Instancing

• In particle system we need to display lots of similar shapes
• • Multiple draw calls (N>1000) can be costly

// Slow for large N
for(int k=0; k<N; ++k)
   someOperator(k)
   draw(shape) // ... glDrawElements(...)

NVIDIA

• Solution: Use Instancing

// 1 unique call, N is a parameter
drawInstanced(shape, N) // ... glDrawElementsInstanced(...,N)
// No more explicit loop

// ...
someOperator(gl_InstanceID)
// ...