glsl着色器-混色，正常模式(如在Photoshop中) [英] glsl shader - color blend, normal mode (like in Photoshop)

问题描述

我正在尝试创建混合2种颜色(实际上是图像和颜色作为叠加在图像上的颜色)的效果，就像在Photoshop中使用常规混合"模式的颜色叠加"

Im trying to create effect of blending 2 colors (actually image and color as overlay over image), like in photoshop "Color Overlay" with "Normal Blending" mode

我正在使用libgdx

Im using libgdx

这是我到目前为止所拥有的

This is what i have so far

attribute vec4 a_position;
attribute vec4 a_color;
attribute vec2 a_texCoord0;

uniform mat4 u_projTrans;

varying vec4 v_color;
varying vec2 v_texCoords;

void main()
{
   v_color = a_color;
   v_texCoords = a_texCoord0;
   gl_Position =  u_projTrans * a_position;
}

还有片段

#ifdef GL_ES
#define LOWP lowp
precision mediump float;
#else
#define LOWP
#endif

varying LOWP vec4 v_color;
varying vec2 v_texCoords;

uniform sampler2D u_texture;

void main()
{
  vec4 curColor = texture2D(u_texture, v_texCoords);

  vec3 cA = curColor.rgb;//color A, background
  vec3 cB = v_color.rgb;//color B, overlay

  float aA = curColor.a;
  float aB = v_color.a;

  vec3 color = (cA * aA + cB * aB * (1 - aA)) / aA + aB * (1 - aA);
  float alpha = aA + aB * (1 - aA);
  gl_FragColor = vec4(color, alpha);
}

我使用了维基百科

当我使用此着色器时，什么也没有发生，使用此着色器绘制的对象是透明的，不可见的

When i use this shader, nothing happens, object which is drawn with this shader is transparent, invisible

推荐答案

gl_FragColor = texture2D(u_texture, v_texCoords); 
gl_FragColor.rgb = mix(gl_FragColor.rgb, vec3(1.0), v_color.a);

这是解决方案，这要感谢@ Tenfour04

This is the solution, thanks to @Tenfour04

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