Class GLShader¶

Defined in File glutil.h

Page Contents

Nested Relationships
- Nested Types
Class Documentation

Nested Relationships¶

Nested Types¶

Struct GLShader::Buffer

Class Documentation¶

class GLShader¶

Helper class for compiling and linking OpenGL shaders and uploading associated vertex and index buffers from Eigen matrices.

Public Functions

GLShader()¶: Create an unitialized OpenGL shader.

bool init(const std::string &name, const std::string &vertex_str, const std::string &fragment_str, const std::string &geometry_str = "")¶

Initialize the shader using the specified source strings.

Parameters

name: The name this shader will be registered as.
vertex_str: The source of the vertex shader as a string.
fragment_str: The source of the fragment shader as a string.
geometry_str: The source of the geometry shader as a string. The default value is the empty string, which indicates no geometry shader will be used.

bool initFromFiles(const std::string &name, const std::string &vertex_fname, const std::string &fragment_fname, const std::string &geometry_fname = "")¶

Initialize the shader using the specified files on disk.

Parameters

name: The name this shader will be registered as.
vertex_fname: The path to the file containing the source of the fragment shader.
fragment_fname: The path to the file containing the source of the vertex shader.
geometry_fname: The path to the file containing the source of the geometry shader. The default value is the empty string, which indicates no geometry shader will be used.

const std::string &name() const¶: Return the name of the shader.

void define(const std::string &key, const std::string &value)¶: Set a preprocessor definition. Custom preprocessor definitions must be added before initializing the shader (e.g., via initFromFiles). See also: mDefinitions.

void bind()¶: Select this shader for subsequent draw calls. Simply executes glUseProgram with mProgramShader, and glBindVertexArray with mVertexArrayObject.

void free()¶: Release underlying OpenGL objects.

GLint attrib(const std::string &name, bool warn = true) const¶: Return the handle of a named shader attribute (-1 if it does not exist)

GLint uniform(const std::string &name, bool warn = true) const¶: Return the handle of a uniform attribute (-1 if it does not exist)

template<typename Matrix> void uploadAttrib(const std::string &name, const Matrix &M, int version = -1)¶: Upload an Eigen matrix as a vertex buffer object (refreshing it as needed)

template<typename Matrix> void downloadAttrib(const std::string &name, Matrix &M)¶: Download a vertex buffer object into an Eigen matrix.

template<typename Matrix> void uploadIndices(const Matrix &M, int version = -1)¶: Upload an index buffer.

void invalidateAttribs()¶: Invalidate the version numbers associated with attribute data.

void freeAttrib(const std::string &name)¶: Completely free an existing attribute buffer.

bool hasAttrib(const std::string &name) const¶: Check if an attribute was registered a given name.

void shareAttrib(const GLShader &otherShader, const std::string &name, const std::string &as = "")¶: Create a symbolic link to an attribute of another GLShader. This avoids duplicating unnecessary data.

int attribVersion(const std::string &name) const¶: Return the version number of a given attribute.

void resetAttribVersion(const std::string &name)¶: Reset the version number of a given attribute.

void drawArray(int type, uint32_t offset, uint32_t count)¶: Draw a sequence of primitives.

void drawIndexed(int type, uint32_t offset, uint32_t count)¶: Draw a sequence of primitives using a previously uploaded index buffer.

template<typename T> void setUniform(const std::string &name, const Eigen::Matrix<T, 4, 4> &mat, bool warn = true)¶: Initialize a uniform parameter with a 4x4 matrix (float)

template<typename T> void setUniform(const std::string &name, const Eigen::Transform<T, 3, 3> &affine, bool warn = true)¶: Initialize a uniform parameter with a 3x3 affine transform (float)

template<typename T> void setUniform(const std::string &name, const Eigen::Matrix<T, 3, 3> &mat, bool warn = true)¶: Initialize a uniform parameter with a 3x3 matrix (float)

template<typename T> void setUniform(const std::string &name, const Eigen::Transform<T, 2, 2> &affine, bool warn = true)¶: Initialize a uniform parameter with a 2x2 affine transform (float)

void setUniform(const std::string &name, bool value, bool warn = true)¶: Initialize a uniform parameter with a boolean value.

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==1, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, T value, bool warn = true): Initialize a uniform parameter with an integer value.

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==0, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, T value, bool warn = true): Initialize a uniform parameter with a floating point value.

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==1, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 2, 1 > & v, bool warn = true): Initialize a uniform parameter with a 2D vector (int)

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==0, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 2, 1 > & v, bool warn = true): Initialize a uniform parameter with a 2D vector (float)

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==1, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 3, 1 > & v, bool warn = true): Initialize a uniform parameter with a 3D vector (int)

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==0, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 3, 1 > & v, bool warn = true): Initialize a uniform parameter with a 3D vector (float)

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==1, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 4, 1 > & v, bool warn = true): Initialize a uniform parameter with a 4D vector (int)

template<typename T, typename std::enable_if< detail::type_traits< T >::integral==0, int >::type = 0>void nanogui::GLShader::setUniform(const std::string & name, const Eigen::Matrix< T, 4, 1 > & v, bool warn = true): Initialize a uniform parameter with a 4D vector (float)

void setUniform(const std::string &name, const GLUniformBuffer &buf, bool warn = true)¶: Initialize a uniform buffer with a uniform buffer object.

size_t bufferSize() const¶: Return the size of all registered buffers in bytes.

const Buffer &attribBuffer(const std::string &name)¶

(Advanced) Returns a reference to the specified GLShader::Buffer.

Danger

Extreme caution must be exercised when using this method. The user is discouraged from explicitly storing the reference returned, as it can change, become deprecated, or no longer reside in mBufferObjects.

There are generally very few use cases that justify using this method directly. For example, if you need the version of a buffer, call attribVersion. If you want to share data between GLShader objects, call shareAttrib.

One example use case for this method is sharing data between different GPU pipelines such as CUDA or OpenCL. When sharing data, you typically need to map pointers between the API’s. The returned buffer’s Buffer::id is the GLuint you will want to map to the other API.

In short, only use this method if you absolutely need to.

Return

A reference to the current buffer associated with name. Should not be explicitly stored.

Parameters

name: The name of the desired attribute.

Exceptions

std::runtime_error: If name is not found.

void uploadAttrib(const std::string &name, size_t size, int dim, uint32_t compSize, GLuint glType, bool integral, const void *data, int version = -1)¶

void downloadAttrib(const std::string &name, size_t size, int dim, uint32_t compSize, GLuint glType, void *data)¶

Protected Attributes

std::string mName¶: The registered name of this GLShader.

GLuint mVertexShader¶: The vertex shader of this GLShader (as returned by glCreateShader).

GLuint mFragmentShader¶: The fragment shader of this GLShader (as returned by glCreateShader).

GLuint mGeometryShader¶: The geometry shader (if requested) of this GLShader (as returned by glCreateShader).

GLuint mProgramShader¶: The OpenGL program (as returned by glCreateProgram).

GLuint mVertexArrayObject¶: The vertex array associated with this GLShader (as returned by glGenVertexArrays).

std::map<std::string, Buffer> mBufferObjects¶: The map of string names to buffer objects representing the various attributes that have been uploaded using uploadAttrib.

std::map<std::string, std::string> mDefinitions¶

The map of preprocessor names to values (if any have been created). If a definition was added seeking to create #define WIDTH 256, the key would be "WIDTH" and the value would be "256". These definitions will be included automatically in the string that gets compiled for the vertex, geometry, and fragment shader code.

struct Buffer¶

A wrapper struct for maintaining various aspects of items being managed by OpenGL. Buffers are created when GLShader::uploadAttrib is called.

Public Members

GLuint id¶: The identifier used with OpenGL.

GLuint glType¶: The OpenGL type of this buffer.

GLuint dim¶: The dimension of this buffer (typically the row width).

GLuint compSize¶: The size (in bytes) of an individual element in this buffer.

GLuint size¶: The total number of elements represented by this buffer.

int version¶: The current version if this buffer.