standardMunger.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file standardMunger.cxx
 * @author drose
 * @date 2005-03-21
 */

#include "standardMunger.h"

#include "config_gobj.h"

#include "displayRegion.h"
#include "graphicsStateGuardian.h"
#include "lightAttrib.h"
#include "materialAttrib.h"
#include "renderState.h"

TypeHandle StandardMunger::_type_handle;

/**
 * The StandardMunger constructor accepts additional parameters that specify
 * the GSG's preferred color format (since we might be munging the color
 * anyway, we might as well convert it as we munge).
 */
StandardMunger::
StandardMunger(GraphicsStateGuardianBase *gsg, const RenderState *state,
               int num_components,
               StandardMunger::NumericType numeric_type,
               StandardMunger::Contents contents) :
  StateMunger(gsg),
  _num_components(num_components),
  _numeric_type(numeric_type),
  _contents(contents),
  _munge_color(false),
  _munge_color_scale(false),
  _auto_shader(false),
  _shader_skinning(false),
  _remove_material(false)
{
  const ShaderAttrib *shader_attrib;
  state->get_attrib_def(shader_attrib);
#ifdef HAVE_CG
  _auto_shader = shader_attrib->auto_shader();
#endif
  if (shader_attrib->get_flag(ShaderAttrib::F_hardware_skinning)) {
    _shader_skinning = true;
  }

  if (!get_gsg()->get_runtime_color_scale() && !_auto_shader &&
      shader_attrib->get_shader() == nullptr) {
    // We might need to munge the colors.
    const ColorAttrib *color_attrib;
    const ColorScaleAttrib *color_scale_attrib;

    if (state->get_attrib(color_attrib) &&
        color_attrib->get_color_type() != ColorAttrib::T_vertex) {

      // In this case, we don't need to munge anything as we can apply the
      // color and color scale via glColor4f.

    } else if (state->get_attrib(color_scale_attrib) &&
               color_scale_attrib->has_scale()) {
      _color_scale = color_scale_attrib->get_scale();

      const TextureAttrib *tex_attrib = (const TextureAttrib *)
        state->get_attrib(TextureAttrib::get_class_slot());

      // If the GSG says it can't cheat this RGB or alpha scale, we have to
      // apply the color scale directly.
      if ((color_scale_attrib->has_rgb_scale() && !get_gsg()->get_color_scale_via_lighting()) ||
          (color_scale_attrib->has_alpha_scale() && !get_gsg()->get_alpha_scale_via_texture(tex_attrib))) {
        _munge_color_scale = true;
        _should_munge_state = true;
      }

      // Known bug: if there is a material on an object that would obscure the
      // effect of color_scale, we scale the lighting anyway, thus applying
      // the effect even if it should be obscured.  It doesn't seem worth the
      // effort to detect this contrived situation and handle it correctly.
    }
  }

  // If we have no lights but do have a material, we will need to remove it so
  // that it won't appear when we enable color scale via lighting.
  const LightAttrib *light_attrib;
  const MaterialAttrib *material_attrib;
  if (get_gsg()->get_color_scale_via_lighting() &&
      (!state->get_attrib(light_attrib) || !light_attrib->has_any_on_light()) &&
      state->get_attrib(material_attrib) &&
      material_attrib->get_material() != nullptr &&
      shader_attrib->get_shader() == nullptr) {
    _remove_material = true;
    _should_munge_state = true;
  }
}

/**
 *
 */
StandardMunger::
~StandardMunger() {
}

/**
 * Given a source GeomVertexData, converts it as necessary for rendering.
 */
CPT(GeomVertexData) StandardMunger::
munge_data_impl(const GeomVertexData *data) {
  CPT(GeomVertexData) new_data = data;

  if (_munge_color) {
    new_data = new_data->set_color(_color, _num_components, _numeric_type,
                                   _contents);
  } else if (_munge_color_scale) {
    new_data = new_data->scale_color(_color_scale, _num_components,
                                     _numeric_type, _contents);
  }

  GeomVertexAnimationSpec animation = new_data->get_format()->get_animation();
  if (_shader_skinning || (_auto_shader && hardware_animated_vertices &&
      !basic_shaders_only && animation.get_animation_type() == AT_panda)) {
    animation.set_hardware(4, true);

  } else if (hardware_animated_vertices &&
             animation.get_animation_type() == AT_panda &&
             new_data->get_slider_table() == nullptr) {
    // Maybe we can animate the vertices with hardware.
    const TransformBlendTable *table = new_data->get_transform_blend_table();
    if (table != nullptr &&
        table->get_num_transforms() != 0 &&
        table->get_max_simultaneous_transforms() <=
        get_gsg()->get_max_vertex_transforms()) {
      if (matrix_palette &&
          table->get_num_transforms() <= get_gsg()->get_max_vertex_transform_indices()) {

        if (table->get_num_transforms() == table->get_max_simultaneous_transforms()) {
          // We can support an indexed palette, but since that won't save us
          // any per-vertex blends, go ahead and do a plain old nonindexed
          // table instead.
          animation.set_hardware(table->get_num_transforms(), false);

        } else {
          // We can support an indexed palette, and that means we can reduce
          // the number of blends we have to specify for each vertex.
          animation.set_hardware(table->get_max_simultaneous_transforms(), true);
        }

      } else if (table->get_num_transforms() <=
                 get_gsg()->get_max_vertex_transforms()) {
        // We can't support an indexed palette, but we have few enough
        // transforms that we can do a nonindexed table.
        animation.set_hardware(table->get_num_transforms(), false);
      }
    }
  }

  CPT(GeomVertexFormat) orig_format = new_data->get_format();
  CPT(GeomVertexFormat) new_format = munge_format(orig_format, animation);

  if (new_format == orig_format) {
    // Trivial case.
    return new_data;
  }

  return new_data->convert_to(new_format);
}

/**
 * Converts a Geom and/or its data as necessary.
 */
void StandardMunger::
munge_geom_impl(CPT(Geom) &geom, CPT(GeomVertexData) &vertex_data,
                Thread *) {
  int supported_geom_rendering = get_gsg()->get_supported_geom_rendering();

  int unsupported_bits = geom->get_geom_rendering() & ~supported_geom_rendering;
  if (unsupported_bits != 0) {
    // Even beyond munging the vertex format, we have to convert the Geom
    // itself into a new primitive type the GSG can render directly.  If we
    // don't support a strip cut index, it might be faster to just decompose
    // it rather than draw them one by one.
    if ((unsupported_bits & Geom::GR_composite_bits) != 0 ||
        (unsupported_bits & Geom::GR_strip_cut_index) != 0) {

      // This decomposes everything in the primitive, so that if (for
      // instance) the primitive contained both strips and fans, but the GSG
      // didn't support fans, it would decompose the strips too.  To handle
      // this correctly, we'd need a separate decompose_fans() and
      // decompose_strips() call; but for now, we'll just say it's good
      // enough.  In practice, we don't have any GSG's that can support strips
      // without also supporting fans.
      geom = geom->decompose();

      // Decomposing might produce an indexed Geom, so re-check the
      // unsupported bits.
      unsupported_bits = geom->get_geom_rendering() & ~supported_geom_rendering;
    }
    if ((unsupported_bits & Geom::GR_shade_model_bits) != 0) {
      // Rotate the vertices to account for different shade-model expectations
      // (e.g.  SM_flat_last_vertex to SM_flat_first_vertex)
      geom = geom->rotate();
    }
    if ((unsupported_bits & Geom::GR_indexed_bits) != 0) {
      // Convert indexed geometry to nonindexed geometry.
      PT(Geom) new_geom = geom->make_copy();
      new_geom->set_vertex_data(vertex_data);
      new_geom->make_nonindexed(false);
      geom = new_geom;
      vertex_data = new_geom->get_vertex_data();
    }
  }
}

/**
 * Converts a Geom and/or its data as necessary.
 */
void StandardMunger::
premunge_geom_impl(CPT(Geom) &geom, CPT(GeomVertexData) &vertex_data) {
  int supported_geom_rendering = get_gsg()->get_supported_geom_rendering();

  int unsupported_bits = geom->get_geom_rendering() & ~supported_geom_rendering;
  if (unsupported_bits != 0) {
    // Even beyond munging the vertex format, we have to convert the Geom
    // itself into a new primitive type the GSG can render directly.  If we
    // don't support a strip cut index, it might be faster to just decompose
    // it rather than draw them one by one.
    if ((unsupported_bits & Geom::GR_composite_bits) != 0 ||
        (unsupported_bits & Geom::GR_strip_cut_index) != 0) {

      // This decomposes everything in the primitive, so that if (for
      // instance) the primitive contained both strips and fans, but the GSG
      // didn't support fans, it would decompose the strips too.  To handle
      // this correctly, we'd need a separate decompose_fans() and
      // decompose_strips() call; but for now, we'll just say it's good
      // enough.  In practice, we don't have any GSG's that can support strips
      // without also supporting fans.
      geom = geom->decompose();

      // Decomposing might produce an indexed Geom, so re-check the
      // unsupported bits.
      unsupported_bits = geom->get_geom_rendering() & ~supported_geom_rendering;
    }
    if ((unsupported_bits & Geom::GR_shade_model_bits) != 0) {
      // Rotate the vertices to account for different shade-model expectations
      // (e.g.  SM_flat_last_vertex to SM_flat_first_vertex)
      geom = geom->rotate();
    }
    if ((unsupported_bits & Geom::GR_indexed_bits) != 0) {
      // Convert indexed geometry to nonindexed geometry.
      PT(Geom) new_geom = geom->make_copy();
      new_geom->set_vertex_data(vertex_data);
      new_geom->make_nonindexed(false);
      geom = new_geom;
      vertex_data = new_geom->get_vertex_data();
    }
  }
}

/**
 * Called to compare two GeomMungers who are known to be of the same type, for
 * an apples-to-apples comparison.  This will never be called on two pointers
 * of a different type.
 */
int StandardMunger::
compare_to_impl(const GeomMunger *other) const {
  const StandardMunger *om = (const StandardMunger *)other;

  if (_munge_color != om->_munge_color) {
    return (int)_munge_color - (int)om->_munge_color;
  }
  if (_munge_color_scale != om->_munge_color_scale) {
    return (int)_munge_color_scale - (int)om->_munge_color_scale;
  }
  if (_munge_color) {
    int compare = _color.compare_to(om->_color);
    if (compare != 0) {
      return compare;
    }
  }
  if (_munge_color_scale) {
    int compare = _color_scale.compare_to(om->_color_scale);
    if (compare != 0) {
      return compare;
    }
  }
  if (_shader_skinning != om->_shader_skinning) {
    return (int)_shader_skinning - (int)om->_shader_skinning;
  }
  if (_auto_shader != om->_auto_shader) {
    return (int)_auto_shader - (int)om->_auto_shader;
  }
  if (_remove_material != om->_remove_material) {
    return (int)_remove_material - (int)om->_remove_material;
  }

  return StateMunger::compare_to_impl(other);
}

/**
 * Compares two GeomMungers, considering only whether they would produce a
 * different answer to munge_format(), munge_data(), or munge_geom().  (They
 * still might be different in other ways, but if they would produce the same
 * answer, this function consider them to be the same.)
 */
int StandardMunger::
geom_compare_to_impl(const GeomMunger *other) const {
  const StandardMunger *om = (const StandardMunger *)other;

  if (_munge_color != om->_munge_color) {
    return (int)_munge_color - (int)om->_munge_color;
  }
  if (_munge_color_scale != om->_munge_color_scale) {
    return (int)_munge_color_scale - (int)om->_munge_color_scale;
  }
  if (_munge_color) {
    int compare = _color.compare_to(om->_color);
    if (compare != 0) {
      return compare;
    }
  }
  if (_munge_color_scale) {
    int compare = _color_scale.compare_to(om->_color_scale);
    if (compare != 0) {
      return compare;
    }
  }
  if (_shader_skinning != om->_shader_skinning) {
    return (int)_shader_skinning - (int)om->_shader_skinning;
  }

  return StateMunger::geom_compare_to_impl(other);
}

/**
 * Given an input state, returns the munged state.
 */
CPT(RenderState) StandardMunger::
munge_state_impl(const RenderState *state) {
  CPT(RenderState) munged_state = state;

  if (_munge_color) {
    munged_state = munged_state->remove_attrib(ColorAttrib::get_class_slot());
    munged_state = munged_state->remove_attrib(ColorScaleAttrib::get_class_slot());
  } else if (_munge_color_scale) {
    munged_state = munged_state->remove_attrib(ColorScaleAttrib::get_class_slot());
  }

  if (_remove_material) {
    munged_state = munged_state->remove_attrib(MaterialAttrib::get_class_slot());
  }

  return munged_state;
}