| #pragma version(1) |
| #pragma rs java_package_name(com.android.rs.image) |
| #pragma rs_fp_relaxed |
| |
| |
| int height; |
| int width; |
| static int radius; |
| |
| rs_allocation InPixel; |
| rs_allocation ScratchPixel1; |
| rs_allocation ScratchPixel2; |
| |
| const int MAX_RADIUS = 25; |
| |
| // Store our coefficients here |
| static float gaussian[MAX_RADIUS * 2 + 1]; |
| |
| void setRadius(int rad) { |
| radius = rad; |
| // 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; |
| for (int 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 (int r = -radius; r <= radius; r ++) { |
| floatR = (float)r; |
| gaussian[r + radius] *= normalizeFactor; |
| } |
| } |
| |
| void copyIn(const uchar4 *in, float4 *out) { |
| *out = convert_float4(*in); |
| } |
| |
| void vert(uchar4 *out, uint32_t x, uint32_t y) { |
| float3 blurredPixel = 0; |
| const float *gPtr = gaussian; |
| if ((y > radius) && (y < (height - radius))) { |
| for (int r = -radius; r <= radius; r ++) { |
| const float4 *i = (const float4 *)rsGetElementAt(ScratchPixel2, x, y + r); |
| blurredPixel += i->xyz * gPtr[0]; |
| gPtr++; |
| } |
| } else { |
| for (int r = -radius; r <= radius; r ++) { |
| int validH = rsClamp((int)y + r, (int)0, (int)(height - 1)); |
| const float4 *i = (const float4 *)rsGetElementAt(ScratchPixel2, x, validH); |
| blurredPixel += i->xyz * gPtr[0]; |
| gPtr++; |
| } |
| } |
| |
| out->xyz = convert_uchar3(clamp(blurredPixel, 0.f, 255.f)); |
| out->w = 0xff; |
| } |
| |
| void horz(float4 *out, uint32_t x, uint32_t y) { |
| float3 blurredPixel = 0; |
| const float *gPtr = gaussian; |
| if ((x > radius) && (x < (width - radius))) { |
| for (int r = -radius; r <= radius; r ++) { |
| const float4 *i = (const float4 *)rsGetElementAt(ScratchPixel1, x + r, y); |
| blurredPixel += i->xyz * gPtr[0]; |
| gPtr++; |
| } |
| } else { |
| for (int r = -radius; r <= radius; r ++) { |
| // Stepping left and right away from the pixel |
| int validX = rsClamp((int)x + r, (int)0, (int)(width - 1)); |
| const float4 *i = (const float4 *)rsGetElementAt(ScratchPixel1, validX, y); |
| blurredPixel += i->xyz * gPtr[0]; |
| gPtr++; |
| } |
| } |
| |
| out->xyz = blurredPixel; |
| } |
| |