src/gallium/drivers/llvmpipe/lp_tex_sample_llvm.c

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   3  * Copyright 2009 VMware, Inc.
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  27
  28 /**
  29  * Texture sampling code generation
  30  *
  31  * This file is nothing more than ugly glue between three largely independent
  32  * entities:
  33  * - TGSI -> LLVM translation (i.e., lp_build_tgsi_soa)
  34  * - texture sampling code generation (i.e., lp_build_sample_soa)
  35  * - LLVM pipe driver
  36  *
  37  * All interesting code is in the functions mentioned above. There is really
  38  * nothing to see here.
  39  *
  40  * @author Jose Fonseca <jfonseca@vmware.com>
  41  */
  42
  43 #include "pipe/p_defines.h"
  44 #include "pipe/p_shader_tokens.h"
  45 #include "gallivm/lp_bld_debug.h"
  46 #include "gallivm/lp_bld_type.h"
  47 #include "gallivm/lp_bld_sample.h"
  48 #include "gallivm/lp_bld_tgsi.h"
  49 #include "lp_jit.h"
  50 #include "lp_tex_sample.h"
  51
  52
  53 /**
  54  * This provides the bridge between the sampler state store in
  55  * lp_jit_context and lp_jit_texture and the sampler code
  56  * generator. It provides the texture layout information required by
  57  * the texture sampler code generator in terms of the state stored in
  58  * lp_jit_context and lp_jit_texture in runtime.
  59  */
  60 struct llvmpipe_sampler_dynamic_state
  61 {
  62    struct lp_sampler_dynamic_state base;
  63
  64    const struct lp_sampler_static_state *static_state;
  65
  66    LLVMValueRef context_ptr;
  67 };
  68
  69
  70 /**
  71  * This is the bridge between our sampler and the TGSI translator.
  72  */
  73 struct lp_llvm_sampler_soa
  74 {
  75    struct lp_build_sampler_soa base;
  76
  77    struct llvmpipe_sampler_dynamic_state dynamic_state;
  78 };
  79
  80
  81 /**
  82  * Fetch the specified member of the lp_jit_texture structure.
  83  * \param emit_load  if TRUE, emit the LLVM load instruction to actually
  84  *                   fetch the field's value.  Otherwise, just emit the
  85  *                   GEP code to address the field.
  86  *
  87  * @sa http://llvm.org/docs/GetElementPtr.html
  88  */
  89 static LLVMValueRef
  90 lp_llvm_texture_member(struct lp_sampler_dynamic_state *base,
  91                        LLVMBuilderRef builder,
  92                        unsigned unit,
  93                        unsigned member_index,
  94                        const char *member_name,
  95                        boolean emit_load)
  96 {
  97    struct llvmpipe_sampler_dynamic_state *state =
  98       (struct llvmpipe_sampler_dynamic_state *)base;
  99    LLVMValueRef indices[4];
 100    LLVMValueRef ptr;
 101    LLVMValueRef res;
 102
 103    assert(unit < PIPE_MAX_SAMPLERS);
 104
 105    /* context[0] */
 106    indices[0] = LLVMConstInt(LLVMInt32Type(), 0, 0);
 107    /* context[0].textures */
 108    indices[1] = LLVMConstInt(LLVMInt32Type(), LP_JIT_CONTEXT_TEXTURES_INDEX, 0);
 109    /* context[0].textures[unit] */
 110    indices[2] = LLVMConstInt(LLVMInt32Type(), unit, 0);
 111    /* context[0].textures[unit].member */
 112    indices[3] = LLVMConstInt(LLVMInt32Type(), member_index, 0);
 113
 114    ptr = LLVMBuildGEP(builder, state->context_ptr, indices, Elements(indices), "");
 115
 116    if (emit_load)
 117       res = LLVMBuildLoad(builder, ptr, "");
 118    else
 119       res = ptr;
 120
 121    lp_build_name(res, "context.texture%u.%s", unit, member_name);
 122
 123    return res;
 124 }
 125
 126
 127 /**
 128  * Helper macro to instantiate the functions that generate the code to
 129  * fetch the members of lp_jit_texture to fulfill the sampler code
 130  * generator requests.
 131  *
 132  * This complexity is the price we have to pay to keep the texture
 133  * sampler code generator a reusable module without dependencies to
 134  * llvmpipe internals.
 135  */
 136 #define LP_LLVM_TEXTURE_MEMBER(_name, _index, _emit_load)  \
 137    static LLVMValueRef \
 138    lp_llvm_texture_##_name( struct lp_sampler_dynamic_state *base, \
 139                             LLVMBuilderRef builder, \
 140                             unsigned unit) \
 141    { \
 142       return lp_llvm_texture_member(base, builder, unit, _index, #_name, _emit_load ); \
 143    }
 144
 145
 146 LP_LLVM_TEXTURE_MEMBER(width,      LP_JIT_TEXTURE_WIDTH, TRUE)
 147 LP_LLVM_TEXTURE_MEMBER(height,     LP_JIT_TEXTURE_HEIGHT, TRUE)
 148 LP_LLVM_TEXTURE_MEMBER(depth,      LP_JIT_TEXTURE_DEPTH, TRUE)
 149 LP_LLVM_TEXTURE_MEMBER(last_level, LP_JIT_TEXTURE_LAST_LEVEL, TRUE)
 150 LP_LLVM_TEXTURE_MEMBER(row_stride, LP_JIT_TEXTURE_ROW_STRIDE, FALSE)
 151 LP_LLVM_TEXTURE_MEMBER(data_ptr,   LP_JIT_TEXTURE_DATA, FALSE)
 152
 153
 154 static void
 155 lp_llvm_sampler_soa_destroy(struct lp_build_sampler_soa *sampler)
 156 {
 157    FREE(sampler);
 158 }
 159
 160
 161 /**
 162  * Fetch filtered values from texture.
 163  * The 'texel' parameter returns four vectors corresponding to R, G, B, A.
 164  */
 165 static void
 166 lp_llvm_sampler_soa_emit_fetch_texel(struct lp_build_sampler_soa *base,
 167                                      LLVMBuilderRef builder,
 168                                      struct lp_type type,
 169                                      unsigned unit,
 170                                      unsigned num_coords,
 171                                      const LLVMValueRef *coords,
 172                                      LLVMValueRef lodbias,
 173                                      LLVMValueRef *texel)
 174 {
 175    struct lp_llvm_sampler_soa *sampler = (struct lp_llvm_sampler_soa *)base;
 176
 177    assert(unit < PIPE_MAX_SAMPLERS);
 178
 179    lp_build_sample_soa(builder,
 180                        &sampler->dynamic_state.static_state[unit],
 181                        &sampler->dynamic_state.base,
 182                        type,
 183                        unit,
 184                        num_coords,
 185                        coords,
 186                        lodbias,
 187                        texel);
 188 }
 189
 190
 191 struct lp_build_sampler_soa *
 192 lp_llvm_sampler_soa_create(const struct lp_sampler_static_state *static_state,
 193                            LLVMValueRef context_ptr)
 194 {
 195    struct lp_llvm_sampler_soa *sampler;
 196
 197    sampler = CALLOC_STRUCT(lp_llvm_sampler_soa);
 198    if(!sampler)
 199       return NULL;
 200
 201    sampler->base.destroy = lp_llvm_sampler_soa_destroy;
 202    sampler->base.emit_fetch_texel = lp_llvm_sampler_soa_emit_fetch_texel;
 203    sampler->dynamic_state.base.width = lp_llvm_texture_width;
 204    sampler->dynamic_state.base.height = lp_llvm_texture_height;
 205    sampler->dynamic_state.base.depth = lp_llvm_texture_depth;
 206    sampler->dynamic_state.base.last_level = lp_llvm_texture_last_level;
 207    sampler->dynamic_state.base.row_stride = lp_llvm_texture_row_stride;
 208    sampler->dynamic_state.base.data_ptr = lp_llvm_texture_data_ptr;
 209    sampler->dynamic_state.static_state = static_state;
 210    sampler->dynamic_state.context_ptr = context_ptr;
 211
 212    return &sampler->base;
 213 }
 214