DYT/Tool/OpenSceneGraph-3.6.5/include/osgEarth/ShaderFactory
2024-12-25 07:49:36 +08:00

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/* -*-c++-*- */
/* osgEarth - Geospatial SDK for OpenSceneGraph
* Copyright 2020 Pelican Mapping
* http://osgearth.org
*
* osgEarth is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
*/
#ifndef OSGEARTH_SHADER_FACTORY_H
#define OSGEARTH_SHADER_FACTORY_H 1
#include <osgEarth/Common>
#include <osgEarth/VirtualProgram>
#include <osgEarth/ColorFilter>
#include <vector>
namespace osgEarth { namespace Util
{
/**
* A factory object that generates shader program "scaffolding" for VirtualProgram
* attributes. Ths factory generates main() functions for each stage in the shader
* pipline. You don't use it directly; instead you just create VirtualProgram
* attributes, and those VPs will automatically invoke this factory object to
* generate their main() functions.
*
* The default ShaderFactory is stored in the osgEarth registry. You can replace it,
* but this is advanced usage and rarely necessary. If you think you need to alter
* the built-in mains, consider whether you can accomplish your goal by using a
* VirtualProgram instead!
*/
class OSGEARTH_EXPORT ShaderFactory : public osg::Referenced
{
public:
/**
* Construtor
*/
ShaderFactory();
/**
* Creates a Shader for each of the stages represented in the function map.
*/
virtual VirtualProgram::StageMask createMains(
osg::State& state,
const VirtualProgram::FunctionLocationMap& unctions,
const VirtualProgram::ShaderMap& in_shaders,
const VirtualProgram::ExtensionsSet& in_extensions,
std::vector< osg::ref_ptr<osg::Shader> >& out_mains) const;
/**
* Builds a shader function that executes an image filter chain.
* @param functionName Name to give to the resulting shader function
* @param chain Color filter chain to execute
*/
virtual osg::Shader* createColorFilterChainFragmentShader(
const std::string& functionName,
const ColorFilterChain& chain ) const;
/**
* The name of the range uniform created by createRangeUniform().
*/
virtual std::string getRangeUniformName() const;
/**
* Creates a uniform that's used by the RangeUniformCullCallback to convey
* "distance to viewpoint" in a shader program.
*/
osg::Uniform* createRangeUniform() const;
//! Remove all preprocessor callbacks
void clearProcessorCallbacks();
//! Install a shader post-processing callback
//! This will run on each shader before it gets included
UID addPreProcessorCallback(
osg::Referenced* host,
std::function<void(std::string&, osg::Referenced*)>);
//! Remove a callback you installed
void removePreProcessorCallback(UID uid);
//! Install a shader post-processing callback
//! This will run on each shader before it gets included
UID addPostProcessorCallback(
osg::Referenced* host,
std::function<void(osg::Shader*, osg::Referenced*)>);
//! Remove a callback you installed
void removePostProcessorCallback(UID uid);
//! Returns a string you can use as your shader header,
//! including the #version, precision, and extensions strings.
static std::string getGLSLHeader();
protected:
/** dtor */
virtual ~ShaderFactory() { }
};
} } // namespace osgEarth
#endif // OSGEARTH_SHADER_FACTORY_H