rokojori-action-library-examples/_Research/Embers/Ember-Shader.tres

[gd_resource type="Shader" format=3 uid="uid://bvjycr2yn7tks"]

[resource]
code = "// NOTE: Shader automatically converted from Godot Engine 4.3.stable.mono's StandardMaterial3D.

shader_type spatial;
render_mode blend_mix, depth_draw_opaque, cull_back, diffuse_burley, specular_schlick_ggx, unshaded;

#include \"res://addons/rokojori_action_library/Runtime/Shading/Library/Transform.gdshaderinc\"
#include \"res://addons/rokojori_action_library/Runtime/Shading/Library/Line3.gdshaderinc\"


uniform vec4 albedo : source_color;
uniform sampler2D texture_albedo : source_color, filter_linear_mipmap, repeat_enable;
uniform vec2 scale = vec2(1, 1 );
uniform float rotation = 0;
uniform float velocity = 1;
uniform float width = 1;
uniform float feather = 1;
varying vec3 worldStart;
varying vec3 worldEnd;
varying vec3 worldVertex;
uniform float size = 1.0;
uniform float power = 1.0;

void vertex() 
{
  /*worldStart = applyMatrix( -velocity, MODEL_MATRIX );
  worldEnd   = applyMatrix(  velocity, MODEL_MATRIX );
  worldVertex = applyMatrix( vec3( 0, 0, 0 ), MODEL_MATRIX );
  */
  //worldStart.z = 0.0;
  //worldEnd.z = 0.0;
  
  
	MODELVIEW_MATRIX = VIEW_MATRIX * mat4(
			MAIN_CAM_INV_VIEW_MATRIX[0],
			MAIN_CAM_INV_VIEW_MATRIX[1],
			MAIN_CAM_INV_VIEW_MATRIX[2],
			MODEL_MATRIX[3] );
      
  MODELVIEW_MATRIX *= rotationZ_m4( rotation );
	MODELVIEW_NORMAL_MATRIX = mat3(MODELVIEW_MATRIX);
   
  vec2 scaledUV = ( UV * 2.0 - vec2( 1, 1 ) ) * scale * 0.5;
   
  
  
  VERTEX += vec3( -scaledUV.x,scaledUV.y, 0 );
  
  
  
  
  //worldVertex.z = 0.0;
  
}

float ember( vec2 uv )
{
  uv = uv * 2.0 - vec2( 1, 1 );
    
  uv.x *= velocity + width;
  uv.y *= width;

  vec2 v = vec2( 2.0 * velocity, 0 );
  vec2 p = uv - vec2( velocity, 0 );
  float r = width;

  float a = dot( v, v );
  float b = dot( v, p );
  float c = dot( p, p ) - r * r;
  float d = b * b - a * c;

  // edge fade
  float h = clamp( -b / a, 0, 1);
  float dist = length( p + h * v);
  float alpha = smoothstep( 0, feather * width, width - dist );
  
  if ( d > 0.0 )
  {
    d = sqrt( d );

    float t0 = max( 0, (-b - d) / a );
    float t1 = min( 1, (-b + d) / a );

    alpha *= clamp( 2.0 * ( t1 - t0 ), 0, 1 );
  }
  
  return alpha;
}

void fragment() 
{
	vec2 base_uv = UV;
  /*
  vec3 world = VERTEX;
  
  Line3 line; 
  line.start = applyMatrix( worldStart, VIEW_MATRIX );
  line.end = applyMatrix( worldEnd, VIEW_MATRIX );
  
  //line.start.z = world.z;
  //line.end.z = world.z;
   
  float d = Line3_getDistance( line, world );
  */
  
  
  
	ALBEDO = albedo.rgb;

	ALPHA *= albedo.a * ember( UV );
}
"