3 #include "simulation.h"
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 - (3 * density * 0.7 * (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 * 3.f;
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, 10, 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 float width = 512, height = 512;
138 float aspect = width / height;
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];
164 const int numPbos = 64;
165 GLuint pboBufs[numPbos];
166 GLbyte sink[1000 * 1000 * 4];
170 glDisable(GL_DEPTH_TEST);
171 // shaderOutput * 0 + buffer * shader alpha
172 glBlendFunc(GL_ZERO, GL_SRC_ALPHA);
175 // sort by ascending distance from the sun
176 sort(metaballs.begin(), metaballs.end(), [](Metaball &a, Metaball &b) {
177 return distance(sunPos, a.pos) < distance(sunPos, b.pos);
180 glActiveTexture(GL_TEXTURE0);
181 glUniform1i(glGetUniformLocation(bbProg, "tex"), 0);
183 GLuint modelLoc = glGetUniformLocation(bbProg, "model");
184 glUniform1i(glGetUniformLocation(bbProg, "debug"), 0);
186 /* glViewport(0, 0, shadeWidth, shadeHeight); */
192 auto begin_time = std::chrono::system_clock::now();
194 for (auto &k : metaballs) {
195 fprintf(stderr, "\rShading metaball %lu/%lu...", i++, metaballs.size());
196 // place the billboard at the center of k
197 mat4 model = translate(mat4(1), k.pos);
199 // rotate the billboard so that its normal is oriented to the sun
200 model = faceView(model);
202 model = scale(model, vec3(metaballScale));
204 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
206 // Set the billboard color as RGBA = (1.0, 1.0, 1.0, 1.0).
207 vec4 color = {1, 1, 1, 1};
208 glUniform4fv(glGetUniformLocation(bbProg, "color"), 1,
209 glm::value_ptr(color));
211 // Map the billboard texture with GL_MODULATE.
212 // i.e. multiply rather than add
213 // but glTexEnv is for the old fixed function pipeline --
214 // need to just tell our fragment shader then to modulate
216 glBindTexture(GL_TEXTURE_2D, bbTexIds[dIdx]);
217 glUniform1i(glGetUniformLocation(bbProg, "modulate"), 1);
219 // Render the billboard.
220 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
222 // Read the pixel value corresponding to the center of metaball k.
223 // 1. First get position in opengl screen space: from [-1,1]
224 // 2. Normalize to [0,1]
225 // 3. Multiply by (width * height)
227 ((vec2(proj * view * model * vec4(0, 0, 0, 1)) + vec2(1)) / vec2(2)) *
232 // TODO: This is a huge bottleneck
233 glReadPixels(screenPos.x, screenPos.y, 1, 1, GL_RGBA, GL_FLOAT, &pixel);
236 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[pboIdx]);
237 glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE,
240 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[(pboIdx + 1) % numPbos]);
241 GLuint offset = screenPos.x * 4 + screenPos.y * (int)width * 4;
242 ivec4 *src = (ivec4 *)glMapBufferRange(GL_PIXEL_PACK_BUFFER, offset, 4, GL_MAP_READ_BIT);
245 ivec4 t = src[(int)screenPos.x + (int)screenPos.y * (int)width];
246 pixel = vec4(t) / vec4(255.f);
248 glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
250 pboIdx = (pboIdx + 1) % numPbos;
252 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
255 // Multiply the pixel value by the sunlight color.
256 pixel *= envColors[envColorIdx][0];
258 // Store the color into an array C[k] as the color of the billboard.
261 fprintf(stderr, "\n");
263 auto elapsed = std::chrono::system_clock::now() - begin_time;
264 double elapsed_seconds = std::chrono::duration_cast<std::chrono::duration<double> >(elapsed).count();
265 fprintf(stderr, "time with pbo: %f\n", elapsed_seconds);
269 /* glViewport(0, 0, width, height); */
272 void renderObject() {
275 glUseProgram(sunProg);
276 mat4 model = translate(mat4(1), sunPos);
277 /* model = lookAt(sunPos, sunPos + sunDir, {0, 1, 0}) * model; */
278 model = translate(scale(translate(model, -sunPos), vec3(0.3)), sunPos);
279 glUniformMatrix4fv(glGetUniformLocation(sunProg, "model"), 1, GL_FALSE,
280 glm::value_ptr(model));
281 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
284 void renderClouds() {
285 glUseProgram(bbProg);
287 // Sort metaballs in descending order from the viewpoint
288 sort(metaballs.begin(), metaballs.end(), [](Metaball &a, Metaball &b) {
289 return distance(camPos, a.pos) > distance(camPos, b.pos);
292 glUniform1i(glGetUniformLocation(bbProg, "debug"), curMode != render);
294 glDisable(GL_DEPTH_TEST);
296 // shaderOutput * 1 + buffer * shader alpha
297 glBlendFunc(GL_ONE, GL_SRC_ALPHA);
299 /* glBlendColor(1.f,1.f,1.f,1.f); */
300 /* glBlendFuncSeparate(GL_ONE, GL_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_SRC_ALPHA);
303 glActiveTexture(GL_TEXTURE0);
304 glUniform1i(glGetUniformLocation(bbProg, "tex"), 0);
306 for (int i = 0; i < metaballs.size(); i++) {
307 Metaball k = metaballs[i];
309 GLuint modelLoc = glGetUniformLocation(bbProg, "model");
311 // Place the billboard at the center of the corresponding metaball n.
312 mat4 model = translate(mat4(1), k.pos);
313 // Rotate the billboard so that its normal is oriented to the viewpoint.
314 model = faceView(model);
316 model = scale(model, vec3(metaballScale));
318 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
320 // Set the billboard color as C[n].
322 glUniform4fv(glGetUniformLocation(bbProg, "color"), 1,
323 glm::value_ptr(k.col));
325 // Map the billboard texture.
326 int dIdx = k.d * (NQ - 1);
327 glBindTexture(GL_TEXTURE_2D, bbTexIds[dIdx]);
329 // Don't modulate it -- blend it
330 glUniform1i(glGetUniformLocation(bbProg, "modulate"), 0);
332 glUniform1f(glGetUniformLocation(bbProg, "debugColor"),
333 curMode == debugColor);
334 if (curMode != render) {
336 if (curMode == debugContDist)
338 else if (curMode == debugProbAct)
339 debugVal = cs.p_act[k.coords.x][k.coords.y][k.coords.z] / P_ACT;
340 else if (curMode == debugProbExt)
341 debugVal = cs.p_ext[k.coords.x][k.coords.y][k.coords.z] / P_EXT;
342 glUniform1f(glGetUniformLocation(bbProg, "debugVal"), debugVal);
343 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
344 model = scale(model, vec3(0.2));
345 glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
348 // Render the billboard with the blending function.
349 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
353 bool needsReshading = true;
355 if (needsReshading) {
356 // TODO: find a way to make sure there's no clipping
357 view = glm::lookAt(sunPos + sunDir * vec3(100.f), sunPos, {0, 0, 1});
358 // TODO: calculate bounds so everything is covered
359 proj = glm::ortho(2.5f, -2.5f, -2.5f, 2.5f, znear, 10000.f);
360 glUseProgram(bbProg);
361 setProjectionAndViewUniforms(bbProg);
363 glClearColor(1, 1, 1, 1);
364 glClear(GL_COLOR_BUFFER_BIT);
366 needsReshading = false;
369 view = glm::lookAt(camPos, viewPos, {0, 1, 0});
370 proj = glm::perspective(45.f, aspect, znear, zfar);
371 glUseProgram(sunProg);
372 setProjectionAndViewUniforms(sunProg);
373 glUseProgram(bbProg);
374 setProjectionAndViewUniforms(bbProg);
376 vec4 skyColor = envColors[envColorIdx][1];
377 glClearColor(skyColor.r, skyColor.g, skyColor.b,
378 skyColor.a); // background color
379 glClear(GL_COLOR_BUFFER_BIT);
380 renderObject(); // render things that aren't clouds
386 bool needsRedisplay = false;
388 /* calculateMetaballs(); */
389 if (needsRedisplay) {
392 needsRedisplay = false;
393 glutTimerFunc(16, timer, 0);
396 void keyboard(unsigned char key, int x, int y) {
398 calculateMetaballs();
399 needsRedisplay = true;
400 needsReshading = curMode == render;
403 needsReshading = curMode != render;
405 needsRedisplay = true;
408 curMode = debugContDist;
409 needsRedisplay = true;
412 curMode = debugColor;
413 needsRedisplay = true;
416 curMode = debugProbAct;
417 needsRedisplay = true;
420 curMode = debugProbExt;
421 needsRedisplay = true;
424 envColorIdx = (envColorIdx + 1) % envColors.size();
425 needsRedisplay = true;
426 needsReshading = true;
430 int prevMouseX, prevMouseY;
431 bool firstMouse = true;
432 void motion(int x, int y) {
438 float dx = x - prevMouseX, dy = y - prevMouseY;
441 const vec3 origin(0, 0, 0);
442 const float sensitivity = 0.003f;
443 auto camMat = translate(mat4(1), origin + camPos);
444 auto rotation = rotate(rotate(mat4(1), -dx * sensitivity, {0, 1, 0}),
445 -dy * sensitivity, {1, 0, 0});
446 auto rotAroundOrig = camMat * rotation * translate(mat4(1), origin - camPos);
447 camPos = rotAroundOrig * glm::vec4(camPos, 0);
448 needsRedisplay = true;
451 void passiveMotion(int x, int y) {
456 int main(int argc, char **argv) {
457 glutInit(&argc, argv);
458 glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA |
459 GLUT_3_2_CORE_PROFILE);
460 glutInitWindowSize(width, height);
461 glutCreateWindow("Clouds");
462 glutDisplayFunc(display);
466 Program prog("billboardvert.glsl", "billboardfrag.glsl");
467 bbProg = prog.progId;
468 Program sProg("sunvert.glsl", "sunfrag.glsl");
469 sunProg = sProg.progId;
471 glGenVertexArrays(1, &bbVao);
472 glUseProgram(sunProg);
473 glBindVertexArray(bbVao);
474 glUseProgram(bbProg);
475 glBindVertexArray(bbVao);
477 glGenBuffers(2, vbos);
479 vector<vec3> poss = {{-1, -1, 0}, {-1, 1, 0}, {1, 1, 0}, {1, -1, 0}};
480 vector<GLuint> indices = {2, 1, 0, 3, 2, 0};
482 GLuint posLoc = glGetAttribLocation(bbProg, "vPosition");
483 glBindBuffer(GL_ARRAY_BUFFER, vbos[0]);
484 glBufferData(GL_ARRAY_BUFFER, poss.size() * sizeof(glm::vec3), &poss[0],
486 glEnableVertexAttribArray(posLoc);
487 glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
489 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbos[1]);
490 glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLuint),
491 &indices[0], GL_STATIC_DRAW);
495 precalculateBillboardTextures();
498 calculateMetaballs();
500 glutKeyboardFunc(keyboard);
501 glutMotionFunc(motion);
502 glutPassiveMotionFunc(passiveMotion);
503 glutTimerFunc(16, timer, 0);
506 // setup PBOs for buffering readPixels
507 glGenBuffers(numPbos, pboBufs);
508 for (int i = 0; i < numPbos; i++) {
509 glBindBuffer(GL_PIXEL_PACK_BUFFER, pboBufs[i]);
510 glBufferData(GL_PIXEL_PACK_BUFFER, width * height * 4, NULL,
513 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);