#version 150 core

in vec2 v_BufPos;
out vec4 Target0;

uniform sampler2D t_CharacterSheet;

const float SHADING_MULTIPLIER = 0.5;

void main() {
  vec4 tex = texture(t_CharacterSheet, v_BufPos).rgba;
  tex *= SHADING_MULTIPLIER;
  if(tex.a < 0.1) {
    discard;
  }
  Target0 = tex;
}

#version 150 core

in vec2 v_BufPos;
out vec4 Target0;

uniform sampler2D t_CharacterSheet;

void main() {
  vec4 tex = texture(t_CharacterSheet, v_BufPos).rgba;
  if(tex.a < 0.1) {
    discard;
  }
  tex.r = smoothstep(0.1, 1.0, tex.r);
  tex.g = smoothstep(0.1, 1.0, tex.g);
  tex.b = smoothstep(0.1, 1.0, tex.b);
  Target0 = tex;
}

Adjust character & zombie sprite shadings
Adjust character & zombie sprite shadings