OpenSubdiv/opensubdiv/osd/glPtexTexture.h
manuelk c399655dcc Landing 3.0.0.alpha
Sync'ing the 'dev' branch with the 'feature_3.0dev' branch at commit 68c6d11fc36761ae1a5e6cdc3457be16f2e9704a

The branch 'feature_3.0dev' is now locked and preserved for historical purposes.
2014-09-05 15:07:46 -07:00

101 lines
3.5 KiB
C++

//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef OSD_GL_PTEX_TEXTURE_H
#define OSD_GL_PTEX_TEXTURE_H
#include "../version.h"
#include "../osd/nonCopyable.h"
#include "../osd/opengl.h"
class PtexTexture;
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
namespace Osd {
/// GLPTexture : implements simple support for ptex textures
///
/// The current implementation declares _texels as a GL_TEXTURE_2D_ARRAY of
/// n pages of a resolution that matches that of the largest face in the PTex file.
///
/// Two GL_TEXTURE_BUFFER constructs are used
/// as lookup tables :
/// * _pages stores the array index in which a given face is located
/// * _layout stores 4 float coordinates : top-left corner and width/height for each face
///
/// GLSL fragments use gl_PrimitiveID and gl_TessCoords to access the _pages and _layout
/// indirection tables, which provide then texture coordinates for the texels stored in
/// the _texels texture array.
///
/// Hbr provides per-face support for a ptex face indexing scheme. OsdGLDrawContext
/// class provides ptex face index lookup table as a texture buffer object that
/// can be accessed by GLSL shaders.
///
class GLPtexTexture : NonCopyable<GLPtexTexture> {
public:
static GLPtexTexture * Create(PtexTexture * reader,
unsigned long int targetMemory = 0,
int gutterWidth = 0,
int pageMargin = 0);
/// Returns the texture buffer containing the lookup table associate each ptex
/// face index with its 3D texture page in the texels texture array.
GLuint GetPagesTextureBuffer() const { return _pages; }
/// Returns the texture buffer containing the layout of the ptex faces in the
/// texels texture array.
GLuint GetLayoutTextureBuffer() const { return _layout; }
/// Returns the texels texture array.
GLuint GetTexelsTexture() const { return _texels; }
~GLPtexTexture();
private:
GLPtexTexture();
GLsizei _width, // widht / height / depth of the 3D texel buffer
_height,
_depth;
GLint _format; // texel color format
GLuint _pages, // per-face page indices into the texel array
_layout, // per-face lookup table (vec4 : top-left corner & width / height)
_texels; // texel data
};
} // end namespace Osd
} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;
} // end namespace OpenSubdiv
#endif // OSD_GL_PTEX_TEXTURE_H