src/mesa/swrast/s_fragprog.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 #include "main/glheader.h"
  26 #include "main/macros.h"
  27 #include "main/samplerobj.h"
  28 #include "main/teximage.h"
  29 #include "program/prog_instruction.h"
  30
  31 #include "s_context.h"
  32 #include "s_fragprog.h"
  33 #include "s_span.h"
  34
  35 /**
  36  * \brief Should swrast use a fragment program?
  37  *
  38  * \return true if the current fragment program exists and is not the fixed
  39  *         function fragment program
  40  */
  41 GLboolean
  42 _swrast_use_fragment_program(struct gl_context *ctx)
  43 {
  44    struct gl_fragment_program *fp = ctx->FragmentProgram._Current;
  45    return fp && !(fp == ctx->FragmentProgram._TexEnvProgram
  46                   && fp->Base.NumInstructions == 0);
  47 }
  48
  49 /**
  50  * Apply texture object's swizzle (X/Y/Z/W/0/1) to incoming 'texel'
  51  * and return results in 'colorOut'.
  52  */
  53 static inline void
  54 swizzle_texel(const GLfloat texel[4], GLfloat colorOut[4], GLuint swizzle)
  55 {
  56    if (swizzle == SWIZZLE_NOOP) {
  57       COPY_4V(colorOut, texel);
  58    }
  59    else {
  60       GLfloat vector[6];
  61       vector[SWIZZLE_X] = texel[0];
  62       vector[SWIZZLE_Y] = texel[1];
  63       vector[SWIZZLE_Z] = texel[2];
  64       vector[SWIZZLE_W] = texel[3];
  65       vector[SWIZZLE_ZERO] = 0.0F;
  66       vector[SWIZZLE_ONE] = 1.0F;
  67       colorOut[0] = vector[GET_SWZ(swizzle, 0)];
  68       colorOut[1] = vector[GET_SWZ(swizzle, 1)];
  69       colorOut[2] = vector[GET_SWZ(swizzle, 2)];
  70       colorOut[3] = vector[GET_SWZ(swizzle, 3)];
  71    }
  72 }
  73
  74
  75 /**
  76  * Fetch a texel with given lod.
  77  * Called via machine->FetchTexelLod()
  78  */
  79 static void
  80 fetch_texel_lod( struct gl_context *ctx, const GLfloat texcoord[4], GLfloat lambda,
  81                  GLuint unit, GLfloat color[4] )
  82 {
  83    const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
  84
  85    if (texObj) {
  86       SWcontext *swrast = SWRAST_CONTEXT(ctx);
  87       GLfloat rgba[4];
  88       const struct gl_sampler_object *samp = _mesa_get_samplerobj(ctx, unit);
  89
  90       lambda = CLAMP(lambda, samp->MinLod, samp->MaxLod);
  91
  92       swrast->TextureSample[unit](ctx, samp, ctx->Texture.Unit[unit]._Current,
  93                                   1, (const GLfloat (*)[4]) texcoord,
  94                                   &lambda, &rgba);
  95       swizzle_texel(rgba, color, texObj->_Swizzle);
  96    }
  97    else {
  98       ASSIGN_4V(color, 0.0F, 0.0F, 0.0F, 1.0F);
  99    }
 100 }
 101
 102
 103 /**
 104  * Fetch a texel with the given partial derivatives to compute a level
 105  * of detail in the mipmap.
 106  * Called via machine->FetchTexelDeriv()
 107  * \param lodBias  the lod bias which may be specified by a TXB instruction,
 108  *                 otherwise zero.
 109  */
 110 static void
 111 fetch_texel_deriv( struct gl_context *ctx, const GLfloat texcoord[4],
 112                    const GLfloat texdx[4], const GLfloat texdy[4],
 113                    GLfloat lodBias, GLuint unit, GLfloat color[4] )
 114 {
 115    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 116    const struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
 117    const struct gl_texture_object *texObj = texUnit->_Current;
 118
 119    if (texObj) {
 120       const struct gl_texture_image *texImg = _mesa_base_tex_image(texObj);
 121       const struct swrast_texture_image *swImg =
 122          swrast_texture_image_const(texImg);
 123       const struct gl_sampler_object *samp = _mesa_get_samplerobj(ctx, unit);
 124       const GLfloat texW = (GLfloat) swImg->WidthScale;
 125       const GLfloat texH = (GLfloat) swImg->HeightScale;
 126       GLfloat lambda;
 127       GLfloat rgba[4];
 128
 129       lambda = _swrast_compute_lambda(texdx[0], texdy[0], /* ds/dx, ds/dy */
 130                                       texdx[1], texdy[1], /* dt/dx, dt/dy */
 131                                       texdx[3], texdy[3], /* dq/dx, dq/dy */
 132                                       texW, texH,
 133                                       texcoord[0], texcoord[1], texcoord[3],
 134                                       1.0F / texcoord[3]);
 135
 136       lambda += lodBias + texUnit->LodBias + samp->LodBias;
 137
 138       lambda = CLAMP(lambda, samp->MinLod, samp->MaxLod);
 139
 140       swrast->TextureSample[unit](ctx, samp, ctx->Texture.Unit[unit]._Current,
 141                                   1, (const GLfloat (*)[4]) texcoord,
 142                                   &lambda, &rgba);
 143       swizzle_texel(rgba, color, texObj->_Swizzle);
 144    }
 145    else {
 146       ASSIGN_4V(color, 0.0F, 0.0F, 0.0F, 1.0F);
 147    }
 148 }
 149
 150
 151 /**
 152  * Initialize the virtual fragment program machine state prior to running
 153  * fragment program on a fragment.  This involves initializing the input
 154  * registers, condition codes, etc.
 155  * \param machine  the virtual machine state to init
 156  * \param program  the fragment program we're about to run
 157  * \param span  the span of pixels we'll operate on
 158  * \param col  which element (column) of the span we'll operate on
 159  */
 160 static void
 161 init_machine(struct gl_context *ctx, struct gl_program_machine *machine,
 162              const struct gl_fragment_program *program,
 163              const SWspan *span, GLuint col)
 164 {
 165    GLfloat *wpos = span->array->attribs[VARYING_SLOT_POS][col];
 166
 167    /* ARB_fragment_coord_conventions */
 168    if (program->OriginUpperLeft)
 169       wpos[1] = ctx->DrawBuffer->Height - 1 - wpos[1];
 170    if (!program->PixelCenterInteger) {
 171       wpos[0] += 0.5F;
 172       wpos[1] += 0.5F;
 173    }
 174
 175    /* Setup pointer to input attributes */
 176    machine->Attribs = span->array->attribs;
 177
 178    machine->DerivX = (GLfloat (*)[4]) span->attrStepX;
 179    machine->DerivY = (GLfloat (*)[4]) span->attrStepY;
 180    machine->NumDeriv = VARYING_SLOT_MAX;
 181
 182    machine->Samplers = program->Base.SamplerUnits;
 183
 184    /* if running a GLSL program (not ARB_fragment_program) */
 185    if (ctx->_Shader->CurrentProgram[MESA_SHADER_FRAGMENT]) {
 186       /* Store front/back facing value */
 187       machine->Attribs[VARYING_SLOT_FACE][col][0] = 1.0F - span->facing;
 188    }
 189
 190    machine->CurElement = col;
 191
 192    /* init call stack */
 193    machine->StackDepth = 0;
 194
 195    machine->FetchTexelLod = fetch_texel_lod;
 196    machine->FetchTexelDeriv = fetch_texel_deriv;
 197 }
 198
 199
 200 /**
 201  * Run fragment program on the pixels in span from 'start' to 'end' - 1.
 202  */
 203 static void
 204 run_program(struct gl_context *ctx, SWspan *span, GLuint start, GLuint end)
 205 {
 206    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 207    const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
 208    const GLbitfield64 outputsWritten = program->Base.OutputsWritten;
 209    struct gl_program_machine *machine = &swrast->FragProgMachine;
 210    GLuint i;
 211
 212    for (i = start; i < end; i++) {
 213       if (span->array->mask[i]) {
 214          init_machine(ctx, machine, program, span, i);
 215
 216          if (_mesa_execute_program(ctx, &program->Base, machine)) {
 217
 218             /* Store result color */
 219             if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_COLOR)) {
 220                COPY_4V(span->array->attribs[VARYING_SLOT_COL0][i],
 221                        machine->Outputs[FRAG_RESULT_COLOR]);
 222             }
 223             else {
 224                /* Multiple drawbuffers / render targets
 225                 * Note that colors beyond 0 and 1 will overwrite other
 226                 * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
 227                 */
 228                GLuint buf;
 229                for (buf = 0; buf < ctx->DrawBuffer->_NumColorDrawBuffers; buf++) {
 230                   if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_DATA0 + buf)) {
 231                      COPY_4V(span->array->attribs[VARYING_SLOT_COL0 + buf][i],
 232                              machine->Outputs[FRAG_RESULT_DATA0 + buf]);
 233                   }
 234                }
 235             }
 236
 237             /* Store result depth/z */
 238             if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_DEPTH)) {
 239                const GLfloat depth = machine->Outputs[FRAG_RESULT_DEPTH][2];
 240                if (depth <= 0.0F)
 241                   span->array->z[i] = 0;
 242                else if (depth >= 1.0F)
 243                   span->array->z[i] = ctx->DrawBuffer->_DepthMax;
 244                else
 245                   span->array->z[i] =
 246                      (GLuint) (depth * ctx->DrawBuffer->_DepthMaxF + 0.5F);
 247             }
 248          }
 249          else {
 250             /* killed fragment */
 251             span->array->mask[i] = GL_FALSE;
 252             span->writeAll = GL_FALSE;
 253          }
 254       }
 255    }
 256 }
 257
 258
 259 /**
 260  * Execute the current fragment program for all the fragments
 261  * in the given span.
 262  */
 263 void
 264 _swrast_exec_fragment_program( struct gl_context *ctx, SWspan *span )
 265 {
 266    const struct gl_fragment_program *program = ctx->FragmentProgram._Current;
 267
 268    /* incoming colors should be floats */
 269    if (program->Base.InputsRead & VARYING_BIT_COL0) {
 270       assert(span->array->ChanType == GL_FLOAT);
 271    }
 272
 273    run_program(ctx, span, 0, span->end);
 274
 275    if (program->Base.OutputsWritten & BITFIELD64_BIT(FRAG_RESULT_COLOR)) {
 276       span->interpMask &= ~SPAN_RGBA;
 277       span->arrayMask |= SPAN_RGBA;
 278    }
 279
 280    if (program->Base.OutputsWritten & BITFIELD64_BIT(FRAG_RESULT_DEPTH)) {
 281       span->interpMask &= ~SPAN_Z;
 282       span->arrayMask |= SPAN_Z;
 283    }
 284 }
 285