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#include "customshadereffect.h"
#include <QGLShaderProgram>

static char const colorizeShaderCode[] =
    "uniform lowp vec4 effectColor;\n"
    "mediump vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords) {\n"
    "    vec4 src = texture2D(imageTexture, textureCoords);\n"
    "    float gray = dot(src.rgb, vec3(0.212671, 0.715160, 0.072169));\n"
    "    vec4 colorize = 1.0-((1.0-gray)*(1.0-effectColor));\n"
    "    return vec4(colorize.rgb * src.a, src.a);\n"
    "}";

CustomShaderEffect::CustomShaderEffect()
    : QGraphicsShaderEffect(),
      color(Qt::red)
{
    setPixelShaderFragment(colorizeShaderCode);
}

void CustomShaderEffect::setEffectColor(const QColor& c)
{
    color = c;
    setUniformsDirty();
}

void CustomShaderEffect::setUniforms(QGLShaderProgram *program)
{
    program->setUniformValue("effectColor", color);
}