From c1f33097f4a6cd33df57dc601ba1733985979a4f Mon Sep 17 00:00:00 2001 From: Michal Krol Date: Fri, 30 Jul 2010 16:59:05 +0200 Subject: [PATCH] util: Fix unpacking of R8G8Bx_SNORM format. Apparently, we must always use integers to perform calculations, otherwise the results won't match D3D's CxV8U8 definition. --- src/gallium/auxiliary/util/u_format_other.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/src/gallium/auxiliary/util/u_format_other.c b/src/gallium/auxiliary/util/u_format_other.c index 723fa8c3bf9..fa42ec37138 100644 --- a/src/gallium/auxiliary/util/u_format_other.c +++ b/src/gallium/auxiliary/util/u_format_other.c @@ -121,6 +121,15 @@ util_format_r1_unorm_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, * A.k.a. D3DFMT_CxV8U8 */ +static uint8_t +r8g8bx_derive(int16_t r, int16_t g) +{ + /* Derive blue from red and green components. + * Apparently, we must always use integers to perform calculations, + * otherwise the results won't match D3D's CxV8U8 definition. + */ + return (uint8_t)sqrtf(0x7f * 0x7f - r * r - g * g) * 0xff / 0x7f; +} void util_format_r8g8bx_snorm_unpack_rgba_float(float *dst_row, unsigned dst_stride, @@ -145,7 +154,7 @@ util_format_r8g8bx_snorm_unpack_rgba_float(float *dst_row, unsigned dst_stride, dst[0] = (float)(r * (1.0f/0x7f)); /* r */ dst[1] = (float)(g * (1.0f/0x7f)); /* g */ - dst[2] = sqrtf(1.0f - dst[0] * dst[0] - dst[1] * dst[1]); /* b */ + dst[2] = r8g8bx_derive(r, g) * (1.0f/0xff); /* b */ dst[3] = 1.0f; /* a */ dst += 4; } @@ -177,7 +186,7 @@ util_format_r8g8bx_snorm_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_strid dst[0] = (uint8_t)(((uint16_t)MAX2(r, 0)) * 0xff / 0x7f); /* r */ dst[1] = (uint8_t)(((uint16_t)MAX2(g, 0)) * 0xff / 0x7f); /* g */ - dst[2] = (uint8_t)sqrtf(0x7f*0x7f - r * r - g * g) * 0xff / 0x7f; /* b */ + dst[2] = r8g8bx_derive(r, g); /* b */ dst[3] = 255; /* a */ dst += 4; } @@ -262,6 +271,6 @@ util_format_r8g8bx_snorm_fetch_rgba_float(float *dst, const uint8_t *src, dst[0] = r * (1.0f/0x7f); /* r */ dst[1] = g * (1.0f/0x7f); /* g */ - dst[2] = sqrtf(1.0f - dst[0] * dst[0] - dst[1] * dst[1]); /* b */ + dst[2] = r8g8bx_derive(r, g) * (1.0f/0xff); /* b */ dst[3] = 1.0f; /* a */ } -- 2.30.2