System, method, and apparatus for early culling
View Patent ↗A method of graphics processing includes determining a non-depth conditional status and an occlusion status of a fragment. Such a method may be used in culling occluded fragments before expending resources such as processing cycles and memory bus usage. In one example, a scratchpad stores depth values of robust fragments and is used for occlusion testing. Graphics architectures, and methods that include use of representative Z values, are also disclosed.
1. A method of graphics processing, said method comprising:
determining a non-depth conditional status of a fragment corresponding to a pixel;
determining that a scratchpad contains an entry mapped to the pixel,
comparing a Z value of the fragment to a value of the entry; and
based on a result of said comparing, passing the fragment to a pixel pipeline,
wherein determining a non-depth conditional status of a fragment includes determining whether incorporation of a second value of the fragment into the pixel is conditional on a non-depth criterion.
2. The method of graphics processing according to claim 1 , said method comprising replacing a line of entries of the scratchpad according to a predetermined cache replacement policy.
3. The method of graphics processing according to claim 1 , wherein the second value of the fragment includes a color value.
4. The method of graphics processing according to claim 1 , wherein determining a non-depth conditional status of a fragment includes determining a current configuration of a pixel pipeline.
5. The method of graphics processing according to claim 4 , wherein determining a current configuration of a pixel pipeline includes determining a value of at least one state variable.
6. The method of graphics processing according to claim 1 , wherein determining a non-depth conditional status of a fragment includes determining whether a non-depth fragment test is enabled.
7. The method of graphics processing according to claim 1 , wherein determining a non-depth conditional status of a fragment includes determining whether an alpha test is enabled.
8. The method of graphics processing according to claim 1 , wherein said determining a non-depth conditional status of a fragment occurs before said comparing a Z value of the fragment to a value of the entry.
9. The method of graphics processing according to claim 1 , wherein said determining a non-depth conditional status of a fragment occurs after said comparing a Z value of the fragment to a value of the entry.
10. The method of graphics processing according to claim 1 , wherein comparing a Z value of the fragment to a value of the entry includes determining whether a Z value of the fragment is less than the value of the entry.
11. The method of graphics processing according to claim 1 , further comprising overwriting the value of the entry with the Z value of the fragment.
12. The method of graphics processing according to claim 1 , wherein said determining that a scratchpad contains an entry mapped to the pixel comprises querying the scratchpad with a location value of the fragment.
13. The method of graphics processing according to claim 1 , wherein determining that a scratchpad contains an entry mapped to the pixel includes determining that the entry is valid.
14. The method of graphics processing according to claim 1 , wherein determining that a scratchpad contains an entry mapped to the pixel includes determining that the scratchpad contains a line of entries, the line being mapped to a block of pixels that includes the pixel.
15. The method of graphics processing according to claim 14 , wherein determining that the scratchpad contains a line of entries includes determining that the line is valid.
16. The method of graphics processing according to claim 14 , further comprising initializing a value of each among the line of entries to the backmost among a set of Z values.
17. The method of graphics processing according to claim 14 , further comprising initializing a value of each among the line of entries to the backmost among a set of representative Z values.
18. The method of graphics processing according to claim 1 , further comprising comparing the Z value of the fragment to a representative Z value corresponding to the fragment.
19. The method of graphics processing according to claim 18 , further comprising overwriting the representative Z value.
20. The method of graphics processing according to claim 19 , wherein determining that a scratchpad contains an entry mapped to the pixel includes determining that the scratchpad contains a line of entries, the line being mapped to a block of pixels that includes the pixel, and
wherein overwriting the representative Z value includes comparing the representative Z value with the backmost Z value of the line.
21. The method of graphics processing according to claim 20 , wherein said comparing the Z value of the fragment to a representative Z value occurs before said determining a non-depth conditional status of a fragment.
22. The method of graphics processing according to claim 1 , further comprising initializing the value of the entry to an initial value.
23. The method of graphics processing according to claim 22 , wherein the initial value is a maximum Z value.
24. The method of graphics processing according to claim 22 , wherein the initial value is the backmost among a set of Z values.
25. The method of graphics processing according to claim 22 , wherein the initial value is the backmost among a set of representative Z values.
26. The method of graphics processing according to claim 22 , wherein the initial value is a representative Z value corresponding to a location to which the entry is mapped.
27. A method of graphics processing, said method comprising:
determining a non-depth conditional status of a fragment corresponding to a pixel;
determining whether a scratchpad contains an entry mapped to the pixel,
if the scratchpad contains an entry mapped to the pixel, comparing a Z value of the fragment to a value of the entry, and otherwise altering a portion of the scratchpad; and
based on a result of said comparing, passing the fragment to a pixel pipeline,
wherein determining a non-depth conditional status of a fragment includes determining whether incorporation of a second value of the fragment into the pixel is conditional on a non-depth criterion.
28. The method of graphics processing according to claim 27 , wherein the second value of the fragment includes a color value.
29. The method of graphics processing according to claim 27 , wherein determining a non-depth conditional status of a fragment includes determining whether a non-depth fragment test is enabled.
30. The method of graphics processing according to claim 27 , wherein comparing a Z value of the fragment to a value of the entry includes determining whether a Z value of the fragment is less than the value of the entry.
31. The method of graphics processing according to claim 27 , further comprising initializing the value of the entry to the backmost among a set of Z values.
32. The method of graphics processing according to claim 27 , further comprising initializing the value of the entry to the backmost among a set of representative Z values.
33. The method of graphics processing according to claim 27 , wherein altering a portion of the scratchpad includes storing the Z value of the fragment to the entry.
34. The method of graphics processing according to claim 27 , wherein altering a portion of the scratchpad includes mapping a line of the scratchpad to a block of pixels that includes the pixel.
35. The method of graphics processing according to claim 34 , wherein altering a portion of the scratchpad includes initializing a value of each among the line of entries to the backmost among a set of Z values.
36. A method of graphics processing, said method comprising:
determining a non-depth conditional status of a fragment corresponding to a pixel;
determining that a scratchpad contains an entry mapped to the pixel;
based on a value of the entry, determining an occlusion status of the fragment; and
subsequent to said determining an occlusion status, altering a value of the fragment,
wherein determining a non-depth conditional status of a fragment includes determining whether incorporation of a color value of the fragment into the pixel is conditional on a non-depth criterion.
37. The method of graphics processing according to claim 36 , wherein determining a non-depth conditional status of a fragment includes determining whether a non-depth fragment test is enabled.
38. A graphics architecture comprising:
a logic circuit configured and arranged to receive a fragment corresponding to a pixel;
a scratchpad; and
a pixel pipeline,
wherein the logic circuit is configured to determine that the scratchpad contains an entry mapped to the pixel, and
wherein the logic circuit is configured to compare a Z value of the fragment to a value of the entry, and
wherein the logic circuit is configured to pass the fragment to the pixel pipeline based on a result of the comparing, and
wherein the logic circuit is configured to determine whether incorporation of a second value of the fragment into the pixel is conditional on a non-depth criterion.
39. The graphics architecture according to claim 38 , wherein
logic circuit is configured to determine whether incorporation of a color value of the fragment into the pixel is conditional on a non-depth criterion.
40. The graphics architecture according to claim 38 , wherein logic circuit is configured to determine whether a non-depth fragment test is enabled.
41. The graphics architecture according to claim 38 , wherein the logic circuit is configured to determine whether a Z value of the fragment is less than the value of the entry.
42. The graphics architecture according to claim 38 , wherein the logic circuit is configured to initialize the value of the entry to the backmost among a set of Z values.
43. The graphics architecture according to claim 38 , wherein the logic circuit is configured to initialize the value of the entry to the backmost among a set of representative Z values.
44. The graphics architecture according to claim 38 , wherein the logic circuit is configured to query the scratchpad with a location value of the fragment.