OpenGL shaders Texture Buffer Object not working

Newbie & Debugging Questions
#1

Shader uniform samplers:


uniform sampler2D u_texture;
uniform samplerBuffer u_lights;

Somewhere in shader program code I link the shader program, use it, bind my texture used for rendering textures to texture unit 1, bind my light texture buffer sampler to texture unit 2 and validate the shader:


		link();
		use();
		GL20.glUniform1i(getUniformLocation("u_texture"), 1);
		GL20.glUniform1i(getUniformLocation("u_lights"), 2);		
		
		validate();

Create texture buffer and buffer object:


		textureBuffer = GL11.glGenTextures();
		lightBuffer = GL15.glGenBuffers();

Here is where I deal with texture buffer data:


		GL15.glBindBuffer(GL31.GL_TEXTURE_BUFFER, lightBuffer);
		FloatBuffer lightData=makeLightData();
		GL15.glBufferData(GL31.GL_TEXTURE_BUFFER, lightData, GL15.GL_STREAM_DRAW);
		
		GL13.glActiveTexture(GL13.GL_TEXTURE2); // activate texture unit 2, which is sampler 'u_lights'
		
		GL11.glBindTexture(GL31.GL_TEXTURE_BUFFER, textureBuffer);
		GL31.glTexBuffer(GL31.GL_TEXTURE_BUFFER, ARBTextureRg.GL_R32F, lightBuffer); // R32F big floats
		
		GL11.glBindTexture(GL31.GL_TEXTURE_BUFFER, 0);
		GL15.glBindBuffer(GL31.GL_TEXTURE_BUFFER, 0);
		GL13.glActiveTexture(GL13.GL_TEXTURE1); // activate my default texture unit

Here is my FloatBuffer creation method:


	private FloatBuffer makeLightData() {

		FloatBuffer buffer = BufferUtils.createFloatBuffer(1);

		buffer.put(1);
		
		buffer.flip();

		return buffer;
	}

Here is somewhere in my fragment shader where I render the scene. The problem is that the scene turns out black. Should be white. If I swap texelFetch() with 1.0, the scene turns out white.


	lighting.rgb+=texelFetch(u_lights, 0).r;
#2

It seems that most of my code was correct. The only thing I had to modify from what I posted in the thread, is remove this line:

GL11.glBindTexture(GL31.GL_TEXTURE_BUFFER, 0);

I didn’t realize you need to keep the texture bound for it to work.