src/compiler/nir/nir_lower_drawpixels.c - platform/external/mesa3d - Git at Google

 /*
  * Copyright © 2015 Red Hat
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */

 #include "nir.h"
 #include "nir_builder.h"

 /* Lower glDrawPixels().
  *
  * This is based on the logic in st_get_drawpix_shader() in TGSI compiler.
  *
  * Run before nir_lower_io.
  */

 typedef struct {
    const nir_lower_drawpixels_options *options;
    nir_shader   *shader;
    nir_builder   b;
    nir_variable *texcoord, *scale, *bias;
 } lower_drawpixels_state;

 static nir_ssa_def *
 get_texcoord(lower_drawpixels_state *state)
 {
    if (state->texcoord == NULL) {
       nir_variable *texcoord = NULL;

       /* find gl_TexCoord, if it exists: */
       nir_foreach_variable(var, &state->shader->inputs) {
          if (var->data.location == VARYING_SLOT_TEX0) {
             texcoord = var;
             break;
          }
       }

       /* otherwise create it: */
       if (texcoord == NULL) {
          texcoord = nir_variable_create(state->shader,
                                         nir_var_shader_in,
                                         glsl_vec4_type(),
                                         "gl_TexCoord");
          texcoord->data.location = VARYING_SLOT_TEX0;
       }

       state->texcoord = texcoord;
    }
    return nir_load_var(&state->b, state->texcoord);
 }

 static nir_variable *
 create_uniform(nir_shader *shader, const char *name, const int state_tokens[5])
 {
    nir_variable *var = nir_variable_create(shader,
                                            nir_var_uniform,
                                            glsl_vec4_type(),
                                            name);
    var->num_state_slots = 1;
    var->state_slots = ralloc_array(var, nir_state_slot, 1);
    memcpy(var->state_slots[0].tokens, state_tokens,
           sizeof(var->state_slots[0].tokens));
    return var;
 }

 static nir_ssa_def *
 get_scale(lower_drawpixels_state *state)
 {
    if (state->scale == NULL) {
       state->scale = create_uniform(state->shader, "gl_PTscale",
                                     state->options->scale_state_tokens);
    }
    return nir_load_var(&state->b, state->scale);
 }

 static nir_ssa_def *
 get_bias(lower_drawpixels_state *state)
 {
    if (state->bias == NULL) {
       state->bias = create_uniform(state->shader, "gl_PTbias",
                                    state->options->bias_state_tokens);
    }
    return nir_load_var(&state->b, state->bias);
 }

 static nir_ssa_def *
 get_texcoord_const(lower_drawpixels_state *state)
 {
    if (state->bias == NULL) {
       state->bias = create_uniform(state->shader, "gl_MultiTexCoord0",
                                    state->options->texcoord_state_tokens);
    }
    return nir_load_var(&state->b, state->bias);
 }

 static void
 lower_color(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 {
    nir_builder *b = &state->b;
    nir_ssa_def *texcoord;
    nir_tex_instr *tex;
    nir_ssa_def *def;

    assert(intr->dest.is_ssa);

    b->cursor = nir_before_instr(&intr->instr);

    texcoord = get_texcoord(state);

    /* replace load_var(gl_Color) w/ texture sample:
     *   TEX def, texcoord, drawpix_sampler, 2D
     */
    tex = nir_tex_instr_create(state->shader, 1);
    tex->op = nir_texop_tex;
    tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
    tex->coord_components = 2;
    tex->sampler_index = state->options->drawpix_sampler;
    tex->texture_index = state->options->drawpix_sampler;
    tex->dest_type = nir_type_float;
    tex->src[0].src_type = nir_tex_src_coord;
    tex->src[0].src = nir_src_for_ssa(texcoord);

    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
    nir_builder_instr_insert(b, &tex->instr);
    def = &tex->dest.ssa;

    /* Apply the scale and bias. */
    if (state->options->scale_and_bias) {
       /* MAD def, def, scale, bias; */
       def = nir_ffma(b, def, get_scale(state), get_bias(state));
    }

    if (state->options->pixel_maps) {
       static const unsigned swiz_xy[4] = {0,1};
       static const unsigned swiz_zw[4] = {2,3};

       /* do four pixel map look-ups with two TEX instructions: */
       nir_ssa_def *def_xy, *def_zw;

       /* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
       tex = nir_tex_instr_create(state->shader, 1);
       tex->op = nir_texop_tex;
       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
       tex->coord_components = 2;
       tex->sampler_index = state->options->pixelmap_sampler;
       tex->texture_index = state->options->pixelmap_sampler;
       tex->dest_type = nir_type_float;
       tex->src[0].src_type = nir_tex_src_coord;
       tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_xy, 2, true));

       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
       nir_builder_instr_insert(b, &tex->instr);
       def_xy = &tex->dest.ssa;

       /* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
       tex = nir_tex_instr_create(state->shader, 1);
       tex->op = nir_texop_tex;
       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
       tex->coord_components = 2;
       tex->sampler_index = state->options->pixelmap_sampler;
       tex->dest_type = nir_type_float;
       tex->src[0].src_type = nir_tex_src_coord;
       tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_zw, 2, true));

       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
       nir_builder_instr_insert(b, &tex->instr);
       def_zw = &tex->dest.ssa;

       /* def = vec4(def.xy, def.zw); */
       def = nir_vec4(b,
                      nir_channel(b, def_xy, 0),
                      nir_channel(b, def_xy, 1),
                      nir_channel(b, def_zw, 0),
                      nir_channel(b, def_zw, 1));
    }

    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
 }

 static void
 lower_texcoord(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 {
    state->b.cursor = nir_before_instr(&intr->instr);

    nir_ssa_def *texcoord_const = get_texcoord_const(state);
    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
 }

 static bool
 lower_drawpixels_block(lower_drawpixels_state *state, nir_block *block)
 {
    nir_foreach_instr_safe(instr, block) {
       if (instr->type == nir_instr_type_intrinsic) {
          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
          if (intr->intrinsic == nir_intrinsic_load_var) {
             nir_deref_var *dvar = intr->variables[0];
             nir_variable *var = dvar->var;

             if (var->data.location == VARYING_SLOT_COL0) {
                /* gl_Color should not have array/struct deref's: */
                assert(dvar->deref.child == NULL);
                lower_color(state, intr);
             } else if (var->data.location == VARYING_SLOT_TEX0) {
                /* gl_TexCoord should not have array/struct deref's: */
                assert(dvar->deref.child == NULL);
                lower_texcoord(state, intr);
             }
          }
       }
    }

    return true;
 }

 static void
 lower_drawpixels_impl(lower_drawpixels_state *state, nir_function_impl *impl)
 {
    nir_builder_init(&state->b, impl);

    nir_foreach_block(block, impl) {
       lower_drawpixels_block(state, block);
    }
    nir_metadata_preserve(impl, nir_metadata_block_index |
                                nir_metadata_dominance);
 }

 void
 nir_lower_drawpixels(nir_shader *shader,
                      const nir_lower_drawpixels_options *options)
 {
    lower_drawpixels_state state = {
       .options = options,
       .shader = shader,
    };

    assert(shader->stage == MESA_SHADER_FRAGMENT);

    nir_foreach_function(function, shader) {
       if (function->impl)
          lower_drawpixels_impl(&state, function->impl);
    }
 }
	/*
	* Copyright © 2015 Red Hat
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*/

	#include "nir.h"
	#include "nir_builder.h"

	/* Lower glDrawPixels().
	*
	* This is based on the logic in st_get_drawpix_shader() in TGSI compiler.
	*
	* Run before nir_lower_io.
	*/

	typedef struct {
	const nir_lower_drawpixels_options *options;
	nir_shader *shader;
	nir_builder b;
	nir_variable texcoord, scale, *bias;
	} lower_drawpixels_state;

	static nir_ssa_def *
	get_texcoord(lower_drawpixels_state *state)
	{
	if (state->texcoord == NULL) {
	nir_variable *texcoord = NULL;

	/* find gl_TexCoord, if it exists: */
	nir_foreach_variable(var, &state->shader->inputs) {
	if (var->data.location == VARYING_SLOT_TEX0) {
	texcoord = var;
	break;
	}
	}

	/* otherwise create it: */
	if (texcoord == NULL) {
	texcoord = nir_variable_create(state->shader,
	nir_var_shader_in,
	glsl_vec4_type(),
	"gl_TexCoord");
	texcoord->data.location = VARYING_SLOT_TEX0;
	}

	state->texcoord = texcoord;
	}
	return nir_load_var(&state->b, state->texcoord);
	}

	static nir_variable *
	create_uniform(nir_shader shader, const char name, const int state_tokens[5])
	{
	nir_variable *var = nir_variable_create(shader,
	nir_var_uniform,
	glsl_vec4_type(),
	name);
	var->num_state_slots = 1;
	var->state_slots = ralloc_array(var, nir_state_slot, 1);
	memcpy(var->state_slots[0].tokens, state_tokens,
	sizeof(var->state_slots[0].tokens));
	return var;
	}

	static nir_ssa_def *
	get_scale(lower_drawpixels_state *state)
	{
	if (state->scale == NULL) {
	state->scale = create_uniform(state->shader, "gl_PTscale",
	state->options->scale_state_tokens);
	}
	return nir_load_var(&state->b, state->scale);
	}

	static nir_ssa_def *
	get_bias(lower_drawpixels_state *state)
	{
	if (state->bias == NULL) {
	state->bias = create_uniform(state->shader, "gl_PTbias",
	state->options->bias_state_tokens);
	}
	return nir_load_var(&state->b, state->bias);
	}

	static nir_ssa_def *
	get_texcoord_const(lower_drawpixels_state *state)
	{
	if (state->bias == NULL) {
	state->bias = create_uniform(state->shader, "gl_MultiTexCoord0",
	state->options->texcoord_state_tokens);
	}
	return nir_load_var(&state->b, state->bias);
	}

	static void
	lower_color(lower_drawpixels_state state, nir_intrinsic_instr intr)
	{
	nir_builder *b = &state->b;
	nir_ssa_def *texcoord;
	nir_tex_instr *tex;
	nir_ssa_def *def;

	assert(intr->dest.is_ssa);

	b->cursor = nir_before_instr(&intr->instr);

	texcoord = get_texcoord(state);

	/* replace load_var(gl_Color) w/ texture sample:
	* TEX def, texcoord, drawpix_sampler, 2D
	*/
	tex = nir_tex_instr_create(state->shader, 1);
	tex->op = nir_texop_tex;
	tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
	tex->coord_components = 2;
	tex->sampler_index = state->options->drawpix_sampler;
	tex->texture_index = state->options->drawpix_sampler;
	tex->dest_type = nir_type_float;
	tex->src[0].src_type = nir_tex_src_coord;
	tex->src[0].src = nir_src_for_ssa(texcoord);

	nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
	nir_builder_instr_insert(b, &tex->instr);
	def = &tex->dest.ssa;

	/* Apply the scale and bias. */
	if (state->options->scale_and_bias) {
	/* MAD def, def, scale, bias; */
	def = nir_ffma(b, def, get_scale(state), get_bias(state));
	}

	if (state->options->pixel_maps) {
	static const unsigned swiz_xy[4] = {0,1};
	static const unsigned swiz_zw[4] = {2,3};

	/* do four pixel map look-ups with two TEX instructions: */
	nir_ssa_def def_xy, def_zw;

	/* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
	tex = nir_tex_instr_create(state->shader, 1);
	tex->op = nir_texop_tex;
	tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
	tex->coord_components = 2;
	tex->sampler_index = state->options->pixelmap_sampler;
	tex->texture_index = state->options->pixelmap_sampler;
	tex->dest_type = nir_type_float;
	tex->src[0].src_type = nir_tex_src_coord;
	tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_xy, 2, true));

	nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
	nir_builder_instr_insert(b, &tex->instr);
	def_xy = &tex->dest.ssa;

	/* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
	tex = nir_tex_instr_create(state->shader, 1);
	tex->op = nir_texop_tex;
	tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
	tex->coord_components = 2;
	tex->sampler_index = state->options->pixelmap_sampler;
	tex->dest_type = nir_type_float;
	tex->src[0].src_type = nir_tex_src_coord;
	tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_zw, 2, true));

	nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
	nir_builder_instr_insert(b, &tex->instr);
	def_zw = &tex->dest.ssa;

	/* def = vec4(def.xy, def.zw); */
	def = nir_vec4(b,
	nir_channel(b, def_xy, 0),
	nir_channel(b, def_xy, 1),
	nir_channel(b, def_zw, 0),
	nir_channel(b, def_zw, 1));
	}

	nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
	}

	static void
	lower_texcoord(lower_drawpixels_state state, nir_intrinsic_instr intr)
	{
	state->b.cursor = nir_before_instr(&intr->instr);

	nir_ssa_def *texcoord_const = get_texcoord_const(state);
	nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
	}

	static bool
	lower_drawpixels_block(lower_drawpixels_state state, nir_block block)
	{
	nir_foreach_instr_safe(instr, block) {
	if (instr->type == nir_instr_type_intrinsic) {
	nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
	if (intr->intrinsic == nir_intrinsic_load_var) {
	nir_deref_var *dvar = intr->variables[0];
	nir_variable *var = dvar->var;

	if (var->data.location == VARYING_SLOT_COL0) {
	/* gl_Color should not have array/struct deref's: */
	assert(dvar->deref.child == NULL);
	lower_color(state, intr);
	} else if (var->data.location == VARYING_SLOT_TEX0) {
	/* gl_TexCoord should not have array/struct deref's: */
	assert(dvar->deref.child == NULL);
	lower_texcoord(state, intr);
	}
	}
	}
	}

	return true;
	}

	static void
	lower_drawpixels_impl(lower_drawpixels_state state, nir_function_impl impl)
	{
	nir_builder_init(&state->b, impl);

	nir_foreach_block(block, impl) {
	lower_drawpixels_block(state, block);
	}
	nir_metadata_preserve(impl, nir_metadata_block_index \|
	nir_metadata_dominance);
	}

	void
	nir_lower_drawpixels(nir_shader *shader,
	const nir_lower_drawpixels_options *options)
	{
	lower_drawpixels_state state = {
	.options = options,
	.shader = shader,
	};

	assert(shader->stage == MESA_SHADER_FRAGMENT);

	nir_foreach_function(function, shader) {
	if (function->impl)
	lower_drawpixels_impl(&state, function->impl);
	}
	}