This function updates the contents of a vertex buffer using data in the given buffer.
IMPORTANT You cannot pass a frozen vertex buffer as the destination buffer.
vertex_update_buffer_from_buffer(dest_vbuff, dest_offset, src_buffer[, src_offset, src_size]);
| Argument | Type | Description |
|---|---|---|
| dest_vbuff | Vertex Buffer | The vertex buffer to copy to |
| dest_offset | Real | The offset in the destination buffer to start writing the data |
| src_buffer | Buffer | The source buffer to copy from |
| src_offset | Real | OPTIONAL The offset in bytes in the source buffer to start copying. Defaults to 0. |
| src_size | Real | OPTIONAL The size of the data in bytes to copy from the source buffer. Defaults to -1. When -1 the whole buffer is copied. |
N/A
vertex_format_begin();
vertex_format_add_position_3d(); // Three buffer_f32 values
vertex_format_add_texcoord(); // Two buffer_f32 values
vertex_format = vertex_format_end();
var _i = 0, _vertex_size = (3 + 2) * buffer_sizeof(buffer_f32), _buff = buffer_create(1000, buffer_fixed, 4);
repeat(51)
{
repeat(3) buffer_write(_buff, buffer_f32, random(500)); // x, y, z
repeat(2) buffer_write(_buff, buffer_f32, ((_i++ mod 6) < 3)); // u, v
}
vb = vertex_create_buffer_from_buffer_ext(_buff, vertex_format, 0, 30);
vertex_update_buffer_from_buffer(vb, 0, _buff, 40 * _vertex_size, 3 * _vertex_size);
The code above first creates a new vertex format that consists of a 3D position attribute and a texture coordinate attribute. It then initialises a couple of temporary variables: a loop counter, the source buffer and the size in bytes of a single vertex. The (3 + 2) refers to the three float values used to store a position and the two float values to store a UV coordinate. The buffer is then filled with some random values to create a total of 51 randomly positioned vertices, or 17 triangles, stored as pr_trianglelist (see Primitive Type Constant). After that, a new vertex buffer is created from the first 30 vertices in the buffer. Finally, the first three vertices in this vertex buffer are updated with a call to vertex_update_buffer_from_buffer; they are overwritten with the data of vertex index 40, 41 and 42 in the original buffer.