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improvements to regions_overlap() function

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This commit is contained in:
Brian Paul 2001-02-22 17:59:24 +00:00
parent ea83bacf9c
commit dab76b4dc5
1 changed files with 33 additions and 13 deletions
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46
src/mesa/swrast/s_copypix.c
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@ -1,4 +1,4 @@
/* $Id: s_copypix.c,v 1.11 2001/02/20 16:42:26 brianp Exp $ */
/* $Id: s_copypix.c,v 1.12 2001/02/22 17:59:24 brianp Exp $ */
/*
* Mesa 3-D graphics library
@ -47,23 +47,43 @@
/*
* Determine if there's overlap in an image copy
* Determine if there's overlap in an image copy.
* This test also compensates for the fact that copies are done from
* bottom to top and overlaps can sometimes be handled correctly
* without making a temporary image copy.
*/
static GLboolean
regions_overlap(int srcx, int srcy, int dstx, int dsty, int width, int height,
float zoomX, float zoomY)
regions_overlap(GLint srcx, GLint srcy,
GLint dstx, GLint dsty,
GLint width, GLint height,
GLfloat zoomX, GLfloat zoomY)
{
if ((srcx > dstx + (width * zoomX) + 1) || (srcx + width + 1 < dstx)) {
return GL_FALSE;
}
else if ((srcy < dsty) && (srcy + height < dsty + (height * zoomY))) {
return GL_FALSE;
}
else if ((srcy > dsty) && (srcy + height > dsty + (height * zoomY))) {
return GL_FALSE;
if (zoomX == 1.0 && zoomY == 1.0) {
/* no zoom */
if (srcx >= dstx + width || (srcx + width <= dstx)) {
return GL_FALSE;
}
else if (srcy < dsty) { /* this is OK */
return GL_FALSE;
}
else {
return GL_TRUE;
}
}
else {
return GL_TRUE;
/* add one pixel of slop when zooming, just to be safe */
if ((srcx > dstx + (width * zoomX) + 1) || (srcx + width + 1 < dstx)) {
return GL_FALSE;
}
else if ((srcy < dsty) && (srcy + height < dsty + (height * zoomY))) {
return GL_FALSE;
}
else if ((srcy > dsty) && (srcy + height > dsty + (height * zoomY))) {
return GL_FALSE;
}
else {
return GL_TRUE;
}
}
}