Java Community | Help. Code. Learn.•10mo ago

OpenGL Occlusion Culling?

I'm making a 3D game with JOGL. I expect to have a world layout like Minecraft, with a lot of cube-like models. That means I can skip faces that touch each other (occlusion culling) to speed up drawing. I want to be able to remove the indices for specific models to make this work. But, I'm using VAOs, which are not meant to be modified or read from the CPU once written. Is there a way to do this? Using JOGL GLJPanel with VAOs and Shaders. Code in comments bc I am running out of space.

4 Replies

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The TyphothanianOP•10mo ago

Here's GLJPanel draw code:

    @Override
    public void display(GLAutoDrawable drawable) {
        requestFocusInWindow();

        GL3 gl = drawable.getGL().getGL3();
        gl.glClearColor(0, 0, 0, 0);
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT);
        gl.glUseProgram(shader.program);

        shader.setUniform(gl, "proj", Matrices.perspective(pos, rot, 90, 0.1, 5000, aspectRatio));

        for (Map.Entry<Model, List<Entity>> entry : entities.entrySet()) {
            entry.getKey().bind(gl);
            shader.setUniform(gl, "sampler", entry.getKey().texture);

            gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MIN_FILTER, gl.GL_NEAREST); // nearest neighbor stuff
            gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MAG_FILTER, gl.GL_NEAREST);

            int[] vbo = new int[1];

            gl.glGenBuffers(1, vbo, 0);
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);

            FloatBuffer fb = FloatBuffer.allocate(entry.getValue().size() * 3);

            for (Entity entity : entry.getValue()) {
                fb.put(entity.pos);
            }

            // give each drawn model the position of itself
            gl.glBufferData(gl.GL_ARRAY_BUFFER, (long) entry.getValue().size() * Float.BYTES * 3, fb.flip(), gl.GL_STATIC_DRAW);
            gl.glVertexAttribPointer(2, 3, gl.GL_FLOAT, false, 0, 0);
            gl.glEnableVertexAttribArray(2);
            gl.glVertexAttribDivisor(2, 1);

            gl.glDrawElementsInstanced(entry.getKey().type[0], entry.getKey().vertexCount[0], gl.GL_UNSIGNED_INT, 0, entry.getValue().size()); // one draw call per model for efficiency

            gl.glDeleteBuffers(1, vbo, 0);

            Model.unbind(gl);
        }
    }

    @Override
    public void display(GLAutoDrawable drawable) {
        requestFocusInWindow();

        GL3 gl = drawable.getGL().getGL3();
        gl.glClearColor(0, 0, 0, 0);
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT);
        gl.glUseProgram(shader.program);

        shader.setUniform(gl, "proj", Matrices.perspective(pos, rot, 90, 0.1, 5000, aspectRatio));

        for (Map.Entry<Model, List<Entity>> entry : entities.entrySet()) {
            entry.getKey().bind(gl);
            shader.setUniform(gl, "sampler", entry.getKey().texture);

            gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MIN_FILTER, gl.GL_NEAREST); // nearest neighbor stuff
            gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MAG_FILTER, gl.GL_NEAREST);

            int[] vbo = new int[1];

            gl.glGenBuffers(1, vbo, 0);
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);

            FloatBuffer fb = FloatBuffer.allocate(entry.getValue().size() * 3);

            for (Entity entity : entry.getValue()) {
                fb.put(entity.pos);
            }

            // give each drawn model the position of itself
            gl.glBufferData(gl.GL_ARRAY_BUFFER, (long) entry.getValue().size() * Float.BYTES * 3, fb.flip(), gl.GL_STATIC_DRAW);
            gl.glVertexAttribPointer(2, 3, gl.GL_FLOAT, false, 0, 0);
            gl.glEnableVertexAttribArray(2);
            gl.glVertexAttribDivisor(2, 1);

            gl.glDrawElementsInstanced(entry.getKey().type[0], entry.getKey().vertexCount[0], gl.GL_UNSIGNED_INT, 0, entry.getValue().size()); // one draw call per model for efficiency

            gl.glDeleteBuffers(1, vbo, 0);

            Model.unbind(gl);
        }
    }

Unknown User•10mo ago

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OpenGL Occlusion Culling?