path: root/src/gallium/drivers/llvmpipe/lp_tex_sample.c

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 * 
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/**
 * Texture sampling code generation
 *
 * This file is nothing more than ugly glue between three largely independent
 * entities:
 * - TGSI -> LLVM translation (i.e., lp_build_tgsi_soa)
 * - texture sampling code generation (i.e., lp_build_sample_soa)
 * - LLVM pipe driver
 *
 * All interesting code is in the functions mentioned above. There is really
 * nothing to see here.
 *
 * @author Jose Fonseca <jfonseca@vmware.com>
 */

#include "pipe/p_defines.h"
#include "pipe/p_shader_tokens.h"
#include "gallivm/lp_bld_debug.h"
#include "gallivm/lp_bld_const.h"
#include "gallivm/lp_bld_type.h"
#include "gallivm/lp_bld_sample.h"
#include "gallivm/lp_bld_tgsi.h"
#include "lp_jit.h"
#include "lp_tex_sample.h"
#include "lp_debug.h"


/**
 * This provides the bridge between the sampler state store in
 * lp_jit_context and lp_jit_texture and the sampler code
 * generator. It provides the texture layout information required by
 * the texture sampler code generator in terms of the state stored in
 * lp_jit_context and lp_jit_texture in runtime.
 */
struct llvmpipe_sampler_dynamic_state
{
   struct lp_sampler_dynamic_state base;

   const struct lp_sampler_static_state *static_state;

   LLVMValueRef context_ptr;
};


/**
 * This is the bridge between our sampler and the TGSI translator.
 */
struct lp_llvm_sampler_soa
{
   struct lp_build_sampler_soa base;

   struct llvmpipe_sampler_dynamic_state dynamic_state;
};


/**
 * Fetch the specified member of the lp_jit_texture structure.
 * \param emit_load  if TRUE, emit the LLVM load instruction to actually
 *                   fetch the field's value.  Otherwise, just emit the
 *                   GEP code to address the field.
 *
 * @sa http://llvm.org/docs/GetElementPtr.html
 */
static LLVMValueRef
lp_llvm_texture_member(const struct lp_sampler_dynamic_state *base,
                       struct gallivm_state *gallivm,
                       unsigned unit,
                       unsigned member_index,
                       const char *member_name,
                       boolean emit_load)
{
   struct llvmpipe_sampler_dynamic_state *state =
      (struct llvmpipe_sampler_dynamic_state *)base;
   LLVMBuilderRef builder = gallivm->builder;
   LLVMValueRef indices[4];
   LLVMValueRef ptr;
   LLVMValueRef res;

   assert(unit < PIPE_MAX_SAMPLERS);

   /* context[0] */
   indices[0] = lp_build_const_int32(gallivm, 0);
   /* context[0].textures */
   indices[1] = lp_build_const_int32(gallivm, LP_JIT_CTX_TEXTURES);
   /* context[0].textures[unit] */
   indices[2] = lp_build_const_int32(gallivm, unit);
   /* context[0].textures[unit].member */
   indices[3] = lp_build_const_int32(gallivm, member_index);

   ptr = LLVMBuildGEP(builder, state->context_ptr, indices, Elements(indices), "");

   if (emit_load)
      res = LLVMBuildLoad(builder, ptr, "");
   else
      res = ptr;

   lp_build_name(res, "context.texture%u.%s", unit, member_name);

   return res;
}


/**
 * Helper macro to instantiate the functions that generate the code to
 * fetch the members of lp_jit_texture to fulfill the sampler code
 * generator requests.
 *
 * This complexity is the price we have to pay to keep the texture
 * sampler code generator a reusable module without dependencies to
 * llvmpipe internals.
 */
#define LP_LLVM_TEXTURE_MEMBER(_name, _index, _emit_load)  \
   static LLVMValueRef \
   lp_llvm_texture_##_name( const struct lp_sampler_dynamic_state *base, \
                            struct gallivm_state *gallivm, \
                            unsigned unit) \
   { \
      return lp_llvm_texture_member(base, gallivm, unit, _index, #_name, _emit_load ); \
   }


LP_LLVM_TEXTURE_MEMBER(width,      LP_JIT_TEXTURE_WIDTH, TRUE)
LP_LLVM_TEXTURE_MEMBER(height,     LP_JIT_TEXTURE_HEIGHT, TRUE)
LP_LLVM_TEXTURE_MEMBER(depth,      LP_JIT_TEXTURE_DEPTH, TRUE)
LP_LLVM_TEXTURE_MEMBER(first_level, LP_JIT_TEXTURE_FIRST_LEVEL, TRUE)
LP_LLVM_TEXTURE_MEMBER(last_level, LP_JIT_TEXTURE_LAST_LEVEL, TRUE)
LP_LLVM_TEXTURE_MEMBER(row_stride, LP_JIT_TEXTURE_ROW_STRIDE, FALSE)
LP_LLVM_TEXTURE_MEMBER(img_stride, LP_JIT_TEXTURE_IMG_STRIDE, FALSE)
LP_LLVM_TEXTURE_MEMBER(data_ptr,   LP_JIT_TEXTURE_DATA, FALSE)
LP_LLVM_TEXTURE_MEMBER(min_lod,    LP_JIT_TEXTURE_MIN_LOD, TRUE)
LP_LLVM_TEXTURE_MEMBER(max_lod,    LP_JIT_TEXTURE_MAX_LOD, TRUE)
LP_LLVM_TEXTURE_MEMBER(lod_bias,   LP_JIT_TEXTURE_LOD_BIAS, TRUE)
LP_LLVM_TEXTURE_MEMBER(border_color, LP_JIT_TEXTURE_BORDER_COLOR, FALSE)


static void
lp_llvm_sampler_soa_destroy(struct lp_build_sampler_soa *sampler)
{
   FREE(sampler);
}


/**
 * Fetch filtered values from texture.
 * The 'texel' parameter returns four vectors corresponding to R, G, B, A.
 */
static void
lp_llvm_sampler_soa_emit_fetch_texel(const struct lp_build_sampler_soa *base,
                                     struct gallivm_state *gallivm,
                                     struct lp_type type,
                                     unsigned unit,
                                     unsigned num_coords,
                                     const LLVMValueRef *coords,
                                     const struct lp_derivatives *derivs,
                                     LLVMValueRef lod_bias, /* optional */
                                     LLVMValueRef explicit_lod, /* optional */
                                     LLVMValueRef *texel)
{
   struct lp_llvm_sampler_soa *sampler = (struct lp_llvm_sampler_soa *)base;

   assert(unit < PIPE_MAX_SAMPLERS);
   
   if (LP_PERF & PERF_NO_TEX) {
      lp_build_sample_nop(gallivm, type, num_coords, coords, texel);
      return;
   }

   lp_build_sample_soa(gallivm,
                       &sampler->dynamic_state.static_state[unit],
                       &sampler->dynamic_state.base,
                       type,
                       unit,
                       num_coords, coords,
                       derivs,
                       lod_bias, explicit_lod,
                       texel);
}

/**
 * Fetch the texture size.
 */
static void
lp_llvm_sampler_soa_emit_size_query(const struct lp_build_sampler_soa *base,
                                    struct gallivm_state *gallivm,
                                    struct lp_type type,
                                    unsigned unit,
                                    LLVMValueRef explicit_lod, /* optional */
                                    LLVMValueRef *sizes_out)
{
   struct lp_llvm_sampler_soa *sampler = (struct lp_llvm_sampler_soa *)base;

   assert(unit < PIPE_MAX_SAMPLERS);
   
   lp_build_size_query_soa(gallivm,
			   &sampler->dynamic_state.static_state[unit],
			   &sampler->dynamic_state.base,
                           type,
			   unit,
			   explicit_lod,
			   sizes_out);
}


struct lp_build_sampler_soa *
lp_llvm_sampler_soa_create(const struct lp_sampler_static_state *static_state,
                           LLVMValueRef context_ptr)
{
   struct lp_llvm_sampler_soa *sampler;

   sampler = CALLOC_STRUCT(lp_llvm_sampler_soa);
   if(!sampler)
      return NULL;

   sampler->base.destroy = lp_llvm_sampler_soa_destroy;
   sampler->base.emit_fetch_texel = lp_llvm_sampler_soa_emit_fetch_texel;
   sampler->base.emit_size_query = lp_llvm_sampler_soa_emit_size_query;
   sampler->dynamic_state.base.width = lp_llvm_texture_width;
   sampler->dynamic_state.base.height = lp_llvm_texture_height;
   sampler->dynamic_state.base.depth = lp_llvm_texture_depth;
   sampler->dynamic_state.base.first_level = lp_llvm_texture_first_level;
   sampler->dynamic_state.base.last_level = lp_llvm_texture_last_level;
   sampler->dynamic_state.base.row_stride = lp_llvm_texture_row_stride;
   sampler->dynamic_state.base.img_stride = lp_llvm_texture_img_stride;
   sampler->dynamic_state.base.data_ptr = lp_llvm_texture_data_ptr;
   sampler->dynamic_state.base.min_lod = lp_llvm_texture_min_lod;
   sampler->dynamic_state.base.max_lod = lp_llvm_texture_max_lod;
   sampler->dynamic_state.base.lod_bias = lp_llvm_texture_lod_bias;
   sampler->dynamic_state.base.border_color = lp_llvm_texture_border_color;

   sampler->dynamic_state.static_state = static_state;
   sampler->dynamic_state.context_ptr = context_ptr;

   return &sampler->base;
}