TerrainLayer layer, int extraBorderPixels = 0);

        /// <summary>
        /// Gets the PaintContext for the normal-map at the bounds specified,
        /// you need to say whether this is to be writable upon acquisition.
        /// </summary>
        /// <param name="writable">Determines if we wish to allow writing to the normal-map.</param>
        /// <param name="terrain">The initial terrain to acquire the normal-map.</param>
        /// <param name="boundsInTerrainSpace">The bounds of the normal-map to use (in pixels).</param>
        /// <param name="extraBorderPixels">Extra padding on the bounds specified.</param>
        /// <returns>Returns the paint context created.</returns>
        PaintContext AcquireNormalmap(bool writable, Terrain terrain, Rect boundsInTerrainSpace, int extraBorderPixels = 0);

        /// <summary>
        /// Gets the PaintContext for the holes at the bounds specified,
        /// you need to say whether this is to be writable upon acquisition.
        /// </summary>
        /// <param name="writable">Determines if we wish to allow writing to the normal-map.</param>
        /// <param name="terrain">The initial terrain to acquire the normal-map.</param>
        /// <param name="boundsInTerrainSpace">The bounds of the normal-map to use (in pixels).</param>
        /// <param name="extraBorderPixels">Extra padding on the bounds specified.</param>
        /// <returns>Returns the paint context created.</returns>
        PaintContext AcquireHolesTexture(bool writable, Terrain terrain, Rect boundsInTerrainSpace, int extraBorderPixels = 0);

        /// <summary>
        /// Releases the PaintContext specified, if this was made writable when
        /// acquired then we write back into the texture at this point.
        /// </summary>
        /// <param name="paintContext">The paint context to be released.</param>
        void Release(PaintContext paintContext);
    }

    /// <summary>
    /// An interface that represent the brush renderers preview on a terrain.
    /// </summary>
    public interface IBrushRenderPreviewWithTerrain : IBrushRenderWithTerrain, IPaintContextRenderPreview
    {
    }
}