k3/src/k3particles.c
2025-09-13 12:00:44 +03:00

186 lines
6.1 KiB
C

#include"k3particles.h"
#include"k3_internal.h"
struct xorshift128_state {
uint32_t x[4];
};
uint32_t xorshift128(struct xorshift128_state *state) {
uint32_t t = state->x[3];
uint32_t s = state->x[0];
state->x[3] = state->x[2];
state->x[2] = state->x[1];
state->x[1] = s;
t ^= t << 11;
t ^= t >> 8;
return state->x[0] = t ^ s ^ (s >> 19);
}
struct xorshift128_state xs = {{1, 2, 3, 4}};
static uint32_t randint(uint32_t min, uint32_t max) {
uint32_t x;
do {
x = xorshift128(&xs);
} while(0x100000000UL - 0x100000000UL % ((uint64_t) max + 1) <= x);
return x / (0x100000000UL / ((uint64_t) max + 1));
}
static float randfloat() {
union { uint32_t u32; float f; } u = { .u32 = xorshift128(&xs) >> 9 | 0x3f800000 };
return u.f - 1.0;
}
void k3CPUQuadParticlesInit(struct k3CPUQuadParticles *this, struct k3Mat *mat) {
uint16_t *inds = calloc(sizeof(*inds), this->capacity * 6);
for(size_t i = 0; i < this->capacity; i++) {
inds[i * 6 + 0] = i * 4 + 0;
inds[i * 6 + 1] = i * 4 + 1;
inds[i * 6 + 2] = i * 4 + 2;
inds[i * 6 + 3] = i * 4 + 0;
inds[i * 6 + 4] = i * 4 + 2;
inds[i * 6 + 5] = i * 4 + 3;
}
this->mdl = k3MdlCreate(this->capacity * 4, this->capacity * 6, 0, k3_ATTRIB_EMPTY, k3_ATTRIB_EMPTY, k3_ATTRIB_EMPTY, k3_ATTRIB_EMPTY, NULL, NULL, inds, NULL, NULL);
k3MdlAddMesh(this->mdl, mat, 0, this->capacity * 6);
k3MdlSetDebugName(this->mdl, "k3CPUQuadParticles");
free(inds);
this->positions = calloc(sizeof(*this->positions), this->capacity);
this->velocities = calloc(sizeof(*this->velocities), this->capacity);
this->sizes = calloc(sizeof(*this->sizes), this->capacity);
this->lifetimes = calloc(sizeof(*this->lifetimes), this->capacity);
}
static void random_cone_vector(float coneAngle, vec3 output) {
float minZ = cosf(coneAngle);
float z = randfloat() * (1 - minZ) + minZ;
float phi = randfloat() * 6.2831853;
output[0] = sqrtf(1 - z * z) * cosf(phi);
output[1] = z;
output[2] = sqrtf(1 - z * z) * sinf(phi);
}
static void regenerate_model(struct k3CPUQuadParticles *this, vec3 cameraRight, vec3 cameraUp, vec3 cameraFront) {
vec3 *vpos = _mm_malloc(sizeof(*vpos) * 4 * this->capacity, 16);
uint8_t *vcols = _mm_malloc(4 * 4 * this->capacity, 16);
vec2 *vuvs = _mm_malloc(sizeof(*vuvs) * 4 * this->capacity, 16);
uint8_t *vnrms = _mm_malloc(3 * 4 * this->capacity, 16);
vec3 halfRight, halfUp;
glm_vec3_scale(cameraRight, 0.5, halfRight);
glm_vec3_scale(cameraUp, 0.5, halfUp);
#pragma omp parallel for
for(size_t i = 0; i < this->count; i++) {
glm_vec3_copy(this->positions[i], vpos[i * 4 + 0]);
glm_vec3_copy(this->positions[i], vpos[i * 4 + 1]);
glm_vec3_copy(this->positions[i], vpos[i * 4 + 2]);
glm_vec3_copy(this->positions[i], vpos[i * 4 + 3]);
glm_vec3_muladds(halfRight, -this->sizes[i], vpos[i * 4 + 0]);
glm_vec3_muladds(halfUp, -this->sizes[i], vpos[i * 4 + 0]);
glm_vec3_muladds(halfRight, this->sizes[i], vpos[i * 4 + 1]);
glm_vec3_muladds(halfUp, -this->sizes[i], vpos[i * 4 + 1]);
glm_vec3_muladds(halfRight, this->sizes[i], vpos[i * 4 + 2]);
glm_vec3_muladds(halfUp, this->sizes[i], vpos[i * 4 + 2]);
glm_vec3_muladds(halfRight, -this->sizes[i], vpos[i * 4 + 3]);
glm_vec3_muladds(halfUp, this->sizes[i], vpos[i * 4 + 3]);
vec4 color;
glm_vec4_lerp(this->colorEnd, this->colorStart, this->lifetimes[i] / this->particleLifetime, color);
for(size_t c = 0; c < 16; c += 4) {
vcols[i * 16 + c + 0] = color[0] * 255;
vcols[i * 16 + c + 1] = color[1] * 255;
vcols[i * 16 + c + 2] = color[2] * 255;
vcols[i * 16 + c + 3] = color[3] * 255;
}
glm_vec2_copy((vec2) {0, 0}, vuvs[i * 4 + 0]);
glm_vec2_copy((vec2) {1, 0}, vuvs[i * 4 + 1]);
glm_vec2_copy((vec2) {1, 1}, vuvs[i * 4 + 2]);
glm_vec2_copy((vec2) {0, 1}, vuvs[i * 4 + 3]);
for(size_t c = 0; c < 12; c += 3) {
vnrms[i * 12 + c + 0] = (uint8_t) (cameraFront[0] * 127);
vnrms[i * 12 + c + 1] = (uint8_t) (cameraFront[1] * 127);
vnrms[i * 12 + c + 2] = (uint8_t) (cameraFront[2] * 127);
}
}
// This update the AABB
k3MdlUpdatePos(this->mdl, vpos);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, this->mdl->vstore->gl);
//glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, this->mdl->offV, sizeof(*vpos) * this->capacity * 4, vpos);
glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, this->mdl->offC, sizeof(*vcols) * this->capacity * 4 * 4, vcols);
glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, this->mdl->offU, sizeof(*vuvs) * this->capacity * 4, vuvs);
glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, this->mdl->offN, sizeof(*vnrms) * this->capacity * 4 * 3, vnrms);
this->mdl->meshes[0].idxNumber = this->count * 6;
_mm_free(vpos);
_mm_free(vcols);
_mm_free(vuvs);
_mm_free(vnrms);
}
static void copy_particle(struct k3CPUQuadParticles *this, size_t from, size_t to) {
glm_vec3_copy(this->positions[from], this->positions[to]);
glm_vec3_copy(this->velocities[from], this->velocities[to]);
this->sizes[to] = this->sizes[from];
this->lifetimes[to] = this->lifetimes[from];
}
void k3CPUQuadParticlesUpdate(struct k3CPUQuadParticles *this, float dt, vec3 cameraRight, vec3 cameraUp, vec3 cameraFront) {
size_t numGenerated = dt * this->emissionRate;
if((this->emissionLifetime -= dt) <= 0) {
this->emissionEnabled = false;
}
if(!this->emissionEnabled) numGenerated = 0;
if(this->count + numGenerated > this->capacity) {
numGenerated = this->capacity - this->count;
}
for(size_t i = this->count, j = 0; j < numGenerated; i++, j++, this->count++) {
glm_vec3_copy(this->origin, this->positions[i]);
random_cone_vector(this->emissionConeAngle, this->velocities[i]);
glm_vec3_scale(this->velocities[i], 2, this->velocities[i]);
this->sizes[i] = 1;
this->lifetimes[i] = this->particleLifetime;
}
vec3 accdt;
glm_vec3_scale(this->gravity, dt, accdt);
for(size_t i = 0; i < this->count;) {
glm_vec3_add(this->velocities[i], accdt, this->velocities[i]);
vec3 veldt;
glm_vec3_scale(this->velocities[i], dt, veldt);
glm_vec3_add(this->positions[i], veldt, this->positions[i]);
this->lifetimes[i] -= dt;
if(this->lifetimes[i] <= 0) {
copy_particle(this, --this->count, i);
} else {
i++;
}
}
regenerate_model(this, cameraRight, cameraUp, cameraFront);
}