131 lines
4.7 KiB
C
131 lines
4.7 KiB
C
#include "tricorn_V0.h"
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#include <immintrin.h>
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static unsigned converge(float c_real, float c_imag, unsigned n);
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/**
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* @brief Generates a Tricorn fractal image using highly optimized SSE/SIMD instructions.
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* @param start The starting complex coordinate (bottom-left or top-left depending on height sign).
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* @param width The width of the target image in pixels.
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* @param height The height of the target image. A negative height reverses the Y-axis calculation.
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* @param res The step size (resolution) per pixel in the complex plane.
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* @param n The maximum number of mathematical iterations per pixel.
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* @param color If true, generates a 24-bit RGB image. If false, writes a grayscale image.
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* @param img Pointer to the pre-allocated memory buffer where the bitmap data will be stored.
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*/
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void tricorn_V0(float complex start, size_t width, ssize_t height, float res, unsigned n, _Bool color, unsigned char* img){
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int bytesPerColor = color ? 3 : 1;
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// Absolute height for iteration purposes
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ssize_t actual_height = height < 0 ? (ssize_t)(-height) : height;
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ssize_t imag_step = height < 0 ? -1:1;
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size_t simd_width = (width / 4) * 4;
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float c_start_real = creal(start);
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float c_start_imag = cimag(start);
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__m128 four = _mm_set1_ps(4.0f);
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__m128 minus_two = _mm_set1_ps(-2.0f);
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float c_imag = c_start_imag;
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__m128 c_imag_vector = _mm_set1_ps(c_imag);
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float four_res = 4 * res;
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float vertical_step = imag_step * res;
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__m128 vertical_step_vector = _mm_set1_ps(vertical_step);
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for(ssize_t y = 0; y < actual_height;y++) {
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size_t x = 0;
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__m128 c_real_vector = _mm_setr_ps(c_start_real,c_start_real + 1.0f*res,c_start_real + 2.0f*res, c_start_real + 3.0f*res);
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for(; x < simd_width;x += 4) { //SIMD Loop
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__m128 real = _mm_setzero_ps();
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__m128 imag = _mm_setzero_ps();
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__m128i iterations = _mm_setzero_si128();
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__m128i active_mask = _mm_set1_epi32(-1);
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for(unsigned i = 0; i < n;i++) {
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__m128 real2 = _mm_mul_ps(real,real);
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__m128 imag2 = _mm_mul_ps(imag,imag);
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__m128 unbounded = _mm_cmple_ps(_mm_add_ps(real2,imag2),four);
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__m128i unbounded_i = _mm_castps_si128(unbounded);
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active_mask = _mm_and_si128(active_mask,unbounded_i);
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if(_mm_test_all_zeros(active_mask,active_mask)) {
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break;
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}
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iterations = _mm_sub_epi32(iterations,active_mask);
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imag = _mm_add_ps(c_imag_vector,_mm_mul_ps(minus_two, _mm_mul_ps(real,imag)));
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real = _mm_add_ps(_mm_sub_ps(real2,imag2),c_real_vector);
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}
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__m128i mod64 = _mm_and_si128(iterations, _mm_set1_epi32(63));
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__m128i times4 = _mm_slli_epi32(mod64, 2);
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__m128i values = _mm_sub_epi32(_mm_set1_epi32(255), times4);
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__m128i max_iter = _mm_set1_epi32(n);
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__m128i is_max = _mm_cmpeq_epi32(iterations, max_iter);
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values = _mm_andnot_si128(is_max, values);
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unsigned int value_array[4];
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_mm_storeu_si128((__m128i*)value_array,values);
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for(unsigned i = 0 ; i < 4;i++) {
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unsigned int value = value_array[i];
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size_t position = (y*width + (x+i)) * bytesPerColor;
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if(!color) {
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img[position] = value;
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}
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else {
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img[position] = ((value*3) % 255);
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img[position + 1] = ((value*2) % 255);
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img[position + 2] = ((value*5) % 255);
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}
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}
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c_real_vector = _mm_add_ps(c_real_vector,_mm_set1_ps(four_res));
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}
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for(;x < width; x++) {
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float c_real = c_start_real + (x*res);
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unsigned int value = converge(c_real,c_imag,n);
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size_t position = (y*width + x) * bytesPerColor;
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if(!color) {
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img[position] = value;
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}
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else {
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img[position] = ((value*3) % 255);
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img[position + 1] = ((value*2) % 255);
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img[position + 2] = ((value*5) % 255);
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}
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c_real += res;
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}
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c_imag -= vertical_step;
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c_imag_vector = _mm_sub_ps(c_imag_vector,vertical_step_vector);
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}
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}
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static unsigned converge(float c_real, float c_imag, unsigned n) {
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float real = 0.0f;
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float imag = 0.0f;
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for (unsigned i = 0; i < n; i++) {
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float real2 = real * real;
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float imag2 = imag * imag;
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if (real2 + imag2 > 4.0f) {
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return 255 - 4 * (i % 64);
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}
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imag = -2.0f * real * imag + c_imag;
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real = real2 - imag2 + c_real;
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}
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return 0;
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} |