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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
_swrast_use_fragment_program(struct gl_context * ctx)42 _swrast_use_fragment_program(struct gl_context *ctx)
43 {
44    struct gl_program *fp = ctx->FragmentProgram._Current;
45    return fp && !(fp == ctx->FragmentProgram._TexEnvProgram
46                   && fp->arb.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
swizzle_texel(const GLfloat texel[4],GLfloat colorOut[4],GLuint swizzle)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
fetch_texel_lod(struct gl_context * ctx,const GLfloat texcoord[4],GLfloat lambda,GLuint unit,GLfloat color[4])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
fetch_texel_deriv(struct gl_context * ctx,const GLfloat texcoord[4],const GLfloat texdx[4],const GLfloat texdy[4],GLfloat lodBias,GLuint unit,GLfloat color[4])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
init_machine(struct gl_context * ctx,struct gl_program_machine * machine,const struct gl_program * program,const SWspan * span,GLuint col)161 init_machine(struct gl_context *ctx, struct gl_program_machine *machine,
162              const struct gl_program *program, const SWspan *span, GLuint col)
163 {
164    GLfloat *wpos = span->array->attribs[VARYING_SLOT_POS][col];
165 
166    /* ARB_fragment_coord_conventions */
167    if (program->OriginUpperLeft)
168       wpos[1] = ctx->DrawBuffer->Height - 1 - wpos[1];
169    if (!program->PixelCenterInteger) {
170       wpos[0] += 0.5F;
171       wpos[1] += 0.5F;
172    }
173 
174    /* Setup pointer to input attributes */
175    machine->Attribs = span->array->attribs;
176 
177    machine->DerivX = (GLfloat (*)[4]) span->attrStepX;
178    machine->DerivY = (GLfloat (*)[4]) span->attrStepY;
179    machine->NumDeriv = VARYING_SLOT_MAX;
180 
181    machine->Samplers = program->SamplerUnits;
182 
183    /* if running a GLSL program (not ARB_fragment_program) */
184    if (ctx->_Shader->CurrentProgram[MESA_SHADER_FRAGMENT]) {
185       /* Store front/back facing value */
186       machine->Attribs[VARYING_SLOT_FACE][col][0] = 1.0F - span->facing;
187    }
188 
189    machine->CurElement = col;
190 
191    /* init call stack */
192    machine->StackDepth = 0;
193 
194    machine->FetchTexelLod = fetch_texel_lod;
195    machine->FetchTexelDeriv = fetch_texel_deriv;
196 }
197 
198 
199 /**
200  * Run fragment program on the pixels in span from 'start' to 'end' - 1.
201  */
202 static void
run_program(struct gl_context * ctx,SWspan * span,GLuint start,GLuint end)203 run_program(struct gl_context *ctx, SWspan *span, GLuint start, GLuint end)
204 {
205    SWcontext *swrast = SWRAST_CONTEXT(ctx);
206    const struct gl_program *program = ctx->FragmentProgram._Current;
207    const GLbitfield64 outputsWritten = program->info.outputs_written;
208    struct gl_program_machine *machine = &swrast->FragProgMachine;
209    GLuint i;
210 
211    for (i = start; i < end; i++) {
212       if (span->array->mask[i]) {
213          init_machine(ctx, machine, program, span, i);
214 
215          if (_mesa_execute_program(ctx, program, machine)) {
216 
217             /* Store result color */
218 	    if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_COLOR)) {
219                COPY_4V(span->array->attribs[VARYING_SLOT_COL0][i],
220                        machine->Outputs[FRAG_RESULT_COLOR]);
221             }
222             else {
223                /* Multiple drawbuffers / render targets
224                 * Note that colors beyond 0 and 1 will overwrite other
225                 * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
226                 */
227                GLuint buf;
228                for (buf = 0; buf < ctx->DrawBuffer->_NumColorDrawBuffers; buf++) {
229                   if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_DATA0 + buf)) {
230                      COPY_4V(span->array->attribs[VARYING_SLOT_COL0 + buf][i],
231                              machine->Outputs[FRAG_RESULT_DATA0 + buf]);
232                   }
233                }
234             }
235 
236             /* Store result depth/z */
237             if (outputsWritten & BITFIELD64_BIT(FRAG_RESULT_DEPTH)) {
238                const GLfloat depth = machine->Outputs[FRAG_RESULT_DEPTH][2];
239                if (depth <= 0.0F)
240                   span->array->z[i] = 0;
241                else if (depth >= 1.0F)
242                   span->array->z[i] = ctx->DrawBuffer->_DepthMax;
243                else
244                   span->array->z[i] =
245                      (GLuint) (depth * ctx->DrawBuffer->_DepthMaxF + 0.5F);
246             }
247          }
248          else {
249             /* killed fragment */
250             span->array->mask[i] = GL_FALSE;
251             span->writeAll = GL_FALSE;
252          }
253       }
254    }
255 }
256 
257 
258 /**
259  * Execute the current fragment program for all the fragments
260  * in the given span.
261  */
262 void
_swrast_exec_fragment_program(struct gl_context * ctx,SWspan * span)263 _swrast_exec_fragment_program( struct gl_context *ctx, SWspan *span )
264 {
265    const struct gl_program *program = ctx->FragmentProgram._Current;
266 
267    /* incoming colors should be floats */
268    if (program->info.inputs_read & VARYING_BIT_COL0) {
269       assert(span->array->ChanType == GL_FLOAT);
270    }
271 
272    run_program(ctx, span, 0, span->end);
273 
274    if (program->info.outputs_written & BITFIELD64_BIT(FRAG_RESULT_COLOR)) {
275       span->interpMask &= ~SPAN_RGBA;
276       span->arrayMask |= SPAN_RGBA;
277    }
278 
279    if (program->info.outputs_written & BITFIELD64_BIT(FRAG_RESULT_DEPTH)) {
280       span->interpMask &= ~SPAN_Z;
281       span->arrayMask |= SPAN_Z;
282    }
283 }
284 
285