diff options
| -rw-r--r-- | src/mesa/main/framebuffer.c | 4 | ||||
| -rw-r--r-- | src/mesa/swrast_setup/ss_tritmp.h | 40 |
2 files changed, 24 insertions, 20 deletions
diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c index 1fd31a53211..dc10d9ffbc8 100644 --- a/src/mesa/main/framebuffer.c +++ b/src/mesa/main/framebuffer.c @@ -65,7 +65,9 @@ compute_depth_max(struct gl_framebuffer *fb) fb->_DepthMax = 0xffffffff; } fb->_DepthMaxF = (GLfloat) fb->_DepthMax; - fb->_MRD = 1.0; /* Minimum resolvable depth value, for polygon offset */ + + /* Minimum resolvable depth value, for polygon offset */ + fb->_MRD = 1.0 / fb->_DepthMaxF; } diff --git a/src/mesa/swrast_setup/ss_tritmp.h b/src/mesa/swrast_setup/ss_tritmp.h index c14468e9514..f6b738d60df 100644 --- a/src/mesa/swrast_setup/ss_tritmp.h +++ b/src/mesa/swrast_setup/ss_tritmp.h @@ -37,7 +37,7 @@ static void TAG(triangle)(GLcontext *ctx, GLuint e0, GLuint e1, GLuint e2 ) SWvertex *verts = SWSETUP_CONTEXT(ctx)->verts; SWvertex *v[3]; GLfloat z[3]; - GLfloat offset; + GLfloat offset, oz0, oz1, oz2; GLenum mode = GL_FILL; GLuint facing = 0; GLchan saved_color[3][4]; @@ -142,12 +142,16 @@ static void TAG(triangle)(GLcontext *ctx, GLuint e0, GLuint e1, GLuint e2 ) } } - if (IND & SS_OFFSET_BIT) - { - offset = ctx->Polygon.OffsetUnits * ctx->DrawBuffer->_MRD; + if (IND & SS_OFFSET_BIT) { + const GLfloat max = ctx->DrawBuffer->_DepthMaxF; + /* save original Z values (restored later) */ z[0] = v[0]->attrib[FRAG_ATTRIB_WPOS][2]; z[1] = v[1]->attrib[FRAG_ATTRIB_WPOS][2]; z[2] = v[2]->attrib[FRAG_ATTRIB_WPOS][2]; + /* Note that Z values are already scaled to [0,65535] (for example) + * so no MRD value is used here. + */ + offset = ctx->Polygon.OffsetUnits; if (cc * cc > 1e-16) { const GLfloat ez = z[0] - z[2]; const GLfloat fz = z[1] - z[2]; @@ -155,35 +159,33 @@ static void TAG(triangle)(GLcontext *ctx, GLuint e0, GLuint e1, GLuint e2 ) const GLfloat dzdx = FABSF((ey * fz - ez * fy) * oneOverArea); const GLfloat dzdy = FABSF((ez * fx - ex * fz) * oneOverArea); offset += MAX2(dzdx, dzdy) * ctx->Polygon.OffsetFactor; - /* Unfortunately, we need to clamp to prevent negative Zs below. - * Technically, we should do the clamping per-fragment. - */ - offset = MAX2(offset, -v[0]->attrib[FRAG_ATTRIB_WPOS][2]); - offset = MAX2(offset, -v[1]->attrib[FRAG_ATTRIB_WPOS][2]); - offset = MAX2(offset, -v[2]->attrib[FRAG_ATTRIB_WPOS][2]); } + /* new Z values */ + oz0 = CLAMP(v[0]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0, max); + oz1 = CLAMP(v[1]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0, max); + oz2 = CLAMP(v[2]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0, max); } } if (mode == GL_POINT) { if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetPoint) { - v[0]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[1]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[2]->attrib[FRAG_ATTRIB_WPOS][2] += offset; + v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0; + v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1; + v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2; } _swsetup_render_point_tri( ctx, e0, e1, e2, facing ); } else if (mode == GL_LINE) { if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetLine) { - v[0]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[1]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[2]->attrib[FRAG_ATTRIB_WPOS][2] += offset; + v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0; + v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1; + v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2; } _swsetup_render_line_tri( ctx, e0, e1, e2, facing ); } else { if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetFill) { - v[0]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[1]->attrib[FRAG_ATTRIB_WPOS][2] += offset; - v[2]->attrib[FRAG_ATTRIB_WPOS][2] += offset; + v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0; + v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1; + v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2; } _swrast_Triangle( ctx, v[0], v[1], v[2] ); } |