WebGL framebuffer not drawing to texture - webgl

Question

I am trying to draw to a texture using a framebuffer. Both programs work individually but when trying to implement the framebuffer I just can't seem to get it to work.
I've created the texture and framebuffer as shown below.
const screenTexture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, screenTexture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.canvas.width, gl.canvas.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
const screenTextureFramebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, screenTextureFramebuffer);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, screenTexture, 0);
My first program simply draws a blue point in the centre of the screen.
#version 300 es
precision mediump float;
in vec2 position;
void main() {
gl_Position = vec4(position, 0.0, 1.0);
gl_PointSize = 15.0;
}
#version 300 es
precision mediump float;
out vec4 fragColor;
void main() {
fragColor = vec4(0.0, 0.0, 1.0, 1.0);
}
The second takes the texture and draws it to the screen.
#version 300 es
precision mediump float;
in vec2 position;
void main() {
gl_Position = vec4(position, 0.0, 1.0);
}
#version 300 es
precision mediump float;
uniform sampler2D screenTexture;
out vec4 fragColor;
void main() {
fragColor = texture(screenTexture, gl_FragCoord.xy);
}
I am using the programs as shown below.
gl.bindFramebuffer(gl.FRAMEBUFFER, screenTextureFramebuffer);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.useProgram(agentProgram);
gl.bindBuffer(gl.ARRAY_BUFFER, agentBuffer);
gl.vertexAttribPointer(gl.getAttribLocation(agentProgram, 'position'), 2, gl.FLOAT, false, 4 * 4, 0);
gl.enableVertexAttribArray(gl.getAttribLocation(agentProgram, 'position'));
gl.drawArrays(gl.POINTS, 0, AGENT_COUNT);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.useProgram(screenProgram);
gl.bindBuffer(gl.ARRAY_BUFFER, screenBuffer);
gl.bindTexture(gl.TEXTURE_2D, screenTexture);
gl.vertexAttribPointer(gl.getAttribLocation(screenProgram, 'position'), 2, gl.FLOAT, false, 2 * 4, 0);
gl.enableVertexAttribArray(gl.getAttribLocation(screenProgram, 'position'));
gl.drawArrays(gl.TRIANGLES, 0, 6);