Hello,
I tried to create water reflection.
I made my render-to-texture code with framebuffer object:
public void reshape(GLDrawable glDrawable, int xstart,int ystart, int width, int height) {
gl.glViewport(0,0,width,height);
gl.glMatrixMode( GL.GL_PROJECTION);
gl.glLoadIdentity();
createNewFrameBuffer( width, height, MeadowLand.FBO, MeadowLand.FBORenderBuffer, MeadowLand.FBOTexture );
gluPerspective(45,(double)width/height,1,10000);
gl.glMatrixMode( GL.GL_MODELVIEW);
gl.glLoadIdentity();
}
public static void createNewFrameBuffer(int width, int height, int[] FBO, int[] FBORenderBuffer, int[] FBOTexture ){
if( FBO[0] > 0) gl.glDeleteFramebuffersEXT( 1, FBO );
if( FBOTexture[0] > 0) gl.glDeleteTextures( 1, FBOTexture );
gl.glGenFramebuffersEXT( 1, FBO );
gl.glGenTextures( 1, FBOTexture );
gl.glBindFramebufferEXT( GL.GL_FRAMEBUFFER_EXT, FBO[0] );
gl.glGenRenderbuffersEXT( 1, FBORenderBuffer );
gl.glBindRenderbufferEXT( GL.GL_RENDERBUFFER_EXT, FBORenderBuffer[0] );
gl.glRenderbufferStorageEXT( GL.GL_RENDERBUFFER_EXT, GL.GL_DEPTH_COMPONENT24, width, height );
gl.glFramebufferRenderbufferEXT( GL.GL_FRAMEBUFFER_EXT, GL.GL_DEPTH_ATTACHMENT_EXT, GL.GL_RENDERBUFFER_EXT, FBORenderBuffer[0] );
gl.glBindTexture( GL.GL_TEXTURE_2D, FBOTexture[0] );
gl.glTexImage2D( GL.GL_TEXTURE_2D, 0, GL.GL_RGB, width, height, 0, GL.GL_RGB, GL.GL_UNSIGNED_BYTE, BufferUtils.bufferOffset(0) );
gl.glTexParameteri( GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_NEAREST );
gl.glTexParameteri( GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_NEAREST );
gl.glFramebufferTexture2DEXT( GL.GL_FRAMEBUFFER_EXT, GL.GL_COLOR_ATTACHMENT0_EXT, GL.GL_TEXTURE_2D, FBOTexture[0], 0 );
if( !checkFrameBufferStatus( width, height ) ){
JOptionPane.showMessageDialog(null, "FBO ohhh", "Some Error", JOptionPane.ERROR_MESSAGE);
System.exit( -1 );
}
gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, 0);
}
My render code:
gl.glBindFramebufferEXT( GL.GL_FRAMEBUFFER_EXT, FBO[0] );
gl.glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
gl.glClear( GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
gl.glPushMatrix();
gl.glScalef( 1.0f, -1.0f, 1.0f );
renderScene();
gl.glPopMatrix();
gl.glBindFramebufferEXT( GL.GL_FRAMEBUFFER_EXT, 0 );
gl.glClearColor(0.0f, 1.0f, 0.0f, 0.0f);
gl.glClear( GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT );
gl.glPushMatrix();
renderscene();
renderWater();
gl.glPopMatrix();
....
public void renderWater() {
gl.glEnable( GL.GL_DEPTH_TEST);
gl.glEnable(GL.GL_MULTISAMPLE_ARB);
gl.glActiveTextureARB( GL.GL_TEXTURE0_ARB + 0);
gl.glBindTexture( GL.GL_TEXTURE_2D, FBOTexture[0]);
gl.glClientActiveTextureARB( GL.GL_TEXTURE0_ARB + 0);
gl.glEnable( GL.GL_TEXTURE_2D);
gl.glBegin( GL.GL_QUADS);
gl.glMultiTexCoord2f( 0, 1, 1 );
gl.glVertex3f( vertexes[0][0], waterLevel, vertexes[0][1] );
gl.glMultiTexCoord2f( 0, 1 , 0 );
gl.glVertex3f( vertexes[1][0], waterLevel, vertexes[1][1] );
gl.glMultiTexCoord2f( 0, 0, 0 );
gl.glVertex3f( vertexes[2][0], waterLevel, vertexes[2][1] );
gl.glMultiTexCoord2f( 0, 0, 1 );
gl.glVertex3f( vertexes[3][0], waterLevel, vertexes[3][1] );
gl.glEnd();
gl.glActiveTextureARB( GL.GL_TEXTURE0_ARB + 0);
gl.glDisable( GL.GL_TEXTURE_2D);
gl.glClientActiveTextureARB( GL.GL_TEXTURE0_ARB + 0);
gl.glDisable( GL.GL_BLEND );
}
My waterplane show the fbo texture very well, but I don't know how to compute the texture coordinates, to see the water like a mirror.
Now, I just put the fbo texture to the water plane. Screenshot: http://delfin.klte.hu/~fazekaim/water.jpg
I should project the texture on the waterplan, but I don't know how.
Thanks.
