gallium: Fix computation of Z values when not using early Z.
[mesa.git] / src / gallium / drivers / softpipe / sp_quad_fs.c
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3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
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27
28 /* Vertices are just an array of floats, with all the attributes
29 * packed. We currently assume a layout like:
30 *
31 * attr[0][0..3] - window position
32 * attr[1..n][0..3] - remaining attributes.
33 *
34 * Attributes are assumed to be 4 floats wide but are packed so that
35 * all the enabled attributes run contiguously.
36 */
37
38 #include "pipe/p_util.h"
39 #include "pipe/p_defines.h"
40 #include "pipe/p_shader_tokens.h"
41
42 #include "sp_context.h"
43 #include "sp_state.h"
44 #include "sp_headers.h"
45 #include "sp_quad.h"
46 #include "sp_texture.h"
47 #include "sp_tex_sample.h"
48
49
50 struct quad_shade_stage
51 {
52 struct quad_stage stage;
53 struct tgsi_sampler samplers[PIPE_MAX_SAMPLERS];
54 struct tgsi_exec_machine machine;
55 struct tgsi_exec_vector *inputs, *outputs;
56 int colorOutSlot, depthOutSlot;
57 };
58
59
60 /** cast wrapper */
61 static INLINE struct quad_shade_stage *
62 quad_shade_stage(struct quad_stage *qs)
63 {
64 return (struct quad_shade_stage *) qs;
65 }
66
67
68
69 /**
70 * Execute fragment shader for the four fragments in the quad.
71 */
72 static void
73 shade_quad(
74 struct quad_stage *qs,
75 struct quad_header *quad )
76 {
77 struct quad_shade_stage *qss = quad_shade_stage( qs );
78 struct softpipe_context *softpipe = qs->softpipe;
79 struct tgsi_exec_machine *machine = &qss->machine;
80
81 /* Consts do not require 16 byte alignment. */
82 machine->Consts = softpipe->mapped_constants[PIPE_SHADER_FRAGMENT];
83
84 machine->InterpCoefs = quad->coef;
85
86 /* run shader */
87 quad->mask &= softpipe->fs->run( softpipe->fs,
88 &qss->machine,
89 quad );
90
91 /* store result color */
92 if (qss->colorOutSlot >= 0) {
93 /* XXX need to handle multiple color outputs someday */
94 assert(qss->stage.softpipe->fs->info.output_semantic_name[qss->colorOutSlot]
95 == TGSI_SEMANTIC_COLOR);
96 memcpy(
97 quad->outputs.color,
98 &machine->Outputs[qss->colorOutSlot].xyzw[0].f[0],
99 sizeof( quad->outputs.color ) );
100 }
101
102 /*
103 * XXX the following code for updating quad->outputs.depth
104 * isn't really needed if we did early z testing.
105 */
106
107 /* store result Z */
108 if (qss->depthOutSlot >= 0) {
109 /* output[slot] is new Z */
110 uint i;
111 for (i = 0; i < 4; i++) {
112 quad->outputs.depth[i] = machine->Outputs[0].xyzw[2].f[i];
113 }
114 }
115 else {
116 /* compute Z values now, as in the quad earlyz stage */
117 /* XXX we should really only do this if the earlyz stage is not used */
118 const float fx = (float) quad->x0;
119 const float fy = (float) quad->y0;
120 const float dzdx = quad->posCoef->dadx[2];
121 const float dzdy = quad->posCoef->dady[2];
122 const float z0 = quad->posCoef->a0[2] + dzdx * fx + dzdy * fy;
123
124 quad->outputs.depth[0] = z0;
125 quad->outputs.depth[1] = z0 + dzdx;
126 quad->outputs.depth[2] = z0 + dzdy;
127 quad->outputs.depth[3] = z0 + dzdx + dzdy;
128 }
129
130 /* shader may cull fragments */
131 if( quad->mask ) {
132 qs->next->run( qs->next, quad );
133 }
134 }
135
136 /**
137 * Per-primitive (or per-begin?) setup
138 */
139 static void shade_begin(struct quad_stage *qs)
140 {
141 struct quad_shade_stage *qss = quad_shade_stage(qs);
142 struct softpipe_context *softpipe = qs->softpipe;
143 unsigned i;
144 unsigned num = MAX2(softpipe->num_textures, softpipe->num_samplers);
145
146 /* set TGSI sampler state that varies */
147 for (i = 0; i < num; i++) {
148 qss->samplers[i].state = softpipe->sampler[i];
149 qss->samplers[i].texture = softpipe->texture[i];
150 }
151
152 /* find output slots for depth, color */
153 qss->colorOutSlot = -1;
154 qss->depthOutSlot = -1;
155 for (i = 0; i < qss->stage.softpipe->fs->info.num_outputs; i++) {
156 switch (qss->stage.softpipe->fs->info.output_semantic_name[i]) {
157 case TGSI_SEMANTIC_POSITION:
158 qss->depthOutSlot = i;
159 break;
160 case TGSI_SEMANTIC_COLOR:
161 qss->colorOutSlot = i;
162 break;
163 }
164 }
165
166 softpipe->fs->prepare( softpipe->fs,
167 &qss->machine,
168 qss->samplers );
169
170 qs->next->begin(qs->next);
171 }
172
173
174 static void shade_destroy(struct quad_stage *qs)
175 {
176 struct quad_shade_stage *qss = (struct quad_shade_stage *) qs;
177
178 tgsi_exec_machine_free_data(&qss->machine);
179 FREE( qss->inputs );
180 FREE( qss->outputs );
181 FREE( qs );
182 }
183
184
185 struct quad_stage *sp_quad_shade_stage( struct softpipe_context *softpipe )
186 {
187 struct quad_shade_stage *qss = CALLOC_STRUCT(quad_shade_stage);
188 uint i;
189
190 /* allocate storage for program inputs/outputs, aligned to 16 bytes */
191 qss->inputs = MALLOC(PIPE_MAX_ATTRIBS * sizeof(*qss->inputs) + 16);
192 qss->outputs = MALLOC(PIPE_MAX_ATTRIBS * sizeof(*qss->outputs) + 16);
193 qss->machine.Inputs = align16(qss->inputs);
194 qss->machine.Outputs = align16(qss->outputs);
195
196 qss->stage.softpipe = softpipe;
197 qss->stage.begin = shade_begin;
198 qss->stage.run = shade_quad;
199 qss->stage.destroy = shade_destroy;
200
201 /* set TGSI sampler state that's constant */
202 for (i = 0; i < PIPE_MAX_SAMPLERS; i++) {
203 assert(softpipe->tex_cache[i]);
204 qss->samplers[i].get_samples = sp_get_samples;
205 qss->samplers[i].pipe = &softpipe->pipe;
206 qss->samplers[i].cache = softpipe->tex_cache[i];
207 }
208
209 tgsi_exec_machine_init( &qss->machine );
210
211 return &qss->stage;
212 }