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Minor clean-up of polygon offset logic. Properly compute _MRD field.

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This commit is contained in:
Brian 2007-07-11 16:19:51 -06:00
parent 34f6243bef
commit b755a2d9de
2 changed files with 24 additions and 20 deletions
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4
src/mesa/main/framebuffer.c
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@ -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;
}

40
src/mesa/swrast_setup/ss_tritmp.h
View file

@ -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] );
}