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Viewing changes to examples/image_renderer.cpp

  • Committer: Kevin DuBois
  • Date: 2013-11-05 21:44:14 UTC
  • mfrom: (1062.1.137 dev)
  • Revision ID: kevin.dubois@canonical.com-20131105214414-d32r52joqrs8tsmo
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Lines of Context:
examples/image_renderer.cpp
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    BOOST_THROW_EXCEPTION(std::runtime_error(object_info_err));
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}
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class GLState
 
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{
 
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public:
 
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    GLState(GLint attrib_loc)
 
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        : attrib_loc{attrib_loc}
 
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    {
 
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        glGetIntegerv(GL_CURRENT_PROGRAM, &program);
 
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        glGetIntegerv(GL_TEXTURE_BINDING_2D, &texture);
 
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        glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &buffer);
 
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        glGetIntegerv(GL_ACTIVE_TEXTURE, &active_texture_unit);
 
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        if (attrib_loc >= 0)
 
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        {
 
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            glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_ENABLED, &attrib_enabled);
 
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            glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_SIZE, &attrib_size);
 
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            glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_TYPE, &attrib_type);
 
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            glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, &attrib_normalized);
 
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            glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_STRIDE, &attrib_stride);
 
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            glGetVertexAttribPointerv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_POINTER, &attrib_pointer);
 
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        }
 
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    }
 
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    GLState() : GLState{invalid_attrib_loc} {}
 
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    ~GLState()
 
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    {
 
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        glUseProgram(program);
 
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        glBindTexture(GL_TEXTURE_2D, texture);
 
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        glBindBuffer(GL_ARRAY_BUFFER, buffer);
 
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        glActiveTexture(active_texture_unit);
 
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        if (attrib_loc >= 0)
 
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        {
 
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            glVertexAttribPointer(attrib_loc, attrib_size, attrib_type,
 
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                                  attrib_normalized, attrib_stride, attrib_pointer);
 
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            if (attrib_enabled)
 
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                glEnableVertexAttribArray(attrib_loc);
 
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            else
 
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                glDisableVertexAttribArray(attrib_loc);
 
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        }
 
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    }
 
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private:
 
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    static GLint const invalid_attrib_loc = -1;
 
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    GLint program = 0;
 
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    GLint texture = 0;
 
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    GLint buffer = 0;
 
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    GLint active_texture_unit = 0;
 
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    GLint attrib_loc = invalid_attrib_loc;
 
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    GLint attrib_enabled = 0;
 
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    GLint attrib_size = 0;
 
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    GLint attrib_type = 0;
 
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    GLint attrib_normalized = 0;
 
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    GLint attrib_stride = 0;
 
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    GLvoid* attrib_pointer = nullptr;
 
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};
 
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}
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mt::ImageRenderer::ImageRenderer(const uint8_t* pixel_data, mir::geometry::Size size,
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                                 uint32_t bytes_per_pixel)
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{
 
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    GLState gl_state;
 
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    resources.setup();
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    /* Upload the texture */
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    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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    glUniform1i(tex_loc, 0);
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    glBindTexture(GL_TEXTURE_2D, 0);
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    /* Create VBO */
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    glGenBuffers(1, &vertex_attribs_vbo);
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    glBindBuffer(GL_ARRAY_BUFFER, vertex_attribs_vbo);
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    glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_attribs),
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                 glm::value_ptr(vertex_attribs[0]), GL_STATIC_DRAW);
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    glBindBuffer(GL_ARRAY_BUFFER, 0);
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    glUseProgram(0);
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}
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void mt::ImageRenderer::render()
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{
 
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    GLState gl_state(resources.position_attr_loc);
 
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    glUseProgram(resources.program);
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    glActiveTexture(GL_TEXTURE0);
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    /* Draw */
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    glEnableVertexAttribArray(resources.position_attr_loc);
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    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
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    glDisableVertexAttribArray(resources.position_attr_loc);
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}