OpenGL 3.3 deferred shading not working - c++

Question

I've setup an OpenGL environment with deferred shading following this tutorial but I can't make the second shader output on my final buffer.
I can see that the first shader (the one that doesn't use lights) is working properly because with gDEBugger I can see that the output buffers are correct, but the second shader really can't display anything. I've also tried to make the second shader output a single color for all the scene just to see if it was displying something, bot nothing is visible (the screen should be completely red but it isn't).
The first pass shader (the one I use to create the buffers for the GBuffer) is working so I'm not add it's code or how I created and implemented my GBuffer, but if you need I'll add them, just tell me.
I think the problem is when I tell OpenGL to output on the FrameBuffer 0 (my video).
This is how I enalbe OpenGL to write to the FrameBuffer 0:
glEnable(GL_BLEND);
m_MotoreGrafico->glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_ONE, GL_ONE);
// Abilito la scrittura sul buffer finale
m_MotoreGrafico->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
m_gBuffer.BindForReading();
glClear(GL_COLOR_BUFFER_BIT);
// Imposto le matrici dello shader
SetUpOGLProjectionViewMatrix(1);
// Passo le texture del GBuffer allo shader
pActiveShader->setUniform1i(_T("gPositionMap"), m_gBuffer.GetPositionTexture());
pActiveShader->setUniform1i(_T("gColorMap"), m_gBuffer.GetDiffuseTexture());
pActiveShader->setUniform1i(_T("gNormalMap"), m_gBuffer.GetNormalTexture());
// Passo variabili necessarie allo shader
float dimensioneFinestra[2], posizioneCamera[3];
dimensioneFinestra[0] = m_nLarghezzaFinestra;
dimensioneFinestra[1] = m_nAltezzaFinestra;
m_MotoreGrafico->GetActiveCameraPosition(posizioneCamera);
pActiveShader->setUniform2f(_T("gScreenSize"), dimensioneFinestra);
pActiveShader->setUniform3f(_T("gCameraPos"), posizioneCamera);
pActiveShader->setUniform1i(_T("gUsaLuci"), 0);
// Disegno le luci
float coloreLuce[3], posizioneLuce[3], direzioneLuce[3], vUpLuce[3], vRightLuce[3], intensita;
for(int i = 0; i < GetDocument()->m_RTL.GetNLights(); i++)
{
CRTLuce* pRTLuce = GetDocument()->m_RTL.GetRTLightAt(i);
...
m_MotoreGrafico->glBindVertexArray(pRTLuce->GetRTLuce()->GetVBO()->getVBAIndex());
glDrawArrays(GL_TRIANGLES, 0, pRTLuce->GetRTLuce()->GetNVertPerShader());
}
The function m_gBuffer.BindForReading() is like this (bot I think it doesn't matter for my problem):
for (unsigned int i = 0 ; i < ARRAY_SIZE_IN_ELEMENTS(m_textures); i++)
{
m_pMotoreGrafico->glActiveTexture(GL_TEXTURE0 + i);
glBindTexture(GL_TEXTURE_2D, m_textures[GBUFFER_TEXTURE_TYPE_POSITION + i]);
}
So far my GBuffer is working (it creates the textures) and my first shader is also working (it's drawing the textures of my GBuffer).
The problem then is that I can't reset OpenGL to draw in my video.
The first 4 textures are the ones create with the first-pass shader.
This is my back buffer (after the second-pass shader)
And this is my front buffer (after the second-pass shader)
This is my second-pass fragment shader code (it outputs only red)
out vec4 outputColor;
void main()
{
outputColor = vec4(1.0, 0.0, 0.0, 1.0);
}
Does anyone have an idea of what I'm doing wrong?
Second-pass vertex shader code:
#version 330
uniform struct Matrici
{
mat4 projectionMatrix;
mat4 modelMatrix;
mat4 viewMatrix;
} matrices;
layout (location = 0) in vec3 inPosition;
void main()
{
vec4 vEyeSpacePosVertex = matrices.viewMatrix * matrices.modelMatrix * vec4(inPosition, 1.0);
gl_Position = matrices.projectionMatrix * vEyeSpacePosVertex;
}
Second-pass fragment shader code:
#version 330
uniform struct MDLight
{
vec3 vColor;
vec3 vPosition;
vec3 vDirection;
float fAmbientIntensity;
float fStrength;
int bOn;
float fConeCosine;
float fAltezza;
float fLarghezza;
vec3 vUp;
vec3 vRight;
} gLuce;
uniform float gSpecularIntensity;
uniform float gSpecularPower;
uniform sampler2D gPositionMap;
uniform sampler2D gColorMap;
uniform sampler2D gNormalMap;
uniform vec3 gCameraPos;
uniform vec2 gScreenSize;
uniform int gLightType;
uniform int gUsaLuci;
vec2 CalcTexCoord()
{
return gl_FragCoord.xy / gScreenSize;
}
out vec4 outputColor;
void main()
{
vec2 TexCoord = CalcTexCoord();
vec4 Color = texture(gColorMap, TexCoord);
outputColor = vec4(1.0, 0.0, 0.0, 1.0);
}