How can I create MTLBuffer with uint32_t

Question

Created Jun ’22

Replies 1

Boosts 0

Participants 1

When we use Metal API

drawIndexedPrimitives:MTLPrimitiveTypeTriangle
                 indexCount:indexCount
                  indexType:MTLIndexTypeUInt32
                 indexBuffer:indexs
              indexBufferOffset:0]
to draw triangles. I have to create a MTLBuffer with uint32_t or uint16_t. When I load an index from a file and save it uint32_t* indices_. I can make sure indices_ have the right values. I try to use

 indexs = [_device newBufferWithBytes:indices_
             length:SCR_WIDTH*SCR_HEIGHT*6*sizeof(uint32_t)
             options:MTLResourceStorageModeShared];

or  use 
indexs = [_device newBufferWithLength:sizeof(uint32_t)*SCR_WIDTH*SCR_HEIGHT*6 options:MTLResourceStorageModeManaged];
     
    memcpy(indexs.contents, indices_, sizeof(uint32_t) * SCR_WIDTH*SCR_HEIGHT*6);
#if TARGET_OS_OSX
    [indexs didModifyRange:NSMakeRange(0, indexs.length)];
#endif

I can not save the index value into the MTLBuffer. I try to debug it, I find that MTLBuffer stores a lot of float value such as 3.0*10-45, and so on. appreciate any comments.

Boost

Answer 1

FlyingEagle_SH OP

Jun ’22

It is my fault, in fact. their values have been stored in MTLBuffer. I have to view their contents with differ type.

0