- const int xstep1 = -tri->dy12;
- const int xstep2 = -tri->dy23;
- const int xstep3 = -tri->dy31;
- const int ystep1 = tri->dx12;
- const int ystep2 = tri->dx23;
- const int ystep3 = tri->dx31;
-
-#define SETUP_STEP(i, x, y) \
- do { \
- tri->inputs.step[0][i] = x * xstep1 + y * ystep1; \
- tri->inputs.step[1][i] = x * xstep2 + y * ystep2; \
- tri->inputs.step[2][i] = x * xstep3 + y * ystep3; \
- } while (0)
-
- SETUP_STEP(0, 0, 0);
- SETUP_STEP(1, 1, 0);
- SETUP_STEP(2, 0, 1);
- SETUP_STEP(3, 1, 1);
-
- SETUP_STEP(4, 2, 0);
- SETUP_STEP(5, 3, 0);
- SETUP_STEP(6, 2, 1);
- SETUP_STEP(7, 3, 1);
-
- SETUP_STEP(8, 0, 2);
- SETUP_STEP(9, 1, 2);
- SETUP_STEP(10, 0, 3);
- SETUP_STEP(11, 1, 3);
-
- SETUP_STEP(12, 2, 2);
- SETUP_STEP(13, 3, 2);
- SETUP_STEP(14, 2, 3);
- SETUP_STEP(15, 3, 3);
-#undef STEP
+ int i;
+ plane[0].dcdy = x[0] - x[1];
+ plane[1].dcdy = x[1] - x[2];
+ plane[2].dcdy = x[2] - x[0];
+ plane[0].dcdx = y[0] - y[1];
+ plane[1].dcdx = y[1] - y[2];
+ plane[2].dcdx = y[2] - y[0];
+
+ for (i = 0; i < 3; i++) {
+ /* half-edge constants, will be interated over the whole render
+ * target.
+ */
+ plane[i].c = plane[i].dcdx * x[i] - plane[i].dcdy * y[i];
+
+ /* correct for top-left vs. bottom-left fill convention.
+ *
+ * note that we're overloading gl_rasterization_rules to mean
+ * both (0.5,0.5) pixel centers *and* bottom-left filling
+ * convention.
+ *
+ * GL actually has a top-left filling convention, but GL's
+ * notion of "top" differs from gallium's...
+ *
+ * Also, sometimes (in FBO cases) GL will render upside down
+ * to its usual method, in which case it will probably want
+ * to use the opposite, top-left convention.
+ */
+ if (plane[i].dcdx < 0) {
+ /* both fill conventions want this - adjust for left edges */
+ plane[i].c++;
+ }
+ else if (plane[i].dcdx == 0) {
+ if (setup->pixel_offset == 0) {
+ /* correct for top-left fill convention:
+ */
+ if (plane[i].dcdy > 0) plane[i].c++;
+ }
+ else {
+ /* correct for bottom-left fill convention:
+ */
+ if (plane[i].dcdy < 0) plane[i].c++;
+ }
+ }
+
+ plane[i].dcdx *= FIXED_ONE;
+ plane[i].dcdy *= FIXED_ONE;
+
+ /* find trivial reject offsets for each edge for a single-pixel
+ * sized block. These will be scaled up at each recursive level to
+ * match the active blocksize. Scaling in this way works best if
+ * the blocks are square.
+ */
+ plane[i].eo = 0;
+ if (plane[i].dcdx < 0) plane[i].eo -= plane[i].dcdx;
+ if (plane[i].dcdy > 0) plane[i].eo += plane[i].dcdy;
+ }
+ }
+#endif
+
+ if (0) {
+ debug_printf("p0: %08x/%08x/%08x/%08x\n",
+ plane[0].c,
+ plane[0].dcdx,
+ plane[0].dcdy,
+ plane[0].eo);
+
+ debug_printf("p1: %08x/%08x/%08x/%08x\n",
+ plane[1].c,
+ plane[1].dcdx,
+ plane[1].dcdy,
+ plane[1].eo);
+
+ debug_printf("p0: %08x/%08x/%08x/%08x\n",
+ plane[2].c,
+ plane[2].dcdx,
+ plane[2].dcdy,
+ plane[2].eo);