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 "lp_bld_debug.h"
  46 #include "lp_bld_type.h"
  47 #include "lp_bld_intr.h"
  48 #include "lp_bld_sample.h"
  49 #include "lp_bld_tgsi.h"
  50 #include "lp_state.h"
  51 #include "lp_tex_sample.h"
  52
  53
  54 /**
  55  * This provides the bridge between the sampler state store in lp_jit_context
  56  * and lp_jit_texture and the sampler code generator. It provides the
  57  * texture layout information required by the texture sampler code generator
  58  * in terms of the state stored in 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  *
  84  * @sa http://llvm.org/docs/GetElementPtr.html
  85  */
  86 static LLVMValueRef
  87 lp_llvm_texture_member(struct lp_sampler_dynamic_state *base,
  88                        LLVMBuilderRef builder,
  89                        unsigned unit,
  90                        unsigned member_index,
  91                        const char *member_name)
  92 {
  93    struct llvmpipe_sampler_dynamic_state *state = (struct llvmpipe_sampler_dynamic_state *)base;
  94    LLVMValueRef indices[4];
  95    LLVMValueRef ptr;
  96    LLVMValueRef res;
  97
  98    assert(unit < PIPE_MAX_SAMPLERS);
  99
 100    /* context[0] */
 101    indices[0] = LLVMConstInt(LLVMInt32Type(), 0, 0);
 102    /* context[0].textures */
 103    indices[1] = LLVMConstInt(LLVMInt32Type(), LP_JIT_CONTEXT_TEXTURES_INDEX, 0);
 104    /* context[0].textures[unit] */
 105    indices[2] = LLVMConstInt(LLVMInt32Type(), unit, 0);
 106    /* context[0].textures[unit].member */
 107    indices[3] = LLVMConstInt(LLVMInt32Type(), member_index, 0);
 108
 109    ptr = LLVMBuildGEP(builder, state->context_ptr, indices, Elements(indices), "");
 110
 111    res = LLVMBuildLoad(builder, ptr, "");
 112
 113    lp_build_name(res, "context.texture%u.%s", unit, member_name);
 114
 115    return res;
 116 }
 117
 118
 119 /**
 120  * Helper macro to instantiate the functions that generate the code to fetch
 121  * the members of lp_jit_texture to fulfill the sampler code generator requests.
 122  *
 123  * This complexity is the price we have to pay to keep the texture sampler code
 124  * generator a reusable module without dependencies to llvmpipe internals.
 125  */
 126 #define LP_LLVM_TEXTURE_MEMBER(_name, _index) \
 127    static LLVMValueRef \
 128    lp_llvm_texture_##_name( struct lp_sampler_dynamic_state *base, \
 129                             LLVMBuilderRef builder, \
 130                             unsigned unit) \
 131    { \
 132       return lp_llvm_texture_member(base, builder, unit, _index, #_name ); \
 133    }
 134
 135
 136 LP_LLVM_TEXTURE_MEMBER(width,    LP_JIT_TEXTURE_WIDTH)
 137 LP_LLVM_TEXTURE_MEMBER(height,   LP_JIT_TEXTURE_HEIGHT)
 138 LP_LLVM_TEXTURE_MEMBER(stride,   LP_JIT_TEXTURE_STRIDE)
 139 LP_LLVM_TEXTURE_MEMBER(data_ptr, LP_JIT_TEXTURE_DATA)
 140
 141
 142 static void
 143 lp_llvm_sampler_soa_destroy(struct lp_build_sampler_soa *sampler)
 144 {
 145    FREE(sampler);
 146 }
 147
 148
 149 static void
 150 lp_llvm_sampler_soa_emit_fetch_texel(struct lp_build_sampler_soa *base,
 151                                      LLVMBuilderRef builder,
 152                                      struct lp_type type,
 153                                      unsigned unit,
 154                                      unsigned num_coords,
 155                                      const LLVMValueRef *coords,
 156                                      LLVMValueRef lodbias,
 157                                      LLVMValueRef *texel)
 158 {
 159    struct lp_llvm_sampler_soa *sampler = (struct lp_llvm_sampler_soa *)base;
 160
 161    assert(unit < PIPE_MAX_SAMPLERS);
 162
 163    lp_build_sample_soa(builder,
 164                        &sampler->dynamic_state.static_state[unit],
 165                        &sampler->dynamic_state.base,
 166                        type,
 167                        unit,
 168                        num_coords,
 169                        coords,
 170                        lodbias,
 171                        texel);
 172 }
 173
 174
 175 struct lp_build_sampler_soa *
 176 lp_llvm_sampler_soa_create(const struct lp_sampler_static_state *static_state,
 177                            LLVMValueRef context_ptr)
 178 {
 179    struct lp_llvm_sampler_soa *sampler;
 180
 181    sampler = CALLOC_STRUCT(lp_llvm_sampler_soa);
 182    if(!sampler)
 183       return NULL;
 184
 185    sampler->base.destroy = lp_llvm_sampler_soa_destroy;
 186    sampler->base.emit_fetch_texel = lp_llvm_sampler_soa_emit_fetch_texel;
 187    sampler->dynamic_state.base.width = lp_llvm_texture_width;
 188    sampler->dynamic_state.base.height = lp_llvm_texture_height;
 189    sampler->dynamic_state.base.stride = lp_llvm_texture_stride;
 190    sampler->dynamic_state.base.data_ptr = lp_llvm_texture_data_ptr;
 191    sampler->dynamic_state.static_state = static_state;
 192    sampler->dynamic_state.context_ptr = context_ptr;
 193
 194    return &sampler->base;
 195 }
 196