Changeset 7768 in orxonox.OLD for branches/atmospheric_engine/src/lib/graphics/effects/cloud_effect.cc

Timestamp:

May 23, 2006, 12:06:44 PM (18 years ago)

Author:

amaechler

Message:

branches/atmospheric_engine: cloud hacking

File:

• branches/atmospheric_engine/src/lib/graphics/effects/cloud_effect.cc (modified) (4 diffs)

branches/atmospheric_engine/src/lib/graphics/effects/cloud_effect.cc

@@ -1 +1 @@
 /*
-   orxonox - the future of 3D-vertical-scrollers
-
-   Copyright (C) 2004 orx
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+        orxonox - the future of 3D-vertical-scrollers
+
+        Copyright (C) 2004 orx
+
+        This program is free software; you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation; either version 2, or (at your option)
+        any later version.
 
 ### File Specific:
-   main-programmer: hdavid, amaechler
+        main-programmer: hdavid, amaechler
 */
 
@@ -19 +19 @@
 
 #include "glincl.h"
+#include "graphics_engine.h"
+
 
 #include "parser/tinyxml/tinyxml.h"
@@ -52 +54 @@
 {
         //Default values
+
+        CloudEffect::setNoise(map32);
+
 }
 
 bool CloudEffect::activate()
 {
-        PRINTF(0)( "Activating CloudEffect ");
+        PRINTF(0)( "Activating CloudEffect\n");
+
+        //Our cloud function  
+        CloudEffect::overlapOctaves(map32, map256);
+        CloudEffect::expFilter(map256);
+
+        for(int i=0; i<256; i++)         //Set cloud color value to temporary array
+                for(int j=0; j<256; j++) 
+                {
+                        float color = map256[i*256+j]; 
+                        texture[i][j][0] = color;
+                        texture[i][j][1] = color;
+                        texture[i][j][2] = color;
+                }
+
+                /* for(int n=0; n<256; n++) {
+                        for(int i=0; i<256; i++)
+                                PRINTF(0)("%f ", map256[n*i]);
+                        PRINTF(0)("\n");
+                } */
+
+        unsigned int ID;                 //Generate an ID for texture binding
+        glGenTextures(1, &ID);           //Texture binding 
+        glBindTexture(GL_TEXTURE_2D, ID);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+        
+        gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB, 256, 256, GL_RGB, GL_UNSIGNED_BYTE, texture);
+
 }
 
@@ -65 +101 @@
 }
 
+void CloudEffect::draw() const
+{
+        glPushAttrib(GL_ENABLE_BIT);
+        glEnable(GL_TEXTURE_2D);
+        glMatrixMode(GL_MODELVIEW);
+        glPushMatrix();
+
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        glEnable(GL_TEXTURE_2D);
+
+        //glLoadIdentity();
+
+        //glMatrixMode(GL_TEXTURE);        //Let's move the clouds from left to right
+        //static float x;    
+        //x+=0.01f;
+        //glTranslatef(x,0,0);
+
+        glBegin(GL_QUADS);
+                // Front Face
+                glTexCoord2f(0.0f, 0.0f); glVertex3f(-100.0f, -100.0f,  100.0f);        // Bottom Left Of The Texture and Quad
+                glTexCoord2f(1.0f, 0.0f); glVertex3f( 100.0f, -100.0f,  100.0f);        // Bottom Right Of The Texture and Quad
+                glTexCoord2f(1.0f, 1.0f); glVertex3f( 100.0f,  100.0f,  100.0f);        // Top Right Of The Texture and Quad
+                glTexCoord2f(0.0f, 1.0f); glVertex3f(-100.0f,  100.0f,  100.0f);        // Top Left Of The Texture and Quad
+        glEnd(); 
+
+        glPopMatrix();
+        glPopAttrib();
+
+}
+
 void CloudEffect::tick (float dt)
 {
-
-}
+}
+
+/* 
+        Random noise generator
+*/
+float CloudEffect::noise(int x, int y, int random)
+{
+                int n = x + y * 57 + random * 131;
+                n = (n<<13) ^ n;
+                return (1.0f - ( (n * (n * n * 15731 + 789221) +
+                                                1376312589)&0x7fffffff)* 0.000000000931322574615478515625f);
+}
+
+/*
+        Set noise for the 32*32 noise map:
+*/
+void CloudEffect::setNoise(float  *map)
+{
+        float temp[34][34];
+
+/* We declare a temporary array to make our function cleaner. Why does the array hold 34*34 elements instead of 32*32? This is because we will need extra elements for side and corner mirroring, as we shall see soon. */
+
+        int random = rand() % 5000;
+
+        for (int y = 1; y < 33; y++)
+                for (int x = 1; x < 33; x++)
+                        temp[x][y] = 128.0f + CloudEffect::noise(x,  y,  random) * 128.0f;
+
+        // Seamless cloud
+        for (int x=1; x<33; x++)
+        {
+                temp[0][x] = temp[32][x];
+                temp[33][x] = temp[1][x];
+                temp[x][0] = temp[x][32];
+                temp[x][33] = temp[x][1];
+        }
+        temp[0][0] = temp[32][32];
+        temp[33][33] = temp[1][1];
+        temp[0][33] = temp[32][1];
+        temp[33][0] = temp[1][32];
+
+        // We mirror the side and corner elements so our final cloud will be seamless without any ugly borders showing.
+        for (int y=1; y<33; y++)
+                for (int x=1; x<33; x++)
+                {
+                        float center = temp[x][y]/4.0f;
+                        float sides = (temp[x+1][y] + temp[x-1][y] + temp[x][y+1] + temp[x][y-1])/8.0f;
+                        float corners = (temp[x+1][y+1] + temp[x+1][y-1] + temp[x-1][y+1] + temp[x-1][y-1])/16.0f;
+
+                        map32[((x-1)*32) + (y-1)] = center + sides + corners;
+                }
+}
+
+/*
+        Interpolation - average the value of each pixel value with that of its neighbors' values.
+*/
+float CloudEffect::interpolate(float x, float y, float  *map)
+{
+        int Xint = (int)x;
+        int Yint = (int)y;
+
+        float Xfrac = x - Xint;
+        float Yfrac = y - Yint;
+
+        int X0 = Xint % 32;
+        int Y0 = Yint % 32;
+        int X1 = (Xint + 1) % 32;
+        int Y1 = (Yint + 1) % 32;
+
+        float bot = map[X0*32 + Y0] + Xfrac * (map[X1*32 + Y0] - map[X0*32 + Y0]);
+        float top = map[X0*32 + Y1] + Xfrac * (map[X1*32 +  Y1] - map[X0*32 + Y1]);
+
+        return (bot + Yfrac * (top - bot));
+}
+
+
+/*
+        Octaves are overlapped together to give cloud more turbulence. We will use four octaves for our cloud.
+*/
+void CloudEffect::overlapOctaves(float  *map32, float  *map256)
+{
+        for (int x=0; x<256*256; x++)
+        {
+                map256[x] = 0;
+        }
+
+        for (int octave=0; octave<4; octave++)
+                for (int x=0; x<256; x++)
+                        for (int y=0; y<256; y++)
+                        {
+                                float scale = 1 / pow(2, 3-octave);
+                                float noise = CloudEffect::interpolate(x*scale, y*scale , map32);
+
+                                //The octaves are added together with the proper weight factors.
+                                //You could replace pow(2, i) with 1<<i for faster computation
+                                map256[(y*256) + x] += noise / pow(2, octave);
+                        }
+}
+
+
+/*
+        Filter the noise with exponential function
+*/
+void CloudEffect::expFilter(float  *map)
+{
+        float cover = 20.0f;
+        float sharpness = 0.95f;
+
+        for (int x=0; x<256*256; x++)
+        {
+                float c = map[x] - (255.0f-cover);
+                if (c<0)     c = 0;
+                map[x] = 255.0f - ((float)(pow(sharpness, c))*255.0f);
+        }
+}