diff options
Diffstat (limited to 'src/osd/modules/opengl/shader/glsl_bilinear_idx16_lut.fsh')
-rw-r--r-- | src/osd/modules/opengl/shader/glsl_bilinear_idx16_lut.fsh | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/osd/modules/opengl/shader/glsl_bilinear_idx16_lut.fsh b/src/osd/modules/opengl/shader/glsl_bilinear_idx16_lut.fsh new file mode 100644 index 00000000000..ef0030b7519 --- /dev/null +++ b/src/osd/modules/opengl/shader/glsl_bilinear_idx16_lut.fsh @@ -0,0 +1,55 @@ + +#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 +uniform vec2 color_texture_pow2_sz; // pow2 tex size + +vec4 lutTex2D(in vec2 texcoord) +{ + vec4 color_tex; + vec2 color_map_coord; + + // normalized texture coordinates .. + color_tex = texture2D(color_texture, texcoord); + + // 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); + + return texture2D(colortable_texture, (color_map_coord+vec2(0.5)) / colortable_pow2_sz); +} + +void main() +{ + vec2 xy = gl_TexCoord[0].st; + + // mix(x,y,a): x*(1-a) + y*a + // + // bilinear filtering includes 2 mix: + // + // pix1 = tex[x0][y0] * ( 1 - u_ratio ) + tex[x1][y0] * u_ratio + // pix2 = tex[x0][y1] * ( 1 - u_ratio ) + tex[x1][y1] * u_ratio + // fin = pix1 * ( 1 - v_ratio ) + pix2 * v_ratio + // + // so we can use the build in mix function for these 2 computations ;-) + // + vec2 uv_ratio = fract(xy*color_texture_pow2_sz); // xy*color_texture_pow2_sz - floor(xy*color_texture_pow2_sz); + vec2 one = 1.0/color_texture_pow2_sz; + + vec4 col1, col2; + + col1 = mix( lutTex2D(xy ), lutTex2D(xy + vec2(one.x, 0.0)), uv_ratio.x); + col2 = mix( lutTex2D(xy + vec2(0.0, one.y)), lutTex2D(xy + one ), uv_ratio.x); + + gl_FragColor = mix ( col1, col2, uv_ratio.y ); +} + |