// license:BSD-3-Clause // copyright-holders:Sven Gothel const char glsl_plain_idx16_lut_fsh_src[] = "\n" "#pragma optimize (on)\n" "#pragma debug (off)\n" "\n" "uniform sampler2D color_texture;\n" "uniform sampler2D colortable_texture;\n" "uniform vec2 colortable_sz; // ct size\n" "uniform vec2 colortable_pow2_sz; // pow2 ct size\n" "\n" "void main()\n" "{\n" " vec4 color_tex;\n" " vec2 color_map_coord;\n" "\n" " // normalized texture coordinates ..\n" " color_tex = texture2D(color_texture, gl_TexCoord[0].st);\n" "\n" " // GL_UNSIGNED_SHORT GL_ALPHA in ALPHA16 conversion:\n" " // general: f = c / ((2*N)-1), c color bitfield, N number of bits\n" " // ushort: c = ((2**16)-1)*f;\n" " color_map_coord.x = floor( 65535.0 * color_tex.a + 0.5 );\n" "\n" " // map it to the 2D lut table\n" " color_map_coord.y = floor(color_map_coord.x/colortable_sz.x);\n" " color_map_coord.x = mod(color_map_coord.x,colortable_sz.x);\n" "\n" " gl_FragColor = texture2D(colortable_texture, (color_map_coord+vec2(0.5)) / colortable_pow2_sz);\n" "}\n" "\n" "\n" ;