VuoImageAverage.c

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#include "VuoImageAverage.h"
#include "VuoImageRenderer.h"
 
#ifdef VUO_COMPILER
VuoModuleMetadata({
                     "title" : "VuoImageAverage",
                     "dependencies" : [
                         "VuoImageRenderer"
                     ]
                 });
#endif
 
typedef struct
{
    VuoShader shader;
} VuoImageAverage_internal;
 
void VuoImageAverage_free(void *average)
{
    VuoImageAverage_internal *bi = (VuoImageAverage_internal *)average;
    VuoRelease(bi->shader);
    free(bi);
}
 
VuoImageAverage VuoImageAverage_make(void)
{
    const char *shaderSource = VUOSHADER_GLSL_SOURCE(120,
        varying vec2 fragmentTextureCoordinate;
        uniform sampler2D textureA;
        uniform sampler2D textureB;
        uniform float factor;
 
        void main(void)
        {
            vec4 colorA = texture2D(textureA, fragmentTextureCoordinate);
            vec4 colorB = texture2D(textureB, fragmentTextureCoordinate);
            vec4 mixed = mix(colorA, colorB, factor);
            gl_FragColor = mixed;
        }
    );
 
    VuoImageAverage_internal *bi = (VuoImageAverage_internal *)malloc(sizeof(VuoImageAverage_internal));
    VuoRegister(bi, VuoImageAverage_free);
 
    bi->shader = VuoShader_make("Average Image Shader");
    VuoRetain(bi->shader);
    VuoShader_addSource(bi->shader, VuoMesh_IndividualTriangles, NULL, NULL, shaderSource);
 
    return (VuoImageAverage)bi;
}
 
VuoImage VuoImageAverage_average(VuoImageAverage average, VuoList_VuoImage images)
{
    unsigned long imageCount = VuoListGetCount_VuoImage(images);
    if (imageCount == 0)
        return NULL;
 
    VuoImage averagedImage = VuoListGetValue_VuoImage(images, 1);
    if (imageCount == 1)
    {
        VuoRetain(averagedImage);
        return averagedImage;
    }
 
    VuoImageColorDepth cd = VuoImage_getColorDepth(averagedImage);
 
 
    VuoImageAverage_internal *bi = (VuoImageAverage_internal *)average;
    VuoRetain(averagedImage);
    double factor = 1.;
    for (unsigned long i = 2; i <= imageCount; ++i)
    {
        VuoImage image = VuoListGetValue_VuoImage(images, i);
 
        VuoShader_setUniform_VuoImage(bi->shader, "textureA", averagedImage);
        VuoShader_setUniform_VuoImage(bi->shader, "textureB", image);
 
        factor *= ((double)i - 1.) / i;
        VuoShader_setUniform_VuoReal(bi->shader, "factor", factor);
 
        VuoImage b = VuoImageRenderer_render(bi->shader, averagedImage->pixelsWide, averagedImage->pixelsHigh, cd);
        VuoRetain(b);
        VuoRelease(averagedImage);
        averagedImage = b;
    }
 
    return averagedImage;
}