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      1 /**************************************************************************
      2  *
      3  * Copyright 2009 VMware, Inc.
      4  * 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
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     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 (at) 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 cyl_wrap:4;     /* TGSI_CYLINDRICAL_WRAP_x flags */
     74    uint padding:12;
     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    boolean simple_interp;
     88    boolean depth_clamp;
     89 
     90    double pos_offset;
     91 
     92    LLVMValueRef x;
     93    LLVMValueRef y;
     94 
     95    LLVMValueRef a[1 + PIPE_MAX_SHADER_INPUTS][TGSI_NUM_CHANNELS];
     96    LLVMValueRef dadq[1 + PIPE_MAX_SHADER_INPUTS][TGSI_NUM_CHANNELS];
     97    LLVMValueRef a0aos[1 + PIPE_MAX_SHADER_INPUTS];
     98    LLVMValueRef dadxaos[1 + PIPE_MAX_SHADER_INPUTS];
     99    LLVMValueRef dadyaos[1 + PIPE_MAX_SHADER_INPUTS];
    100 
    101    LLVMValueRef attribs[1 + PIPE_MAX_SHADER_INPUTS][TGSI_NUM_CHANNELS];
    102 
    103    LLVMValueRef xoffset_store;
    104    LLVMValueRef yoffset_store;
    105 
    106    /*
    107     * Convenience pointers. Callers may access this one.
    108     */
    109    const LLVMValueRef *pos;
    110    const LLVMValueRef (*inputs)[TGSI_NUM_CHANNELS];
    111 };
    112 
    113 
    114 void
    115 lp_build_interp_soa_init(struct lp_build_interp_soa_context *bld,
    116                          struct gallivm_state *gallivm,
    117                          unsigned num_inputs,
    118                          const struct lp_shader_input *inputs,
    119                          boolean pixel_center_integer,
    120                          boolean depth_clamp,
    121                          LLVMBuilderRef builder,
    122                          struct lp_type type,
    123                          LLVMValueRef a0_ptr,
    124                          LLVMValueRef dadx_ptr,
    125                          LLVMValueRef dady_ptr,
    126                          LLVMValueRef x,
    127                          LLVMValueRef y);
    128 
    129 void
    130 lp_build_interp_soa_update_inputs_dyn(struct lp_build_interp_soa_context *bld,
    131                                       struct gallivm_state *gallivm,
    132                                       LLVMValueRef quad_start_index);
    133 
    134 void
    135 lp_build_interp_soa_update_pos_dyn(struct lp_build_interp_soa_context *bld,
    136                                    struct gallivm_state *gallivm,
    137                                    LLVMValueRef quad_start_index);
    138 
    139 #endif /* LP_BLD_INTERP_H */
    140