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authorRobert Ellison <papillo@vmware.com>2009-03-11 16:27:38 -0600
committerRobert Ellison <papillo@vmware.com>2009-03-11 21:19:45 -0600
commit6dceeb2eb804d708639d68a13a924d65f366458a (patch)
tree25baf111f173ea5288c3b092f204e8f4d6750b9b /src/mesa/drivers/dri
parent548be3846db59ad43934a159c051b359db6e56db (diff)
i965: fix polygon face orientation when rendering to FBO
In the i965, the FBO coordinate system is inverted from the standard OpenGL/Mesa coordinate system; that means that the viewport and the polygon face orientation have to be inverted if rendering to a FBO. The viewport was already being handled correctly; but polygon face was not. This caused a conform failure when rendering to texture with two-sided lighting enabled. This fixes the problem in the i965 driver, and adds to the comment about the gl_framebuffer "Name" field so that this isn't a surprise to other driver writers.
Diffstat (limited to 'src/mesa/drivers/dri')
-rw-r--r--src/mesa/drivers/dri/i965/brw_sf.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_sf.c b/src/mesa/drivers/dri/i965/brw_sf.c
index 8c1711538a..c3c85978f4 100644
--- a/src/mesa/drivers/dri/i965/brw_sf.c
+++ b/src/mesa/drivers/dri/i965/brw_sf.c
@@ -167,8 +167,14 @@ static void upload_sf_prog(struct brw_context *brw)
key.do_twoside_color = (ctx->Light.Enabled && ctx->Light.Model.TwoSide);
/* _NEW_POLYGON */
- if (key.do_twoside_color)
- key.frontface_ccw = (ctx->Polygon.FrontFace == GL_CCW);
+ if (key.do_twoside_color) {
+ /* If we're rendering to a FBO, we have to invert the polygon
+ * face orientation, just as we invert the viewport in
+ * sf_unit_create_from_key(). ctx->DrawBuffer->Name will be
+ * nonzero if we're rendering to such an FBO.
+ */
+ key.frontface_ccw = (ctx->Polygon.FrontFace == GL_CCW) ^ (ctx->DrawBuffer->Name != 0);
+ }
dri_bo_unreference(brw->sf.prog_bo);
brw->sf.prog_bo = brw_search_cache(&brw->cache, BRW_SF_PROG,