s_fragprog.c revision c1f859d4 
1/*
2 * Mesa 3-D graphics library
3 * Version:  7.0.3
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
25#include "main/glheader.h"
26#include "main/colormac.h"
27#include "main/context.h"
28#include "main/texstate.h"
29#include "shader/prog_instruction.h"
30
31#include "s_fragprog.h"
32#include "s_span.h"
33
34
35/**
36 * Fetch a texel with given lod.
37 * Called via machine->FetchTexelLod()
38 */
39static void
40fetch_texel_lod( GLcontext *ctx, const GLfloat texcoord[4], GLfloat lambda,
41                 GLuint unit, GLfloat color[4] )
42{
43   const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
44
45   if (texObj) {
46      SWcontext *swrast = SWRAST_CONTEXT(ctx);
47      GLchan rgba[4];
48
49      lambda = CLAMP(lambda, texObj->MinLod, texObj->MaxLod);
50
51      /* XXX use a float-valued TextureSample routine here!!! */
52      swrast->TextureSample[unit](ctx, texObj, 1,
53                                  (const GLfloat (*)[4]) texcoord,
54                                  &lambda, &rgba);
55      color[0] = CHAN_TO_FLOAT(rgba[0]);
56      color[1] = CHAN_TO_FLOAT(rgba[1]);
57      color[2] = CHAN_TO_FLOAT(rgba[2]);
58      color[3] = CHAN_TO_FLOAT(rgba[3]);
59   }
60   else {
61      color[0] = color[1] = color[2] = 0.0F;
62      color[3] = 1.0F;
63   }
64}
65
66
67/**
68 * Fetch a texel with the given partial derivatives to compute a level
69 * of detail in the mipmap.
70 * Called via machine->FetchTexelDeriv()
71 */
72static void
73fetch_texel_deriv( GLcontext *ctx, const GLfloat texcoord[4],
74                   const GLfloat texdx[4], const GLfloat texdy[4],
75                   GLfloat lodBias, GLuint unit, GLfloat color[4] )
76{
77   SWcontext *swrast = SWRAST_CONTEXT(ctx);
78   const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
79
80   if (texObj) {
81      const struct gl_texture_image *texImg =
82         texObj->Image[0][texObj->BaseLevel];
83      const GLfloat texW = (GLfloat) texImg->WidthScale;
84      const GLfloat texH = (GLfloat) texImg->HeightScale;
85      GLfloat lambda;
86      GLchan rgba[4];
87
88      lambda = _swrast_compute_lambda(texdx[0], texdy[0], /* ds/dx, ds/dy */
89                                      texdx[1], texdy[1], /* dt/dx, dt/dy */
90                                      texdx[3], texdy[2], /* dq/dx, dq/dy */
91                                      texW, texH,
92                                      texcoord[0], texcoord[1], texcoord[3],
93                                      1.0F / texcoord[3]) + lodBias;
94
95      lambda = CLAMP(lambda, texObj->MinLod, texObj->MaxLod);
96
97      /* XXX use a float-valued TextureSample routine here!!! */
98      swrast->TextureSample[unit](ctx, texObj, 1,
99                                  (const GLfloat (*)[4]) texcoord,
100                                  &lambda, &rgba);
101      color[0] = CHAN_TO_FLOAT(rgba[0]);
102      color[1] = CHAN_TO_FLOAT(rgba[1]);
103      color[2] = CHAN_TO_FLOAT(rgba[2]);
104      color[3] = CHAN_TO_FLOAT(rgba[3]);
105   }
106   else {
107      color[0] = color[1] = color[2] = 0.0F;
108      color[3] = 1.0F;
109   }
110}
111
112
113/**
114 * Initialize the virtual fragment program machine state prior to running
115 * fragment program on a fragment.  This involves initializing the input
116 * registers, condition codes, etc.
117 * \param machine  the virtual machine state to init
118 * \param program  the fragment program we're about to run
119 * \param span  the span of pixels we'll operate on
120 * \param col  which element (column) of the span we'll operate on
121 */
122static void
123init_machine(GLcontext *ctx, struct gl_program_machine *machine,
124             const struct gl_fragment_program *program,
125             const SWspan *span, GLuint col)
126{
127   if (program->Base.Target == GL_FRAGMENT_PROGRAM_NV) {
128      /* Clear temporary registers (undefined for ARB_f_p) */
129      _mesa_bzero(machine->Temporaries,
130                  MAX_PROGRAM_TEMPS * 4 * sizeof(GLfloat));
131   }
132
133   /* Setup pointer to input attributes */
134   machine->Attribs = span->array->attribs;
135
136   machine->DerivX = (GLfloat (*)[4]) span->attrStepX;
137   machine->DerivY = (GLfloat (*)[4]) span->attrStepY;
138   machine->NumDeriv = FRAG_ATTRIB_MAX;
139
140   machine->Samplers = program->Base.SamplerUnits;
141
142   /* if running a GLSL program (not ARB_fragment_program) */
143   if (ctx->Shader.CurrentProgram) {
144      /* Store front/back facing value in register FOGC.Y */
145      machine->Attribs[FRAG_ATTRIB_FOGC][col][1] = 1.0 - span->facing;
146      /* Note FOGC.ZW is gl_PointCoord if drawing a sprite */
147   }
148
149   machine->CurElement = col;
150
151   /* init condition codes */
152   machine->CondCodes[0] = COND_EQ;
153   machine->CondCodes[1] = COND_EQ;
154   machine->CondCodes[2] = COND_EQ;
155   machine->CondCodes[3] = COND_EQ;
156
157   /* init call stack */
158   machine->StackDepth = 0;
159
160   machine->FetchTexelLod = fetch_texel_lod;
161   machine->FetchTexelDeriv = fetch_texel_deriv;
162}
163
164
165/**
166 * Run fragment program on the pixels in span from 'start' to 'end' - 1.
167 */
168static void
169run_program(GLcontext *ctx, SWspan *span, GLuint start, GLuint end)
170{
171   SWcontext *swrast = SWRAST_CONTEXT(ctx);
172   const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
173   const GLbitfield outputsWritten = program->Base.OutputsWritten;
174   struct gl_program_machine *machine = &swrast->FragProgMachine;
175   GLuint i;
176
177   for (i = start; i < end; i++) {
178      if (span->array->mask[i]) {
179         init_machine(ctx, machine, program, span, i);
180
181         if (_mesa_execute_program(ctx, &program->Base, machine)) {
182
183            /* Store result color */
184            if (outputsWritten & (1 << FRAG_RESULT_COLR)) {
185               COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0][i],
186                       machine->Outputs[FRAG_RESULT_COLR]);
187            }
188            else {
189               /* Multiple drawbuffers / render targets
190                * Note that colors beyond 0 and 1 will overwrite other
191                * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
192                */
193               GLuint buf;
194               for (buf = 0; buf < ctx->DrawBuffer->_NumColorDrawBuffers; buf++) {
195                  if (outputsWritten & (1 << (FRAG_RESULT_DATA0 + buf))) {
196                     COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0 + buf][i],
197                             machine->Outputs[FRAG_RESULT_DATA0 + buf]);
198                  }
199               }
200            }
201
202            /* Store result depth/z */
203            if (outputsWritten & (1 << FRAG_RESULT_DEPR)) {
204               const GLfloat depth = machine->Outputs[FRAG_RESULT_DEPR][2];
205               if (depth <= 0.0)
206                  span->array->z[i] = 0;
207               else if (depth >= 1.0)
208                  span->array->z[i] = ctx->DrawBuffer->_DepthMax;
209               else
210                  span->array->z[i] = IROUND(depth * ctx->DrawBuffer->_DepthMaxF);
211            }
212         }
213         else {
214            /* killed fragment */
215            span->array->mask[i] = GL_FALSE;
216            span->writeAll = GL_FALSE;
217         }
218      }
219   }
220}
221
222
223/**
224 * Execute the current fragment program for all the fragments
225 * in the given span.
226 */
227void
228_swrast_exec_fragment_program( GLcontext *ctx, SWspan *span )
229{
230   const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
231
232   /* incoming colors should be floats */
233   if (program->Base.InputsRead & FRAG_BIT_COL0) {
234      ASSERT(span->array->ChanType == GL_FLOAT);
235   }
236
237   ctx->_CurrentProgram = GL_FRAGMENT_PROGRAM_ARB; /* or NV, doesn't matter */
238
239   run_program(ctx, span, 0, span->end);
240
241   if (program->Base.OutputsWritten & (1 << FRAG_RESULT_COLR)) {
242      span->interpMask &= ~SPAN_RGBA;
243      span->arrayMask |= SPAN_RGBA;
244   }
245
246   if (program->Base.OutputsWritten & (1 << FRAG_RESULT_DEPR)) {
247      span->interpMask &= ~SPAN_Z;
248      span->arrayMask |= SPAN_Z;
249   }
250
251   ctx->_CurrentProgram = 0;
252}
253
254