From fe186d3a598837ba7337f06399dfb8ae7930a070 Mon Sep 17 00:00:00 2001 From: Yuri Kunde Schlesner Date: Tue, 23 Dec 2014 12:27:56 -0200 Subject: [PATCH] GPU: Bitwise texture swizzling Replace the loop-based texture address swizzling code by a bit-twiddling implementation, providing a very small speed up. Also simplify addressing code. --- src/video_core/debug_utils/debug_utils.cpp | 49 ++++++++++------------ 1 file changed, 23 insertions(+), 26 deletions(-) diff --git a/src/video_core/debug_utils/debug_utils.cpp b/src/video_core/debug_utils/debug_utils.cpp index 328386b7e..5921185a6 100644 --- a/src/video_core/debug_utils/debug_utils.cpp +++ b/src/video_core/debug_utils/debug_utils.cpp @@ -304,7 +304,6 @@ std::unique_ptr FinishPicaTracing() } const Math::Vec4 LookupTexture(const u8* source, int x, int y, const TextureInfo& info, bool disable_alpha) { - // Images are split into 8x8 tiles. Each tile is composed of four 4x4 subtiles each // of which is composed of four 2x2 subtiles each of which is composed of four texels. // Each structure is embedded into the next-bigger one in a diagonal pattern, e.g. @@ -323,41 +322,39 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture // 02 03 06 07 18 19 22 23 // 00 01 04 05 16 17 20 21 - // TODO(neobrain): Not sure if this swizzling pattern is used for all textures. - // To be flexible in case different but similar patterns are used, we keep this - // somewhat inefficient code around for now. - int texel_index_within_tile = 0; - for (int block_size_index = 0; block_size_index < 3; ++block_size_index) { - int sub_tile_width = 1 << block_size_index; - int sub_tile_height = 1 << block_size_index; + const unsigned int block_width = 8; + const unsigned int block_height = 8; - int sub_tile_index = (x & sub_tile_width) << block_size_index; - sub_tile_index += 2 * ((y & sub_tile_height) << block_size_index); - texel_index_within_tile += sub_tile_index; - } + const unsigned int coarse_x = x & ~7; + const unsigned int coarse_y = y & ~7; - const int block_width = 8; - const int block_height = 8; + // Interleave the lower 3 bits of each coordinate to get the intra-block offsets, which are + // arranged in a Z-order curve. More details on the bit manipulation at: + // https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/ + unsigned int i = (x | (y << 8)) & 0x0707; // ---- -210 + i = (i ^ (i << 2)) & 0x1313; // ---2 --10 + i = (i ^ (i << 1)) & 0x1515; // ---2 -1-0 + i = (i | (i >> 7)) & 0x3F; - int coarse_x = (x / block_width) * block_width; - int coarse_y = (y / block_height) * block_height; + source += coarse_y * info.stride; + const unsigned int offset = coarse_x * block_height + i; switch (info.format) { case Regs::TextureFormat::RGBA8: { - const u8* source_ptr = source + coarse_x * block_height * 4 + coarse_y * info.stride + texel_index_within_tile * 4; + const u8* source_ptr = source + offset * 4; return { source_ptr[3], source_ptr[2], source_ptr[1], disable_alpha ? (u8)255 : source_ptr[0] }; } case Regs::TextureFormat::RGB8: { - const u8* source_ptr = source + coarse_x * block_height * 3 + coarse_y * info.stride + texel_index_within_tile * 3; + const u8* source_ptr = source + offset * 3; return { source_ptr[2], source_ptr[1], source_ptr[0], 255 }; } case Regs::TextureFormat::RGBA5551: { - const u16 source_ptr = *(const u16*)(source + coarse_x * block_height * 2 + coarse_y * info.stride + texel_index_within_tile * 2); + const u16 source_ptr = *(const u16*)(source + offset * 2); u8 r = (source_ptr >> 11) & 0x1F; u8 g = ((source_ptr) >> 6) & 0x1F; u8 b = (source_ptr >> 1) & 0x1F; @@ -367,7 +364,7 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::RGB565: { - const u16 source_ptr = *(const u16*)(source + coarse_x * block_height * 2 + coarse_y * info.stride + texel_index_within_tile * 2); + const u16 source_ptr = *(const u16*)(source + offset * 2); u8 r = (source_ptr >> 11) & 0x1F; u8 g = ((source_ptr) >> 5) & 0x3F; u8 b = (source_ptr) & 0x1F; @@ -376,7 +373,7 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::RGBA4: { - const u8* source_ptr = source + coarse_x * block_height * 2 + coarse_y * info.stride + texel_index_within_tile * 2; + const u8* source_ptr = source + offset * 2; u8 r = source_ptr[1] >> 4; u8 g = source_ptr[1] & 0xFF; u8 b = source_ptr[0] >> 4; @@ -390,7 +387,7 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::IA8: { - const u8* source_ptr = source + coarse_x * block_height * 2 + coarse_y * info.stride + texel_index_within_tile * 2; + const u8* source_ptr = source + offset * 2; // TODO: component order not verified @@ -404,13 +401,13 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::I8: { - const u8* source_ptr = source + coarse_x * block_height + coarse_y * info.stride + texel_index_within_tile; + const u8* source_ptr = source + offset; return { *source_ptr, *source_ptr, *source_ptr, 255 }; } case Regs::TextureFormat::A8: { - const u8* source_ptr = source + coarse_x * block_height + coarse_y * info.stride + texel_index_within_tile; + const u8* source_ptr = source + offset; if (disable_alpha) { return { *source_ptr, *source_ptr, *source_ptr, 255 }; @@ -421,7 +418,7 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::IA4: { - const u8* source_ptr = source + coarse_x * block_height / 2 + coarse_y * info.stride + texel_index_within_tile / 2; + const u8* source_ptr = source + offset / 2; // TODO: component order not verified @@ -440,7 +437,7 @@ const Math::Vec4 LookupTexture(const u8* source, int x, int y, const Texture case Regs::TextureFormat::A4: { - const u8* source_ptr = source + coarse_x * block_height / 2 + coarse_y * info.stride + texel_index_within_tile / 2; + const u8* source_ptr = source + offset / 2; // TODO: component order not verified