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#include "ShaderStructs.h"

__global__ void sinewave_gen_kernel(Vertex *vertices, unsigned int width, unsigned int height, float time)
{
    unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
    unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;

    // calculate uv coordinates
    float u = x / (float)width;
    float v = y / (float)height;
    u       = u * 2.0f - 1.0f;
    v       = v * 2.0f - 1.0f;

    // calculate simple sine wave pattern
    float freq = 4.0f;
    float w    = sinf(u * freq + time) * cosf(v * freq + time) * 0.5f;

    if (y < height && x < width) {
        // write output vertex
        vertices[y * width + x].position.x = u;
        vertices[y * width + x].position.y = w;
        vertices[y * width + x].position.z = v;
        // vertices[y*width+x].position[3] = 1.0f;
        vertices[y * width + x].color.x = 1.0f;
        vertices[y * width + x].color.y = 0.0f;
        vertices[y * width + x].color.z = 0.0f;
        vertices[y * width + x].color.w = 0.0f;
    }
}

// The host CPU Sinewave thread spawner
void RunSineWaveKernel(size_t       mesh_width,
                       size_t       mesh_height,
                       Vertex      *cudaDevVertptr,
                       cudaStream_t streamToRun,
                       float        AnimTime)
{
    dim3    block(16, 16, 1);
    dim3    grid(mesh_width / 16, mesh_height / 16, 1);
    Vertex *vertices = (Vertex *)cudaDevVertptr;
    sinewave_gen_kernel<<<grid, block, 0, streamToRun>>>(vertices, mesh_width, mesh_height, AnimTime);

    getLastCudaError("sinewave_gen_kernel execution failed.\n");
}
