glBindBuffer example c c++ objc java

Name

glBindBuffer — bind a named buffer object

C Specification

`void glBindBuffer(`	GLenum	`target`,
	GLuint	`buffer)`;

Parameters

target: Specifies the target to which the buffer object is bound. The symbolic constant must be GL_ARRAY_BUFFER,GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, or GL_PIXEL_UNPACK_BUFFER.
buffer: Specifies the name of a buffer object.

Description

glBindBuffer lets you create or use a named buffer object. Calling glBindBuffer with target set to GL_ARRAY_BUFFER,GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER or GL_PIXEL_UNPACK_BUFFER and buffer set to the name of the new buffer object binds the buffer object name to the target. When a buffer object is bound to a target, the previous binding for that target is automatically broken.
Buffer object names are unsigned integers. The value zero is reserved, but there is no default buffer object for each buffer object target. Instead, buffer set to zero effectively unbinds any buffer object previously bound, and restores client memory usage for that buffer object target. Buffer object names and the corresponding buffer object contents are local to the shared display-list space (see glXCreateContext) of the current GL rendering context; two rendering contexts share buffer object names only if they also share display lists.
You may use glGenBuffers to generate a set of new buffer object names.
The state of a buffer object immediately after it is first bound is an unmapped zero-sized memory buffer withGL_READ_WRITE access and GL_STATIC_DRAW usage.
While a non-zero buffer object name is bound, GL operations on the target to which it is bound affect the bound buffer object, and queries of the target to which it is bound return state from the bound buffer object. While buffer object name zero is bound, as in the initial state, attempts to modify or query state on the target to which it is bound generates anGL_INVALID_OPERATION error.
When vertex array pointer state is changed, for example by a call to glNormalPointer, the current buffer object binding (GL_ARRAY_BUFFER_BINDING) is copied into the corresponding client state for the vertex array type being changed, for example GL_NORMAL_ARRAY_BUFFER_BINDING. While a non-zero buffer object is bound to the GL_ARRAY_BUFFER target, the vertex array pointer parameter that is traditionally interpreted as a pointer to client-side memory is instead interpreted as an offset within the buffer object measured in basic machine units.
While a non-zero buffer object is bound to the GL_ELEMENT_ARRAY_BUFFER target, the indices parameter of glDrawElements,glDrawRangeElements, or glMultiDrawElements that is traditionally interpreted as a pointer to client-side memory is instead interpreted as an offset within the buffer object measured in basic machine units.
While a non-zero buffer object is bound to the GL_PIXEL_PACK_BUFFER target, the following commands are affected:glGetCompressedTexImage, glGetConvolutionFilter, glGetHistogram, glGetMinmax, glGetPixelMap, glGetPolygonStipple,glGetSeparableFilter, glGetTexImage, and glReadPixels. The pointer parameter that is traditionally interpreted as a pointer to client-side memory where the pixels are to be packed is instead interpreted as an offset within the buffer object measured in basic machine units.
While a non-zero buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target, the following commands are affected:glBitmap, glColorSubTable, glColorTable, glCompressedTexImage1D, glCompressedTexImage2D,glCompressedTexImage3D, glCompressedTexSubImage1D, glCompressedTexSubImage2D,glCompressedTexSubImage3D, glConvolutionFilter1D, glConvolutionFilter2D, glDrawPixels, glPixelMap, glPolygonStipple,glSeparableFilter2D, glTexImage1D, glTexImage2D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, andglTexSubImage3D. The pointer parameter that is traditionally interpreted as a pointer to client-side memory from which the pixels are to be unpacked is instead interpreted as an offset within the buffer object measured in basic machine units.
A buffer object binding created with glBindBuffer remains active until a different buffer object name is bound to the same target, or until the bound buffer object is deleted with glDeleteBuffers.
Once created, a named buffer object may be re-bound to any target as often as needed. However, the GL implementation may make choices about how to optimize the storage of a buffer object based on its initial binding target.

Notes

glBindBuffer is available only if the GL version is 1.5 or greater.
GL_PIXEL_PACK_BUFFER and GL_PIXEL_UNPACK_BUFFER are available only if the GL version is 2.1 or greater.

Errors

GL_INVALID_ENUM is generated if target is not one of the allowable values.
GL_INVALID_OPERATION is generated if glBindBuffer is executed between the execution of glBegin and the corresponding execution of glEnd.

Associated Gets

glGet with argument GL_ARRAY_BUFFER_BINDING
glGet with argument GL_ELEMENT_ARRAY_BUFFER_BINDING
glGet with argument GL_PIXEL_PACK_BUFFER_BINDING
glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING

Copyright

Example

GLfloat afVertices[] = { -0.4f,-0.4f,0.0f, // Position
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0.4f ,-0.4f,0.0f,
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0.0f ,0.4f ,0.0f};
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GLuint ui32Vbo;
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// Generate and Bind the vertex buffer object (VBO)
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glGenBuffers(1, &ui32Vbo);
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glBindBuffer(GL_ARRAY_BUFFER, ui32Vbo);
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unsigned int uiSize = 3 * (sizeof(GLfloat) * 3);
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glBufferData(GL_ARRAY_BUFFER, uiSize, afVertices, GL_STATIC_DRAW);
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// Frame
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glClear(GL_COLOR_BUFFER_BIT);
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// First gets the location of that variable in the shader using its name
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int i32Location = glGetUniformLocation(uiProgramObject, "myPMVMatrix");
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glUniformMatrix4fv( i32Location, 1, GL_FALSE, pfIdentity);
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glEnableVertexAttribArray(VERTEX_ARRAY);
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glVertexAttribPointer(VERTEX_ARRAY, 3, GL_FLOAT, GL_FALSE, 0, 0);
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glDrawArrays(GL_TRIANGLES, 0, 3);
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eglSwapBuffers(eglDisplay, eglSurface);

Example source code bank

Friday, May 27, 2011