Function drawRectangle

dgl/src/OpenGL3.cpp:372–410

template<typename T>
static void drawRectangle(const GraphicsContext& context, const Rectangle<T>& rect, const bool outline)
{
    DISTRHO_SAFE_ASSERT_RETURN(rect.isValid(),);

    const OpenGL3GraphicsContext& gl3context = static_cast<const OpenGL3GraphicsContext&>(context);

    if (gl3context.program == 0)
        return;

    const GLfloat x = (static_cast<double>(rect.getX()) / gl3context.width) * 2 - 1;
    const GLfloat y = (static_cast<double>(rect.getY()) / gl3context.height) * -2 + 1;
    const GLfloat w = (static_cast<double>(rect.getWidth()) / gl3context.width) * 2;
    const GLfloat h = (static_cast<double>(rect.getHeight()) / gl3context.height) * -2;

    const GLfloat vertices[] = { x, y, x, y + h, x + w, y + h, x + w, y };

    glBindBuffer(GL_ARRAY_BUFFER, gl3context.buffers[0]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STREAM_DRAW);
    glEnableVertexAttribArray(gl3context.bounds);
    glVertexAttribPointer(gl3context.bounds, 2, GL_FLOAT, GL_FALSE, 0, nullptr);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gl3context.buffers[1]);

    if (outline)
    {
        static constexpr const GLubyte order[] = { 0, 1, 1, 2, 2, 3, 3, 0 };
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(order), order, GL_STATIC_DRAW);
        glDrawElements(GL_LINES, ARRAY_SIZE(order), GL_UNSIGNED_BYTE, nullptr);
    }
    else
    {
        static constexpr const GLubyte order[] = { 0, 1, 2, 0, 2, 3 };
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(order), order, GL_STATIC_DRAW);
        glDrawElements(GL_TRIANGLES, ARRAY_SIZE(order), GL_UNSIGNED_BYTE, nullptr);
    }

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    glDisableVertexAttribArray(gl3context.bounds);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

template<typename T>
void Rectangle<T>::draw(const GraphicsContext& context)