4 #include "simulation.hpp"
11 #include <glm/ext.hpp>
12 #include <glm/glm.hpp>
16 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
18 enum Mode { render, debugContDist, debugColor, debugProbExt, debugProbAct };
19 Mode curMode = render;
24 const float metaballR = 1.f / 16.f;
25 inline float metaballField(float r) {
28 const float a = r / (1);
29 return (-4.f / 9.f * powf(a, 6)) + (17.f / 9.f * powf(a, 4)) -
30 (22.f / 9.f * powf(a, 2)) + 1;
33 const float normalizationFactor = (748.f / 405.f) * M_PI;
36 if (GLenum e = glGetError()) {
37 fprintf(stderr, "%s\n", gluErrorString(e));
42 GLuint bbProg, sunProg;
45 // Here we need to generate n_q textures for different densities of metaballs
46 // These textures then go on the billboards
47 // The texture stores attenuation ratio?
52 // Stores attenuation ratio inside r channel
53 // Should be highest value at center
54 void precalculateBillboardTextures() {
55 fprintf(stderr, "Calculating billboard textures...\n");
56 glGenTextures(NQ, bbTexIds);
58 for (int d = 0; d < NQ; d++) {
60 for (int j = 0; j < 32; j++) {
61 for (int i = 0; i < 32; i++) {
62 // TODO: properly calculate this instead of whatever this is
63 float r = distance(vec2(i, j), vec2(16, 16)) / 16;
64 float density = (float)d / NQ;
66 1 - fmin(1, (3 * density * (metaballField(r) / normalizationFactor)));
72 snprintf(path, 32, "bbtex/%i.tga", d);
73 saveGrayscale(data, 32, 32, path);
75 glBindTexture(GL_TEXTURE_2D, bbTexIds[d]);
77 glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, 32, 32, 0, GL_RED, GL_FLOAT, data);
78 glGenerateMipmap(GL_TEXTURE_2D); // required, otherwise texture is blank
80 fprintf(stderr, "\r%i out of %i densities calculated%s", d + 1, NQ,
81 d == NQ - 1 ? "\n" : "");
93 array<Metaball, CLOUD_DIM_X * CLOUD_DIM_Y * CLOUD_DIM_Z> metaballs;
95 const float cloudScale = metaballR;
96 const float metaballScale = metaballR * 1.5f;
99 void calculateMetaballs() {
101 /* for (int i = 0; i < 256; i++) { */
102 /* float x = ((float)rand()/(float)(RAND_MAX) - 0.5) * 2; */
103 /* float y = ((float)rand()/(float)(RAND_MAX) - 0.5) * 2; */
104 /* float z = ((float)rand()/(float)(RAND_MAX) - 0.5) * 2; */
105 /* float r = (float)rand()/(float)(RAND_MAX) * 1; */
106 /* Metaball m = {{x,y,z}, r}; */
107 /* metaballs.push_back(m); */
109 for (int i = 0; i < CLOUD_DIM_X; i++) {
110 for (int j = 0; j < CLOUD_DIM_Y; j++) {
111 for (int k = 0; k < CLOUD_DIM_Z; k++) {
112 Metaball m = {vec3(i, j, k) * vec3(cloudScale), {i, j, k}};
113 /* m.pos = (m.pos * vec3(2)) - (cloudScale / 2); */
114 m.pos -= vec3(CLOUD_DIM_X, CLOUD_DIM_Y, CLOUD_DIM_Z) * cloudScale / 2.f;
117 metaballs[i * CLOUD_DIM_Y * CLOUD_DIM_Z + j * CLOUD_DIM_Z + k] = m;
121 /* for (int z = 0; z < CLOUD_DIM_Z; z++) */
122 /* metaballs[32 * CLOUD_DIM_Y * CLOUD_DIM_Z + 32 * CLOUD_DIM_Z + z].d = 1;
126 vec3 sunPos = {0, 5, 0}, sunDir = {0, -1, 0};
127 size_t envColorIdx = 0;
128 // First color is sun color, second is sky color
129 std::array<std::array<vec4, 2>, 3> envColors{
130 {{vec4(1, 1, 1, 1), vec4(0.9, 1, 1, 1)},
131 {vec4(0.939, 0.632, 0.815, 1), vec4(0.9, 1, 1, 1)},
132 {vec4(0.999, 0.999, 0.519, 1), vec4(0.981, 0.667, 0.118, 1)}}};
133 vec3 camPos = {0, 0, -3}, viewPos = {0, 0, 0};
134 mat4 proj; // projection matrix
135 mat4 view; // view matrix
136 float znear = 0.001, zfar = 1000;
137 // for performance with glReadPixels these should be powers of 2!
138 float width = 1200, height = 800;
140 void setProjectionAndViewUniforms(GLuint progId) {
141 GLuint projLoc = glGetUniformLocation(progId, "projection");
142 glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(proj));
144 GLuint viewLoc = glGetUniformLocation(progId, "view");
145 glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
148 /** Orientates the transformation matrix to face the camera in the view matrix
150 mat4 faceView(mat4 m) {
151 m[0][0] = view[0][0];
152 m[0][1] = view[1][0];
153 m[0][2] = view[2][0];
154 m[1][0] = view[0][1];
155 m[1][1] = view[1][1];
156 m[1][2] = view[2][1];
157 m[2][0] = view[0][2];
158 m[2][1] = view[1][2];
159 m[2][2] = view[2][2];
165 /* const int shadeWidth = 256, shadeHeight = 256; */
166 const int shadeWidth = 256, shadeHeight = 256;
169 const int numPbos = 64;
170 GLuint pboBufs[numPbos];
171 GLbyte sink[shadeWidth * shadeHeight * 4];
173 void inline mapPixelRead(int pboBuf, int metaball) {
174 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[pboBuf]);
175 GLubyte *src = (GLubyte *)glMapBufferRange(GL_PIXEL_PACK_BUFFER, 0, 4 * sizeof(GLubyte),
177 vec4 pixel = vec4(src[0], src[1], src[2], src[3]) / vec4(255.f);
178 glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
180 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
182 // Multiply the pixel value by the sunlight color.
183 pixel *= envColors[envColorIdx][0];
185 // Store the color for the previous set of pixels
186 metaballs[metaball].col = pixel;
193 glDisable(GL_DEPTH_TEST);
194 // shaderOutput * 0 + buffer * shader alpha
195 glBlendFunc(GL_ZERO, GL_SRC_ALPHA);
198 // sort by ascending distance from the sun
199 sort(metaballs.begin(), metaballs.end(), [](Metaball &a, Metaball &b) {
200 return distance(sunPos, a.pos) < distance(sunPos, b.pos);
203 glActiveTexture(GL_TEXTURE0);
204 glUniform1i(glGetUniformLocation(bbProg, "tex"), 0);
206 GLuint modelLoc = glGetUniformLocation(bbProg, "model");
207 glUniform1i(glGetUniformLocation(bbProg, "debug"), 0);
209 glViewport(0, 0, shadeWidth, shadeHeight);
215 auto begin_time = std::chrono::system_clock::now();
217 for (auto &k : metaballs) {
218 /* fprintf(stderr, "\rShading metaball %lu/%lu...", i, metaballs.size()); */
219 // place the billboard at the center of k
220 mat4 model = translate(mat4(1), k.pos);
222 // rotate the billboard so that its normal is oriented to the sun
223 model = faceView(model);
225 model = scale(model, vec3(metaballScale));
227 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
229 // Set the billboard color as RGBA = (1.0, 1.0, 1.0, 1.0).
230 vec4 color = {1, 1, 1, 1};
231 glUniform4fv(glGetUniformLocation(bbProg, "color"), 1,
232 glm::value_ptr(color));
234 // Map the billboard texture with GL_MODULATE.
235 // i.e. multiply rather than add
236 // but glTexEnv is for the old fixed function pipeline --
237 // need to just tell our fragment shader then to modulate
239 glBindTexture(GL_TEXTURE_2D, bbTexIds[dIdx]);
240 glUniform1i(glGetUniformLocation(bbProg, "modulate"), 1);
242 // Render the billboard.
243 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
245 // Read the pixel value corresponding to the center of metaball k.
246 // 1. First get position in opengl screen space: from [-1,1]
247 // 2. Normalize to [0,1]
248 // 3. Multiply by (width * height)
250 ((vec2(proj * view * model * vec4(0, 0, 0, 1)) + vec2(1)) / vec2(2)) *
251 vec2(shadeWidth, shadeHeight);
255 // TODO: This is a huge bottleneck
256 glReadPixels(screenPos.x, screenPos.y, 1, 1, GL_RGBA, GL_FLOAT, &pixel);
258 // Multiply the pixel value by the sunlight color.
259 pixel *= envColors[envColorIdx][0];
261 // Store the color into an array C[k] as the color of the billboard.
265 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[pboIdx]);
266 glReadPixels(screenPos.x, screenPos.y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE,
269 /* glReadPixels(0, 0, shadeWidth, shadeHeight, GL_RGBA, GL_UNSIGNED_BYTE, */
272 int nextPbo = (pboIdx + 1) % numPbos;
273 if (i >= numPbos - 1) {
274 // start mapping the read values back
275 mapPixelRead(nextPbo, i - numPbos + 1);
282 /* fprintf(stderr, "\n"); */
285 // sink remaining reads
286 for (int i = 0; i < numPbos; i++) {
287 mapPixelRead(i, metaballs.size() - numPbos + i);
291 auto elapsed = std::chrono::system_clock::now() - begin_time;
292 double elapsed_seconds =
293 std::chrono::duration_cast<std::chrono::duration<double>>(elapsed)
295 fprintf(stderr, "Time taken to shade: %fs\n", elapsed_seconds);
299 glViewport(0, 0, width, height);
302 void renderObject() {
305 glUseProgram(sunProg);
306 mat4 model = translate(mat4(1), sunPos);
307 model = lookAt(sunPos, sunPos + sunDir, {0, 1, 0}) * model;
308 model = translate(scale(translate(model, -sunPos), vec3(0.3)), sunPos);
309 glUniformMatrix4fv(glGetUniformLocation(sunProg, "model"), 1, GL_FALSE,
310 glm::value_ptr(model));
311 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
314 void renderClouds() {
315 glUseProgram(bbProg);
317 // Sort metaballs in descending order from the viewpoint
318 sort(metaballs.begin(), metaballs.end(), [](Metaball &a, Metaball &b) {
319 return distance(camPos, a.pos) > distance(camPos, b.pos);
322 glUniform1i(glGetUniformLocation(bbProg, "debug"), curMode != render);
324 glDisable(GL_DEPTH_TEST);
326 // shaderOutput * 1 + buffer * shader alpha
327 glBlendFunc(GL_ONE, GL_SRC_ALPHA);
329 /* glBlendColor(1.f,1.f,1.f,1.f); */
330 /* glBlendFuncSeparate(GL_ONE, GL_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_SRC_ALPHA);
333 glActiveTexture(GL_TEXTURE0);
334 glUniform1i(glGetUniformLocation(bbProg, "tex"), 0);
336 for (int i = 0; i < metaballs.size(); i++) {
337 Metaball k = metaballs[i];
339 GLuint modelLoc = glGetUniformLocation(bbProg, "model");
341 // Place the billboard at the center of the corresponding metaball n.
342 mat4 model = translate(mat4(1), k.pos);
343 // Rotate the billboard so that its normal is oriented to the viewpoint.
344 model = faceView(model);
346 model = scale(model, vec3(metaballScale));
348 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
350 // Set the billboard color as C[n].
352 glUniform4fv(glGetUniformLocation(bbProg, "color"), 1,
353 glm::value_ptr(k.col));
355 // Map the billboard texture.
356 int dIdx = k.d * (NQ - 1);
357 glBindTexture(GL_TEXTURE_2D, bbTexIds[dIdx]);
359 // Don't modulate it -- blend it
360 glUniform1i(glGetUniformLocation(bbProg, "modulate"), 0);
362 glUniform1f(glGetUniformLocation(bbProg, "debugColor"),
363 curMode == debugColor);
364 if (curMode != render) {
366 if (curMode == debugContDist)
368 else if (curMode == debugProbAct)
369 debugVal = cs.p_act[k.coords.x][k.coords.y][k.coords.z] / P_ACT;
370 else if (curMode == debugProbExt)
371 debugVal = cs.p_ext[k.coords.x][k.coords.y][k.coords.z] / P_EXT;
372 glUniform1f(glGetUniformLocation(bbProg, "debugVal"), debugVal);
373 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
374 model = scale(model, vec3(0.1));
375 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
378 // Render the billboard with the blending function.
379 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
383 bool curBeenShaded = false;
386 if (!curBeenShaded && (curMode == render || curMode == debugColor)) {
387 // TODO: find a way to make sure there's no clipping
388 view = glm::lookAt(sunPos + sunDir * vec3(100.f), sunPos, {0, 0, 1});
389 // TODO: calculate bounds so everything is covered
390 proj = glm::ortho(2.5f, -2.5f, -2.5f, 2.5f, znear, 10000.f);
391 glUseProgram(bbProg);
392 setProjectionAndViewUniforms(bbProg);
394 glClearColor(1, 1, 1, 1);
395 glClear(GL_COLOR_BUFFER_BIT);
397 curBeenShaded = true;
400 view = glm::lookAt(camPos, viewPos, {0, 1, 0});
401 const float aspect = width / height;
402 proj = glm::perspective(45.f, aspect, znear, zfar);
403 glUseProgram(sunProg);
404 setProjectionAndViewUniforms(sunProg);
405 glUseProgram(bbProg);
406 setProjectionAndViewUniforms(bbProg);
408 vec4 skyColor = envColors[envColorIdx][1];
409 glClearColor(skyColor.r, skyColor.g, skyColor.b,
410 skyColor.a); // background color
411 glClear(GL_COLOR_BUFFER_BIT);
412 renderObject(); // render things that aren't clouds
418 bool needsRedisplay = false;
420 if (needsRedisplay) {
423 needsRedisplay = false;
424 glutTimerFunc(16, timer, 0);
427 void keyboard(unsigned char key, int x, int y) {
429 calculateMetaballs();
430 needsRedisplay = true;
431 curBeenShaded = false;
435 needsRedisplay = true;
438 curMode = debugContDist;
439 needsRedisplay = true;
442 curMode = debugColor;
443 needsRedisplay = true;
446 curMode = debugProbAct;
447 needsRedisplay = true;
450 curMode = debugProbExt;
451 needsRedisplay = true;
454 envColorIdx = (envColorIdx + 1) % envColors.size();
455 needsRedisplay = true;
456 curBeenShaded = false;
460 int prevMouseX, prevMouseY;
461 bool firstMouse = true;
462 void motion(int x, int y) {
468 float dx = x - prevMouseX, dy = y - prevMouseY;
471 const vec3 origin(0, 0, 0);
472 const float sensitivity = 0.003f;
473 auto camMat = translate(mat4(1), origin + camPos);
474 auto rotation = rotate(rotate(mat4(1), -dx * sensitivity, {0, 1, 0}),
475 -dy * sensitivity, {1, 0, 0});
476 auto rotAroundOrig = camMat * rotation * translate(mat4(1), origin - camPos);
477 camPos = rotAroundOrig * glm::vec4(camPos, 0);
478 needsRedisplay = true;
481 void passiveMotion(int x, int y) {
486 void reshape(int w, int h) {
491 int main(int argc, char **argv) {
492 glutInit(&argc, argv);
493 glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA |
494 GLUT_3_2_CORE_PROFILE);
495 glutInitWindowSize(width, height);
496 glutCreateWindow("Clouds");
497 glutDisplayFunc(display);
498 glutReshapeFunc(reshape);
499 glutKeyboardFunc(keyboard);
500 glutMotionFunc(motion);
501 glutPassiveMotionFunc(passiveMotion);
502 glutTimerFunc(16, timer, 0);
506 Program prog("billboardvert.glsl", "billboardfrag.glsl");
507 bbProg = prog.progId;
508 Program sProg("sunvert.glsl", "sunfrag.glsl");
509 sunProg = sProg.progId;
511 glGenVertexArrays(1, &bbVao);
512 glUseProgram(sunProg);
513 glBindVertexArray(bbVao);
514 glUseProgram(bbProg);
515 glBindVertexArray(bbVao);
517 glGenBuffers(2, vbos);
519 vector<vec3> poss = {{-1, -1, 0}, {-1, 1, 0}, {1, 1, 0}, {1, -1, 0}};
520 vector<GLuint> indices = {2, 1, 0, 3, 2, 0};
522 GLuint posLoc = glGetAttribLocation(bbProg, "vPosition");
523 glBindBuffer(GL_ARRAY_BUFFER, vbos[0]);
524 glBufferData(GL_ARRAY_BUFFER, poss.size() * sizeof(glm::vec3), &poss[0],
526 glEnableVertexAttribArray(posLoc);
527 glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
529 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbos[1]);
530 glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLuint),
531 &indices[0], GL_STATIC_DRAW);
535 precalculateBillboardTextures();
538 calculateMetaballs();
541 // setup PBOs for buffering readPixels
542 glGenBuffers(numPbos, pboBufs);
543 for (int i = 0; i < numPbos; i++) {
544 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[i]);
545 glBufferData(GL_PIXEL_PACK_BUFFER, shadeWidth * shadeHeight * 4, NULL,
548 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);