gpu绘制波纹

每个线程绘制一个像素点，可以显示高清的动画

#include "cuda_runtime.h"
#include "device_launch_parameters.h"

#include <stdio.h>
#include "common/book.h"
#include "common/cpu_bitmap.h"
#include "common/cpu_anim.h"

const int DIM_WIDTH = 1920;
const int DIM_HEIGHT = 1080;


__global__ void rippleKernel(unsigned char* ptr, int ticks) {
    // mapping threadIdx/BlockIdx to cell pos
    int x = threadIdx.x + blockIdx.x * blockDim.x;
    int y = threadIdx.y + blockIdx.y * blockDim.y;
    int offset = x + y * blockDim.x * gridDim.x;
    //calculate the value on the cell
    float fx = x - DIM_WIDTH / 2;
    float fy = y - DIM_HEIGHT / 2;
    float d = sqrtf(fx * fx + fy * fy);
    unsigned char grey = (unsigned char)(128.0f + 127.0f * 
        cos(d / 10.0f - ticks / 7.0f) / (d / 10.0f + 1.0f));
    ptr[offset * 4 + 0] = grey;
    ptr[offset * 4 + 1] = grey;
    ptr[offset * 4 + 2] = grey;
    ptr[offset * 4 + 3] = 255;
}

struct DataBlock {
    unsigned char* dev_bitmap;
    CPUAnimBitmap* bitmap;
};
void cleanup(DataBlock* d) {
    cudaFree(d->dev_bitmap);
}
void generate_frame(DataBlock* d, int ticks) {
    dim3 blocks(DIM_WIDTH / 16, DIM_HEIGHT / 16);
    dim3 threads(16, 16);
    //dim3 threads(DIM_WIDTH, DIM_HEIGHT);
    rippleKernel << <blocks, threads >> > (d->dev_bitmap, ticks);
    HANDLE_ERROR(cudaMemcpy (d->bitmap->get_ptr(), d->dev_bitmap,
        d->bitmap->image_size(), cudaMemcpyDeviceToHost));
    
}

void testGPURipple() {
    DataBlock data;
    CPUAnimBitmap bitmap(DIM_WIDTH, DIM_HEIGHT, &data);
    data.bitmap = &bitmap;
    HANDLE_ERROR(cudaMalloc((void**)&data.dev_bitmap,bitmap.image_size()));
    bitmap.anim_and_exit((void(*)(void*, int))generate_frame, (void(*)(void*))cleanup);
}

int main()
{
    //testSaclarAdd();
    //getDeviceProp();
    //testJuliaSet();
    //testGPUJuliaSet();
    testGPURipple();
    return 0;
}