src/gallium/drivers/llvmpipe/lp_tex_sample_llvm.c

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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_sample.h"
  48 #include "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 lp_jit_context
  55  * and lp_jit_texture and the sampler code generator. It provides the
  56  * texture layout information required by the texture sampler code generator
  57  * in terms of the state stored in lp_jit_context and lp_jit_texture in runtime.
  58  */
  59 struct llvmpipe_sampler_dynamic_state
  60 {
  61    struct lp_sampler_dynamic_state base;
  62
  63    const struct lp_sampler_static_state *static_state;
  64
  65    LLVMValueRef context_ptr;
  66 };
  67
  68
  69 /**
  70  * This is the bridge between our sampler and the TGSI translator.
  71  */
  72 struct lp_llvm_sampler_soa
  73 {
  74    struct lp_build_sampler_soa base;
  75
  76    struct llvmpipe_sampler_dynamic_state dynamic_state;
  77 };
  78
  79
  80 /**
  81  * Fetch the specified member of the lp_jit_texture structure.
  82  *
  83  * @sa http://llvm.org/docs/GetElementPtr.html
  84  */
  85 static LLVMValueRef
  86 lp_llvm_texture_member(struct lp_sampler_dynamic_state *base,
  87                        LLVMBuilderRef builder,
  88                        unsigned unit,
  89                        unsigned member_index,
  90                        const char *member_name)
  91 {
  92    struct llvmpipe_sampler_dynamic_state *state = (struct llvmpipe_sampler_dynamic_state *)base;
  93    LLVMValueRef indices[4];
  94    LLVMValueRef ptr;
  95    LLVMValueRef res;
  96
  97    assert(unit < PIPE_MAX_SAMPLERS);
  98
  99    /* context[0] */
 100    indices[0] = LLVMConstInt(LLVMInt32Type(), 0, 0);
 101    /* context[0].textures */
 102    indices[1] = LLVMConstInt(LLVMInt32Type(), LP_JIT_CONTEXT_TEXTURES_INDEX, 0);
 103    /* context[0].textures[unit] */
 104    indices[2] = LLVMConstInt(LLVMInt32Type(), unit, 0);
 105    /* context[0].textures[unit].member */
 106    indices[3] = LLVMConstInt(LLVMInt32Type(), member_index, 0);
 107
 108    ptr = LLVMBuildGEP(builder, state->context_ptr, indices, Elements(indices), "");
 109
 110    res = LLVMBuildLoad(builder, ptr, "");
 111
 112    lp_build_name(res, "context.texture%u.%s", unit, member_name);
 113
 114    return res;
 115 }
 116
 117
 118 /**
 119  * Helper macro to instantiate the functions that generate the code to fetch
 120  * the members of lp_jit_texture to fulfill the sampler code generator requests.
 121  *
 122  * This complexity is the price we have to pay to keep the texture sampler code
 123  * generator a reusable module without dependencies to llvmpipe internals.
 124  */
 125 #define LP_LLVM_TEXTURE_MEMBER(_name, _index) \
 126    static LLVMValueRef \
 127    lp_llvm_texture_##_name( struct lp_sampler_dynamic_state *base, \
 128                             LLVMBuilderRef builder, \
 129                             unsigned unit) \
 130    { \
 131       return lp_llvm_texture_member(base, builder, unit, _index, #_name ); \
 132    }
 133
 134
 135 LP_LLVM_TEXTURE_MEMBER(width,    LP_JIT_TEXTURE_WIDTH)
 136 LP_LLVM_TEXTURE_MEMBER(height,   LP_JIT_TEXTURE_HEIGHT)
 137 LP_LLVM_TEXTURE_MEMBER(stride,   LP_JIT_TEXTURE_STRIDE)
 138 LP_LLVM_TEXTURE_MEMBER(data_ptr, LP_JIT_TEXTURE_DATA)
 139
 140
 141 static void
 142 lp_llvm_sampler_soa_destroy(struct lp_build_sampler_soa *sampler)
 143 {
 144    FREE(sampler);
 145 }
 146
 147
 148 static void
 149 lp_llvm_sampler_soa_emit_fetch_texel(struct lp_build_sampler_soa *base,
 150                                      LLVMBuilderRef builder,
 151                                      struct lp_type type,
 152                                      unsigned unit,
 153                                      unsigned num_coords,
 154                                      const LLVMValueRef *coords,
 155                                      LLVMValueRef lodbias,
 156                                      LLVMValueRef *texel)
 157 {
 158    struct lp_llvm_sampler_soa *sampler = (struct lp_llvm_sampler_soa *)base;
 159
 160    assert(unit < PIPE_MAX_SAMPLERS);
 161
 162    lp_build_sample_soa(builder,
 163                        &sampler->dynamic_state.static_state[unit],
 164                        &sampler->dynamic_state.base,
 165                        type,
 166                        unit,
 167                        num_coords,
 168                        coords,
 169                        lodbias,
 170                        texel);
 171 }
 172
 173
 174 struct lp_build_sampler_soa *
 175 lp_llvm_sampler_soa_create(const struct lp_sampler_static_state *static_state,
 176                            LLVMValueRef context_ptr)
 177 {
 178    struct lp_llvm_sampler_soa *sampler;
 179
 180    sampler = CALLOC_STRUCT(lp_llvm_sampler_soa);
 181    if(!sampler)
 182       return NULL;
 183
 184    sampler->base.destroy = lp_llvm_sampler_soa_destroy;
 185    sampler->base.emit_fetch_texel = lp_llvm_sampler_soa_emit_fetch_texel;
 186    sampler->dynamic_state.base.width = lp_llvm_texture_width;
 187    sampler->dynamic_state.base.height = lp_llvm_texture_height;
 188    sampler->dynamic_state.base.stride = lp_llvm_texture_stride;
 189    sampler->dynamic_state.base.data_ptr = lp_llvm_texture_data_ptr;
 190    sampler->dynamic_state.static_state = static_state;
 191    sampler->dynamic_state.context_ptr = context_ptr;
 192
 193    return &sampler->base;
 194 }
 195