src/mesa/swrast/s_fragprog.c

   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_instruction.h"
  29 #include "texstate.h"
  30
  31 #include "s_fragprog.h"
  32 #include "s_span.h"
  33
  34
  35 /**
  36  * Fetch a texel.
  37  */
  38 static void
  39 fetch_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  */
  60 static void
  61 fetch_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  */
  98 static void
  99 init_machine(GLcontext *ctx, struct gl_program_machine *machine,
 100              const struct gl_fragment_program *program,
 101              const SWspan *span, GLuint col)
 102 {
 103    if (program->Base.Target == GL_FRAGMENT_PROGRAM_NV) {
 104       /* Clear temporary registers (undefined for ARB_f_p) */
 105       _mesa_bzero(machine->Temporaries,
 106                   MAX_PROGRAM_TEMPS * 4 * sizeof(GLfloat));
 107    }
 108
 109    /* Setup pointer to input attributes */
 110    machine->Attribs = span->array->attribs;
 111
 112    machine->DerivX = (GLfloat (*)[4]) span->attrStepX;
 113    machine->DerivY = (GLfloat (*)[4]) span->attrStepY;
 114    machine->NumDeriv = FRAG_ATTRIB_MAX;
 115
 116    if (ctx->Shader.CurrentProgram) {
 117       /* Store front/back facing value in register FOGC.Y */
 118       machine->Attribs[FRAG_ATTRIB_FOGC][col][1] = (GLfloat) ctx->_Facing;
 119    }
 120
 121    machine->CurElement = col;
 122
 123    /* init condition codes */
 124    machine->CondCodes[0] = COND_EQ;
 125    machine->CondCodes[1] = COND_EQ;
 126    machine->CondCodes[2] = COND_EQ;
 127    machine->CondCodes[3] = COND_EQ;
 128
 129    /* init call stack */
 130    machine->StackDepth = 0;
 131
 132    machine->FetchTexelLod = fetch_texel;
 133    machine->FetchTexelDeriv = fetch_texel_deriv;
 134 }
 135
 136
 137 /**
 138  * Run fragment program on the pixels in span from 'start' to 'end' - 1.
 139  */
 140 static void
 141 run_program(GLcontext *ctx, SWspan *span, GLuint start, GLuint end)
 142 {
 143    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 144    const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
 145    const GLbitfield outputsWritten = program->Base.OutputsWritten;
 146    struct gl_program_machine *machine = &swrast->FragProgMachine;
 147    GLuint i;
 148
 149    for (i = start; i < end; i++) {
 150       if (span->array->mask[i]) {
 151          init_machine(ctx, machine, program, span, i);
 152
 153          if (_mesa_execute_program(ctx, &program->Base, machine)) {
 154
 155             /* Store result color */
 156             if (outputsWritten & (1 << FRAG_RESULT_COLR)) {
 157                COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0][i],
 158                        machine->Outputs[FRAG_RESULT_COLR]);
 159             }
 160             else {
 161                /* Multiple drawbuffers / render targets
 162                 * Note that colors beyond 0 and 1 will overwrite other
 163                 * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
 164                 */
 165                GLuint output;
 166                for (output = 0; output < swrast->_NumColorOutputs; output++) {
 167                   if (outputsWritten & (1 << (FRAG_RESULT_DATA0 + output))) {
 168                      COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0+output][i],
 169                              machine->Outputs[FRAG_RESULT_DATA0 + output]);
 170                   }
 171                }
 172             }
 173
 174             /* Store result depth/z */
 175             if (outputsWritten & (1 << FRAG_RESULT_DEPR)) {
 176                const GLfloat depth = machine->Outputs[FRAG_RESULT_DEPR][2];
 177                if (depth <= 0.0)
 178                   span->array->z[i] = 0;
 179                else if (depth >= 1.0)
 180                   span->array->z[i] = ctx->DrawBuffer->_DepthMax;
 181                else
 182                   span->array->z[i] = IROUND(depth * ctx->DrawBuffer->_DepthMaxF);
 183             }
 184          }
 185          else {
 186             /* killed fragment */
 187             span->array->mask[i] = GL_FALSE;
 188             span->writeAll = GL_FALSE;
 189          }
 190       }
 191    }
 192 }
 193
 194
 195 /**
 196  * Execute the current fragment program for all the fragments
 197  * in the given span.
 198  */
 199 void
 200 _swrast_exec_fragment_program( GLcontext *ctx, SWspan *span )
 201 {
 202    const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
 203
 204    /* incoming colors should be floats */
 205    if (program->Base.InputsRead & FRAG_BIT_COL0) {
 206       ASSERT(span->array->ChanType == GL_FLOAT);
 207    }
 208
 209    ctx->_CurrentProgram = GL_FRAGMENT_PROGRAM_ARB; /* or NV, doesn't matter */
 210
 211    run_program(ctx, span, 0, span->end);
 212
 213    if (program->Base.OutputsWritten & (1 << FRAG_RESULT_COLR)) {
 214       span->interpMask &= ~SPAN_RGBA;
 215       span->arrayMask |= SPAN_RGBA;
 216    }
 217
 218    if (program->Base.OutputsWritten & (1 << FRAG_RESULT_DEPR)) {
 219       span->interpMask &= ~SPAN_Z;
 220       span->arrayMask |= SPAN_Z;
 221    }
 222
 223    ctx->_CurrentProgram = 0;
 224 }
 225