SDK Buffer API documentation

Version: stable

<dmsdk/dlib/buffer.h>

Buffer API for data buffers as the main way to communicate between systems.

FUNCTION
dmBuffer::Create()

create Buffer

dmBuffer::Destroy()

destroy Buffer.

dmBuffer::GetBytes()

get buffer as a byte array.

dmBuffer::GetCount()

get buffer count.

dmBuffer::GetResultString()

result to string

dmBuffer::GetSizeForValueType()

get size of a value type

dmBuffer::GetStream()

get stream from buffer.

dmBuffer::GetStreamType()

get stream type and type count

dmBuffer::GetValueTypeString()

value type to string

dmBuffer::IsBufferValid()

check buffer handle

dmBuffer::ValidateBuffer()

validate buffer.

Functions

dmBuffer::Create()

dmBuffer::Create(count,streams_decl,streams_decl_count,out_buffer)

Creates a new HBuffer with a number of different streams.

PARAMETERS

count

uint32_t The number of "structs" the buffer should hold (e.g. vertex count)

streams_decl

const dmBuffer::StreamDeclaration* Array of stream declarations

streams_decl_count

uint8_t Number of stream declarations inside the decl array (max 256)

out_buffer

dmBuffer::HBuffer* Pointer to HBuffer where to store the newly allocated buffer

RETURNS

result

dmBuffer::Result BUFFER_OK if buffer was allocated successfully

EXAMPLES

const dmBuffer::StreamDeclaration streams_decl[] = {
    {dmHashString64("position"), dmBuffer::VALUE_TYPE_FLOAT32, 3},
    {dmHashString64("texcoord0"), dmBuffer::VALUE_TYPE_UINT16, 2},
    {dmHashString64("color"), dmBuffer::VALUE_TYPE_UINT8, 4},
};
dmBuffer::HBuffer buffer = 0x0;
dmBuffer::Result r = dmBuffer::Create(1024, streams_decl, 3, &buffer);

if (r == dmBuffer::RESULT_OK) {
    // success
} else {
    // handle error
}

dmBuffer::Destroy()

dmBuffer::Destroy(buffer)

Destroys a HBuffer and it's streams.

PARAMETERS

buffer

dmBuffer::HBuffer Buffer handle to the buffer to free

EXAMPLES

const dmBuffer::StreamDeclaration streams_decl[] = {
    {dmHashString64("position"), dmBuffer::VALUE_TYPE_FLOAT32, 3},
};
dmBuffer::HBuffer buffer = 0x0;
dmBuffer::Result r = dmBuffer::Create(4, streams_decl, 1, &buffer);

if (r == dmBuffer::RESULT_OK) {
    dmBuffer::Destroy(buffer);
} else {
    // handle error
}

dmBuffer::GetBytes()

dmBuffer::GetBytes(buffer,out_bytes,out_size)

Gets the buffer as a byte array. If the buffer is interleaved (default), a pointer to the whole memory is returned.

PARAMETERS

buffer

dmBuffer::HBuffer buffer handle.

out_bytes

void** Pointer to void* where to store the bytes

out_size

uint32_t* Pointer to uint32_t where to store the array size

RETURNS

result

dmBuffer::Result BUFFER_OK if the buffer was successfully accessed

EXAMPLES

uint8_t* bytes = 0x0;
uint32_t size = 0;

dmBuffer::Result r = dmBuffer::GetBytes(buffer, (void**)&bytes, &size);

if (r == dmBuffer::RESULT_OK) {
    for (int i = 0; i < size; ++i)
    {
        stream[i] = (uint8_t)(i & 0xFF);
    }
} else {
    // handle error
}

dmBuffer::GetCount()

dmBuffer::GetCount(buffer,count)

Get (struct) count for a buffer.

PARAMETERS

buffer

dmBuffer::HBuffer buffer handle.

count

uint32_t* Pointer to uint32_t where to store the element count

RETURNS

result

dmBuffer::Result BUFFER_OK if the element count was successfully accessed

EXAMPLES

uint32_t count = 0;
dmBuffer::Result r = dmBuffer::GetCount(buffer, &count);

if (r == dmBuffer::RESULT_OK) {
    printf("buffer %p has %d number of elements", buffer, count);
} else {
    // handle error
}

dmBuffer::GetResultString()

dmBuffer::GetResultString(result)

Converts result to string

PARAMETERS

result

dmBuffer::Result The result

RETURNS

result

const char* The result as a string


dmBuffer::GetSizeForValueType()

dmBuffer::GetSizeForValueType(type)

Gets the size of a value type

PARAMETERS

type

dmBuffer::ValueType The value type

RETURNS

size

uint32_t The size in bytes


dmBuffer::GetStream()

dmBuffer::GetStream(buffer,stream_name,stream,count,components,stride)

Get a stream from a buffer. Output stream is 16 byte aligned.

PARAMETERS

buffer

dmBuffer::HBuffer buffer handle.

stream_name

dmhash_t Hash of stream name to get

stream

void** Where to store the stream

count

uint32_t* Where to store the count (e.g. vertex count). May be null.

components

uint32_t* Where to store the number of components (e.g. 3 for a Vector3). May be null.

stride

uint32_t* Where to store the stride. The stride can be added to the value pointer. May be null. E.g. for a float array, the stride is (sizeof(Struct) / sizeof(float))

RETURNS

result

dmBuffer::Result BUFFER_OK if the stream was successfully accessed

EXAMPLES

float* positions = 0x0;
uint32_t size = 0;
uint32_t components = 0;
uint32_t stride = 0;
dmBuffer::Result r = dmBuffer::GetStream(buffer, dmHashString64("position"), (void**)&positions, &count, &components, &stride);

if (r == dmBuffer::RESULT_OK) {
    for (int i = 0; i < count; ++i)
    {
        for (int c = 0; c < components; ++c)
        {
             positions[c] *= 1.1f;
        }
        positions += stride;
    }
} else {
    // handle error
}

dmBuffer::GetStreamType()

dmBuffer::GetStreamType(buffer,stream_name,type,components)

Gets the stream type

PARAMETERS

buffer

dmBuffer::HBuffer Pointer to a buffer.

stream_name

dmhash_t Hash of stream name to get

type

dmBuffer::ValueType* The value type

components

uint32_t* The number of values (E.g. 3 for a Vector3)

RETURNS

result

dmBuffer::Result Returns BUFFER_OK if all went ok


dmBuffer::GetValueTypeString()

dmBuffer::GetValueTypeString(result)

Converts a value type to string

PARAMETERS

result

dmBuffer::ValueType The value type

RETURNS

result

const char* The value type as a string


dmBuffer::IsBufferValid()

dmBuffer::IsBufferValid(buffer)

Checks if a handle is still valid

PARAMETERS

buffer

dmBuffer::HBuffer The buffer

RETURNS

result

bool True if the handle is valid


dmBuffer::ValidateBuffer()

dmBuffer::ValidateBuffer(buffer)

Validate a buffer and it's streams.

PARAMETERS

buffer

dmBuffer::HBuffer Buffer handle to the buffer to validate

EXAMPLES

// Pass buffer to third party library that does operations on the buffer or streams.
ThirdPartyLib::PerformOperation(buffer);

r = dmBuffer::ValidateBuffer(buffer);
if (r == dmBuffer::RESULT_OK) {
    // buffer and streams are valid
} else {
    // the third party lib made the buffer invalid
}