Function macroSamples

  • macroSamples(state, on?): string

  • Defines the texture samples/reads per-pass, as GLSL preprocessor macros.

    The macros define the mapping between the values and those they derive from, as step/texture locations in a samples list, and indexes to read values from sampled data in a reads list (once sampled into a data list, as in macroTaps or similar).

    They're set up as function-like macros that may be called from the shader to initialise the mappings arrays with a given name. Caches the result if macros generation is enabled, to help reuse shaders.

    Parameters

    • state: any

      Properties used to generate the macros. See toData.

    • Optionalon: string

      Any further macro hooks specifier; if given, both the hook key and this specifier are checked (e.g: key and key_on).

    Returns string

    GLSL preprocessor macros defining the mappings for samples and reads, for each value.

    See

    Example: ```javascript const values = [2, 4, 1]; const derives = [2, , [[1, 0], true]]; const maps = { values, derives, channelsMax: 4 }; // No optimisations - values not packed, single texture output per pass. const state = { pre: '', maps: mapStep({ ...maps, buffersMax: 1, packed: 0 }) }; // Uses the first pass by default. macroSamples(state); // => '#define useSamples'+lf+ 'const int samples_l = 1;'+lf+ 'const ivec2 samples_0 = ivec2(0, 2);\n'+ '// Index macro `samples_i` (e.g: `samples_i(0)`) may be slow, '+ 'use name (e.g: `samples_0`) if possible.\n'+ '#define samples_i(i) samples_0\n'+ '\n'+ '#define useReads_0'+lf+ 'const int reads_0_l = 1;'+lf+ 'const int reads_0_0 = int(0);\n'+ '// Index macro `reads_0_i` (e.g: `reads_0_i(0)`) may be slow, '+ 'use name (e.g: `reads_0_0`) if possible.\n'+ '#define reads_0_i(i) reads_0_0\n'+ '\n'; // Next pass in this step - no derives, no samples nor reads. state.passNow = 1; macroSamples(state); // => ''; // Next pass in this step. ++state.passNow; macroSamples(state); // => '#define useSamples'+lf+ 'const int samples_l = 4;'+lf+ 'const ivec2 samples_0 = ivec2(1, 0);'+lf+ 'const ivec2 samples_1 = ivec2(0, 0);'+lf+ 'const ivec2 samples_2 = ivec2(0, 1);'+lf+ 'const ivec2 samples_3 = ivec2(0, 2);\n'+ '// Index macro `samples_i` (e.g: `samples_i(0)`) may be slow, '+ 'use name (e.g: `samples_0`) if possible.\n'+ '#define samples_i(i) ((i == 3)? samples_3 : ((i == 2)? samples_2 '+ ': ((i == 1)? samples_1 : samples_0)))\n'+ '\n'+ '#define useReads_2'+lf+ 'const int reads_2_l = 4;'+lf+ 'const int reads_2_0 = int(0);'+lf+ 'const int reads_2_1 = int(1);'+lf+ 'const int reads_2_2 = int(2);'+lf+ 'const int reads_2_3 = int(3);\n'+ '// Index macro `reads_2_i` (e.g: `reads_2_i(0)`) may be slow, '+ 'use name (e.g: `reads_2_0`) if possible.\n'+ '#define reads_2_i(i) ((i == 3)? reads_2_3 : ((i == 2)? reads_2_2 '+ ': ((i == 1)? reads_2_1 : reads_2_0)))\n'+ '\n'; // Automatically packed values - values across fewer textures/passes. // Can bind more texture outputs per pass - values across fewer passes. // Also fewer samples where values share derives or textures. state.maps = mapGroups({ ...maps, buffersMax: 4 }); state.passNow = 0; macroSamples(state); // => '#define useSamples'+lf+ 'const int samples_l = 3;'+lf+ 'const ivec2 samples_0 = ivec2(0, 1);'+lf+ 'const ivec2 samples_1 = ivec2(1, 1);'+lf+ 'const ivec2 samples_2 = ivec2(0, 0);\n'+ '// Index macro `samples_i` (e.g: `samples_i(0)`) may be slow, '+ 'use name (e.g: `samples_0`) if possible.\n'+ '#define samples_i(i) '+ '((i == 2)? samples_2 : ((i == 1)? samples_1 : samples_0))\n'+ '\n'+ '#define useReads_0'+lf+ 'const int reads_0_l = 1;'+lf+ 'const int reads_0_0 = int(0);\n'+ '// Index macro `reads_0_i` (e.g: `reads_0_i(0)`) may be slow, '+ 'use name (e.g: `reads_0_0`) if possible.\n'+ '#define reads_0_i(i) reads_0_0\n'+ '\n'+ '#define useReads_2'+lf+ 'const int reads_2_l = 4;'+lf+ 'const int reads_2_0 = int(1);'+lf+ 'const int reads_2_1 = int(0);'+lf+ 'const int reads_2_2 = int(2);'+lf+ 'const int reads_2_3 = int(0);\n'+ '// Index macro `reads_2_i` (e.g: `reads_2_i(0)`) may be slow, '+ 'use name (e.g: `reads_2_0`) if possible.\n'+ '#define reads_2_i(i) ((i == 3)? reads_2_3 : ((i == 2)? reads_2_2 '+ ': ((i == 1)? reads_2_1 : reads_2_0)))\n'+ '\n'; ```

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