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Added st_fb_orientation() function to determine the up/down orientation of the framebuffer.

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This commit is contained in:
Brian 2007-08-13 18:16:11 -06:00
parent cd308dfa79
commit 4698483f84
3 changed files with 42 additions and 15 deletions
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14
src/mesa/state_tracker/st_atom_viewport.c
View file

@ -39,27 +39,19 @@
* - depthrange
* - window pos/size or FBO size
*/
static void update_viewport( struct st_context *st )
static void
update_viewport( struct st_context *st )
{
GLcontext *ctx = st->ctx;
GLfloat yScale, yBias;
/* Negate Y scale to flip image vertically.
* The NDC Y coords prior to viewport transformation are in the range
* [y=-1=bottom, y=1=top]
* Hardware window coords are in the range [y=0=top, y=H-1=bottom] where H
* is the window height.
* Use the viewport transformation to invert Y.
*/
/* _NEW_BUFFERS
*/
if (ctx->DrawBuffer) {
if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
yScale = -1;
yBias = ctx->DrawBuffer->Height ;
}
else {
/* we won't be rendering anything */
yScale = 1.0;
yBias = 0.0;
}

16
src/mesa/state_tracker/st_cb_readpixels.c
View file

@ -60,7 +60,7 @@ st_readpixels(GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
struct pipe_context *pipe = ctx->st->pipe;
GLfloat temp[MAX_WIDTH][4];
const GLbitfield transferOps = ctx->_ImageTransferState;
GLint i, yInv, dfStride;
GLint i, yStep, dfStride;
GLfloat *df;
struct st_renderbuffer *strb;
struct gl_pixelstore_attrib clippedPacking = *pack;
@ -104,11 +104,19 @@ st_readpixels(GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
dfStride = 0;
}
/* determine bottom-to-top vs. top-to-bottom order */
if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
y = strb->Base.Height - 1 - y;
yStep = -1;
}
else {
yStep = 1;
}
/* Do a row at a time to flip image data vertically */
yInv = strb->Base.Height - 1 - y;
for (i = 0; i < height; i++) {
strb->surface->get_tile(strb->surface, x, yInv, width, 1, df);
yInv--;
strb->surface->get_tile(strb->surface, x, y, width, 1, df);
y += yStep;
df += dfStride;
if (!dfStride) {
/* convert GLfloat to user's format/type */

27
src/mesa/state_tracker/st_context.h
View file

@ -118,5 +118,32 @@ extern void st_init_driver_functions(struct dd_function_table *functions);
#define Y_0_TOP 1
#define Y_0_BOTTOM 2
static INLINE GLuint
st_fb_orientation(const struct gl_framebuffer *fb)
{
if (fb && fb->Name == 0) {
/* Drawing into a window (on-screen buffer).
*
* Negate Y scale to flip image vertically.
* The NDC Y coords prior to viewport transformation are in the range
* [y=-1=bottom, y=1=top]
* Hardware window coords are in the range [y=0=top, y=H-1=bottom] where
* H is the window height.
* Use the viewport transformation to invert Y.
*/
return Y_0_TOP;
}
else {
/* Drawing into user-created FBO (very likely a texture).
*
* For textures, T=0=Bottom, so by extension Y=0=Bottom for rendering.
*/
return Y_0_BOTTOM;
}
}
#endif