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Issue #7: Use GL_EXT_framebuffer_object when OpenGL version < 3.0

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Add runtime check of OpenGL version and extensions.
If OpenGL version >= 3.0, use core functions.
Else check for framebuffer object extension and use EXT functions.
If none of the above, do nothing but return GL_FRAMEBUFFER_COMPLETE.
This commit is contained in:
vrld
2010-08-27 13:51:11 +02:00
parent 5ae3573c32
commit f9f7e83f0e
1 changed files with 182 additions and 32 deletions
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src/modules/graphics/opengl/Framebuffer.cpp
+182 -32
View File
@@ -1,6 +1,170 @@
#include "Framebuffer.h"
#include <common/Matrix.h>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
namespace {
// functions to get opengl capabilities at runtime
vector<string> tokenize(const string& str)
{
vector<string> tokens;
istringstream iss( str );
copy(istream_iterator<string>(iss), istream_iterator<string>(),
back_inserter< vector<string> >(tokens));
return tokens;
}
float getOpenGLVersionNumber()
{
vector<string> tokens = tokenize( (const char*)glGetString(GL_VERSION) );
stringstream toNumber( tokens.at(0) );
double version;
toNumber >> version;
return version;
}
bool hasFramebufferExtension()
{
vector<string> ext = tokenize( (const char*)glGetString(GL_EXTENSIONS) );
return find(ext.begin(), ext.end(), "GL_EXT_framebuffer_object") != ext.end();
}
// strategy for fbo creation, interchangable at runtime:
// none, opengl >= 3.0, extensions
struct FramebufferStrategy {
/// create a new framebuffer, depthbuffer and texture
/**
* @param[out] framebuffer Framebuffer name
* @param[out] depthbuffer Depthbuffer name
* @param[out] img Texture name
* @param[in] width Width of framebuffer
* @param[in] height Height of framebuffer
* @return Creation status
*/
virtual GLenum createFBO(GLuint& framebuffer, GLuint& depthbuffer, GLuint& img, int width, int height)
{ return GL_FRAMEBUFFER_UNSUPPORTED; }
/// remove objects
/**
* @param[in] framebuffer Framebuffer name
* @param[in] depthbuffer Depthbuffer name
* @param[in] img Texture name
*/
virtual void deleteFBO(GLuint framebuffer, GLuint depthbuffer, GLuint img) {}
virtual void bindFBO(GLuint framebuffer) {}
};
#ifdef GL_VERSION_3_0
struct FramebufferStrategyGL3 : public FramebufferStrategy {
virtual GLenum createFBO(GLuint& framebuffer, GLuint& depthbuffer, GLuint& img, int width, int height)
{
// generate depth buffer
glGenRenderbuffers(1, &depthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, width, height);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
// generate texture save target
glGenTextures(1, &img);
glBindTexture(GL_TEXTURE_2D, img);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindTexture(GL_TEXTURE_2D, 0);
// create framebuffer
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, img, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, depthbuffer);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
// unbind buffers and texture
glBindFramebuffer(GL_FRAMEBUFFER, 0);
return status;
}
virtual void deleteFBO(GLuint framebuffer, GLuint depthbuffer, GLuint img)
{
glDeleteTextures(1, &framebuffer);
glDeleteRenderbuffers(1, &depthbuffer);
glDeleteFramebuffers(1, &img);
}
virtual void bindFBO(GLuint framebuffer)
{
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
}
};
#endif
struct FramebufferStrategyEXT : public FramebufferStrategy {
virtual GLenum createFBO(GLuint& framebuffer, GLuint& depthbuffer, GLuint& img, int width, int height)
{
// generate depth buffer
glGenRenderbuffersEXT(1, &depthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER_EXT, depthbuffer);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT16, width, height);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);
// generate texture save target
glGenTextures(1, &img);
glBindTexture(GL_TEXTURE_2D, img);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindTexture(GL_TEXTURE_2D, 0);
// create framebuffer
glGenFramebuffersEXT(1, &framebuffer);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_TEXTURE_2D, img, 0);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, depthbuffer);
GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
// unbind buffers and texture
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
return status;
}
virtual void deleteFBO(GLuint framebuffer, GLuint depthbuffer, GLuint img)
{
glDeleteTextures(1, &framebuffer);
glDeleteRenderbuffersEXT(1, &depthbuffer);
glDeleteFramebuffersEXT(1, &img);
}
virtual void bindFBO(GLuint framebuffer)
{
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer);
}
};
FramebufferStrategy* strategy = NULL;
FramebufferStrategy strategyNone;
#ifdef GL_VERSION_3_0
FramebufferStrategyGL3 strategyGL3;
#endif
FramebufferStrategyEXT strategyEXT;
};
namespace love
{
namespace graphics
@@ -25,32 +189,21 @@ namespace opengl
vertices[2].s = 1; vertices[2].t = 0;
vertices[3].s = 1; vertices[3].t = 1;
// generate depth buffer
glGenRenderbuffers(1, &depthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, width, height);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
if (!strategy) {
#ifdef GL_VERSION_3_0
if (getOpenGLVersionNumber() >= 3.0)
strategy = &strategyGL3;
else if (hasFramebufferExtension())
#else
if (hasFramebufferExtension())
#endif
strategy = &strategyEXT;
else
strategy = &strategyNone;
}
// generate texture save target
glGenTextures(1, &img);
glBindTexture(GL_TEXTURE_2D, img);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindTexture(GL_TEXTURE_2D, 0);
// create framebuffer
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, img, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, depthbuffer);
status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
// unbind buffers and texture
glBindFramebuffer(GL_FRAMEBUFFER, 0);
status = strategy->createFBO(fbo, depthbuffer, img, width, height);
}
Framebuffer::~Framebuffer()
@@ -59,10 +212,7 @@ namespace opengl
if (current == this)
stopGrab();
// clear fbo
glDeleteTextures(1, &fbo);
glDeleteRenderbuffers(1, &depthbuffer);
glDeleteFramebuffers(1, &img);
strategy->deleteFBO(fbo, depthbuffer, img);
}
void Framebuffer::bindDefaultBuffer()
@@ -83,12 +233,12 @@ namespace opengl
// bind buffer and clear screen
glPushAttrib(GL_VIEWPORT_BIT | GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
strategy->bindFBO(fbo);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glClearColor(.0f, .0f, .0f, .0f);
glViewport(0, 0, width, height);
// indicate
// indicate we are using this fbo
current = this;
}
@@ -99,7 +249,7 @@ namespace opengl
return;
// bind default
glBindFramebuffer(GL_FRAMEBUFFER, 0);
strategy->bindFBO( 0 );
glPopAttrib();
current = NULL;
}