From 6dceeb2eb804d708639d68a13a924d65f366458a Mon Sep 17 00:00:00 2001 From: Robert Ellison Date: Wed, 11 Mar 2009 16:27:38 -0600 Subject: [PATCH] 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. --- src/mesa/drivers/dri/i965/brw_sf.c | 10 ++++++++-- src/mesa/main/mtypes.h | 10 +++++++++- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_sf.c b/src/mesa/drivers/dri/i965/brw_sf.c index 8c1711538af..c3c85978f4d 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, diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h index f2058641911..9080c83da4e 100644 --- a/src/mesa/main/mtypes.h +++ b/src/mesa/main/mtypes.h @@ -2236,7 +2236,15 @@ struct gl_renderbuffer_attachment struct gl_framebuffer { _glthread_Mutex Mutex; /**< for thread safety */ - GLuint Name; /**< if zero, this is a window system framebuffer */ + /** + * If zero, this is a window system framebuffer. If non-zero, this + * is a FBO framebuffer; note that for some devices (i.e. those with + * a natural pixel coordinate system for FBOs that differs from the + * OpenGL/Mesa coordinate system), this means that both the viewport + * and polygon face orientation will have to be inverted. + */ + GLuint Name; + GLint RefCount; GLboolean DeletePending; -- 2.30.2