diff options
Diffstat (limited to 'vcl/opengl/shaders/areaHashCRC64TFragmentShader.glsl')
-rw-r--r-- | vcl/opengl/shaders/areaHashCRC64TFragmentShader.glsl | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/vcl/opengl/shaders/areaHashCRC64TFragmentShader.glsl b/vcl/opengl/shaders/areaHashCRC64TFragmentShader.glsl new file mode 100644 index 000000000000..901b481d8081 --- /dev/null +++ b/vcl/opengl/shaders/areaHashCRC64TFragmentShader.glsl @@ -0,0 +1,87 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +/* TODO Use textureOffset for newest version of GLSL */ + + +#version 130 + +uniform sampler2D crc_table; +uniform sampler2D sampler; +uniform float xstep; +uniform float ystep; + +varying vec2 tex_coord; + +const int scale = 4; +const float ratio = 16.0; + + +ivec2 crc64( ivec2 hval, int color ) +{ + int dx = 2 * ((hval[0] ^ color) & 0xff); + float s = dx / 255.0; + vec4 table_value_lo = round(texture2D( crc_table, vec2( s, 0.0 ) ) * 255.0); + s = (dx+1) / 255.0; + vec4 table_value_hi = round(texture2D( crc_table, vec2( s, 0.0 ) ) * 255.0); + + int tvalue_lo = int(table_value_lo[0]) | (int(table_value_lo[1]) << 8) | (int(table_value_lo[2]) << 16) | (int(table_value_lo[3]) << 24); + int tvalue_hi = int(table_value_hi[0]) | (int(table_value_hi[1]) << 8) | (int(table_value_hi[2]) << 16) | (int(table_value_hi[3]) << 24); + + hval[1] = tvalue_hi ^ (hval[1] >> 8); + hval[0] = tvalue_lo ^ ( (hval[1] << 24) | (hval[0] >> 8) ); + + return hval; +} + + +void main(void) +{ + ivec2 Crc = ivec2( 0xffffffff, 0xffffffff ); + vec2 offset = vec2( 0.0, 0.0 ); + vec2 next_coord = tex_coord.st; + for( int y = 0; y < scale && next_coord.y <= 1.0; ++y ) + { + for( int x = 0; x < scale && next_coord.x <= 1.0; ++x ) + { + vec4 pixel = round(texture2D( sampler, next_coord ) * 255.0); + + int r = int(pixel.r); // 0..255 + int g = int(pixel.g); // 0..255 + int b = int(pixel.b); // 0..255 + int a = int(pixel.a); // 0..255 + + Crc = crc64( Crc, r ); + Crc = crc64( Crc, g ); + Crc = crc64( Crc, b ); + Crc = crc64( Crc, a ); + + offset.x += xstep; + next_coord = tex_coord.st + offset; + } + offset.y += ystep; + offset.x = 0.0; + next_coord = tex_coord.st + offset; + } + + Crc[0] = ~Crc[0]; + Crc[1] = ~Crc[1]; + + int Hash = Crc[0] ^ Crc[1]; + + float fr = ( Hash & 0xff) / 255.0; + float fg = ((Hash >> 8) & 0xff) / 255.0; + float fb = ((Hash >> 16) & 0xff) / 255.0; + float fa = ((Hash >> 24) & 0xff) / 255.0; + + + gl_FragColor = vec4(fr, fg, fb, fa); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |