Particles: DeleteParticleData

       Name: DeleteParticleData                                      [Show more]
       Type: Subroutine
   Category: Particles
    Summary: Delete a particle from the particle data buffer and move the last
             particle's data down to take its place
  Deep dive: Particles and particle clouds
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * AddSmallExplosionToBuffer calls DeleteParticleData
             * BounceParticle calls DeleteParticleData
             * MoveAndDrawParticles (Part 1 of 4) calls DeleteParticleData
             * ProcessObjectDestruction calls DeleteParticleData
             * SplashParticleIntoSea calls DeleteParticleData


 Arguments:

   R10                              The address in the particle data buffer of
                                    the particle to delete


.DeleteParticleData

 LDR     R8, [R11, #particleEnd]    \ Decrease the address of the end of the
 SUB     R8, R8, #8*4               \ particle data buffer by eight words, so it
 STR     R8, [R11, #particleEnd]    \ points to the last particle's data in the
                                    \ buffer

 LDMIA   R8, {R0-R7}                \ Copy the eight bytes of particle data from
 STMIA   R10, {R0-R7}               \ the end of the buffer to the address in
                                    \ R10

 MOV     R7, #0                     \ Zero the last word of the last particle's
 STR     R7, [R8, #7*4]             \ data, so the last particle in the buffer
                                    \ now acts as a null terminator

 LDR     R8, [R11, #particleCount]  \ Decrement the particle counter to reflect
 SUB     R8, R8, #1                 \ the new number of particles on-screen
 STR     R8, [R11, #particleCount]

 B       dpar1                      \ Jump to the start of the main loop in
                                    \ MoveAndDrawParticles to process the next
                                    \ particle in the particle data buffer