#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 ); }