rcmagic

Readme: In the following pseudo code, [] indicates a subroutine.
Sometimes I choose to write the subroutine inline under the [] in order to maintain context. 
One important fact about the way rollbacks are handled here is that we are storing state for every frame. 
In any real implementation you only need to store one game state at a time. Storing a game 
state for every frame allows us to only rollback to the first frame where the predicted inputs don't match the true ones.


==Constants==
MAX_ROLLBACK_FRAMES     := Any Positive Integer         # Specifies the maximum number of frames that can be resimulated
FRAME_ADVANTAGE_LIMIT   := Any Positive Integer         # Specifies the number of frames the local client can progress ahead of the remote client before time synchronizing. 

pervognsen

Multi-dimensional array views for systems programmers

As C programmers, most of us think of pointer arithmetic for multi-dimensional arrays in a nested way:

The address for a 1-dimensional array is base + x. The address for a 2-dimensional array is base + x + y*x_size for row-major layout and base + y + x*y_size for column-major layout. The address for a 3-dimensional array is base + x + (y + z*y_size)*x_size for row-column-major layout. And so on.

vurtun

vurtun

/* ===========================================================================
 *
 *                                  LIBRARY
 *
 * =========================================================================== */
/*  Proof of Concept GUI:
 *  - PoC UI implementation in ~2.5kLOC of C89 (ANSI C)
 *      => Core solutions has no external dependencies (removing standard library dependency is trival)
 *      => Does not use or require any special language constructs or macro constructs just pointers and enums
 *  - Combines both "retained" and "immediate mode" UI by providing control over update frequency

bryanedds

No matter the business domain or programming language, programmers always end up needing support for ALL of these things
in some form -

* Resource Semantics (such as RAII in C++, or finalizers in C#)

* Error Semantics (such as exceptions in most languages, or conditions in Common Lisp)

* Algebraic Types (such as structs and unions in C, or records and DUs in F#)

* Data Abstraction (such as that which is often badly entangled within object systems in OO languages)

vurtun

Graphical User Interfaces

For the last few weeks I spend some time coding, writing and cleaning up my notes from almost a year since I published nuklear.

Basically this is a possible implementation for a graphical user interface builder backend with support for an immediate mode style API. So it provides a way to define non-mutating UI state, an immediate mode style API for dynamic UI components (lists,trees,...) and a combination of both.

The core implementation is ~800 LOC without any kind of default widgets or extensions. At first this seems quite counter intuitive. However since the inherent design allows for lots of different ways to define any widget like buttons it does not make sense to provide a specific default implementation. The way this code was architectured furthermore removes the need for style/skinning configurations used in Nuklear since widget painting is just calling a small

rygorous

Brief explanation what I did to get the speed-up, and the thought process behind it.

The original code went:

EnterLoop:
			movaps		xmm3, xmmword ptr [edx+ecx*2]		// Box1YZ
			cmpnltps	xmm3, xmm2
			movmskps	eax, xmm3

			cmp			eax, 0Ch

dwilliamson

struct Data
{
  Data()
  {
  }
  
  ~Data()
  {
  }
  

pervognsen

typedef int task_t; // Lower bits as table index, upper bits as generation counter for use-after-free detection.
typedef void (*task_function_t)(void *task_data);
task_t task_create(task_function_t task_function, void *task_data);
void task_depends(task_t task, task_t dependency);
void task_start(task_t task);

Upon completion, tasks signal their dependencies and are released.

Memory requirements for a minimal implementation: 16/24 bytes per task and 8 bytes per dependency edge.
Even so, you still don't want to have one task instance for every array entry in a gigabyte array. Always assign

pervognsen

typedef union {
	struct { char pad_x[31]; int x; } __attribute__((packed));
	struct { char pad_y[512]; int y; } __attribute__((packed));
	// ...
} __attribute__((packed)) overlay;

// Macrofied:

#define JOIN1(x, y) x##y
#define JOIN(x, y) JOIN1(x, y)