Instead of using rgb_scale, make the color blend effect with a Local

[Pablo Antonio Navarro Reyes]

It would be nice to be able to blend the map's colors in rendering time by using a local variable, instead of using rgb_scale manually everytime I want to change it.

Instead of cloning a FPG in memory and then changing the color in every map of that cloned FPG with rgb_scale, we would use just one FPG in different "Process" with a different local variable (something like color_blend) and the rendering engine would change the color just at rendering time.

Ps: I don't know if I've explained myself enough, so Spanish here:

El objetivo sería tener un FPG en memoria y hacer ese cambio de color sólo en el momento de renderizar ese gráfico en base a una variable local.

[Joseba Echevarria García]

Thanks for the report.

Implementing this involves adding three local variables in mod_grproc (one per channel) and making changes to draw_at at mod_grproc/mod_grproc.c and gr_blit in libblit/gr_blit.c, so that the latter accepts the values as inputs and acts accordingly.

[Joseba Echevarria García]

The previous comment was probably not right. For what I'm seeing, I should probably modify draw_instance_at() at librender/g_instance.c instead of mod_grproc. The locals should go in librender, too.

[Joseba Echevarria García]

This'll also need to be supported by the following:

• mouse
• map_xputnp
• xput
• ¿Software blitting?

[Joseba Echevarria García]

Commit a50d2ce provides an initial implementation by defining three local vars: MODR, MODG, MODB with values ranging 0-255 that control per-channel colour modulation.

As I said, there are some missing pieces, but the basic funtionality should be there.

[Joseba Echevarria García]

Closing this bug report.

The blitting side is done, and these effects can be regarded in the same way alpha is: since modr, modg and modb are effects applied to how a process looks, they needn't apply to the graphics themselves.