Implementation of CompositorPass This implementation will render a fullscreen triangle/quad to the RenderTarget using the parameters from definition (rectangle area, whether triangle or quad pass, whether to include frustum corners, etc)
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#include <OgreCompositorPassCompute.h>
Implementation of CompositorPass This implementation will render a fullscreen triangle/quad to the RenderTarget using the parameters from definition (rectangle area, whether triangle or quad pass, whether to include frustum corners, etc)
- A fullscreen quad are two triangles that form a rectangle, which cover the entire screen. This is however an inefficient way of harnessing the GPU's power. Modern GPUs iterate a whole bounding rect that encloses each triangle (it's highly more parallelizable & scalable than the scanline algorithm used by older Voodoo cards in the 90's). That means we're wasting 50% of GPU reasources in pixels that aren't drawn.
- A much faster approach made famous by Emil Persson (see max area triangulation http://www.humus.name/index.php?page=News&ID=228) is to render a single oversized triangle that covers the entire screen, which has it's UV scaled up; so that when interpolated at screen position, it appears it goes from the range [0; 1) like a regular quad pass. The difference is that pixels that go past the viewport are much better clipped/earlied-out by the GPU than those that fall inside the viewport but outside the triangle (like the rectangle approach)
- This faster technique only works for passes that cover the entire screen. When the viewport is not 0 0 1 1; the CompositorPassCompute automatically switches to a fullscreen quad.
- IMPORTANT: The texel-to-pixel adjustment offset is included in the world matrix passed to the vertex shader. This differs from Ogre 1.x which tried to embed the offset into the vertices.
- IMPORTANT: When the viewport is not 0 0 1 1; the scale & position factors are passed through the world matrix. This behavior differs from Ogre 1.x
- Author
- Matias N. Goldberg
- Version
- 1.0
◆ CompositorPassCompute()
◆ ~CompositorPassCompute()
Ogre::CompositorPassCompute::~CompositorPassCompute |
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◆ execute()
void Ogre::CompositorPassCompute::execute |
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const Camera * |
lodCamera | ) |
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The documentation for this class was generated from the following file: