| 4,7 → 4,7 |
|---|
| ================================= |
| |
| Filter Foundry tries to be as compatible with Filter Factory as possible. |
| However, there are some differences that are explained in this documentation. |
| However, there are some differences which are explained in this documentation. |
| |
| Various implementations |
| ----------------------- |
| 17,7 → 17,7 |
|---|
| If required, the compiler-definitions `use_filterfactory_implementation_*` |
| can be set or unset to select the implementation. |
| |
| In Filter Foundry 1.7.0.8, the following functions have been updated to the Filter Factory replica: |
| In Filter Foundry 1.7.0.8, following functions have been updated to the Filter Factory replica: |
| - `rnd(x)` |
| - `cos(x)` |
| - `sin(x)` |
| 40,7 → 40,7 |
|---|
| |
| sqr(x)=x for x < 0 |
| |
| Can be tested with the following expression: |
| Can be tested with following expression: |
| sqr(-20)+21 == 1 |
| |
| Filter Foundry (prior to 1.7.0.8): |
| 47,9 → 47,7 |
|---|
| |
| sqr(x)=0 for x < 0 |
| |
| Beginning with Filter Foundry 1.7.0.8, the behavior of Filter Factory was implemented. |
| |
| |
| i, u, v (Testcase iuv.afs) |
| ------- |
| |
| 68,21 → 66,6 |
|---|
| Both formulas follow the same YUV standard but have different accuracy. |
| |
| |
| I, U, V, imin, umin, vmin (Testcase iuv_minmax.afs) |
| ------------------------- |
| |
| In Filter Foundry 1.7.0.8, the previously undocumented variables I, U, V as well as imin, umin, vmin |
| have been changed to represent the actual results of the i,u,v variables: |
| |
| I, imax = 255 (stayed the same) |
| U, umax = 55 (was 255 in Filter Factory) |
| V, vmax = 78 (was 255 in Filter Factory) |
| |
| imin = 0 (stayed the same) |
| umin = -55 (was 0 in Filter Factory) |
| vmin = -78 (was 0 in Filter Factory) |
| |
| |
| get(i) (Testcase getput.afs) |
| ------ |
| |
| 122,7 → 105,8 |
|---|
| Filter Factory contains an undocumented function that sets the seed for the random number generator. |
| |
| Filter Factory and Filter Foundry beginning with 1.7.0.8 accept a seed between 0 and 32767, inclusively. |
| If the argument is not within this range, the operation lowest 15 bits are taken. |
| If the argument is not within this range, the operation "and 0x7FFF" will be applied to it |
| to extract the low 15 bits. |
| |
| There are many differences in the implementation between Filter Factory and Filter Foundry in regards rst(i): |
| |
| 146,7 → 130,7 |
|---|
| In Filter Foundry, the function rnd(a,b) retrieves a random number in "realtime"; therefore, if the |
| seed is changed via rst(i), there is an immediate effect on the next call of the rnd(a,b) function. |
| |
| For example, the following filter would generate an one-colored picture without any randomness: |
| For example, following filter would generate an one-colored picture without any randomness: |
| R: rst(123), rnd(0,255) |
| G: rnd(0,255) |
| B: rnd(0,255) |
| 168,7 → 152,7 |
|---|
| |
| Only the branches which will be chosen due to the conditional expression will be evaluated. |
| |
| This means that the following filter would generate a black canvas: (Testcase conditional_eval_1.afs) |
| This means that following filter would generate a black canvas: (Testcase conditional_eval_1.afs) |
| |
| R: 1==0 ? put(255,0) : 0 |
| G: get(0) |
| 190,14 → 174,14 |
|---|
| |
| **Filter Factory:** |
| |
| Each branch inside an if-then-else expression will be evaluated. |
| This means that the following filter would generate a green canvas: (Testcase conditional_eval_1.afs) |
| Each branch inside a if-then-else expression will be evaluated. |
| This means that following filter would generate a green canvas: (Testcase conditional_eval_1.afs) |
| |
| R: 1==0 ? put(255,0) : 0 |
| G: get(0) |
| B: 0 |
| |
| Also, all arguments of a boolean expression will be fully evaluated. |
| Also, all arguments of an boolean expression will be fully evaluated. |
| So, this will also generate a green canvas: (Testcase conditional_eval_2.afs) |
| |
| R: 1==0 && put(255,0) ? 0: 0 |