Stencil test #58
Merged
Stencil test #58
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The stencil functionality is not directly implemented by the GX API, so we have to emulate it by using an additional TEV stage to mask out the pixels we don't want to draw and perform some drawing operations on an offscreen EFB in order to build the stencil buffer in the first place.
We should not rely on the fact that the _ogx_efb_restore_texobj() function will only e called when color updates are enabled -- or, at the very least, if we accept this requirement we should document it. It's more robust if we always enable color updates within the function and set the dirty bit, as we do for all other GX settings that we modify.
Draw to the stencil buffer before drawing the graphic primitive, otherwise the stencil drawing operations which perform a Z-buffer test (the `zpass` and `zfail` ones set with glStencilOp) will be affected by it. When moving the stencil drawing operations before the main drawing, special care must be taken to avoid using the updated stencil buffer already when drawing the current primitive (which should be drawn using the old stencil buffer). We use the `draw_count` variable to achieve this.
|
Added a couple of commits to fix one issue with the Z-buffer being wrongly updated before the stencil test. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Finally it's here :-)
This is a big changeset all in one commit, but that's because I didn't find it worthwhile splitting it into smaller chunks (if you disagree, please let me know, I can try to come up with some splits).
The code has some inline comments, but for an overview one should read the "Stencil Test" section in the OpenGL 1.5 specification first, then the documentation changes from the second commit of this PR.
This has been tested with the tutorial №27 from swiftless.com and with the dinoshade.c program that can be found online in the examples of the GLU library.