diff options
Diffstat (limited to 'src/osd/modules/opengl/shader/glsl_plain_idx16_lut.fsh')
-rw-r--r-- | src/osd/modules/opengl/shader/glsl_plain_idx16_lut.fsh | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/osd/modules/opengl/shader/glsl_plain_idx16_lut.fsh b/src/osd/modules/opengl/shader/glsl_plain_idx16_lut.fsh new file mode 100644 index 00000000000..465aa610d59 --- /dev/null +++ b/src/osd/modules/opengl/shader/glsl_plain_idx16_lut.fsh @@ -0,0 +1,30 @@ + +#pragma optimize (on) +#pragma debug (off) + +uniform sampler2D color_texture; +uniform sampler2D colortable_texture; +uniform vec2 colortable_sz; // ct size +uniform vec2 colortable_pow2_sz; // pow2 ct size + +void main() +{ + vec4 color_tex; + vec2 color_map_coord; + + // normalized texture coordinates .. + color_tex = texture2D(color_texture, gl_TexCoord[0].st); + + // GL_UNSIGNED_SHORT GL_ALPHA in ALPHA16 conversion: + // general: f = c / ((2*N)-1), c color bitfield, N number of bits + // ushort: c = ((2**16)-1)*f; + color_map_coord.x = floor( 65535.0 * color_tex.a + 0.5 ); + + // map it to the 2D lut table + color_map_coord.y = floor(color_map_coord.x/colortable_sz.x); + color_map_coord.x = mod(color_map_coord.x,colortable_sz.x); + + gl_FragColor = texture2D(colortable_texture, (color_map_coord+vec2(0.5)) / colortable_pow2_sz); +} + + |