colmap/lib/SiftGPU/SiftMatch.cpp

////////////////////////////////////////////////////////////////////////////
//	File:		SiftMatch.cpp
//	Author:		Changchang Wu
//	Description :	implementation of SiftMatchGPU and SiftMatchGL
//
//
//	Copyright (c) 2007 University of North Carolina at Chapel Hill
//	All Rights Reserved
//
//	Permission to use, copy, modify and distribute this software and its
//	documentation for educational, research and non-profit purposes, without
//	fee, and without a written agreement is hereby granted, provided that the
//	above copyright notice and the following paragraph appear in all copies.
//
//	The University of North Carolina at Chapel Hill make no representations
//	about the suitability of this software for any purpose. It is provided
//	'as is' without express or implied warranty.
//
//	Please send BUG REPORTS to ccwu@cs.unc.edu
//
////////////////////////////////////////////////////////////////////////////

#include "GL/glew.h"
#include <iostream>
#include <iomanip>
#include <vector>
#include <sstream>
#include <algorithm>
using namespace std;
#include <string.h>
#include "GlobalUtil.h"

#include "ProgramGLSL.h"
#include "GLTexImage.h"
#include "SiftGPU.h"
#include "SiftMatch.h"
#include "FrameBufferObject.h"

#if defined(CUDA_SIFTGPU_ENABLED)
#include "CuTexImage.h"
#include "SiftMatchCU.h"
#endif


SiftMatchGL::SiftMatchGL(int max_sift, int use_glsl): SiftMatchGPU()
{
	s_multiply = s_col_max = s_row_max = s_guided_mult = NULL;
	_num_sift[0] = _num_sift[1] = 0;
	_id_sift[0] = _id_sift[1] = 0;
	_have_loc[0] = _have_loc[1] = 0;
	__max_sift = max_sift <=0 ? 4096 : ((max_sift + 31)/ 32 * 32) ;
	_pixel_per_sift = 32; //must be 32
	_sift_num_stripe = 1;
	_sift_per_stripe = 1;
	_sift_per_row = _sift_per_stripe * _sift_num_stripe;
	_initialized = 0;
}

SiftMatchGL::~SiftMatchGL()
{
	if(s_multiply) delete s_multiply;
	if(s_guided_mult) delete s_guided_mult;
	if(s_col_max) delete s_col_max;
	if(s_row_max) delete s_row_max;
}

bool SiftMatchGL::Allocate(int max_sift, int mbm) {
  SetMaxSift(max_sift);
  return glGetError() == GL_NO_ERROR;
}

void SiftMatchGL::SetMaxSift(int max_sift)
{

	max_sift = ((max_sift + 31)/32)*32;
	if(max_sift > GlobalUtil::_texMaxDimGL) max_sift = GlobalUtil::_texMaxDimGL;
	if(max_sift > __max_sift)
	{
		__max_sift = max_sift;
		AllocateSiftMatch();
		_have_loc[0] = _have_loc[1] = 0;
		_id_sift[0] = _id_sift[1] = -1;
		_num_sift[0] = _num_sift[1] = 1;
	}else
	{
		__max_sift = max_sift;
	}
}

void SiftMatchGL::AllocateSiftMatch()
{
	//parameters, number of sift is limited by the texture size
	if(__max_sift > GlobalUtil::_texMaxDimGL) __max_sift = GlobalUtil::_texMaxDimGL;
	///
	int h = __max_sift / _sift_per_row;
	int n = (GlobalUtil::_texMaxDimGL + h - 1) / GlobalUtil::_texMaxDimGL;
	if ( n > 1) {_sift_num_stripe *= n; _sift_per_row *= n; }

	//initialize

	_texDes[0].InitTexture(_sift_per_row * _pixel_per_sift, __max_sift / _sift_per_row, 0,GL_RGBA8);
	_texDes[1].InitTexture(_sift_per_row * _pixel_per_sift, __max_sift / _sift_per_row, 0, GL_RGBA8);
	_texLoc[0].InitTexture(_sift_per_row , __max_sift / _sift_per_row, 0);
	_texLoc[1].InitTexture(_sift_per_row , __max_sift / _sift_per_row, 0);

	if(GlobalUtil::_SupportNVFloat || GlobalUtil::_SupportTextureRG)
	{
		//use single-component texture to save memory
#ifndef GL_R32F
#define GL_R32F 0x822E
#endif
		GLuint format = GlobalUtil::_SupportNVFloat ? GL_FLOAT_R_NV : GL_R32F;
		_texDot.InitTexture(__max_sift, __max_sift, 0, format);
		_texMatch[0].InitTexture(16, __max_sift / 16, 0, format);
		_texMatch[1].InitTexture(16, __max_sift / 16, 0, format);
	}else
	{
		_texDot.InitTexture(__max_sift, __max_sift, 0);
		_texMatch[0].InitTexture(16, __max_sift / 16, 0);
		_texMatch[1].InitTexture(16, __max_sift / 16, 0);
	}

}
void SiftMatchGL::InitSiftMatch()
{
	if(_initialized) return;
	GlobalUtil::InitGLParam(0);
	if(GlobalUtil::_GoodOpenGL == 0) return;
	AllocateSiftMatch();
	LoadSiftMatchShadersGLSL();
	_initialized = 1;
}


void SiftMatchGL::SetDescriptors(int index, int num, const unsigned char* descriptors, int id)
{
	if(_initialized == 0) return;
	if (index > 1) index = 1;
	if (index < 0) index = 0;
	_have_loc[index] = 0;

	//the same feature is already set
	if(id !=-1 && id == _id_sift[index]) return ;
	_id_sift[index] = id;

	if(num > __max_sift) num = __max_sift;

	sift_buffer.resize(num * 128 /4);
	memcpy(&sift_buffer[0], descriptors, 128 * num);
	_num_sift[index] = num;
	int w = _sift_per_row * _pixel_per_sift;
	int h = (num + _sift_per_row  - 1)/ _sift_per_row;
	sift_buffer.resize(w * h * 4, 0);
	_texDes[index].SetImageSize(w , h);
	_texDes[index].BindTex();
	if(_sift_num_stripe == 1)
	{
		glTexSubImage2D(GlobalUtil::_texTarget, 0, 0, 0, w, h, GL_RGBA,  GL_UNSIGNED_BYTE, &sift_buffer[0]);
	}else
	{
		for(int i = 0; i < _sift_num_stripe; ++i)
		{
			int ws = _sift_per_stripe * _pixel_per_sift;
			int x = i * ws;
			int pos = i * ws * h * 4;
			glTexSubImage2D(GlobalUtil::_texTarget, 0, x, 0, ws, h, GL_RGBA, GL_UNSIGNED_BYTE, &sift_buffer[pos]);
		}
	}
	_texDes[index].UnbindTex();

}

void SiftMatchGL::SetFeautreLocation(int index, const float* locations, int gap)
{
	if(_num_sift[index] <=0) return;
	int w = _sift_per_row ;
	int h = (_num_sift[index] + _sift_per_row  - 1)/ _sift_per_row;
	sift_buffer.resize(_num_sift[index] * 2);
	if(gap == 0)
	{
		memcpy(&sift_buffer[0], locations, _num_sift[index] * 2 * sizeof(float));
	}else
	{
		for(int i = 0; i < _num_sift[index]; ++i)
		{
			sift_buffer[i*2] = *locations++;
			sift_buffer[i*2+1]= *locations ++;
			locations += gap;
		}
	}
	sift_buffer.resize(w * h * 2, 0);
	_texLoc[index].SetImageSize(w , h);
	_texLoc[index].BindTex();
	if(_sift_num_stripe == 1)
	{
		glTexSubImage2D(GlobalUtil::_texTarget, 0, 0, 0, w, h, GL_LUMINANCE_ALPHA , GL_FLOAT , &sift_buffer[0]);
	}else
	{
		for(int i = 0; i < _sift_num_stripe; ++i)
		{
			int ws = _sift_per_stripe;
			int x = i * ws;
			int pos = i * ws * h * 2;
			glTexSubImage2D(GlobalUtil::_texTarget, 0, x, 0, ws, h, GL_LUMINANCE_ALPHA , GL_FLOAT, &sift_buffer[pos]);
		}
	}
	_texLoc[index].UnbindTex();
	_have_loc[index] = 1;
}

void SiftMatchGL::SetDescriptors(int index, int num, const float* descriptors, int id)
{
	if(_initialized == 0) return;
	if (index > 1) index = 1;
	if (index < 0) index = 0;
	_have_loc[index] = 0;

	//the same feature is already set
	if(id !=-1 && id == _id_sift[index]) return ;
	_id_sift[index] = id;

	if(num > __max_sift) num = __max_sift;

	sift_buffer.resize(num * 128 /4);
	unsigned char * pub = (unsigned char*) &sift_buffer[0];
	for(int i = 0; i < 128 * num; ++i)
	{
		pub[i] = int(512 * descriptors[i] + 0.5);
	}
	_num_sift[index] = num;
	int w = _sift_per_row * _pixel_per_sift;
	int h = (num + _sift_per_row  - 1)/ _sift_per_row;
	sift_buffer.resize(w * h * 4, 0);
	_texDes[index].SetImageSize(w, h);
	_texDes[index].BindTex();
	if(_sift_num_stripe == 1)
	{
		glTexSubImage2D(GlobalUtil::_texTarget, 0, 0, 0, w, h, GL_RGBA,  GL_UNSIGNED_BYTE, &sift_buffer[0]);
	}else
	{
		for(int i = 0; i < _sift_num_stripe; ++i)
		{
			int ws = _sift_per_stripe * _pixel_per_sift;
			int x = i * ws;
			int pos = i * ws * h * 4;
			glTexSubImage2D(GlobalUtil::_texTarget, 0, x, 0, ws, h, GL_RGBA, GL_UNSIGNED_BYTE, &sift_buffer[pos]);
		}
	}
	_texDes[index].UnbindTex();
}


void SiftMatchGL::LoadSiftMatchShadersGLSL()
{
	ProgramGLSL * program;
	ostringstream out;
	if(GlobalUtil::_IsNvidia)
	out <<  "#pragma optionNV(ifcvt none)\n"
			"#pragma optionNV(unroll all)\n";

    out <<  "#define SIFT_PER_STRIPE " << _sift_per_stripe << ".0\n"
			"#define PIXEL_PER_SIFT " << _pixel_per_sift << "\n"
			"uniform sampler2DRect tex1, tex2; uniform vec2	size;\n"
			"void main()		\n"
		    "{\n"
		<<	"   vec4 val = vec4(0.0, 0.0, 0.0, 0.0), data1, buf;\n"
			"   vec2 index = gl_FragCoord.yx; \n"
			"   vec2 stripe_size = size.xy * SIFT_PER_STRIPE;\n"
			"	vec2 temp_div1 = index / stripe_size;\n"
			"   vec2 stripe_index = floor(temp_div1);\n"
			"   index = floor(stripe_size * (temp_div1 - stripe_index));\n"
			"	vec2 temp_div2 = index * vec2(1.0 / float(SIFT_PER_STRIPE));\n"
			"	vec2 temp_floor2 = floor(temp_div2);\n"
			"   vec2 index_v = temp_floor2 + vec2(0.5);\n "
			"   vec2 index_h = vec2(SIFT_PER_STRIPE)* (temp_div2 - temp_floor2);\n"
			"   vec2 tx = (index_h + stripe_index * vec2(SIFT_PER_STRIPE))* vec2(PIXEL_PER_SIFT) + 0.5;\n"
			"   vec2 tpos1, tpos2; \n"
			"	vec4 tpos = vec4(tx, index_v);\n"
			//////////////////////////////////////////////////////
			"   for(int i = 0; i < PIXEL_PER_SIFT; ++i){\n"
			"		buf = texture2DRect(tex2, tpos.yw);\n"
			"		data1 = texture2DRect(tex1, tpos.xz);\n"
			"		val += (data1 * buf);\n"
			"		tpos.xy = tpos.xy + vec2(1.0, 1.0);\n"
			"	}\n"
			"	const float factor = 0.248050689697265625; \n"
			"	gl_FragColor =vec4(dot(val, vec4(factor)), index,  0);\n"
			"}"
		<<	'\0';

	s_multiply = program= new ProgramGLSL(out.str().c_str());

	_param_multiply_tex1 = glGetUniformLocation(*program, "tex1");
	_param_multiply_tex2 = glGetUniformLocation(*program, "tex2");
	_param_multiply_size = glGetUniformLocation(*program, "size");

	out.seekp(ios::beg);
    if(GlobalUtil::_IsNvidia)
    out <<  "#pragma optionNV(ifcvt none)\n"
			"#pragma optionNV(unroll all)\n";

    out <<  "#define SIFT_PER_STRIPE " << _sift_per_stripe << ".0\n"
			"#define PIXEL_PER_SIFT " << _pixel_per_sift << "\n"
			"uniform sampler2DRect tex1, tex2;\n"
			"uniform sampler2DRect texL1;\n"
			"uniform sampler2DRect texL2; \n"
			"uniform mat3 H; \n"
			"uniform mat3 F; \n"
			"uniform vec4	size; \n"
			"void main()		\n"
		    "{\n"
		<<	"   vec4 val = vec4(0.0, 0.0, 0.0, 0.0), data1, buf;\n"
			"   vec2 index = gl_FragCoord.yx; \n"
			"   vec2 stripe_size = size.xy * SIFT_PER_STRIPE;\n"
			"	vec2 temp_div1 = index / stripe_size;\n"
			"   vec2 stripe_index = floor(temp_div1);\n"
			"   index = floor(stripe_size * (temp_div1 - stripe_index));\n"
			"	vec2 temp_div2 = index  * vec2(1.0/ float(SIFT_PER_STRIPE));\n"
			"	vec2 temp_floor2 = floor(temp_div2);\n"
			"   vec2 index_v = temp_floor2 + vec2(0.5);\n "
			"   vec2 index_h = vec2(SIFT_PER_STRIPE)* (temp_div2 - temp_floor2);\n"

			//read feature location data
			"   vec4 tlpos = vec4((index_h + stripe_index * vec2(SIFT_PER_STRIPE)) + 0.5, index_v);\n"
			"   vec3 loc1 = vec3(texture2DRect(texL1, tlpos.xz).xw, 1.0);\n"
			"   vec3 loc2 = vec3(texture2DRect(texL2, tlpos.yw).xw, 1.0);\n"

			//check the guiding homography
			"   vec3 hxloc1 = H* loc1;\n"
			"   vec2 diff = loc2.xy- (hxloc1.xy/hxloc1.z);\n"
			"   float disth = diff.x * diff.x + diff.y * diff.y;\n"
			"   if(disth > size.z ) {gl_FragColor = vec4(0.0, index, 0.0); return;}\n"

			//check the guiding fundamental
			"   vec3 fx1 = (F * loc1), ftx2 = (loc2 * F);\n"
			"   float x2tfx1 = dot(loc2, fx1);\n"
			"   vec4 temp = vec4(fx1.xy, ftx2.xy); \n"
			"   float sampson_error = (x2tfx1 * x2tfx1) / dot(temp, temp);\n"
			"   if(sampson_error > size.w) {gl_FragColor = vec4(0.0, index, 0.0); return;}\n"

			//compare feature descriptor
			"   vec2 tx = (index_h + stripe_index * SIFT_PER_STRIPE)* vec2(PIXEL_PER_SIFT) + 0.5;\n"
			"   vec2 tpos1, tpos2; \n"
			"	vec4 tpos = vec4(tx, index_v);\n"
			"   for(int i = 0; i < PIXEL_PER_SIFT; ++i){\n"
			"		buf = texture2DRect(tex2, tpos.yw);\n"
			"		data1 = texture2DRect(tex1, tpos.xz);\n"
			"		val += data1 * buf;\n"
			"		tpos.xy = tpos.xy + vec2(1.0, 1.0);\n"
			"	}\n"
			"	const float factor = 0.248050689697265625; \n"
			"	gl_FragColor =vec4(dot(val, vec4(factor)), index,  0.0);\n"
			"}"
		<<	'\0';

	s_guided_mult = program= new ProgramGLSL(out.str().c_str());

	_param_guided_mult_tex1 = glGetUniformLocation(*program, "tex1");
	_param_guided_mult_tex2= glGetUniformLocation(*program, "tex2");
	_param_guided_mult_texl1 = glGetUniformLocation(*program, "texL1");
	_param_guided_mult_texl2 = glGetUniformLocation(*program, "texL2");
	_param_guided_mult_h = glGetUniformLocation(*program, "H");
	_param_guided_mult_f = glGetUniformLocation(*program, "F");
	_param_guided_mult_param = glGetUniformLocation(*program, "size");

	//row max
	out.seekp(ios::beg);
	out <<	"#define BLOCK_WIDTH 16.0\n"
			"uniform sampler2DRect tex;	uniform vec3 param;\n"
			"void main ()\n"
			"{\n"
			"	float index = gl_FragCoord.x + floor(gl_FragCoord.y) * BLOCK_WIDTH; \n"
			"	vec2 bestv = vec2(-1.0); float imax = -1.0;\n"
			"	for(float i = 0.0; i < param.x; i ++){\n "
			"		float v = texture2DRect(tex, vec2(i + 0.5, index)).r; \n"
			"		imax = v > bestv.r ? i : imax; \n "
			"		bestv  = v > bestv.r? vec2(v, bestv.r) : max(bestv, vec2(v));\n "
			"	}\n"
			"	bestv = acos(min(bestv, 1.0));\n"
			"	if(bestv.x >= param.y || bestv.x >= param.z * bestv.y) imax = -1.0;\n"
			"	gl_FragColor = vec4(imax, bestv, index);\n"
			"}"
		<<  '\0';
	s_row_max = program= new ProgramGLSL(out.str().c_str());
	_param_rowmax_param = glGetUniformLocation(*program, "param");

	out.seekp(ios::beg);
	out <<	"#define BLOCK_WIDTH 16.0\n"
			"uniform sampler2DRect tex; uniform vec3 param;\n"
			"void main ()\n"
			"{\n"
			"	float index = gl_FragCoord.x + floor(gl_FragCoord.y) * BLOCK_WIDTH; \n"
			"	vec2 bestv = vec2(-1.0); float imax = -1.0;\n"
			"	for(float i = 0.0; i < param.x; i ++){\n "
			"		float v = texture2DRect(tex, vec2(index, i + 0.5)).r; \n"
			"		imax = (v > bestv.r)? i : imax; \n "
			"		bestv  = v > bestv.r? vec2(v, bestv.r) : max(bestv, vec2(v));\n "
			"	}\n"
			"	bestv = acos(min(bestv, 1.0));\n"
			"	if(bestv.x >= param.y || bestv.x >= param.z * bestv.y) imax = -1.0;\n"
			"	gl_FragColor = vec4(imax, bestv, index);\n"
			"}"
		<<  '\0';
	s_col_max = program =new ProgramGLSL(out.str().c_str());
	_param_colmax_param = glGetUniformLocation(*program, "param");


}

int  SiftMatchGL::GetGuidedSiftMatch(int max_match, uint32_t match_buffer[][2], float* H, float* F,
									 float distmax, float ratiomax, float hdistmax, float fdistmax, int mbm)
{

	int dw = _num_sift[1];
	int dh = _num_sift[0];
	if(_initialized ==0) return 0;
	if(dw <= 0 || dh <=0) return 0;
	if(_have_loc[0] == 0 || _have_loc[1] == 0) return 0;

	FrameBufferObject fbo;
	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
	_texDot.SetImageSize(dw, dh);


	//data
	_texDot.AttachToFBO(0);
	_texDot.FitTexViewPort();
	glActiveTexture(GL_TEXTURE0);
	_texDes[0].BindTex();
	glActiveTexture(GL_TEXTURE1);
	_texDes[1].BindTex();
	glActiveTexture(GL_TEXTURE2);
	_texLoc[0].BindTex();
	glActiveTexture(GL_TEXTURE3);
	_texLoc[1].BindTex();

	//multiply the descriptor matrices
	s_guided_mult->UseProgram();


	//set parameters glsl
	float dot_param[4] = {(float)_texDes[0].GetDrawHeight(), (float) _texDes[1].GetDrawHeight(), hdistmax, fdistmax};
	glUniform1i(_param_guided_mult_tex1, 0);
	glUniform1i(_param_guided_mult_tex2, 1);
	glUniform1i(_param_guided_mult_texl1, 2);
	glUniform1i(_param_guided_mult_texl2, 3);
	glUniformMatrix3fv(_param_guided_mult_h, 1, GL_TRUE, H);
	glUniformMatrix3fv(_param_guided_mult_f, 1, GL_TRUE, F);
	glUniform4fv(_param_guided_mult_param, 1, dot_param);

	_texDot.DrawQuad();

	GLTexImage::UnbindMultiTex(4);

	return GetBestMatch(max_match, match_buffer, distmax, ratiomax, mbm);
}

int SiftMatchGL::GetBestMatch(int max_match, uint32_t match_buffer[][2], float distmax, float ratiomax, int mbm)
{

	glActiveTexture(GL_TEXTURE0);
	_texDot.BindTex();

	//readback buffer
	sift_buffer.resize(_num_sift[0] + _num_sift[1] + 16);
	float * buffer1 = &sift_buffer[0], * buffer2 = &sift_buffer[_num_sift[0]];

	//row max
	_texMatch[0].AttachToFBO(0);
	_texMatch[0].SetImageSize(16, ( _num_sift[0] + 15) / 16);
	_texMatch[0].FitTexViewPort();

	///set parameter glsl
	s_row_max->UseProgram();
	glUniform3f(_param_rowmax_param, (float)_num_sift[1], distmax, ratiomax);

	_texMatch[0].DrawQuad();
	glReadPixels(0, 0, 16, (_num_sift[0] + 15)/16, GL_RED, GL_FLOAT, buffer1);

	//col max
	if(mbm)
	{
		_texMatch[1].AttachToFBO(0);
		_texMatch[1].SetImageSize(16, (_num_sift[1] + 15) / 16);
		_texMatch[1].FitTexViewPort();
		//set parameter glsl
		s_col_max->UseProgram();
		glUniform3f(_param_rowmax_param, (float)_num_sift[0], distmax, ratiomax);
		_texMatch[1].DrawQuad();
		glReadPixels(0, 0, 16, (_num_sift[1] + 15) / 16, GL_RED, GL_FLOAT, buffer2);
	}


	//unload
	glUseProgram(0);

	GLTexImage::UnbindMultiTex(2);
	GlobalUtil::CleanupOpenGL();

	//write back the matches
	int nmatch = 0, j ;
	for(int i = 0; i < _num_sift[0] && nmatch < max_match; ++i)
	{
		j = int(buffer1[i]);
		if( j>= 0 && (!mbm ||int(buffer2[j]) == i))
		{
			match_buffer[nmatch][0] = i;
			match_buffer[nmatch][1] = j;
			nmatch++;
		}
	}

  const GLenum error_code(glGetError());
  if (error_code != GL_NO_ERROR) {
    return -1;
  }

	return nmatch;
}

int  SiftMatchGL::GetSiftMatch(int max_match, uint32_t match_buffer[][2], float distmax, float ratiomax, int mbm)
{
	int dw = _num_sift[1];
	int dh =  _num_sift[0];
	if(_initialized ==0) return 0;
	if(dw <= 0 || dh <=0) return 0;

	FrameBufferObject fbo;
	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
	_texDot.SetImageSize(dw, dh);

	//data
	_texDot.AttachToFBO(0);
	_texDot.FitTexViewPort();
	glActiveTexture(GL_TEXTURE0);
	_texDes[0].BindTex();
	glActiveTexture(GL_TEXTURE1);
	_texDes[1].BindTex();

	//////////////////
	//multiply the descriptor matrices
	s_multiply->UseProgram();
	//set parameters
	float heights[2] = {(float)_texDes[0].GetDrawHeight(), (float)_texDes[1].GetDrawHeight()};

	glUniform1i(_param_multiply_tex1, 0);
	glUniform1i(_param_multiply_tex2 , 1);
	glUniform2fv(_param_multiply_size, 1, heights);

	_texDot.DrawQuad();

	glActiveTexture(GL_TEXTURE1);
	glBindTexture(GlobalUtil::_texTarget, 0);

	return GetBestMatch(max_match, match_buffer, distmax, ratiomax, mbm);
}


int SiftMatchGPU::_CreateContextGL()
{
	//Create an OpenGL Context?
    if (__language >= SIFTMATCH_CUDA) {}
	else if(!GlobalUtil::CreateWindowEZ())
	{
#if CUDA_SIFTGPU_ENABLED
		__language = SIFTMATCH_CUDA;
#else
		return 0;
#endif
	}
	return VerifyContextGL();
}


int SiftMatchGPU::_VerifyContextGL()
{
	if(__matcher) return GlobalUtil::_GoodOpenGL;

#ifdef CUDA_SIFTGPU_ENABLED

    if(__language >= SIFTMATCH_CUDA) {}
    else if(__language == SIFTMATCH_SAME_AS_SIFTGPU && GlobalUtil::_UseCUDA){}
    else  GlobalUtil::InitGLParam(0);
    if(GlobalUtil::_GoodOpenGL == 0) __language = SIFTMATCH_CUDA;

    if(((__language == SIFTMATCH_SAME_AS_SIFTGPU && GlobalUtil::_UseCUDA) || __language >= SIFTMATCH_CUDA)
        && SiftMatchCU::CheckCudaDevice (GlobalUtil::_DeviceIndex))
    {
		__language = SIFTMATCH_CUDA;
		__matcher = ::new SiftMatchCU(__max_sift);
	}else
#else
    if((__language == SIFTMATCH_SAME_AS_SIFTGPU && GlobalUtil::_UseCUDA) || __language >= SIFTMATCH_CUDA)
    {
	    std::cerr	<< "---------------------------------------------------------------------------\n"
				    << "CUDA not supported in this binary! To enable it, please use SiftGPU_CUDA_Enable\n"
				    << "Project for VS2005+ or set siftgpu_enable_cuda to 1 in makefile\n"
				    << "----------------------------------------------------------------------------\n";
    }
#endif
	{
		__language = SIFTMATCH_GLSL;
		__matcher = ::new SiftMatchGL(__max_sift, 1);
	}

	if(GlobalUtil::_verbose)
        std::cout   << "[SiftMatchGPU]: " << (__language == SIFTMATCH_CUDA? "CUDA" : "GLSL") <<"\n\n";

	__matcher->InitSiftMatch();
	return GlobalUtil::_GoodOpenGL;
}

SiftMatchGPU::SiftMatchGPU(int max_sift)
{
	__max_sift = max(max_sift, 1024);
	__language = 0;
	__matcher = NULL;
}

void SiftMatchGPU::SetLanguage(int language)
{
	if(__matcher) return;
    ////////////////////////
#ifdef CUDA_SIFTGPU_ENABLED
	if(language >= SIFTMATCH_CUDA) GlobalUtil::_DeviceIndex = language - SIFTMATCH_CUDA;
#endif
    __language = language > SIFTMATCH_CUDA ? SIFTMATCH_CUDA : language;
}

void SiftMatchGPU::SetDeviceParam(int argc, char**argv)
{
    if(__matcher) return;
    GlobalUtil::SetDeviceParam(argc, argv);
}

bool SiftMatchGPU::Allocate(int max_sift, int mbm) {
  if(__matcher) {
    const bool success = __matcher->Allocate(max_sift, mbm);
    __max_sift = __matcher->__max_sift;
    return success;
  }

  return false;
}

void SiftMatchGPU::SetMaxSift(int max_sift)
{
	if(__matcher)	{
    __matcher->SetMaxSift(max(128, max_sift));
    __max_sift = __matcher->__max_sift;
  } else {
    __max_sift = max(128, max_sift);
  }
}

SiftMatchGPU::~SiftMatchGPU()
{
	if(__matcher) delete __matcher;
}

void SiftMatchGPU::SetDescriptors(int index, int num, const unsigned char* descriptors, int id)
{
	__matcher->SetDescriptors(index, num,  descriptors, id);
}

void SiftMatchGPU::SetDescriptors(int index, int num, const float* descriptors, int id)
{
	__matcher->SetDescriptors(index, num, descriptors, id);
}

void SiftMatchGPU::SetFeautreLocation(int index, const float* locations, int gap)
{
	__matcher->SetFeautreLocation(index, locations, gap);

}
int  SiftMatchGPU::GetGuidedSiftMatch(int max_match, uint32_t match_buffer[][2], float* H, float* F,
				float distmax, float ratiomax, float hdistmax, float fdistmax, int mutual_best_match)
{
	if(H == NULL && F == NULL)
	{
		return __matcher->GetSiftMatch(max_match, match_buffer, distmax, ratiomax, mutual_best_match);
	}else
	{
		float Z[9] = {1, 0, 0, 0, 1, 0, 0, 0, 1}, ti = (1.0e+20F);

		return __matcher->GetGuidedSiftMatch(max_match, match_buffer, H? H : Z, F? F : Z,
			distmax, ratiomax, H? hdistmax: ti,  F? fdistmax: ti, mutual_best_match);
	}
}

int  SiftMatchGPU::GetSiftMatch(int max_match, uint32_t match_buffer[][2], float distmax, float ratiomax, int mutual_best_match)
{
	return __matcher->GetSiftMatch(max_match, match_buffer, distmax, ratiomax, mutual_best_match);
}

SiftMatchGPU* CreateNewSiftMatchGPU(int max_sift)
{
	return new SiftMatchGPU(max_sift);
}