I tried to modify the example of the article “Who gives a blit” to use
PgDraw… functions to draw into offscreen buffers. I used code similar to
the doc section “Raw Drawing and Animation/Video memory offscreen”.
Specifically, I changed the place where the two for loops were to:
/* Make it the current context and draw a purple
rectangle in it. /
olddc=PhDCSetCurrent(images_->ctx);
PgSetFillColor(Pg_PURPLE);
PgDrawIRect(0,0,99,99,Pg_DRAW_FILL);
PgFlush(); / Draws the rectangle. /
PhDCSetCurrent(olddc);
/ for (y=0;y<RAD;y++)
for (x=0;x<RAD;x++)
{
int val=((x<y)?x:y);
val+=(iRAD)/NUMIMAGES;
val=(val128)/RAD;
if (val&0x40) val=0x3f-(val&0x3f);
images->buffer[(y*(images->pitch>>1))+x]=
images->buffer[(((WH-1)-y)(images->pitch>>1))+x]=
images->buffer[(y(images->pitch>>1))+((WH-1)-x)]=
images->buffer[(((WH-1)-y)(images->pitch>>1))+((WH-1)-x)]=
(val&0x3f)<<5;
}
/
}
Result: Nothing shows up when the offscreen is copied to the screen
What’s wrong?
Markus
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