Method initBuffers

core/3d/Skybox.cpp:101–135

}

void Skybox::initBuffers()
{

    // The skybox is rendered using a purpose-built shader which makes use of
    // the shader language's inherent support for cubemaps. Hence there is no
    // need to build a cube mesh. All that is needed is a single quad that
    // covers the entire screen. The vertex shader will draw the appropriate
    // view of the cubemap onto that quad.
    //
    // The vertex shader does not apply either the model/view matrix or the
    // projection matrix, so the appropriate quad is one with unit coordinates
    // in the x and y dimensions. Such a quad will exactly cover the screen.
    // To ensure that the skybox is rendered behind all other objects, z needs
    // to be 1.0, but the vertex shader overwrites z to 1.0, so - for the sake
    // of z-buffering - it is unimportant what we set it to for the vertices
    // of the quad.
    //
    // The quad vertex positions are also used in deriving a direction
    // vector for the cubemap lookup. We choose z = -1 which matches the
    // negative-z pointing direction of the camera and gives a field of
    // view of 90deg in both x and y, if not otherwise adjusted. That fov
    // is then adjusted to exactly match the camera by applying a prescaling
    // to the camera's world transformation before sending it to the shader.

    // init vertex buffer object
    Vec3 vexBuf[] = {Vec3(1, -1, -1), Vec3(1, 1, -1), Vec3(-1, 1, -1), Vec3(-1, -1, -1)};

    uint16_t idxBuf[] = {0, 1, 2, 0, 2, 3};

    _customCommand.createVertexBuffer(sizeof(Vec3), sizeof(vexBuf), CustomCommand::BufferUsage::STATIC);
    _customCommand.createIndexBuffer(CustomCommand::IndexFormat::U_SHORT, 6, CustomCommand::BufferUsage::STATIC);

    _customCommand.updateVertexBuffer(&vexBuf[0], sizeof(vexBuf));
    _customCommand.updateIndexBuffer(&idxBuf[0], sizeof(idxBuf));
}

void Skybox::draw(Renderer* renderer, const Mat4& transform, uint32_t flags)
{