pandory500/SDL-mirror
2
0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Added some comments.

Browse source
This commit is contained in:
Sunny Sachanandani 2010-08-02 17:14:09 +05:30
parent d96742b024
commit 0669fef25b
1 changed files with 16 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

18
src/video/x11/SDL_x11render.c
View file

@ -1886,6 +1886,8 @@ X11_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
Picture src, mask;
XRenderPictureAttributes attr;
const SDL_Rect *mrect;
/* mrect is the rectangular area of the mask
* picture that is aligned with the source. */
if (texture->modMode == SDL_TEXTUREMODULATE_NONE) {
src = texturedata->picture;
@ -1901,11 +1903,16 @@ X11_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
}
else if (texture->blendMode == SDL_BLENDMODE_MOD)
{
/* SDL_BLENDMODE_MOD requires a temporary buffer
* i.e. stencil_pict */
mask = data->stencil_pict;
mrect = dstrect;
}
else
{
/* This trick allows on-the-fly multiplication
* of the src color channels with it's alpha
* channel. */
mask = src;
mrect = srcrect;
}
@ -1925,6 +1932,7 @@ X11_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
mrect->x, mrect->y, dstrect->x, dstrect->y,
dstrect->w, dstrect->h);
} else {
/* The transformation is from the dst to src picture. */
double xscale = ((double) srcrect->w) / dstrect->w;
double yscale = ((double) srcrect->h) / dstrect->h;
XTransform xform = {{
@ -1933,16 +1941,20 @@ X11_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
{XDoubleToFixed(0), XDoubleToFixed(0), XDoubleToFixed(xscale * yscale)}}};
XRenderSetPictureTransform(data->display, src, &xform);
/* Black magic follows. */
if (texture->blendMode == SDL_BLENDMODE_MOD) {
/* Copy the dst to a temp buffer. */
XRenderComposite(data->display, PictOpSrc, data->drawable_pict,
src, data->stencil_pict,
dstrect->x, dstrect->y, srcrect->x, srcrect->y,
dstrect->x, dstrect->y, dstrect->w, dstrect->h);
/* Set the compnent alpha flag on the temp buffer. */
attr.component_alpha = True;
XRenderChangePicture(data->display, data->stencil_pict,
CPComponentAlpha, &attr);
}
/* Set the picture filter only if a scaling mode is set. */
if (texture->scaleMode != SDL_TEXTURESCALEMODE_NONE) {
XRenderSetPictureFilter(data->display, src,
texturedata->filter, 0, 0);
@ -1952,14 +1964,16 @@ X11_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
src, mask, data->drawable_pict,
srcrect->x, srcrect->y, mrect->x, mrect->y,
dstrect->x, dstrect->y, dstrect->w, dstrect->h);
/* Set the texture transformation back to the identity matrix. */
XTransform identity = {{
{XDoubleToFixed(1), XDoubleToFixed(0), XDoubleToFixed(0)},
{XDoubleToFixed(0), XDoubleToFixed(1), XDoubleToFixed(0)},
{XDoubleToFixed(0), XDoubleToFixed(0), XDoubleToFixed(1)}}};
XRenderSetPictureTransform(data->display, src, &identity);
}
/* Reset the component alpha flag only when
* the blending mode is SDL_BLENDMODE_MOD. */
if (renderer->blendMode == SDL_BLENDMODE_MOD) {
attr.component_alpha = False;
XRenderChangePicture(data->display, data->stencil_pict,