1 /*
2  * Mesa 3-D graphics library
3  * Version:  7.1
4  *
5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a
8  * copy of this software and associated documentation files (the "Software"),
9  * to deal in the Software without restriction, including without limitation
10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11  * and/or sell copies of the Software, and to permit persons to whom the
12  * Software is furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included
15  * in all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23  *
24  * Authors:
25  *    Keith Whitwell <keith@tungstengraphics.com>
26  */
27 
28 
29 /**
30  * This is where we handle assigning vertex colors based on front/back
31  * facing, compute polygon offset and handle glPolygonMode().
32  */
TAG(triangle)33 static void TAG(triangle)(struct gl_context *ctx, GLuint e0, GLuint e1, GLuint e2 )
34 {
35    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
36    SScontext *swsetup = SWSETUP_CONTEXT(ctx);
37    SWvertex *verts = SWSETUP_CONTEXT(ctx)->verts;
38    SWvertex *v[3];
39    GLfloat z[3];
40    GLfloat offset, oz0, oz1, oz2;
41    GLenum mode = GL_FILL;
42    GLuint facing = 0;
43    GLchan saved_color[3][4] = { { 0 } };
44    GLfloat saved_col0[3][4] = { { 0 } };
45    GLfloat saved_spec[3][4] = { { 0 } };
46 
47    v[0] = &verts[e0];
48    v[1] = &verts[e1];
49    v[2] = &verts[e2];
50 
51    if (IND & (SS_TWOSIDE_BIT | SS_OFFSET_BIT | SS_UNFILLED_BIT))
52    {
53       GLfloat ex = v[0]->attrib[FRAG_ATTRIB_WPOS][0] - v[2]->attrib[FRAG_ATTRIB_WPOS][0];
54       GLfloat ey = v[0]->attrib[FRAG_ATTRIB_WPOS][1] - v[2]->attrib[FRAG_ATTRIB_WPOS][1];
55       GLfloat fx = v[1]->attrib[FRAG_ATTRIB_WPOS][0] - v[2]->attrib[FRAG_ATTRIB_WPOS][0];
56       GLfloat fy = v[1]->attrib[FRAG_ATTRIB_WPOS][1] - v[2]->attrib[FRAG_ATTRIB_WPOS][1];
57       GLfloat cc  = ex*fy - ey*fx;
58 
59       if (IND & (SS_TWOSIDE_BIT | SS_UNFILLED_BIT))
60       {
61 	 facing = (cc < 0.0) ^ ctx->Polygon._FrontBit;
62 
63 	 if (IND & SS_UNFILLED_BIT)
64 	    mode = facing ? ctx->Polygon.BackMode : ctx->Polygon.FrontMode;
65 
66 	 if (facing == 1) {
67 	    if (IND & SS_TWOSIDE_BIT) {
68                if (VB->BackfaceColorPtr) {
69                   GLfloat (*vbcolor)[4] = VB->BackfaceColorPtr->data;
70 
71                   if (swsetup->intColors) {
72                      COPY_CHAN4(saved_color[0], v[0]->color);
73                      COPY_CHAN4(saved_color[1], v[1]->color);
74                      COPY_CHAN4(saved_color[2], v[2]->color);
75                   }
76                   else {
77                      COPY_4V(saved_col0[0], v[0]->attrib[FRAG_ATTRIB_COL0]);
78                      COPY_4V(saved_col0[1], v[1]->attrib[FRAG_ATTRIB_COL0]);
79                      COPY_4V(saved_col0[2], v[2]->attrib[FRAG_ATTRIB_COL0]);
80                   }
81 
82                   if (VB->BackfaceColorPtr->stride) {
83                      if (swsetup->intColors) {
84                         SS_COLOR(v[0]->color, vbcolor[e0]);
85                         SS_COLOR(v[1]->color, vbcolor[e1]);
86                         SS_COLOR(v[2]->color, vbcolor[e2]);
87                      }
88                      else {
89                         COPY_4V(v[0]->attrib[FRAG_ATTRIB_COL0], vbcolor[e0]);
90                         COPY_4V(v[1]->attrib[FRAG_ATTRIB_COL0], vbcolor[e1]);
91                         COPY_4V(v[2]->attrib[FRAG_ATTRIB_COL0], vbcolor[e2]);
92                      }
93                   }
94                   else {
95                      /* flat shade */
96                      if (swsetup->intColors) {
97                         SS_COLOR(v[0]->color, vbcolor[0]);
98                         SS_COLOR(v[1]->color, vbcolor[0]);
99                         SS_COLOR(v[2]->color, vbcolor[0]);
100                      }
101                      else {
102                         COPY_4V(v[0]->attrib[FRAG_ATTRIB_COL0], vbcolor[0]);
103                         COPY_4V(v[1]->attrib[FRAG_ATTRIB_COL0], vbcolor[0]);
104                         COPY_4V(v[2]->attrib[FRAG_ATTRIB_COL0], vbcolor[0]);
105                      }
106                   }
107                }
108 
109                if (VB->BackfaceSecondaryColorPtr) {
110 		  GLfloat (*vbspec)[4] = VB->BackfaceSecondaryColorPtr->data;
111 
112 		  COPY_4V(saved_spec[0], v[0]->attrib[FRAG_ATTRIB_COL1]);
113 		  COPY_4V(saved_spec[1], v[1]->attrib[FRAG_ATTRIB_COL1]);
114 		  COPY_4V(saved_spec[2], v[2]->attrib[FRAG_ATTRIB_COL1]);
115 
116 		  if (VB->BackfaceSecondaryColorPtr->stride) {
117 		    SS_SPEC(v[0]->attrib[FRAG_ATTRIB_COL1], vbspec[e0]);
118 		    SS_SPEC(v[1]->attrib[FRAG_ATTRIB_COL1], vbspec[e1]);
119 		    SS_SPEC(v[2]->attrib[FRAG_ATTRIB_COL1], vbspec[e2]);
120 		  }
121 		  else {
122 		    SS_SPEC(v[0]->attrib[FRAG_ATTRIB_COL1], vbspec[0]);
123 		    SS_SPEC(v[1]->attrib[FRAG_ATTRIB_COL1], vbspec[0]);
124 		    SS_SPEC(v[2]->attrib[FRAG_ATTRIB_COL1], vbspec[0]);
125 		  }
126 	       }
127 	    }
128 	 }
129       }
130 
131       if (IND & SS_OFFSET_BIT) {
132          const GLfloat max = ctx->DrawBuffer->_DepthMaxF;
133          /* save original Z values (restored later) */
134 	 z[0] = v[0]->attrib[FRAG_ATTRIB_WPOS][2];
135 	 z[1] = v[1]->attrib[FRAG_ATTRIB_WPOS][2];
136 	 z[2] = v[2]->attrib[FRAG_ATTRIB_WPOS][2];
137          /* Note that Z values are already scaled to [0,65535] (for example)
138           * so no MRD value is used here.
139           */
140 	 offset = ctx->Polygon.OffsetUnits;
141 	 if (cc * cc > 1e-16) {
142 	    const GLfloat ez = z[0] - z[2];
143 	    const GLfloat fz = z[1] - z[2];
144 	    const GLfloat oneOverArea = 1.0F / cc;
145 	    const GLfloat dzdx = FABSF((ey * fz - ez * fy) * oneOverArea);
146 	    const GLfloat dzdy = FABSF((ez * fx - ex * fz) * oneOverArea);
147 	    offset += MAX2(dzdx, dzdy) * ctx->Polygon.OffsetFactor;
148 	 }
149          /* new Z values */
150          oz0 = CLAMP(v[0]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0F, max);
151          oz1 = CLAMP(v[1]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0F, max);
152          oz2 = CLAMP(v[2]->attrib[FRAG_ATTRIB_WPOS][2] + offset, 0.0F, max);
153       }
154    }
155 
156    if (mode == GL_POINT) {
157       if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetPoint) {
158 	 v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0;
159 	 v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1;
160 	 v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2;
161       }
162       _swsetup_render_tri(ctx, e0, e1, e2, facing, _swsetup_edge_render_point_tri);
163    } else if (mode == GL_LINE) {
164       if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetLine) {
165 	 v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0;
166 	 v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1;
167 	 v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2;
168       }
169       _swsetup_render_tri(ctx, e0, e1, e2, facing, _swsetup_edge_render_line_tri);
170    } else {
171       if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetFill) {
172 	 v[0]->attrib[FRAG_ATTRIB_WPOS][2] = oz0;
173 	 v[1]->attrib[FRAG_ATTRIB_WPOS][2] = oz1;
174 	 v[2]->attrib[FRAG_ATTRIB_WPOS][2] = oz2;
175       }
176       _swrast_Triangle( ctx, v[0], v[1], v[2] );
177    }
178 
179    /*
180     * Restore original vertex colors, etc.
181     */
182    if (IND & SS_OFFSET_BIT) {
183       v[0]->attrib[FRAG_ATTRIB_WPOS][2] = z[0];
184       v[1]->attrib[FRAG_ATTRIB_WPOS][2] = z[1];
185       v[2]->attrib[FRAG_ATTRIB_WPOS][2] = z[2];
186    }
187 
188    if (IND & SS_TWOSIDE_BIT) {
189       if (facing == 1) {
190 	if (VB->BackfaceColorPtr) {
191 	  if (swsetup->intColors) {
192 	    COPY_CHAN4(v[0]->color, saved_color[0]);
193 	    COPY_CHAN4(v[1]->color, saved_color[1]);
194 	    COPY_CHAN4(v[2]->color, saved_color[2]);
195 	  }
196 	  else {
197 	    COPY_4V(v[0]->attrib[FRAG_ATTRIB_COL0], saved_col0[0]);
198 	    COPY_4V(v[1]->attrib[FRAG_ATTRIB_COL0], saved_col0[1]);
199 	    COPY_4V(v[2]->attrib[FRAG_ATTRIB_COL0], saved_col0[2]);
200 	  }
201 	}
202 
203 	if (VB->BackfaceSecondaryColorPtr) {
204 	  COPY_4V(v[0]->attrib[FRAG_ATTRIB_COL1], saved_spec[0]);
205 	  COPY_4V(v[1]->attrib[FRAG_ATTRIB_COL1], saved_spec[1]);
206 	  COPY_4V(v[2]->attrib[FRAG_ATTRIB_COL1], saved_spec[2]);
207 	}
208       }
209    }
210 }
211 
212 
213 
214 /* Need to fixup edgeflags when decomposing to triangles:
215  */
TAG(quadfunc)216 static void TAG(quadfunc)( struct gl_context *ctx, GLuint v0,
217 		       GLuint v1, GLuint v2, GLuint v3 )
218 {
219    if (IND & SS_UNFILLED_BIT) {
220       struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
221       if (VB->EdgeFlag) { /* XXX this test shouldn't be needed (bug 12614) */
222          GLubyte ef1 = VB->EdgeFlag[v1];
223          GLubyte ef3 = VB->EdgeFlag[v3];
224          VB->EdgeFlag[v1] = 0;
225          TAG(triangle)( ctx, v0, v1, v3 );
226          VB->EdgeFlag[v1] = ef1;
227          VB->EdgeFlag[v3] = 0;
228          TAG(triangle)( ctx, v1, v2, v3 );
229          VB->EdgeFlag[v3] = ef3;
230       }
231    } else {
232       TAG(triangle)( ctx, v0, v1, v3 );
233       TAG(triangle)( ctx, v1, v2, v3 );
234    }
235 }
236 
237 
238 
239 
TAG(init)240 static void TAG(init)( void )
241 {
242    tri_tab[IND] = TAG(triangle);
243    quad_tab[IND] = TAG(quadfunc);
244 }
245 
246 
247 #undef IND
248 #undef TAG
249