Re: [AD] minor issues

[Milan Mimica <milan.mimica1@xxxxxxxxxx>]

Elias Pschernig wrote:
> Hm, I guess, memset() makes use of special asm instructions which
> allegro's clear does not, or something. Can you post a simple test
> program which compares the two, and if possible, a patch which does the
> change - so the old vs. new clear_bitmap could be directly compared.

Attached patch and the test progam.
Here are my test results on linux, P4:

patched:
15-bit: 2000 calls, 1.105000 ms per call
16-bit: 2000 calls, 1.115000 ms per call
24-bit: 2000 calls, 1.870000 ms per call
32-bit: 2000 calls, 2.650000 ms per call

vanilla:
15-bit: 2000 calls, 1.475000 ms per call
16-bit: 2000 calls, 1.465000 ms per call
24-bit: 2000 calls, 2.225000 ms per call
32-bit: 2000 calls, 2.655000 ms per call

I was wondering, is it OK to clear the 16th bit when in 15-bit mode?


--
Milan Mimica

diff -u3r allegro-4.1.18/src/gfx.c allegro-4.1.18-fix/src/gfx.c
--- allegro-4.1.18/src/gfx.c	2005-01-27 12:14:01.000000000 +0100
+++ allegro-4.1.18-fix/src/gfx.c	2005-01-27 12:08:26.000000000 +0100
@@ -23,6 +23,7 @@
 
 
 #include <math.h>
+#include <string.h>
 #include "allegro.h"
 #include "allegro/internal/aintern.h"
 
@@ -158,7 +159,10 @@
  */
 void clear_bitmap(BITMAP *bitmap)
 {
-   clear_to_color(bitmap, 0);
+   if (is_memory_bitmap(bitmap))
+      memset(bitmap->line[0], 0,  BYTES_PER_PIXEL(bitmap_color_depth(bitmap)) * bitmap->w * bitmap->h);
+   else
+      clear_to_color(bitmap, 0);
 }
 
 

#include <allegro.h>
#include <time.h>
#include <stdio.h>

int main() {
	int c;
	int t;
	BITMAP *bmp;
	const int iter = 2000;

	allegro_init();


	bmp = create_bitmap_ex(15, 800, 600);

	t = clock();
	for (c = 0; c < iter; ++c)
		clear_bitmap(bmp);
	t = clock() - t;
	printf("15-bit: %i calls, %f ms per call\n", iter, 1000.0 * t / (iter * (double)CLOCKS_PER_SEC));
	destroy_bitmap(bmp);


	bmp = create_bitmap_ex(16, 800, 600);

	t = clock();
	for (c = 0; c < iter; ++c)
		clear_bitmap(bmp);
	t = clock() - t;
	printf("16-bit: %i calls, %f ms per call\n", iter, 1000.0 * t / (iter * (double)CLOCKS_PER_SEC));
	destroy_bitmap(bmp);


	bmp = create_bitmap_ex(24, 800, 600);

	t = clock();
	for (c = 0; c < iter; ++c)
		clear_bitmap(bmp);
	t = clock() - t;
	printf("24-bit: %i calls, %f ms per call\n", iter, 1000.0 * t / (iter * (double)CLOCKS_PER_SEC));
	destroy_bitmap(bmp);
	

	bmp = create_bitmap_ex(32, 800, 600);

	t = clock();
	for (c = 0; c < iter; ++c)
		clear_bitmap(bmp);
	t = clock() - t;
	printf("32-bit: %i calls, %f ms per call\n", iter, 1000.0 * t / (iter * (double)CLOCKS_PER_SEC));
	destroy_bitmap(bmp);


	return 0;
}
END_OF_MAIN()