| #pragma version(1) |
| |
| #include "ip.rsh" |
| |
| int height; |
| int width; |
| int radius; |
| |
| uchar4 * InPixel; |
| uchar4 * OutPixel; |
| float4 * ScratchPixel1; |
| float4 * ScratchPixel2; |
| |
| #pragma rs export_func(filter); |
| |
| rs_script vBlurScript; |
| rs_script hBlurScript; |
| |
| const int CMD_FINISHED = 1; |
| |
| // Store our coefficients here |
| static float gaussian[MAX_RADIUS * 2 + 1]; |
| |
| |
| static void computeGaussianWeights() { |
| // Compute gaussian weights for the blur |
| // e is the euler's number |
| float e = 2.718281828459045f; |
| float pi = 3.1415926535897932f; |
| // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 ) |
| // x is of the form [-radius .. 0 .. radius] |
| // and sigma varies with radius. |
| // Based on some experimental radius values and sigma's |
| // we approximately fit sigma = f(radius) as |
| // sigma = radius * 0.4 + 0.6 |
| // The larger the radius gets, the more our gaussian blur |
| // will resemble a box blur since with large sigma |
| // the gaussian curve begins to lose its shape |
| float sigma = 0.4f * (float)radius + 0.6f; |
| |
| // Now compute the coefficints |
| // We will store some redundant values to save some math during |
| // the blur calculations |
| // precompute some values |
| float coeff1 = 1.0f / (sqrt( 2.0f * pi ) * sigma); |
| float coeff2 = - 1.0f / (2.0f * sigma * sigma); |
| |
| float normalizeFactor = 0.0f; |
| float floatR = 0.0f; |
| int r; |
| for (r = -radius; r <= radius; r ++) { |
| floatR = (float)r; |
| gaussian[r + radius] = coeff1 * pow(e, floatR * floatR * coeff2); |
| normalizeFactor += gaussian[r + radius]; |
| } |
| |
| //Now we need to normalize the weights because all our coefficients need to add up to one |
| normalizeFactor = 1.0f / normalizeFactor; |
| for (r = -radius; r <= radius; r ++) { |
| floatR = (float)r; |
| gaussian[r + radius] *= normalizeFactor; |
| } |
| } |
| |
| |
| static void copyInput() { |
| rs_allocation ain = {0}; |
| rsSetObject(&ain,rsGetAllocation(InPixel)); |
| uint32_t dimx = rsAllocationGetDimX(ain); |
| uint32_t dimy = rsAllocationGetDimY(ain); |
| for (uint32_t y = 0; y < dimy; y++) { |
| for (uint32_t x = 0; x < dimx; x++) { |
| ScratchPixel1[x + y * dimx] = convert_float4(InPixel[x + y * dimx]); |
| } |
| } |
| rsClearObject(&ain); |
| } |
| |
| void filter() { |
| copyInput(); |
| computeGaussianWeights(); |
| |
| FilterStruct fs; |
| fs.gaussian = gaussian; |
| fs.width = width; |
| fs.height = height; |
| fs.radius = radius; |
| |
| fs.ain = rsGetAllocation(ScratchPixel1); |
| rsForEach(hBlurScript, fs.ain, rsGetAllocation(ScratchPixel2), &fs); |
| |
| fs.ain = rsGetAllocation(ScratchPixel2); |
| rsForEach(vBlurScript, fs.ain, rsGetAllocation(OutPixel), &fs); |
| rsSendToClientBlocking(CMD_FINISHED); |
| } |
| |