s_fragprog.c revision 17ad1d12ebf04ebf4b2b35c1c37d36bb4d2bb550 
1/*
2 * Mesa 3-D graphics library
3 * Version:  6.5.2
4 *
5 * Copyright (C) 1999-2006  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
25#include "glheader.h"
26#include "colormac.h"
27#include "context.h"
28#include "prog_execute.h"
29#include "prog_instruction.h"
30
31#include "s_fragprog.h"
32#include "s_span.h"
33
34
35/**
36 * Fetch a texel.
37 */
38static void
39fetch_texel( GLcontext *ctx, const GLfloat texcoord[4], GLfloat lambda,
40             GLuint unit, GLfloat color[4] )
41{
42   GLchan rgba[4];
43   SWcontext *swrast = SWRAST_CONTEXT(ctx);
44
45   /* XXX use a float-valued TextureSample routine here!!! */
46   swrast->TextureSample[unit](ctx, ctx->Texture.Unit[unit]._Current,
47                               1, (const GLfloat (*)[4]) texcoord,
48                               &lambda, &rgba);
49   color[0] = CHAN_TO_FLOAT(rgba[0]);
50   color[1] = CHAN_TO_FLOAT(rgba[1]);
51   color[2] = CHAN_TO_FLOAT(rgba[2]);
52   color[3] = CHAN_TO_FLOAT(rgba[3]);
53}
54
55
56/**
57 * Fetch a texel with the given partial derivatives to compute a level
58 * of detail in the mipmap.
59 */
60static void
61fetch_texel_deriv( GLcontext *ctx, const GLfloat texcoord[4],
62                   const GLfloat texdx[4], const GLfloat texdy[4],
63                   GLuint unit, GLfloat color[4] )
64{
65   SWcontext *swrast = SWRAST_CONTEXT(ctx);
66   const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
67   const struct gl_texture_image *texImg = texObj->Image[0][texObj->BaseLevel];
68   const GLfloat texW = (GLfloat) texImg->WidthScale;
69   const GLfloat texH = (GLfloat) texImg->HeightScale;
70   GLchan rgba[4];
71
72   GLfloat lambda = _swrast_compute_lambda(texdx[0], texdy[0], /* ds/dx, ds/dy */
73                                         texdx[1], texdy[1], /* dt/dx, dt/dy */
74                                         texdx[3], texdy[2], /* dq/dx, dq/dy */
75                                         texW, texH,
76                                         texcoord[0], texcoord[1], texcoord[3],
77                                         1.0F / texcoord[3]);
78
79   swrast->TextureSample[unit](ctx, ctx->Texture.Unit[unit]._Current,
80                               1, (const GLfloat (*)[4]) texcoord,
81                               &lambda, &rgba);
82   color[0] = CHAN_TO_FLOAT(rgba[0]);
83   color[1] = CHAN_TO_FLOAT(rgba[1]);
84   color[2] = CHAN_TO_FLOAT(rgba[2]);
85   color[3] = CHAN_TO_FLOAT(rgba[3]);
86}
87
88
89/**
90 * Initialize the virtual fragment program machine state prior to running
91 * fragment program on a fragment.  This involves initializing the input
92 * registers, condition codes, etc.
93 * \param machine  the virtual machine state to init
94 * \param program  the fragment program we're about to run
95 * \param span  the span of pixels we'll operate on
96 * \param col  which element (column) of the span we'll operate on
97 */
98static void
99init_machine(GLcontext *ctx, struct gl_program_machine *machine,
100             const struct gl_fragment_program *program,
101             const SWspan *span, GLuint col)
102{
103   GLuint inputsRead = program->Base.InputsRead;
104
105   if (ctx->FragmentProgram.CallbackEnabled)
106      inputsRead = ~0;
107
108   if (program->Base.Target == GL_FRAGMENT_PROGRAM_NV) {
109      /* Clear temporary registers (undefined for ARB_f_p) */
110      _mesa_bzero(machine->Temporaries,
111                  MAX_PROGRAM_TEMPS * 4 * sizeof(GLfloat));
112   }
113
114   /* Setup pointer to input attributes */
115   machine->Attribs = span->array->attribs;
116
117   /* Store front/back facing value in register FOGC.Y */
118   machine->Attribs[FRAG_ATTRIB_FOGC][col][1] = (GLfloat) ctx->_Facing;
119
120   machine->CurElement = col;
121
122   /* init condition codes */
123   machine->CondCodes[0] = COND_EQ;
124   machine->CondCodes[1] = COND_EQ;
125   machine->CondCodes[2] = COND_EQ;
126   machine->CondCodes[3] = COND_EQ;
127
128   /* init call stack */
129   machine->StackDepth = 0;
130
131   machine->FetchTexelLod = fetch_texel;
132   machine->FetchTexelDeriv = fetch_texel_deriv;
133}
134
135
136/**
137 * Run fragment program on the pixels in span from 'start' to 'end' - 1.
138 */
139static void
140run_program(GLcontext *ctx, SWspan *span, GLuint start, GLuint end)
141{
142   SWcontext *swrast = SWRAST_CONTEXT(ctx);
143   const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
144   const GLbitfield outputsWritten = program->Base.OutputsWritten;
145   struct gl_program_machine machine;
146   GLuint i;
147
148   for (i = start; i < end; i++) {
149      if (span->array->mask[i]) {
150         init_machine(ctx, &machine, program, span, i);
151
152         if (_mesa_execute_program(ctx, &program->Base, &machine)) {
153
154            /* Store result color */
155            if (outputsWritten & (1 << FRAG_RESULT_COLR)) {
156               COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0][i],
157                       machine.Outputs[FRAG_RESULT_COLR]);
158            }
159            else {
160               /* Multiple drawbuffers / render targets
161                * Note that colors beyond 0 and 1 will overwrite other
162                * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
163                */
164               GLuint output;
165               for (output = 0; output < swrast->_NumColorOutputs; output++) {
166                  if (outputsWritten & (1 << (FRAG_RESULT_DATA0 + output))) {
167                     COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0+output][i],
168                             machine.Outputs[FRAG_RESULT_DATA0 + output]);
169                  }
170               }
171            }
172
173            /* Store result depth/z */
174            if (outputsWritten & (1 << FRAG_RESULT_DEPR)) {
175               const GLfloat depth = machine.Outputs[FRAG_RESULT_DEPR][2];
176               if (depth <= 0.0)
177                  span->array->z[i] = 0;
178               else if (depth >= 1.0)
179                  span->array->z[i] = ctx->DrawBuffer->_DepthMax;
180               else
181                  span->array->z[i] = IROUND(depth * ctx->DrawBuffer->_DepthMaxF);
182            }
183         }
184         else {
185            /* killed fragment */
186            span->array->mask[i] = GL_FALSE;
187            span->writeAll = GL_FALSE;
188         }
189      }
190   }
191}
192
193
194/**
195 * Execute the current fragment program for all the fragments
196 * in the given span.
197 */
198void
199_swrast_exec_fragment_program( GLcontext *ctx, SWspan *span )
200{
201   const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
202
203   /* incoming colors should be floats */
204   if (program->Base.InputsRead & FRAG_BIT_COL0) {
205      ASSERT(span->array->ChanType == GL_FLOAT);
206   }
207
208   ctx->_CurrentProgram = GL_FRAGMENT_PROGRAM_ARB; /* or NV, doesn't matter */
209
210   run_program(ctx, span, 0, span->end);
211
212   if (program->Base.OutputsWritten & (1 << FRAG_RESULT_COLR)) {
213      span->interpMask &= ~SPAN_RGBA;
214      span->arrayMask |= SPAN_RGBA;
215   }
216
217   if (program->Base.OutputsWritten & (1 << FRAG_RESULT_DEPR)) {
218      span->interpMask &= ~SPAN_Z;
219      span->arrayMask |= SPAN_Z;
220   }
221
222   ctx->_CurrentProgram = 0;
223}
224
225