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// OpenCSG - library for image-based CSG rendering for OpenGL
// Copyright (C) 2010-2026, Florian Kirsch
//
// This library 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 2 of the License, or
// (at your option) any later version.
//
// This library 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, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110 - 1301 USA.
//
// context.cpp
//
#include "opencsgConfig.h"
#include "context.h"
#include "offscreenBuffer.h"
#include "frameBufferObject.h"
#include "frameBufferObjectExt.h"
#include "openglHelper.h"
#include <map>
namespace OpenCSG {
static int gContext = 0;
/// redeclared from opencsg.h
void setContext(int context) {
gContext = context;
}
/// redeclared from opencsg.h
int getContext() {
return gContext;
}
/// redeclared from opencsg.h
void freeResources() {
OpenGL::freeResources();
}
namespace OpenGL {
struct ContextData {
ContextData() : fARB(0), fEXT(0)
{}
FrameBufferObject* fARB;
FrameBufferObjectExt* fEXT;
std::map<const char*, GLuint> idFP;
std::map<const char*, GLuint> idGLSL;
};
static std::map<int, ContextData> gContextDataMap;
void ensureFunctionPointers()
{
// In theory (and probably under Windows only), OpenGL function
// pointers could be context specific. I.e., after changing to
// a different context, it may be required to update the function
// pointers again, or, to store them per context in the first place.
// When changing from GLEW to glad, it turned out that this had
// never been correctly considered. So I decided to ignore this
// potential problem until I get concrete complaints.
static bool sHaveOpenGLFunctions = false;
if (!sHaveOpenGLFunctions)
initExtensionLibrary();
sHaveOpenGLFunctions = true;
}
OffscreenBuffer* getOffscreenBuffer(OffscreenType type) {
int context = getContext();
ContextData& contextData = gContextDataMap[context];
if (type == OpenCSG::FrameBufferObjectARB) {
if (!contextData.fARB)
contextData.fARB = new FrameBufferObject;
return contextData.fARB;
}
else if (type == OpenCSG::FrameBufferObjectEXT) {
if (!contextData.fEXT)
contextData.fEXT = new FrameBufferObjectExt;
return contextData.fEXT;
}
return 0;
}
static GLuint getARBProgram(GLenum target, const char* prog, int len)
{
int context = getContext();
ContextData& contextData = gContextDataMap[context];
std::map<const char*, GLuint>::iterator it = contextData.idFP.find(prog);
if (it == contextData.idFP.end())
{
GLuint id;
glGenProgramsARB(1, &id);
glBindProgramARB(target, id);
glProgramStringARB(target, GL_PROGRAM_FORMAT_ASCII_ARB, len, prog);
// GLint errorPos;
// glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorPos);
// const char * error = (const char*)glGetString(GL_PROGRAM_ERROR_STRING_ARB);
// printf("%s", error);
it = contextData.idFP.insert(std::pair<const char*, GLuint>(prog, id)).first;
}
return it->second;
}
GLuint getARBVertexProgram(const char* prog, int len)
{
return getARBProgram(GL_VERTEX_PROGRAM_ARB, prog, len);
}
GLuint getARBFragmentProgram(const char* prog, int len)
{
return getARBProgram(GL_FRAGMENT_PROGRAM_ARB, prog, len);
}
static GLuint getGLSLShader(GLenum target, const char* prog)
{
GLuint id = glCreateShader(target);
glShaderSource(id, 1, &prog, 0);
glCompileShader(id);
GLint success;
char infoLog[512];
glGetShaderiv(id, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(id, 512, NULL, infoLog);
//std::cerr << "Vertex Shader Compilation Error: " << infoLog << std::endl;
}
return id;
}
GLuint getGLSLVertexShader(const char* prog)
{
return getGLSLShader(GL_VERTEX_SHADER, prog);
}
GLuint getGLSLFragmentShader(const char* prog)
{
return getGLSLShader(GL_FRAGMENT_SHADER, prog);
}
GLuint getGLSLProgram(const char* programId, const char* vertexProg, const char* fragmentProg)
{
int context = getContext();
ContextData& contextData = gContextDataMap[context];
std::map<const char*, GLuint>::iterator it = contextData.idGLSL.find(programId);
if (it == contextData.idGLSL.end())
{
GLuint vertexShader = getGLSLVertexShader(vertexProg);
GLuint fragmentShader = getGLSLFragmentShader(fragmentProg);
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
it = contextData.idGLSL.insert(std::pair<const char*, GLuint>(programId, shaderProgram)).first;
}
return it->second;
}
void freeResources()
{
int context = getContext();
std::map<int, ContextData>::iterator itr = gContextDataMap.find(context);
if (itr != gContextDataMap.end())
{
delete itr->second.fARB;
delete itr->second.fEXT;
{
std::map<const char*, GLuint> & idFP = itr->second.idFP;
for (std::map<const char*, GLuint>::iterator it = idFP.begin(); it != idFP.end(); ++it)
{
glDeleteProgramsARB(1, &(it->second));
}
}
{
std::map<const char*, GLuint> & idGLSL = itr->second.idGLSL;
for (std::map<const char*, GLuint>::iterator it = idGLSL.begin(); it != idGLSL.end(); ++it)
{
glDeleteProgram(it->second);
}
}
gContextDataMap.erase(itr);
}
}
} // namespace OpenGL
} // namespace OpenCSG