RenderToTexture.cpp

void SpriteBatch::Render() {
	glBindVertexArray(m_vao);

	/// 1. Draw normal maps to the buffer
	glEnable(GL_DEPTH_TEST);
	m_gbuffer->Bind();
	glDepthFunc(GL_LESS);
	glDepthMask(true);
	
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	
	m_geomShader->Bind();
	m_geomShader->SetMatrix4("projection", m_projection);
	m_geomShader->SetMatrix4("view", m_view);
		
	for (auto it = m_batches.begin(); it != m_batches.end(); ++it) {
		RenderBatch b = *it;
		if (b.normal != nullptr) {
			b.normal->Bind(0);
			m_geomShader->SetSampler("normal", 0);
			m_geomShader->SetInt("use_normal", 1);
		} else {
			m_geomShader->SetInt("use_normal", 0);
		}
		if (b.diffuse != nullptr) {
			b.diffuse->Bind(1);
			m_geomShader->SetSampler("diffuse", 1);
			m_geomShader->SetInt("use_diffuse", 1);
		} else {
			m_geomShader->SetInt("use_diffuse", 0);
		}

		glDrawArrays(GL_TRIANGLE_STRIP, b.offset, b.vertex_count);
		glBindTexture(GL_TEXTURE_2D, 0);
	}
	
	m_geomShader->Unbind();
	m_gbuffer->Unbind();
	glDepthMask(false);
	glDisable(GL_DEPTH_TEST);
	
	glBindVertexArray(0);
	
	/// 2. Lighting pass
	m_sbuffer->Bind();
	glClear(GL_COLOR_BUFFER_BIT);
	m_lightShader->Bind();

	m_lightShader->SetVector2("resolution", Vector2(w, h));
	m_lightShader->SetMatrix4("projection", m_projection);
	m_lightShader->SetMatrix4("scale", m_scale);

	m_normal->Bind(0);
	m_depth->Bind(1);
	m_diffuse->Bind(2);
	m_alpha->Bind(3);
	m_lightShader->SetSampler("t_normal", 0);
	m_lightShader->SetSampler("t_depth", 1);
	m_lightShader->SetSampler("t_diffuse", 2);
	m_lightShader->SetSampler("t_alpha", 3);

	m_lightShader->SetColor("ambient", m_ambientColor);
	m_lightShader->SetInt("ambient_only", 1);
	m_quad->Draw();
	m_lightShader->SetInt("ambient_only", 0);
	
	glBlendFunc(GL_ONE, GL_ONE);
	for (auto it = m_lights.begin(); it != m_lights.end(); ++it) {
		Light* l = *it;
		if (l->intensity > 0.0f) {
			m_lightShader->SetVector3("lightPosition", l->position);
			m_lightShader->SetVector2("lightDirection", l->direction);
			m_lightShader->SetColor("lightColor", l->color);
			m_lightShader->SetFloat("lightIntensity", l->intensity);
			m_lightShader->SetFloat("lightRadius", l->radius);
			m_lightShader->SetFloat("lightCutOff", l->cutOff);
			m_lightShader->SetInt("lightType", (int) l->type);

			m_quad->Draw();
		}
	}
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	
	m_lightShader->Unbind();
	m_sbuffer->Unbind();

	m_flatShader->Bind();
	m_screen->Bind(0);
	m_flatShader->SetMatrix4("projection", m_projection);
	m_flatShader->SetSampler("tex", 0);
	m_quad->Draw();
	m_flatShader->Unbind();
	m_screen->Unbind();
}