package com.marshalchen.common.uimodule.imageprocessing.filter.colour;
import com.marshalchen.common.uimodule.imageprocessing.filter.BasicFilter;
import android.opengl.GLES20;
/**
* Uses the luminance of the image to mix between two user-specified colors
* firstColor: The color used replace the dark areas of the image
* secondColor: The color used replace the light areas of the image
* @author Chris Batt
*/
public class FalseColourFilter extends BasicFilter {
private static final String UNIFORM_SHADOW_COLOUR = "u_ShadowColour";
private static final String UNIFORM_HIGHLIGHT_COLOUR = "u_HightlightColour";
private int shadowColourHandle;
private int highlightColourHandle;
private float[] shadowColour;
private float[] highlightColour;
public FalseColourFilter(float[] shadowColour, float[] highlightColour) {
this.shadowColour = shadowColour;
this.highlightColour = highlightColour;
}
@Override
protected String getFragmentShader() {
return
"precision mediump float;\n"
+"uniform sampler2D "+UNIFORM_TEXTURE0+";\n"
+"varying vec2 "+VARYING_TEXCOORD+";\n"
+"uniform vec3 "+UNIFORM_SHADOW_COLOUR+";\n"
+"uniform vec3 "+UNIFORM_HIGHLIGHT_COLOUR+";\n"
+"vec3 luminanceWeighting = vec3(0.2125, 0.7154, 0.0721);\n"
+"void main(){\n"
+" vec4 color = texture2D("+UNIFORM_TEXTURE0+","+VARYING_TEXCOORD+");\n"
+" float luminance = dot(color.rgb, luminanceWeighting);\n"
+" gl_FragColor = vec4(mix("+UNIFORM_SHADOW_COLOUR+", "+UNIFORM_HIGHLIGHT_COLOUR+", luminance), color.a);\n"
+"}\n";
}
@Override
protected void initShaderHandles() {
super.initShaderHandles();
shadowColourHandle = GLES20.glGetUniformLocation(programHandle, UNIFORM_SHADOW_COLOUR);
highlightColourHandle = GLES20.glGetUniformLocation(programHandle, UNIFORM_HIGHLIGHT_COLOUR);
}
@Override
protected void passShaderValues() {
super.passShaderValues();
GLES20.glUniform3f(shadowColourHandle, shadowColour[0], shadowColour[1], shadowColour[2]);
GLES20.glUniform3f(highlightColourHandle, highlightColour[0], highlightColour[1], highlightColour[2]);
}
}