blend perlin noise

README.md

@@ -33,27 +33,6 @@ It will have features as following:
 
 -   and so on.
 
-# Tricks to reduce cost
-
-There are `three` things to calculate each frame.
-
-1.  Height (`Eq. 19`). (`1` dimension, `1` IFFT)
-
-2.  Normal (`Eq. 20`). (`2` dimension, `2` IFFT)
-
-3.  Horizontal displacement (`Eq. 29`). (`2` dimension, `2` IFFT)
-
-Normally, `5` IFFT are needed `per frame`,
-as each equation has different frequency term.
-However, given the number of sampling points `N` along each axis,
-their complex exponent terms are always the same, i.e.
-
-![Wk](./image/Wk.png)
-
-So it is better to calculate these exponents once before simulation,
-and write them into a lookup table.
-Then, access that table when performing IFFT in each frame.
-
 # A specially designed IFFT
 
 Using standard FFT codes (e.g. [Cooley–Tukey FFT](https://rosettacode.org/wiki/Fast_Fourier_transform#C.2B.2B)) results in incorrect geometry changes.
@@ -120,6 +99,14 @@ A GPU-based parallelization is needed.
 
 ## Periodic artifact
 
+According to [5], there are two ways to reduce the periodic (or tiling) artifact.
+
+I have tried the one that blends the result with some noise [6, 7] and it actually can reduce the periodic artifact a little bit.
+
+## Shading
+
+I would like to try the BRDF shading method proposed by [8] in the future.
+
 # Reference
 
 [1] Tessendorf, Jerry. "Simulating ocean water." Simulating nature: realistic and interactive techniques. SIGGRAPH 1.2 (2001): 5.
@@ -129,3 +116,11 @@ A GPU-based parallelization is needed.
 [3] An introduction to Realistic Ocean Rendering through FFT - Fabio Suriano - Codemotion Rome 2017 ([slide](https://www.slideshare.net/Codemotion/an-introduction-to-realistic-ocean-rendering-through-fft-fabio-suriano-codemotion-rome-2017), [video](https://www.youtube.com/watch?v=ClW3fo94KR4))
 
 [4] Claes, J. "Real-time water rendering-introducing the projected grid concept." Master's thesis (2004).
+
+[5] Gamper, Thomas. "Ocean Surface Generation and Rendering." (2018).
+
+[6] Rydahl, Björn. "A VFX ocean toolkit with real time preview." (2009).
+
+[7] Ocean Surface Simulation ([slide](http://www-evasion.imag.fr/~Fabrice.Neyret/images/fluids-nuages/waves/Jonathan/articlesCG/NV_OceanCS_Slides.pdf))
+
+[8] Bruneton, Eric, Fabrice Neyret, and Nicolas Holzschuch. "Real‐time realistic ocean lighting using seamless transitions from geometry to BRDF." Computer Graphics Forum. Vol. 29. No. 2. Oxford, UK: Blackwell Publishing Ltd, 2010.

header/ocean.h

@@ -47,10 +47,12 @@ class cOcean {
   GLuint shader;
   GLuint tboHeight, tboNormal, tboFresnel;
   GLuint tboDispX, tboDispZ;
+  GLuint tboPerlin;
   GLint uniM, uniV, uniP;
   GLint uniLightColor, uniLightPos;
   GLint uniTexReflect, uniTexRefract, uniTexHeight, uniTexNormal, uniTexSkybox;
   GLint uniTexDispX, uniTexDispZ;
+  GLint uniTexPerlin;
   GLint uniTexFresnel;
   GLint uniEyePoint;
   GLint uniDudvMove;

shader/fsOcean.glsl

@@ -55,9 +55,7 @@ void main() {
 
   // farther the ocean, flatter the appearance
   float dist2 = max(length(eyePoint - worldPos), 0.01);
-  dist2 = exp(-0.2 * dist2);
+  dist2 = exp(-0.1 * dist2);
 
   fragColor = mix(fragColor, refr, 1 - dist2);
-
-  // fragColor = vec4(dist2);
 }

shader/tcsQuad.glsl

@@ -18,7 +18,9 @@ float getTessLevel(float dist0, float dist1) {
   if (avgDist <= 8.0) {
     return 128.0;
   } else if (avgDist <= 16.0) {
-    return 32.0;
+    return 64.0;
+  } else if (avgDist < 32.0) {
+    return 16.0;
   } else {
     return 2.0;
   }

shader/tesQuad.glsl

@@ -3,7 +3,9 @@
 layout(quads, equal_spacing, ccw) in;
 
 uniform mat4 M, V, P;
-uniform sampler2D texHeight, texNormal, texDispX, texDispZ;
+uniform sampler2D texHeight, texDispX, texDispZ;
+uniform sampler2D texPerlin;
+uniform vec2 dudvMove;
 uniform vec3 eyePoint;
 
 in vec3 esInWorldPos[];
@@ -45,28 +47,42 @@ void main() {
   float alpha = max(length(eyePoint - worldPos), 0.01);
   alpha = exp(-0.05 * alpha);
 
-  // height map
-  vec3 tempY = texture(texHeight, mod(uv, 1.0)).rgb;
+  // float scale = 0.3 * alpha;
+  // float offset = texture(texHeight, mod(uv + dudvMove, 1.0)).r * 2.0 - 1.0;
+  // worldPos.y = offset * scale;
+
+  // perlin noise
+  float perlinZ = texture(texPerlin, uv.xy / 16.0).r * 2.0 - 1.0;
+  float perlinX = texture(texPerlin, uv.yx / 16.0).r * 2.0 - 1.0;
+
+  vec3 tempY = texture(texHeight, uv).rgb;
   float offsetY = tempY.x;
   // using tempY.y < 0.01 or == 0 causes strong artifact
   float signY = (tempY.y < 0.5) ? -1.0 : 1.0;
-  float scaleY = 0.3 * (tempY.z * 255.0) * alpha;
-  worldPos.y += offsetY * signY * scaleY;
+  float scaleY = 0.5 * (tempY.z * 255.0) * alpha;
+  float finalY = offsetY * signY * scaleY;
+  float noiseY = (perlinX + perlinZ) * 0.5 * 10.0 * alpha;
+  worldPos.y += mix(finalY, noiseY, 0.35);
 
   // x-displacement
   vec3 tempX = texture(texDispX, mod(uv, 1.0)).rgb;
   float offsetX = tempX.x;
   float signX = (tempX.y < 0.5) ? -1.0 : 1.0;
-  float scaleX = 0.3 * (tempX.z * 255.0) * alpha;
-  worldPos.x += offsetX * signX * scaleX;
+  float scaleX = 0.5 * (tempX.z * 255.0) * alpha;
+  float finalX = offsetX * signX * scaleX;
+  float noiseX = perlinX * 5.0 * alpha;
+  worldPos.x += mix(finalX, noiseX, 0.35);
 
   // z-displacement
   vec3 tempZ = texture(texDispZ, mod(uv, 1.0)).rgb;
   float offsetZ = tempZ.x;
   float signZ = (tempZ.y < 0.5) ? -1.0 : 1.0;
-  float scaleZ = 0.3 * (tempZ.z * 255.0) * alpha;
-  worldPos.z += offsetZ * signZ * scaleZ;
+  float scaleZ = 0.5 * (tempZ.z * 255.0) * alpha;
+  float finalZ = offsetZ * signZ * scaleZ;
+  float noiseZ = perlinZ * 5.0 * alpha;
+  worldPos.z += mix(finalZ, noiseZ, 0.35);
 
   gl_Position = P * V * vec4(worldPos, 1.0);
+
   clipSpace = gl_Position;
 }

src/main.cpp

@@ -22,7 +22,7 @@ Skybox *skybox;
 cOcean *ocean;
 ScreenQuad *screenQuad;
 
-bool saveTrigger = false;
+bool saveTrigger = true;
 int frameNumber = 0;
 bool resume = true;
 bool saveMap = true;
@@ -40,6 +40,8 @@ vec3 eyeDirection =
          sin(verticalAngle) * sin(horizontalAngle));
 vec3 up = vec3(0.f, 1.f, 0.f);
 
+vec3 direction;
+
 mat4 model, view, projection;
 bool isRising = false, isDiving = false;
 
@@ -125,13 +127,14 @@ int main(int argc, char *argv[]) {
 
     // ocean
     glDisable(GL_CULL_FACE);
-    vec3 tempLightPos = eyePoint + vec3(4.0, 2.0, 0.0);
+    vec3 tempLightPos =
+        eyePoint + vec3(direction.x * 4.0, 2.0, direction.z * 4.0);
 
-    double start = omp_get_wtime();
+    // double start = omp_get_wtime();
     ocean->render(t, model, view, projection, eyePoint, lightColor,
                   tempLightPos, resume, frameNumber);
-    double end = omp_get_wtime();
-    std::cout << end - start << '\n';
+    // double end = omp_get_wtime();
+    // std::cout << end - start << '\n';
 
     // for pre-computed FFT water
     // if (t < 200.0) {
@@ -274,7 +277,7 @@ void computeMatricesFromInputs() {
   verticalAngleReflect = 3.1415f - verticalAngle;
 
   // Direction : Spherical coordinates to Cartesian coordinates conversion
-  vec3 direction =
+  direction =
       vec3(sin(verticalAngle) * cos(horizontalAngle), cos(verticalAngle),
            sin(verticalAngle) * sin(horizontalAngle));
 

src/ocean.cpp

@@ -155,6 +155,7 @@ void cOcean::initTexture() {
   setTexture(tboDispX, 13, "./image/xDisp.png", FIF_PNG);
   setTexture(tboDispZ, 14, "./image/zDisp.png", FIF_PNG);
   setTexture(tboFresnel, 15, "./image/fresnel.png", FIF_PNG);
+  setTexture(tboPerlin, 16, "./image/perlin.png", FIF_PNG);
 }
 
 void cOcean::initUniform() {
@@ -174,12 +175,14 @@ void cOcean::initUniform() {
   uniTexDispZ = myGetUniformLocation(shader, "texDispZ");
   uniTexSkybox = myGetUniformLocation(shader, "texSkybox");
   uniTexFresnel = myGetUniformLocation(shader, "texFresnel");
+  uniTexPerlin = myGetUniformLocation(shader, "texPerlin");
 
   glUniform1i(uniTexHeight, 11);
   glUniform1i(uniTexNormal, 12);
   glUniform1i(uniTexDispX, 13);
   glUniform1i(uniTexDispZ, 14);
   glUniform1i(uniTexFresnel, 15);
+  glUniform1i(uniTexPerlin, 16);
   glUniform1i(uniTexReflect, 3);
   glUniform1i(uniTexRefract, 2);