Shader transparent_modularized

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transparent_modularized.mi
declare shader 
    color "transparent_modularized" ( 
        color "color" default 1 1 1 1, 
        color "transparency" default .5 .5 .5 .5 ) 
    version 1 
    apply material 
end declare 

transparent_modularized.c
#include "shader.h" 
#include "miaux.h" 
 
struct transparent_modularized {  
    miColor color;  
    miColor transparency; 
}; 
 
DLLEXPORT 
int transparent_modularized_version(void) { return(1); } 
 
DLLEXPORT 
miBoolean transparent_modularized (  
    miColor *result, miState *state, struct transparent_modularized *params  ) 
{ 
    miColor *transparency = mi_eval_color(&params->transparency); 
 
    if (miaux_all_channels_equal(transparency, 0.0))  
      *result = *mi_eval_color(&params->color); 
 
    else if (miaux_all_channels_equal(transparency, 1.0)) 
      mi_trace_transparent(result, state);       
 
    else { 
      miColor *color = mi_eval_color(&params->color), opacity; 
      mi_trace_transparent(result, state); 
      miaux_invert_channels(&opacity, transparency); 
      mi_opacity_set(state, &opacity); 
      miaux_blend_channels(result, color, transparency); 
    } 
 
    return miTRUE; 
} 

transparent_modularized_util.c
miBoolean miaux_all_channels_equal(miColor *c, miScalar v) 
{ 
    if (c->r == v && c->g == v && c->b == v && c->a == v) 
	return miTRUE; 
    else 
	return miFALSE; 
} 
 
void miaux_invert_channels(miColor *result, miColor *color) 
{ 
    result->r = 1.0 - color->r; 
    result->g = 1.0 - color->g; 
    result->b = 1.0 - color->b; 
    result->a = 1.0 - color->a; 
} 
 
void miaux_blend_channels(miColor *result, 
			  miColor *blend_color, miColor *blend_fraction) 
{ 
    result->r = miaux_blend(result->r, blend_color->r, blend_fraction->r); 
    result->g = miaux_blend(result->g, blend_color->g, blend_fraction->g); 
    result->b = miaux_blend(result->b, blend_color->b, blend_fraction->b); 
} 
 
double miaux_blend(miScalar a, miScalar b, miScalar factor) 
{ 
    return a * factor + b * (1.0 - factor); 
} 

22 April 2008 23:39:54