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