hi,
i want to write a small program which processes input data with a shader. unfortunately i don’t get the results i would like to have. the fragment shader should calculate new values depending on the old values(texture information). therefor i have a simple test shader:
uniform sampler2D BaseImage;
void main(void) {
vec4 tmp = texture2D(BaseImage,gl_TexCoord[0].st);
tmp += 0.5;
gl_FragColor = tmp;
}
and here is my code for the java part:
public abstract class GPUCalculator implements GLEventListener {
private GLPbuffer pbuffer;
private GL gl;
private int texture_target = GL.GL_TEXTURE_RECTANGLE_ARB;
private int texture_format = GL.GL_RGB;
private int data_type = GL.GL_FLOAT;
private int[] texID = new int[1];
private int width;
private int height;
private float[] data;
public GPUCalculator ( int width, int height, float[] data ) {
this.width = width;
this.height = height;
this.data = data;
GLDrawableFactory factory = GLDrawableFactory.getFactory ();
if ( factory.canCreateGLPbuffer () ) {
try {
this.pbuffer = factory.createGLPbuffer ( new GLCapabilities (), null, this.width, this.height, null );
this.pbuffer.addGLEventListener ( this );
this.pbuffer.display ();
// this.pbuffer.getContext ().destroy ();
} catch ( Exception e ) {
System.out.println ( "PBuffer error" );
e.printStackTrace ();
}
}
}
public void display ( GLAutoDrawable drawable ) {
this.gl.glDrawBuffer (GL.GL_COLOR_ATTACHMENT0_EXT);
renderQuad ( this.gl );
readDataFromGPU ();
}
public void displayChanged ( GLAutoDrawable drawable, boolean arg1, boolean arg2 ) {
}
public void reshape ( GLAutoDrawable drawable, int arg1, int arg2, int arg3, int arg4 ) {
}
public void init ( GLAutoDrawable drawable ) {
System.out.println ( "initializing" );
this.gl = drawable.getGL ();
if ( this.gl.glCheckFramebufferStatusEXT ( GL.GL_FRAMEBUFFER_EXT ) == 0 ) {
return;
}
defineViewport ();
defineTextures ();
updateTexture ( this.data, this.width, this.height );
defineFBO ();
bindTexture ();
defineShader ();
}
private void defineViewport () {
GLU glu = new GLU ();
this.gl.glMatrixMode ( GL.GL_PROJECTION );
this.gl.glLoadIdentity ();
glu.gluOrtho2D ( 0, this.width, 0, this.height );
this.gl.glMatrixMode ( GL.GL_MODELVIEW );
this.gl.glLoadIdentity ();
this.gl.glViewport ( 0, 0, this.width, this.height );
}
private void defineFBO () {
int[] fb = new int[1];
this.gl.glGenFramebuffersEXT ( 1, fb, 0 );
this.gl.glBindFramebufferEXT ( GL.GL_FRAMEBUFFER_EXT, fb[0] );
}
private void defineShader () {
int program = gl.glCreateProgramObjectARB ();
int frag = gl.glCreateShaderObjectARB ( GL.GL_FRAGMENT_SHADER_ARB );
this.gl.glAttachObjectARB ( program, frag );
this.gl.glShaderSourceARB ( frag, 1, getShaderSource ( "shader/simpleShader.glsl" ), null );
this.gl.glCompileShaderARB ( frag );
this.gl.glLinkProgramARB ( program );
int texImage = gl.glGetUniformLocationARB ( program, "BaseImage" );
this.gl.glUseProgramObjectARB ( program );
//this.gl.glActiveTexture ( GL.GL_TEXTURE0 );
this.gl.glUniform1iARB ( texImage, 0 );
}
private void defineTextures () {
this.gl.glGenTextures ( 1, texID, 0 );
this.gl.glBindTexture ( this.texture_target, texID[0] );
this.gl.glTexParameteri ( this.texture_target, GL.GL_TEXTURE_MIN_FILTER, GL.GL_NEAREST );
this.gl.glTexParameteri ( this.texture_target, GL.GL_TEXTURE_MAG_FILTER, GL.GL_NEAREST );
this.gl.glTexParameteri ( this.texture_target, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP );
this.gl.glTexParameteri ( this.texture_target, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP );
}
public void updateTexture ( float[] newData, int newWidth, int newHeight ) {
this.data = newData;
this.gl.glTexImage2D ( this.texture_target, 0, GL.GL_RGB32F_ARB, newWidth, newHeight, 0, this.texture_format,
this.data_type, FloatBuffer.wrap ( this.data ) );
}
private void bindTexture () {
this.gl.glFramebufferTexture2DEXT ( GL.GL_FRAMEBUFFER_EXT, GL.GL_COLOR_ATTACHMENT0_EXT, this.texture_target,
texID[0], 0 );
this.gl.glBindTexture ( this.texture_target, this.texID[0] );
}
private void renderQuad ( GL gl ) {
this.gl.glPolygonMode ( GL.GL_FRONT, GL.GL_FILL );
this.gl.glBegin ( GL.GL_QUADS );
this.gl.glTexCoord2f ( 0.0f, 0.0f );
this.gl.glVertex2f ( 0.0f, 0.0f );
this.gl.glTexCoord2f ( this.width, 0.0f );
this.gl.glVertex2f ( this.width, 0.0f );
this.gl.glTexCoord2f ( this.width, this.height );
this.gl.glVertex2f ( this.width, this.height );
this.gl.glTexCoord2f ( 0.0f, this.height );
this.gl.glVertex2f ( 0.0f, this.height );
this.gl.glEnd ();
}
public void transferDataToGPU () {
this.gl.glTexSubImage2D ( this.texture_target, 0, 0, 0, this.width, this.height, this.texture_format,
this.data_type, FloatBuffer.wrap ( this.data ) );
}
public float[] readDataFromGPU () {
float[] outData = new float[this.data.length];
this.gl.glReadBuffer ( GL.GL_COLOR_ATTACHMENT0_EXT );
this.gl.glReadPixels ( 0, 0, this.width, this.height, this.texture_format, this.data_type, FloatBuffer
.wrap ( outData ) );
for ( int i = 0; i < data.length; i++ ) {
System.out.println ( "temp: " + outData[i] );
}
return outData;
}
private String[] getShaderSource ( String fileName ) {
[...]
}
}
the shader seems to replace all values by 0.5. so i guess that the input to the shader are not the desired value.
example:
input: 0.1, 0.2, 0.3
output: 0.5, 0.5, 0.5
i hope soomeone can help me…
