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27 
28 /**
29  * @file
30  * Position and shader input interpolation.
31  *
32  * Special attention is given to the interpolation of side by side quads.
33  * Multiplications are made only for the first quad. Interpolation of
34  * inputs for posterior quads are done exclusively with additions, and
35  * perspective divide if necessary.
36  *
37  * @author Jose Fonseca <jfonseca@vmware.com>
38  */
39 
40 #ifndef LP_BLD_INTERP_H
41 #define LP_BLD_INTERP_H
42 
43 
44 #include "gallivm/lp_bld.h"
45 #include "gallivm/lp_bld_type.h"
46 
47 #include "tgsi/tgsi_exec.h"
48 
49 /**
50  * Describes how to compute the interpolation coefficients (a0, dadx, dady)
51  * from the vertices passed into our triangle/line/point functions by the
52  * draw module.
53  *
54  * Vertices are treated as an array of float[4] values, indexed by
55  * src_index.
56  *
57  * LP_INTERP_COLOR is translated to either LP_INTERP_CONSTANT or
58  * PERSPECTIVE depending on flatshade state.
59  */
60 enum lp_interp {
61    LP_INTERP_CONSTANT,
62    LP_INTERP_COLOR,
63    LP_INTERP_LINEAR,
64    LP_INTERP_PERSPECTIVE,
65    LP_INTERP_POSITION,
66    LP_INTERP_FACING
67 };
68 
69 struct lp_shader_input {
70    uint interp:4;       /* enum lp_interp */
71    uint usage_mask:4;   /* bitmask of TGSI_WRITEMASK_x flags */
72    uint src_index:8;    /* where to find values in incoming vertices */
73    uint location:2;     /* TGSI_INTERPOLOATE_LOC_* */
74    uint padding:14;
75 };
76 
77 
78 struct lp_build_interp_soa_context
79 {
80    /* TGSI_QUAD_SIZE x float */
81    struct lp_build_context coeff_bld;
82    struct lp_build_context setup_bld;
83 
84    unsigned num_attribs;
85    unsigned mask[1 + PIPE_MAX_SHADER_INPUTS]; /**< TGSI_WRITE_MASK_x */
86    enum lp_interp interp[1 + PIPE_MAX_SHADER_INPUTS];
87    unsigned interp_loc[1 + PIPE_MAX_SHADER_INPUTS];
88    boolean depth_clamp;
89 
90    double pos_offset;
91    unsigned coverage_samples;
92    LLVMValueRef num_loop;
93    LLVMValueRef sample_pos_array;
94 
95    LLVMValueRef x;
96    LLVMValueRef y;
97 
98    LLVMValueRef a0_ptr;
99    LLVMValueRef dadx_ptr;
100    LLVMValueRef dady_ptr;
101 
102    LLVMValueRef a0aos[1 + PIPE_MAX_SHADER_INPUTS];
103    LLVMValueRef dadxaos[1 + PIPE_MAX_SHADER_INPUTS];
104    LLVMValueRef dadyaos[1 + PIPE_MAX_SHADER_INPUTS];
105 
106    LLVMValueRef attribs[1 + PIPE_MAX_SHADER_INPUTS][TGSI_NUM_CHANNELS];
107 
108    LLVMValueRef xoffset_store;
109    LLVMValueRef yoffset_store;
110 
111    /*
112     * Convenience pointers. Callers may access this one.
113     */
114    const LLVMValueRef *pos;
115    const LLVMValueRef (*inputs)[TGSI_NUM_CHANNELS];
116 };
117 
118 
119 void
120 lp_build_interp_soa_init(struct lp_build_interp_soa_context *bld,
121                          struct gallivm_state *gallivm,
122                          unsigned num_inputs,
123                          const struct lp_shader_input *inputs,
124                          boolean pixel_center_integer,
125                          unsigned coverage_samples,
126                          LLVMValueRef sample_pos_array,
127                          LLVMValueRef num_loop,
128                          boolean depth_clamp,
129                          LLVMBuilderRef builder,
130                          struct lp_type type,
131                          LLVMValueRef a0_ptr,
132                          LLVMValueRef dadx_ptr,
133                          LLVMValueRef dady_ptr,
134                          LLVMValueRef x,
135                          LLVMValueRef y);
136 
137 void
138 lp_build_interp_soa_update_inputs_dyn(struct lp_build_interp_soa_context *bld,
139                                       struct gallivm_state *gallivm,
140                                       LLVMValueRef quad_start_index,
141                                       LLVMValueRef mask_store,
142                                       LLVMValueRef sample_id);
143 
144 void
145 lp_build_interp_soa_update_pos_dyn(struct lp_build_interp_soa_context *bld,
146                                    struct gallivm_state *gallivm,
147                                    LLVMValueRef quad_start_index,
148                                    LLVMValueRef sample_id);
149 
150 LLVMValueRef
151 lp_build_interp_soa(struct lp_build_interp_soa_context *bld,
152                     struct gallivm_state *gallivm,
153                     LLVMValueRef loop_iter,
154                     LLVMValueRef mask_store,
155                     unsigned attrib, unsigned chan,
156                     unsigned loc,
157                     LLVMValueRef indir_index,
158                     LLVMValueRef offsets[2]);
159 
160 #endif /* LP_BLD_INTERP_H */
161