SDI Technologies iH30 Especificações descarregar pdf (Página 69)

Advanced Topics

Quadro SDI Output PG-03776-001_v06 | 64

Code Listing 45: Requesting a Multi-Sampled Pixel Format During

Pbuffer Creation

// Request multisampled pixel format.

int attribList = {

WGL_RED_BITS_ARB, 8,

WGL_GREEN_BITS_ARB, 8,

WGL_BLUE_BITS_ARB, 8,

WGL_ALPHA_BITS_ARB, 8,

WGL_STENCIL_BITS_ARB, 8,

WGL_DEPTH_BITS_ARB, 24,

WGL_SAMPLE_BUFFERS_ARB, GL_TRUE,

WGL_SAMPLES_ARB, num_samples,

WGL_DRAW_TO_PBUFFER_ARB, true,

WGL_BIND_TO_VIDEO_RGBA_NV, true,

0 };

wglChoosePixelFormat(hWindowDC, attribList, NULL, 1, &format,

&nformats);

// Enable multisampling.

if (gbFSAA) {

glEnable(GL_MULTISAMPLE_ARB);

}

In Code Listing 45, num_samples, can be specified as1, 2, 4, 8 or 16, the number of desired

samples per pixel. The greater the number, the more samples per pixel and improved

image quality. However, the application programmer should be aware, that increasing

the number of samples per pixel increases the video memory requirements of the

application and in some cases, especially in the cases of HD video formats, the capacity

of video memory may be exceeded. This may lead to reduced performance caused by

swapping of textures and other video data to main memory, or pbuffer creation may fail

due to lack of available video memory.

When the multi-sampled pbuffer is sent to the SDI video device with either

wglSendPbufferToVideoNV() or glxSendPbufferToVideoNV(), the driver will

automatically do the down sample blit prior to the SDI scanout.

For more information on multisampling, refer to the

GL_ARB_multisample extension

specification.

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