examples/qwindow-compositor/surfacerenderer.cpp

   1 #include "surfacerenderer.h"
   2
   3 #include <QOpenGLFunctions>
   4
   5 SurfaceRenderer::SurfaceRenderer(QOpenGLContext *context, QWindow *surface)
   6     : m_context(context)
   7     , m_surface(surface)
   8 {
   9     const char *textureVertexProgram =
  10             "uniform highp mat4 matrix;\n"
  11             "attribute highp vec3 vertexCoordEntry;\n"
  12             "attribute highp vec2 textureCoordEntry;\n"
  13             "varying highp vec2 textureCoord;\n"
  14             "void main() {\n"
  15             "   textureCoord = textureCoordEntry;\n"
  16             "   gl_Position = matrix * vec4(vertexCoordEntry, 1);\n"
  17             "}\n";
  18
  19     const char *textureFragmentProgram =
  20             "uniform sampler2D texture;\n"
  21             "varying highp vec2 textureCoord;\n"
  22             "void main() {\n"
  23             "   gl_FragColor = texture2D(texture, textureCoord);\n"
  24             "}\n";
  25
  26     m_context->makeCurrent(m_surface);
  27
  28     //Enable transparent windows
  29     glEnable(GL_BLEND);
  30     glBlendFunc (GL_ONE,GL_ONE_MINUS_SRC_ALPHA);
  31
  32     //May need to manually set context here
  33     m_shaderProgram = new QGLShaderProgram();
  34
  35     m_shaderProgram->addShaderFromSourceCode(QGLShader::Vertex, textureVertexProgram);
  36     m_shaderProgram->addShaderFromSourceCode(QGLShader::Fragment, textureFragmentProgram);
  37     m_shaderProgram->link();
  38     m_shaderProgram->bind();
  39
  40     m_vertexCoordEntry = m_shaderProgram->attributeLocation("vertexCoordEntry");
  41     m_textureCoordEntry = m_shaderProgram->attributeLocation("textureCoordEntry");
  42     m_matrixLocation = m_shaderProgram->uniformLocation("matrix");
  43
  44 }
  45
  46 void SurfaceRenderer::drawImage(const QImage &image, const QRect &geometry)
  47 {
  48     drawTexture(textureFromImage(image), geometry);
  49 }
  50
  51 void SurfaceRenderer::drawTexture(int textureId, const QRect &geometry, int depth)
  52 {
  53     GLfloat zValue = depth / 1000.0f;
  54     //Set Texture and Vertex coordinates
  55     GLfloat textureCoordinates[] = { 0, 0,
  56                                      1, 0,
  57                                      1, 1,
  58                                      0, 1
  59                                    };
  60
  61     GLfloat vertexCoordinates[] = { geometry.left(), geometry.top(), zValue,
  62                                     geometry.right(), geometry.top(), zValue,
  63                                     geometry.right(), geometry.bottom(), zValue,
  64                                     geometry.left(), geometry.bottom(), zValue
  65                                   };
  66
  67     //Set matrix to transfrom geometry values into gl coordinate space.
  68     m_transformMatrix.setToIdentity();
  69     m_transformMatrix.scale( 2.0f / m_surface->geometry().width(), 2.0f / m_surface->geometry().height());
  70     m_transformMatrix.translate(-m_surface->geometry().width() / 2.0f, -m_surface->geometry().height() / 2.0f);
  71
  72     m_shaderProgram->bind();
  73
  74     //attach the data!
  75     m_context->functions()->glEnableVertexAttribArray(m_vertexCoordEntry);
  76     m_context->functions()->glEnableVertexAttribArray(m_textureCoordEntry);
  77
  78     m_context->functions()->glVertexAttribPointer(m_vertexCoordEntry, 3, GL_FLOAT, GL_FALSE, 0, vertexCoordinates);
  79     m_context->functions()->glVertexAttribPointer(m_textureCoordEntry, 2, GL_FLOAT, GL_FALSE, 0, textureCoordinates);
  80     m_shaderProgram->setUniformValue(m_matrixLocation, m_transformMatrix);
  81
  82     glBindTexture(GL_TEXTURE_2D, textureId);
  83
  84     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
  85
  86     glBindTexture(GL_TEXTURE_2D, 0);
  87
  88     m_context->functions()->glDisableVertexAttribArray(m_vertexCoordEntry);
  89     m_context->functions()->glDisableVertexAttribArray(m_textureCoordEntry);
  90     m_shaderProgram->release();
  91 }
  92
  93 GLuint SurfaceRenderer::textureFromImage(const QImage &image)
  94 {
  95     //TODO: Replace this line
  96     QImage convertedImage = QGLWidget::convertToGLFormat(image);
  97
  98     GLuint textureId;
  99     //Copy QImage data to Texture
 100     glBindTexture(GL_TEXTURE_2D, textureId);
 101     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, convertedImage.width(), convertedImage.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, convertedImage.constBits());
 102
 103     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 104     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 105     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 106     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 107
 108     return textureId;
 109 }