/**
- * Emit the TGSI instructions to adjust the WPOS pixel center convention
- * Basically, add (adjX, adjY) to the fragment position.
- */
-static void
-emit_adjusted_wpos( struct st_translate *t,
- const struct gl_program *program,
- GLfloat adjX, GLfloat adjY)
-{
- struct ureg_program *ureg = t->ureg;
- struct ureg_dst wpos_temp = ureg_DECL_temporary(ureg);
- struct ureg_src wpos_input = t->inputs[t->inputMapping[FRAG_ATTRIB_WPOS]];
-
- /* Note that we bias X and Y and pass Z and W through unchanged.
- * The shader might also use gl_FragCoord.w and .z.
- */
- ureg_ADD(ureg, wpos_temp, wpos_input,
- ureg_imm4f(ureg, adjX, adjY, 0.0f, 0.0f));
-
- t->inputs[t->inputMapping[FRAG_ATTRIB_WPOS]] = ureg_src(wpos_temp);
-}
-
-
-/**
- * Emit the TGSI instructions for inverting the WPOS y coordinate.
+ * Emit the TGSI instructions for inverting and adjusting WPOS.
* This code is unavoidable because it also depends on whether
* a FBO is bound (STATE_FB_WPOS_Y_TRANSFORM).
*/
static void
-emit_wpos_inversion( struct st_translate *t,
- const struct gl_program *program,
- boolean invert)
+emit_wpos_adjustment( struct st_translate *t,
+ const struct gl_program *program,
+ boolean invert,
+ GLfloat adjX, GLfloat adjY[2])
{
struct ureg_program *ureg = t->ureg;
wposTransformState);
struct ureg_src wpostrans = ureg_DECL_constant( ureg, wposTransConst );
- struct ureg_dst wpos_temp;
+ struct ureg_dst wpos_temp = ureg_DECL_temporary( ureg );
struct ureg_src wpos_input = t->inputs[t->inputMapping[FRAG_ATTRIB_WPOS]];
- /* MOV wpos_temp, input[wpos]
- */
- if (wpos_input.File == TGSI_FILE_TEMPORARY)
- wpos_temp = ureg_dst(wpos_input);
- else {
- wpos_temp = ureg_DECL_temporary( ureg );
+ /* First, apply the coordinate shift: */
+ if (adjX || adjY[0] || adjY[1]) {
+ if (adjY[0] != adjY[1]) {
+ /* Adjust the y coordinate by adjY[1] or adjY[0] respectively
+ * depending on whether inversion is actually going to be applied
+ * or not, which is determined by testing against the inversion
+ * state variable used below, which will be either +1 or -1.
+ */
+ struct ureg_dst adj_temp = ureg_DECL_temporary(ureg);
+
+ ureg_CMP(ureg, adj_temp,
+ ureg_scalar(wpostrans, invert ? 2 : 0),
+ ureg_imm4f(ureg, adjX, adjY[0], 0.0f, 0.0f),
+ ureg_imm4f(ureg, adjX, adjY[1], 0.0f, 0.0f));
+ ureg_ADD(ureg, wpos_temp, wpos_input, ureg_src(adj_temp));
+ } else {
+ ureg_ADD(ureg, wpos_temp, wpos_input,
+ ureg_imm4f(ureg, adjX, adjY[0], 0.0f, 0.0f));
+ }
+ wpos_input = ureg_src(wpos_temp);
+ } else {
+ /* MOV wpos_temp, input[wpos]
+ */
ureg_MOV( ureg, wpos_temp, wpos_input );
}
+ /* Now the conditional y flip: STATE_FB_WPOS_Y_TRANSFORM.xy/zw will be
+ * inversion/identity, or the other way around if we're drawing to an FBO.
+ */
if (invert) {
/* MAD wpos_temp.y, wpos_input, wpostrans.xxxx, wpostrans.yyyy
*/
const struct gl_fragment_program *fp =
(const struct gl_fragment_program *) program;
struct pipe_screen *pscreen = st->pipe->screen;
+ GLfloat adjX = 0.0f;
+ GLfloat adjY[2] = { 0.0f, 0.0f };
boolean invert = FALSE;
+ /* Query the pixel center conventions supported by the pipe driver and set
+ * adjX, adjY to help out if it cannot handle the requested one internally.
+ *
+ * The bias of the y-coordinate depends on whether y-inversion takes place
+ * (adjY[1]) or not (adjY[0]), which is in turn dependent on whether we are
+ * drawing to an FBO (causes additional inversion), and whether the the pipe
+ * driver origin and the requested origin differ (the latter condition is
+ * stored in the 'invert' variable).
+ *
+ * For height = 100 (i = integer, h = half-integer, l = lower, u = upper):
+ *
+ * center shift only:
+ * i -> h: +0.5
+ * h -> i: -0.5
+ *
+ * inversion only:
+ * l,i -> u,i: ( 0.0 + 1.0) * -1 + 100 = 99
+ * l,h -> u,h: ( 0.5 + 0.0) * -1 + 100 = 99.5
+ * u,i -> l,i: (99.0 + 1.0) * -1 + 100 = 0
+ * u,h -> l,h: (99.5 + 0.0) * -1 + 100 = 0.5
+ *
+ * inversion and center shift:
+ * l,i -> u,h: ( 0.0 + 0.5) * -1 + 100 = 99.5
+ * l,h -> u,i: ( 0.5 + 0.5) * -1 + 100 = 99
+ * u,i -> l,h: (99.0 + 0.5) * -1 + 100 = 0.5
+ * u,h -> l,i: (99.5 + 0.5) * -1 + 100 = 0
+ */
if (fp->OriginUpperLeft) {
/* Fragment shader wants origin in upper-left */
if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT)) {
if (fp->PixelCenterInteger) {
/* Fragment shader wants pixel center integer */
- if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER))
+ if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER)) {
/* the driver supports pixel center integer */
+ adjY[1] = 1.0f;
ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
- else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER))
+ }
+ else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER)) {
/* the driver supports pixel center half integer, need to bias X,Y */
- emit_adjusted_wpos(t, program, 0.5f, invert ? 0.5f : -0.5f);
+ adjX = -0.5f;
+ adjY[0] = -0.5f;
+ adjY[1] = 0.5f;
+ }
else
assert(0);
}
}
else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER)) {
/* the driver supports pixel center integer, need to bias X,Y */
+ adjX = adjY[0] = adjY[1] = 0.5f;
ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
- emit_adjusted_wpos(t, program, 0.5f, invert ? -0.5f : 0.5f);
}
else
assert(0);
/* we invert after adjustment so that we avoid the MOV to temporary,
* and reuse the adjustment ADD instead */
- emit_wpos_inversion(t, program, invert);
+ emit_wpos_adjustment(t, program, invert, adjX, adjY);
}
projects / mesa.git / commitdiff