Writing syphon texture into GPUImage framebuffer problem

[eight]

I am reading a syphon texture from a syphon client into GPUImage outputframebuffer, but the image in the said buffer is textured wrongly.

[outputframebuffer is a means to pass images between the filters in GPUImage framework]

Spent a week trying to debug it, and now kindly asking for support.

static const GLfloat squareVertices[] = {
    -1.0f, -1.0f,
    1.0f, -1.0f,
    -1.0f,  1.0f,
    1.0f,  1.0f,
};

static const GLfloat textureCoordinates[] = {
    -1.0f, -1.0f,
    1.0f, -1.0f,
    -1.0f,  1.0f,
    1.0f,  1.0f,
};

NSString *const kGPUImageSyphonVertexShaderString = SHADER_STRING
(
 attribute vec4 position;
 attribute vec4 inputTextureCoordinate;
 
 varying vec2 textureCoordinate;
 
 void main()
 {
     gl_Position = position;
     textureCoordinate = inputTextureCoordinate.xy;
 }
 );

NSString *const kGPUImageSyphonFragmentShaderString = SHADER_STRING
(
 varying vec2 textureCoordinate;
 uniform sampler2DRect inputImageTexture;
 uniform float width;
 uniform float height;
 
 void main()
 {
     vec2 texCoord = vec2(textureCoordinate.x * width, textureCoordinate.y*height);
     gl_FragColor = texture2DRect(inputImageTexture, texCoord);
 }
 );

-(void) processSyphonFrame:(SyphonClient*) client;
{
    CGLContextObj context = CGLGetCurrentContext();
    runSynchronouslyOnVideoProcessingQueue(^{
            // ...then we check to see if our dimensions display or window shape needs to be updated
            SyphonImage *syFrame = [client newFrameImageForContext:context];

            GLsizei w = syFrame.textureSize.width;
            GLsizei h = syFrame.textureSize.height;
            
            ///================draw to output framebuffer
            [GPUImageContext useImageProcessingContext];

            //this fbo already has a texture attached to it (to write into)
            outputFramebuffer = [[GPUImageContext sharedFramebufferCache] fetchFramebufferForSize:CGSizeMake(w, h) textureOptions:self.outputTextureOptions onlyTexture:NO];

            [self->outputFramebuffer lock];

            //bind framebuffer and set the viewport
            [outputFramebuffer activateFramebuffer];

            //clear framebuffer attachments -- a hint for future ops to ignore the existing content
            glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
            glClear(GL_COLOR_BUFFER_BIT);
            
            [GPUImageContext setActiveShaderProgram:syphonImageConversionProg];
            
            //now, specify the source texture for the framebuffer
            //first select an active texture unit
            //////
            glActiveTexture(GL_TEXTURE0);
            glClientActiveTexture(GL_TEXTURE0);
            glEnable(GL_TEXTURE_RECTANGLE_ARB);

            glBindTexture(GL_TEXTURE_RECTANGLE_EXT, syFrame.textureName);

            GLint whichID;
            glGetIntegerv(GL_TEXTURE_BINDING_RECTANGLE_ARB, &whichID);
            if (whichID != syFrame.textureName) {
                NSLog(@"did not bind syphon texture");
            }

        // Configure texturing as we want it
            glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_S, GL_CLAMP);
            glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_T, GL_CLAMP);
            glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
            glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
            
            glUniform1i (inputImageTextureUniform, 0);
            glUniform1f (widthUniform, w);
            glUniform1f (heightUniform, h);
            
            glVertexAttribPointer(syPosAttribute, 2, GL_FLOAT, 0, 0, squareVertices);
            glVertexAttribPointer(syTexCoordAttribute, 2, GL_FLOAT, 0, 0, textureCoordinates);
            glEnableVertexAttribArray(syPosAttribute);
            glEnableVertexAttribArray(syTexCoordAttribute);
            //finally, draw to the buffer
            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE){
                NSLog(@"framebuffer incomplete");
            }
            glBindFramebuffer(GL_FRAMEBUFFER, 0);
        

//for debugging save the image
            CGImageRef imageRef = [outputFramebuffer newCGImageFromFramebufferContents];
            CGImageWriteToFile(imageRef, @"/Users/eigh_io/tmp.png");
//end saving the image
            [self updateTargetsForSyphonUsingCacheTextureAtWidth:w height:h];

    });
};

• This topic was modified 2 years, 4 months ago by eight.
• This topic was modified 2 years, 4 months ago by eight.

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