Texture object generated in run time from another texture. More...

#include <SLGLTextureIBL.h>

Inheritance diagram for SLGLTextureIBL:

Public Member Functions
	SLGLTextureIBL ()
	Default constructor. More...

	SLGLTextureIBL (SLAssetManager assetMgr, SLstring shaderPath, SLGLTexture sourceTexture, SLVec2i size, SLTextureType texType, SLenum target, SLbool readBackPixels=true, SLint min_filter=GL_LINEAR, SLint mag_filter=GL_LINEAR)
	ctor for generated textures More...

virtual	~SLGLTextureIBL ()

virtual void	build (SLint texID=0)

void	logFramebufferStatus ()

Public Member Functions inherited from SLGLTexture
	SLGLTexture ()
	Default ctor for all stack instances (not created with new) More...

	SLGLTexture (SLAssetManager *assetMgr, const SLVCol4f &colors, SLint min_filter=GL_LINEAR, SLint mag_filter=GL_LINEAR, SLint wrapS=GL_REPEAT, const SLstring &name="2D-Texture")
	ctor for 1D texture with internal image allocation More...

	SLGLTexture (SLAssetManager *assetMgr, SLint min_filter, SLint mag_filter, SLint wrapS, SLint wrapT, SLenum target=GL_TEXTURE_2D)
	ctor for empty 2D textures More...

	SLGLTexture (SLAssetManager assetMgr, unsigned char data, int width, int height, int cvtype, SLint min_filter, SLint mag_filter, SLTextureType type, SLint wrapS, SLint wrapT)
	ctor for 2D textures from byte pointer More...

	SLGLTexture (SLAssetManager *assetMgr, const SLstring &imageFilename, SLint min_filter=GL_LINEAR_MIPMAP_LINEAR, SLint mag_filter=GL_LINEAR, SLTextureType type=TT_unknown, SLint wrapS=GL_REPEAT, SLint wrapT=GL_REPEAT)
	ctor for 2D textures with internal image allocation More...

	SLGLTexture (SLAssetManager *assetMgr, const SLVstring &imageFilenames, SLint min_filter=GL_LINEAR, SLint mag_filter=GL_LINEAR, SLint wrapS=GL_REPEAT, SLint wrapT=GL_REPEAT, const SLstring &name="3D-Texture", SLbool loadGrayscaleIntoAlpha=false)
	ctor for 3D texture with internal image allocation More...

	SLGLTexture (SLAssetManager *assetMgr, SLint depth, const SLstring &imageFilename, SLint min_filter=GL_LINEAR, SLint mag_filter=GL_LINEAR, SLint wrapS=GL_REPEAT, SLint wrapT=GL_REPEAT, const SLstring &name="3D-Texture", SLbool loadGrayscaleIntoAlpha=false)
	ctor for 3D texture from a single file with depth as 3rd dimension More...

	SLGLTexture (SLAssetManager *assetMgr, const SLstring &imageFilenameXPos, const SLstring &imageFilenameXNeg, const SLstring &imageFilenameYPos, const SLstring &imageFilenameYNeg, const SLstring &imageFilenameZPos, const SLstring &imageFilenameZNeg, SLint min_filter=GL_LINEAR, SLint mag_filter=GL_LINEAR, SLTextureType type=TT_unknown)
	ctor for cube mapping with internal image allocation More...

	~SLGLTexture () override

void	deleteData (SLbool deleteAlsoOnGPU)
	Delete all data (CVImages and GPU textures) More...

void	deleteDataGpu ()
	Deletes the OpenGL texture objects and releases the memory on the GPU. More...

void	deleteImages ()
	Deletes the CVImages in _images. No more texture mapping in ray tracing. More...

void	bindActive (SLuint texUnit=0)

void	fullUpdate ()

void	drawSprite (SLbool doUpdate, SLfloat x, SLfloat y, SLfloat w, SLfloat h)
	Draws the texture as 2D sprite with OpenGL buffers. More...

void	cubeUV2XYZ (SLint index, SLfloat u, SLfloat v, SLfloat &x, SLfloat &y, SLfloat &z)
	Computes the unnormalised vector x,y,z from tex. coords. uv with cubemap index. More...

void	cubeXYZ2UV (SLfloat x, SLfloat y, SLfloat z, SLint &index, SLfloat &u, SLfloat &v)
	Computes the uv and cubemap image index from a unnormalised vector x,y,z. More...

SLstring	filterString (SLint glFilter)
	Returns OpenGL texture filter as string. More...

void	texType (SLTextureType bt)

void	uvIndex (SLbyte i)

void	bumpScale (SLfloat bs)

void	minFiler (SLint minF)

void	magFiler (SLint magF)

void	needsUpdate (SLbool update)

void	textureSize (int width, int height)

void	deleteImageAfterBuild (SLbool delImg)
	If deleteImageAfterBuild is set to true you won't be able to ray trace the scene. More...

SLuint	width ()

SLuint	height ()

SLuint	depth ()

SLbyte	uvIndex ()

SLint	bytesPerPixel ()

SLint	bytesOnGPU ()

SLint	bytesInFile ()

CVVImage &	images ()

SLenum	target () const

SLuint	texID () const

SLTextureType	texType ()

SLfloat	bumpScale () const

SLCol4f	getTexelf (SLfloat u, SLfloat v, SLuint imgIndex=0)
	SLGLTexture::getTexelf returns a pixel color from u & v texture coordinates. More...

SLCol4f	getTexelf (const SLVec3f &cubemapDir)
	SLGLTexture::getTexelf returns a pixel color at the specified cubemap direction. More...

SLbool	hasAlpha ()

SLMat4f	tm ()

SLbool	autoCalcTM3D () const

SLbool	needsUpdate ()

SLstring	typeName ()
	Returns the texture type as string. More...

SLstring	typeShortName ()
	Returns the texture type short. More...

bool	isTexture ()

SLstring	minificationFilterName ()

SLstring	magnificationFilterName ()

void	build2DMipmaps (SLint target, SLuint index)

SLbool	copyVideoImage (SLint camWidth, SLint camHeight, CVPixelFormatGL glFormat, SLuchar *data, SLbool isContinuous, SLbool isTopLeft)
	Copies the image data from a video camera into the current video image. More...

SLbool	copyVideoImage (SLint camWidth, SLint camHeight, CVPixelFormatGL srcFormat, CVPixelFormatGL dstFormat, SLuchar *data, SLbool isContinuous, SLbool isTopLeft)

void	calc3DGradients (SLint sampleRadius, const function< void(int)> &onUpdateProgress=nullptr)

void	smooth3DGradients (SLint smoothRadius, function< void(int)> onUpdateProgress=nullptr)

SLVec2f	dudv (SLfloat u, SLfloat v)

Public Member Functions inherited from SLObject
	SLObject (const SLstring &Name="", const SLstring &url="")

virtual	~SLObject ()

void	name (const SLstring &Name)

void	url (const SLstring &url)

const SLstring &	name () const

const SLstring &	url () const

Protected Member Functions
void	renderCube ()
	Renders 2x2 cube, used to project a texture to a cube texture with 6 sides. More...

void	renderQuad ()
	Renders a 2x2 XY quad, used for rendering and capturing the BRDF integral. More...

void	readPixels (int width, int height, string name, bool savePNG)
	Reads back the pixels into an image. More...

Protected Member Functions inherited from SLGLTexture
void	load (const SLstring &filename, SLbool flipVertical=true, SLbool loadGrayscaleIntoAlpha=false)
	Loads the texture, converts color depth & applies vertical mirroring. More...

void	load (const SLVCol4f &colors)
	Loads the 1D color data into an image of height 1. More...

Protected Attributes
SLuint	_cubeVAO = 0

SLuint	_cubeVBO = 0

SLuint	_quadVAO = 0

SLuint	_quadVBO = 0

SLGLTexture *	_sourceTexture
	2D Texture from the HDR Image More...

SLGLProgram *	_shaderProgram
	Shader program to render the texture. More...

SLMat4f	_captureProjection
	Projection matrix for capturing the textures. More...

SLVMat4f	_captureViews
	All 6 positions of the views that represent the 6 sides of the cube map. More...

SLbool	_readBackPixels
	Flag if generated texture should be read back from GPU into cvMat. More...

Protected Attributes inherited from SLGLTexture
CVVImage	_images
	Vector of CVImage pointers. More...

SLuint	_texID
	OpenGL texture ID. More...

SLTextureType	_texType
	See SLTextureType. More...

SLint	_width
	Texture image width in pixels (images exist either in _images or on the GPU or on both) More...

SLint	_height
	Texture image height in pixels (images exist either in _images or on the GPU or on both) More...

SLint	_depth
	3D Texture image depth (images exist either in _images or on the GPU or on both) More...

SLbyte	_uvIndex
	Texture coordinate index in SLMesh (0 = default) More...

SLint	_internalFormat
	Internal OpenGL format. More...

SLint	_bytesPerPixel
	Bytes per texture image pixel (images exist either in _images or on the GPU or on both) More...

SLint	_min_filter
	Minification filter. More...

SLint	_mag_filter
	Magnification filter. More...

SLint	_wrap_s
	Wrapping in s direction. More...

SLint	_wrap_t
	Wrapping in t direction. More...

SLenum	_target
	texture target More...

SLMat4f	_tm
	texture matrix More...

SLuint	_bytesOnGPU
	NO. of bytes on GPU. More...

SLuint	_bytesInFile
	NO. of bytes in file. More...

SLbool	_autoCalcTM3D
	Flag if texture matrix should be calculated from AABB for 3D mapping. More...

SLfloat	_bumpScale
	Bump mapping scale factor. More...

SLbool	_resizeToPow2
	Flag if image should be resized to n^2. More...

SLGLVertexArray	_vaoSprite
	Vertex array object for sprite rendering. More...

std::atomic< bool >	_needsUpdate {}
	Flag if image needs an single update. More...

std::mutex	_mutex
	Mutex to protect parallel access (used in ray tracing) More...

SLbool	_deleteImageAfterBuild
	Flag if images should be deleted after build on GPU. More...

SLbool	_compressedTexture = false
	True for compressed texture format on GPU. More...

Protected Attributes inherited from SLObject
SLstring	_name
	name of an object More...

SLstring	_url
	uniform resource locator More...

Additional Inherited Members
Static Public Member Functions inherited from SLGLTexture
static SLTextureType	detectType (const SLstring &filename)
	Detects the texture type from the filename appendix (See SLTexType def.) More...

static string	internalFormatStr (int internalFormat)
	Returns the internal pixel format from OpenGL. More...

Static Public Attributes inherited from SLGLTexture
static SLfloat	maxAnisotropy = -1.0f
	Returns the derivation as [s,t]. More...

static SLuint	totalNumBytesOnGPU = 0
	Total NO. of bytes used for textures on GPU. More...

Detailed Description

Texture object generated in run time from another texture.

This class is mainly used to generate the textures used for reflections in the Image Base Lighting (IBL) techniques. It takes a source texture and projects it into a cube map with different rendering techniques to produces the textures needed in IBL like the irradiance or the prefilter map. This textures can be given to the SLMaterial with IBL. It uses the SLGLFrameBuffer class to render the scene into a cube map. These generated textures only exist on the GPU. There are no images in the SLGLTexture::_images vector.

Definition at line 31 of file SLGLTextureIBL.h.

Constructor & Destructor Documentation

◆ SLGLTextureIBL() [1/2]

SLGLTextureIBL::SLGLTextureIBL ( )

inline

Default constructor.

Definition at line 35 of file SLGLTextureIBL.h.

35 : SLGLTexture() { ; }

SLGLTexture::SLGLTexture

SLGLTexture()

Default ctor for all stack instances (not created with new)

Definition: SLGLTexture.cpp:37

◆ SLGLTextureIBL() [2/2]

SLGLTextureIBL::SLGLTextureIBL	(	SLAssetManager *	am,
		SLstring	shaderPath,
		SLGLTexture *	sourceTexture,
		SLVec2i	size,
		SLTextureType	texType,
		SLenum	target,
		SLbool	readBackPixels = `true`,
		SLint	min_filter = `GL_LINEAR`,
		SLint	mag_filter = `GL_LINEAR`
	)

ctor for generated textures

Number of mip levels for roughness cubemaps.

ctor for generated textures from hdr textures

Definition at line 18 of file SLGLTextureIBL.cpp.

 {
     if (sourceTexture != nullptr)
     {
         assert(sourceTexture->texType() >= TT_hdr);
         assert(texType > TT_hdr);
     }
  
     _sourceTexture         = sourceTexture;
     _texType               = texType;
     _min_filter            = min_filter;
     _mag_filter            = mag_filter;
     _wrap_s                = GL_CLAMP_TO_EDGE;
     _wrap_t                = GL_CLAMP_TO_EDGE;
     _target                = target;
     _texID                 = 0;
     _bumpScale             = 1.0f;
     _resizeToPow2          = false;
     _autoCalcTM3D          = false;
     _needsUpdate           = false;
     _bytesOnGPU            = 0;
     _width                 = size.x;
     _height                = size.y;
     _bytesPerPixel         = 0;
     _deleteImageAfterBuild = false;
     _readBackPixels        = readBackPixels;
  
     name("Generated " + typeName());
  
     if (texType == TT_environmentCubemap)
         _shaderProgram = new SLGLProgramGeneric(am,
                                                 shaderPath + "PBR_CubeMap.vert",
                                                 shaderPath + "PBR_CylinderToCubeMap.frag");
     else if (texType == TT_irradianceCubemap)
         _shaderProgram = new SLGLProgramGeneric(am,
                                                 shaderPath + "PBR_CubeMap.vert",
                                                 shaderPath + "PBR_IrradianceConvolution.frag");
     else if (texType == TT_roughnessCubemap)
         _shaderProgram = new SLGLProgramGeneric(am,
                                                 shaderPath + "PBR_CubeMap.vert",
                                                 shaderPath + "PBR_PrefilterRoughness.frag");
     else if (texType == TT_brdfLUT)
         _shaderProgram = new SLGLProgramGeneric(am,
                                                 shaderPath + "PBR_BRDFIntegration.vert",
                                                 shaderPath + "PBR_BRDFIntegration.frag");
  
     // perspective projection with field of view of 90 degrees
     _captureProjection.perspective(90.0f, 1.0f, 0.1f, 10.0f);
  
     // initialize capture views: 6 views each at all 6 directions of the faces of a cube map
     // clang-format off
     SLMat4f mat;
     mat.lookAt(0, 0, 0, 1, 0, 0, 0,-1, 0); _captureViews.push_back(mat);
     mat.lookAt(0, 0, 0,-1, 0, 0, 0,-1, 0); _captureViews.push_back(mat);
     mat.lookAt(0, 0, 0, 0, 1, 0, 0, 0, 1); _captureViews.push_back(mat);
     mat.lookAt(0, 0, 0, 0,-1, 0, 0, 0,-1); _captureViews.push_back(mat);
     mat.lookAt(0, 0, 0, 0, 0, 1, 0,-1, 0); _captureViews.push_back(mat);
     mat.lookAt(0, 0, 0, 0, 0,-1, 0,-1, 0); _captureViews.push_back(mat);
     // clang-format on
  
     // Add pointer to the global resource vectors for deallocation
     if (am)
         am->textures().push_back(this);
 }

◆ ~SLGLTextureIBL()

SLGLTextureIBL::~SLGLTextureIBL ( )

virtual

Definition at line 91 of file SLGLTextureIBL.cpp.

 {
     deleteData(true);
  
     glDeleteVertexArrays(1, &_cubeVAO);
     _cubeVAO = 0;
     glDeleteBuffers(1, &_cubeVBO);
     _cubeVBO = 0;
     glDeleteVertexArrays(1, &_quadVAO);
     _quadVAO = 0;
     glDeleteBuffers(1, &_quadVBO);
     _quadVBO = 0;
     GET_GL_ERROR;
 }

Member Function Documentation

◆ build()

void SLGLTextureIBL::build ( SLint texUnit = 0 )

virtual

Build the texture into a cube map, rendering the texture 6 times and capturing each time one side of the cube (except for the BRDF LUT texture, which is completely generated by calculations directly with the shader). This is probably the most difficult OpenGL code in the project.

Reimplemented from SLGLTexture.

Definition at line 112 of file SLGLTextureIBL.cpp.

 {
     // Assure to delete all images if we read the pixels back
     if (_readBackPixels)
         deleteImages();
     bool saveReadbackTextures = false;
  
     glGenTextures(1, &_texID);
     glBindTexture(_target, _texID);
  
     GLuint fboID;
     glGenFramebuffers(1, &fboID);
  
     GLuint rboID;
     glGenRenderbuffers(1, &rboID);
  
     if (_texType == TT_environmentCubemap ||
         _texType == TT_irradianceCubemap)
     {
         _bytesPerPixel  = SL_HDR_PIXEL_BYTES;
         _internalFormat = SL_HDR_GL_INTERNAL_FORMAT;
  
         // Build the textures for the 6 faces of a cubemap with no data
         for (SLuint i = 0; i < 6; i++)
         {
             glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                          0,
                          _internalFormat,
                          _width,
                          _height,
                          0,
                          SL_HDR_GL_FORMAT,
                          SL_HDR_GL_TYPE,
                          nullptr);
         }
  
         glTexParameteri(_target, GL_TEXTURE_WRAP_S, _wrap_s);
         glTexParameteri(_target, GL_TEXTURE_WRAP_T, _wrap_t);
         glTexParameteri(_target, GL_TEXTURE_WRAP_R, _wrap_t);
         glTexParameteri(_target, GL_TEXTURE_MIN_FILTER, _min_filter);
         glTexParameteri(_target, GL_TEXTURE_MAG_FILTER, _mag_filter);
  
         _shaderProgram->useProgram();
  
         if (_sourceTexture != nullptr)
             _sourceTexture->bindActive();
  
         _shaderProgram->uniform1i("u_environmentMap", texUnit);
  
         glActiveTexture(GL_TEXTURE0 + texUnit);
         glBindTexture(_sourceTexture->target(),
                       _sourceTexture->texID());
         glViewport(0, 0, _width, _height);
         glBindFramebuffer(GL_FRAMEBUFFER, fboID);
         glBindRenderbuffer(GL_RENDERBUFFER, rboID);
         glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, _width, _height);
         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, rboID);
  
         logFramebufferStatus();
  
         // Set the list of draw buffers.
         GLenum DrawBuffers[1] = {GL_COLOR_ATTACHMENT0};
         glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
  
         for (SLuint i = 0; i < 6; i++)
         {
             SLMat4f mvp = _captureProjection * _captureViews[i];
             _shaderProgram->uniformMatrix4fv("u_mvpMatrix", 1, mvp.m());
  
             glFramebufferTexture2D(GL_FRAMEBUFFER,
                                    GL_COLOR_ATTACHMENT0,
                                    GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                                    _texID,
                                    0);
  
             glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
             renderCube();
  
             if (_readBackPixels)
             {
                 string name = (_texType == TT_environmentCubemap)
                                 ? "environmentCubemap_side"
                                 : "irradianceCubemap_side";
                 name += std::to_string(i) + ".png";
                 readPixels(_width,
                            _height,
                            name,
                            saveReadbackTextures);
             }
         }
  
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
         glBindRenderbuffer(GL_RENDERBUFFER, 0);
  
         if (_texType == TT_environmentCubemap)
         {
             glBindTexture(GL_TEXTURE_CUBE_MAP, _texID);
             glGenerateMipmap(GL_TEXTURE_CUBE_MAP);
         }
     }
     else if (_texType == TT_roughnessCubemap)
     {
         assert(_sourceTexture->texType() == TT_environmentCubemap &&
                "the source texture is not an environment map");
  
         _bytesPerPixel  = SL_HDR_PIXEL_BYTES;
         _internalFormat = SL_HDR_GL_INTERNAL_FORMAT;
  
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_BASE_LEVEL, 0);
         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAX_LEVEL, ROUGHNESS_NUM_MIP_LEVELS - 1);
  
         // Define textures for all mip levels of all six sides of the cube map
         for (SLint mipLevel = 0; mipLevel < ROUGHNESS_NUM_MIP_LEVELS; mipLevel++)
         {
             // Calculate the size of this mip level
             SLint mipWidth  = _width / (1 << mipLevel);
             SLint mipHeight = _height / (1 << mipLevel);
  
             for (SLint i = 0; i < 6; i++)
             {
                 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                              mipLevel,
                              _internalFormat,
                              mipWidth,
                              mipHeight,
                              0,
                              SL_HDR_GL_FORMAT,
                              SL_HDR_GL_TYPE,
                              nullptr);
             }
         }
  
         _shaderProgram->useProgram();
  
         if (_sourceTexture != nullptr)
             _sourceTexture->bindActive();
  
         _shaderProgram->uniform1i("u_environmentMap", texUnit);
         _shaderProgram->uniform1f("u_environmentMapSize", (float)_sourceTexture->width());
  
         glActiveTexture(GL_TEXTURE0 + texUnit);
         glBindTexture(_sourceTexture->target(), _sourceTexture->texID());
  
         for (SLint mipLevel = 0; mipLevel < ROUGHNESS_NUM_MIP_LEVELS; ++mipLevel)
         {
             // Resize framebuffer according to mip level size
             SLint mipWidth  = _width / (1 << mipLevel);
             SLint mipHeight = _height / (1 << mipLevel);
             glViewport(0, 0, mipWidth, mipHeight);
  
             glBindFramebuffer(GL_FRAMEBUFFER, fboID);
  
             SLfloat roughness = (SLfloat)mipLevel / (SLfloat)(ROUGHNESS_NUM_MIP_LEVELS - 1);
             _shaderProgram->uniform1f("u_roughness", roughness);
  
             for (SLuint i = 0; i < 6; ++i)
             {
                 SLMat4f mvp = _captureProjection * _captureViews[i];
                 _shaderProgram->uniformMatrix4fv("u_mvpMatrix", 1, mvp.m());
                 glFramebufferTexture2D(GL_FRAMEBUFFER,
                                        GL_COLOR_ATTACHMENT0,
                                        GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                                        _texID,
                                        mipLevel);
  
                 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
                 logFramebufferStatus();
  
                 renderCube();
  
                 if (_readBackPixels)
                 {
                     string name = "roughnessCubemap_mip" +
                                   std::to_string(mipLevel) + "_side" +
                                   std::to_string(i) + ".png";
                     readPixels((SLint)mipWidth,
                                (SLint)mipHeight,
                                name,
                                saveReadbackTextures);
                 }
             }
  
             glBindFramebuffer(GL_FRAMEBUFFER, 0);
         }
     }
     else if (_texType == TT_brdfLUT)
     {
         _bytesPerPixel  = SL_BRDF_LUT_PIXEL_BYTES;
         _internalFormat = SL_BRDF_LUT_GL_INTERNAL_FORMAT;
  
         glTexImage2D(_target,
                      0,
                      _internalFormat,
                      _width,
                      _height,
                      0,
                      SL_BRDF_LUT_GL_FORMAT,
                      SL_BRDF_LUT_GL_TYPE,
                      0);
         glTexParameteri(_target, GL_TEXTURE_WRAP_S, _wrap_s);
         glTexParameteri(_target, GL_TEXTURE_WRAP_T, _wrap_t);
         glTexParameteri(_target, GL_TEXTURE_MIN_FILTER, _min_filter);
         glTexParameteri(_target, GL_TEXTURE_MAG_FILTER, _mag_filter);
  
         glBindFramebuffer(GL_FRAMEBUFFER, fboID);
  
         glFramebufferTexture2D(GL_FRAMEBUFFER,
                                GL_COLOR_ATTACHMENT0,
                                GL_TEXTURE_2D,
                                _texID,
                                0);
  
         glViewport(0, 0, _width, _height);
         _shaderProgram->useProgram();
  
         if (_sourceTexture != nullptr)
             _sourceTexture->bindActive();
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
         logFramebufferStatus();
  
         renderQuad();
  
         if (_readBackPixels)
         {
             string name = "brdfLUT.png";
             readPixels(_width,
                        _height,
                        name,
                        saveReadbackTextures);
         }
  
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
     }
  
     glDeleteFramebuffers(1, &fboID);
     glDeleteRenderbuffers(1, &rboID);
  
     // Reset the viewport
     SLGLState* state = SLGLState::instance();
     auto       vp    = state->viewport();
     glViewport(vp.x, vp.y, vp.z, vp.w);
     glFinish();
     GET_GL_ERROR;
 }

◆ logFramebufferStatus()

void SLGLTextureIBL::logFramebufferStatus ( )

Definition at line 503 of file SLGLTextureIBL.cpp.

 {
 #if defined(DEBUG) || defined(_DEBUG)
     GLenum fbStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);
     switch (fbStatus)
     {
         case GL_FRAMEBUFFER_COMPLETE: break;
         case GL_FRAMEBUFFER_UNDEFINED: SL_LOG("**** GL_FRAMEBUFFER_UNDEFINED ****"); break;
         case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: SL_LOG("**** GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT ****"); break;
         case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: SL_LOG("GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT ****"); break;
         case GL_FRAMEBUFFER_UNSUPPORTED: SL_LOG("**** GL_FRAMEBUFFER_UNSUPPORTED ****"); break;
         case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE: SL_LOG("**** GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE ****"); break;
         // case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER: SL_LOG("**** GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER ****"); break;
         // case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER: SL_LOG("**** GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER ****"); break;
         // case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS: SL_LOG("**** GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS ****"); break;
         default: SL_LOG("Unknown framebuffer status!!!");
     }
 #endif
 }

◆ readPixels()

void SLGLTextureIBL::readPixels	(	int	width,
		int	height,
		string	name,
		bool	savePNG
	)

protected

Reads back the pixels into an image.

Definition at line 482 of file SLGLTextureIBL.cpp.

 {
     CVImage* image = new CVImage(width,
                                  height,
                                  SL_READ_PIXELS_CV_FORMAT,
                                  name);
     glReadPixels(0,
                  0,
                  width,
                  height,
                  SL_READ_PIXELS_GL_FORMAT,
                  GL_UNSIGNED_BYTE,
                  image->data());
     GET_GL_ERROR;
  
     if (savePNG)
         image->savePNG(name, 9, false);
  
     _images.push_back(image);
 }

◆ renderCube()

void SLGLTextureIBL::renderCube ( )

protected

Renders 2x2 cube, used to project a texture to a cube texture with 6 sides.

Definition at line 365 of file SLGLTextureIBL.cpp.

 {
     // initialize (if necessary)
     if (_cubeVAO == 0)
     {
         // clang-format off
         // Define vertex positions of an inward facing cube
         // The original code from learnopengl.com used an outwards facing cube
         // with disabled face culling. With our default enabled face culling this
         // lead to a horrible error that cost us about 10kFr. of debugging.
         // Thanks to the tip of Michael Goettlicher we finally got it correct.
         float vertices[] = {
           // back face
           -1.0f, -1.0f, -1.0f, // bottom-left
            1.0f, -1.0f, -1.0f, // bottom-right
            1.0f,  1.0f, -1.0f, // top-right
            1.0f,  1.0f, -1.0f, // top-right
           -1.0f,  1.0f, -1.0f, // top-left
           -1.0f, -1.0f, -1.0f, // bottom-left
           // front face
           -1.0f, -1.0f,  1.0f, // bottom-left
            1.0f,  1.0f,  1.0f, // top-right
            1.0f, -1.0f,  1.0f, // bottom-right
            1.0f,  1.0f,  1.0f, // top-right
           -1.0f, -1.0f,  1.0f, // bottom-left
           -1.0f,  1.0f,  1.0f, // top-left
           // left face
           -1.0f,  1.0f,  1.0f, // top-right
           -1.0f, -1.0f, -1.0f, // bottom-left
           -1.0f,  1.0f, -1.0f, // top-left
           -1.0f, -1.0f, -1.0f, // bottom-left
           -1.0f,  1.0f,  1.0f, // top-right
           -1.0f, -1.0f,  1.0f, // bottom-right
           // right face
            1.0f,  1.0f,  1.0f, // top-left
            1.0f,  1.0f, -1.0f, // top-right
            1.0f, -1.0f, -1.0f, // bottom-right
            1.0f, -1.0f, -1.0f, // bottom-right
            1.0f, -1.0f,  1.0f, // bottom-left
            1.0f,  1.0f,  1.0f, // top-left
           // bottom face
           -1.0f, -1.0f, -1.0f, // top-right
            1.0f, -1.0f,  1.0f, // bottom-left
            1.0f, -1.0f, -1.0f, // top-left
            1.0f, -1.0f,  1.0f, // bottom-left
           -1.0f, -1.0f, -1.0f, // top-right
           -1.0f, -1.0f,  1.0f, // bottom-right
           // top face
            1.0f,  1.0f,  1.0f, // right-top-front
           -1.0f,  1.0f,  1.0f, // left-top-front
           -1.0f,  1.0f, -1.0f, // left-top-back
           -1.0f,  1.0f, -1.0f, // left-top-back
            1.0f,  1.0f, -1.0f, // right-top-back
            1.0f,  1.0f , 1.0f  // right-top-front
         };
  
         // clang-format on
         glGenVertexArrays(1, &_cubeVAO);
         glGenBuffers(1, &_cubeVBO);
  
         // fill buffer
         glBindBuffer(GL_ARRAY_BUFFER, _cubeVBO);
         glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
  
         // link vertex attributes
         glBindVertexArray(_cubeVAO);
         glEnableVertexAttribArray(0);
         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
         glBindBuffer(GL_ARRAY_BUFFER, 0);
         glBindVertexArray(0);
     }
  
     // render inwards facing cube with face culling enabled
     glBindVertexArray(_cubeVAO);
     glDrawArrays(GL_TRIANGLES, 0, 36);
     glBindVertexArray(0);
 }

◆ renderQuad()

void SLGLTextureIBL::renderQuad ( )

protected

Renders a 2x2 XY quad, used for rendering and capturing the BRDF integral.

Definition at line 444 of file SLGLTextureIBL.cpp.

 {
     if (_quadVAO == 0)
     {
         // clang-format off
         // Define a front (+Z) facing quad with texture coordinates
         float quadVertices[] = {
             // positions         // texture Coords
             -1.0f,  1.0f, 0.0f,  0.0f, 1.0f,
             -1.0f, -1.0f, 0.0f,  0.0f, 0.0f,
              1.0f,  1.0f, 0.0f,  1.0f, 1.0f,
              1.0f, -1.0f, 0.0f,  1.0f, 0.0f,
         };
         // clang-format on
  
         // setup plane VAO
         glGenVertexArrays(1, &_quadVAO);
         glGenBuffers(1, &_quadVBO);
         glBindVertexArray(_quadVAO);
         glBindBuffer(GL_ARRAY_BUFFER, _quadVBO);
         glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
         glEnableVertexAttribArray(0);
         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
         glEnableVertexAttribArray(1);
         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
     }
  
     // Render quad
     glBindVertexArray(_quadVAO);
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     glBindVertexArray(0);
 }

Member Data Documentation

◆ _captureProjection

SLMat4f SLGLTextureIBL::_captureProjection

protected

Projection matrix for capturing the textures.

Definition at line 69 of file SLGLTextureIBL.h.

◆ _captureViews

SLVMat4f SLGLTextureIBL::_captureViews

protected

All 6 positions of the views that represent the 6 sides of the cube map.

Definition at line 70 of file SLGLTextureIBL.h.

◆ _cubeVAO

SLuint SLGLTextureIBL::_cubeVAO = 0

protected

Definition at line 62 of file SLGLTextureIBL.h.

◆ _cubeVBO

SLuint SLGLTextureIBL::_cubeVBO = 0

protected

Definition at line 63 of file SLGLTextureIBL.h.

◆ _quadVAO

SLuint SLGLTextureIBL::_quadVAO = 0

protected

Definition at line 64 of file SLGLTextureIBL.h.

◆ _quadVBO

SLuint SLGLTextureIBL::_quadVBO = 0

protected

Definition at line 65 of file SLGLTextureIBL.h.

◆ _readBackPixels

SLbool SLGLTextureIBL::_readBackPixels

protected

Flag if generated texture should be read back from GPU into cvMat.

Definition at line 71 of file SLGLTextureIBL.h.

◆ _shaderProgram

SLGLProgram* SLGLTextureIBL::_shaderProgram

protected

Shader program to render the texture.

Definition at line 68 of file SLGLTextureIBL.h.

◆ _sourceTexture

SLGLTexture* SLGLTextureIBL::_sourceTexture

protected

2D Texture from the HDR Image

Definition at line 67 of file SLGLTextureIBL.h.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ SLGLTextureIBL() [1/2]

◆ SLGLTextureIBL() [2/2]

◆ ~SLGLTextureIBL()

Member Function Documentation

◆ build()

◆ logFramebufferStatus()

◆ readPixels()

◆ renderCube()

◆ renderQuad()

Member Data Documentation

◆ _captureProjection

◆ _captureViews

◆ _cubeVAO

◆ _cubeVBO

◆ _quadVAO

◆ _quadVBO

◆ _readBackPixels

◆ _shaderProgram

◆ _sourceTexture