examples/example7/InfoWidget.cpp

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#include "InfoWidget.h"

InfoWidget::InfoWidget(OverlayWidget *parent) : QGLWidget(parent) {
    programObject = -1; 
}

void InfoWidget::setFrame(FCam::Frame::Ptr f) { 
    frame = f;
    if (f) {
    update();
    }
};

void InfoWidget::paintGL() {
    if (programObject < 0) {
    // OpenGL ES basic shaders boilerplate
    GLuint vertShader = glCreateShader(GL_VERTEX_SHADER);
    const char vertSource[] = 
        "attribute vec4 position, color;\n"
        "varying vec4 fragColor;\n"
        "void main() {\n"
        "   gl_Position = position;\n"
        "   fragColor = color;\n"
        "}\n";
    const char *sourcePtr = &(vertSource[0]);
    glShaderSource(vertShader, 1, &sourcePtr, NULL);
    glCompileShader(vertShader);
    
    GLuint fragShader = glCreateShader(GL_FRAGMENT_SHADER);
    const char fragSource[] = 
        "precision mediump float;\n"
        "varying vec4 fragColor;\n"
        "void main() {\n"
        "   gl_FragColor = fragColor;\n"
        "}\n";
    
    sourcePtr = &(fragSource[0]);
    glShaderSource(fragShader, 1, &sourcePtr, NULL);
    glCompileShader(fragShader);
    
    GLint compileStatus = 0;
    glGetShaderiv(fragShader, GL_COMPILE_STATUS, &compileStatus);
    if (!compileStatus) {
        printf("Frag shader didn't compile\n");
        GLint infoLen;
        glGetShaderiv(fragShader, GL_INFO_LOG_LENGTH, &infoLen);        
        char *infoLog = new char[infoLen];
        glGetShaderInfoLog(fragShader, infoLen, NULL, infoLog);
        printf(infoLog);
        delete[] infoLog;       
    }
    glGetShaderiv(vertShader, GL_COMPILE_STATUS, &compileStatus);
    if (!compileStatus) {
        printf("Vert shader didn't compile\n");
        GLint infoLen;
        glGetShaderiv(vertShader, GL_INFO_LOG_LENGTH, &infoLen);        
        char *infoLog = new char[infoLen];
        glGetShaderInfoLog(vertShader, infoLen, NULL, infoLog);
        printf(infoLog);
        delete[] infoLog;
    }
    
    programObject = glCreateProgram();
    glAttachShader(programObject, vertShader);
    glAttachShader(programObject, fragShader);
    
    glBindAttribLocation(programObject, 0, "position");
    glBindAttribLocation(programObject, 1, "color");
        
    glLinkProgram(programObject);
    printf("Vertex and Fragment shaders compiled\n");
    }
    
    qglClearColor(OverlayWidget::colorKey());
    glViewport(0, 0, width(), height());
    glClear(GL_COLOR_BUFFER_BIT);
    
    if (!frame) return;
    
    glUseProgram(programObject);
    
    glLineWidth(2);
    glDisable(GL_DITHER);
    
    // draw the sharpness map
    if (frame->sharpness.valid) {
    GLfloat vertices[4*2];
    // set the color to green
    glVertexAttrib3f(1, 0, 1, 0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, vertices);
    glEnableVertexAttribArray(0);
    for (int sx = 0; sx < frame->sharpness.size.width; sx++) {
        for (int sy = 0; sy < frame->sharpness.size.height; sy++) {
        float x = 2*((sx + 0.5f) / frame->sharpness.size.width) -1;
        float y = 1-2*((sy + 0.5f) / frame->sharpness.size.height);
        int s = frame->sharpness(sx, sy);
        s >>= 15;
        s -= 2;
        if (s > 19) s = 19;
        if (s < 0) s = 0;
        float r = s/200.0f;
        vertices[0] = x-r; vertices[1] = y-r; 
        vertices[2] = x+r; vertices[3] = y-r; 
        vertices[4] = x+r; vertices[5] = y+r; 
        vertices[6] = x-r; vertices[7] = y+r; 
        glDrawArrays(GL_LINE_LOOP, 0, 4);
        }
    }
    }   

    // draw other useful things about the image...

}

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