谁能告诉我 DDCAPS_BLTFOURCC 到底有什么用？

[Sodar]

从MSDN来看如果显卡有这个能力，就能够在RGB surface和YUV surface之间直接交换数据（我错了？），可是测试中发现，即使显卡有这个能力，也无法在两个不同格式的surface之间直接blit。
即使在RGB32 surface和RGB16 surface之间也不能互相blit数据。难道这样的转换只能通过软件实现吗？

[Sodar]

这段话我之前也看到过，不过看的不够仔细，没理解什么意思。误事啊

[IONPhantom]

1.BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
2."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
3.BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
4."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
5."BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
6."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
7.BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
8.BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
9."BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
10."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
11."BLT, FourCC to RGB conversion" performs Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC flag.
12."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.
12."BLT, FourCC to RGB stretch" performs Stretched Blts from YUV (FOURCC) surfaces to an RGB primary surface. This test is run only if the driver sets the DDCAPS_BLTFOURCC and DDCAPS_BLTSTRETCH flags.

From MSDN.

从上面可以看出
1. primary surface 必须是 RGB
2. surface 可以是 YUV 但是只能是 Blt 到 primary surface 而没有 get from primary surface 功能

也就是只能是 YUV->RGB,RGB不能转回为YUV,是一个单向的,而且primary surface必须为RGB,也就是无法从primary surface读会YUV的数据

[wutaihua]

mark 非常有用