I'm working on a project in OpenGL. Earlier this week, I successfully implemented Deferred Shading, but I'm not sure how to pass the information from the Deferred Shader to the Post Processing Shader.
glBindFramebuffer(GL_FRAMEBUFFER, fboId);
glViewport(0, 0, int(ScreenSize.x), int(ScreenSize.y)); // Render on the whole framebuffer, complete from the lower left corner to the upper right
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//...Drawing for Opaque objects, pass all transparent objects to a seperate texture
//after having drawn them using Forward Shading
//glBindFramebuffer(GL_FRAMEBUFFER, 0);
glViewport(0, 0, int(ScreenSize.x), int(ScreenSize.y));
// Clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Use our shader
glUseProgram(quad_programID);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, gBuffTextures[0]);
glUniform1i(gBuffPosnID, 0);
//More Textures
//Uniforms
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, quad_vertexbuffer);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0 );
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); // 2*3 indices starting at 0 -> 2 triangles
glDisableVertexAttribArray(0);
So far this works just fine. Now here's the difficult part - passing the final image to the post processing shader.
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glViewport(0, 0, int(ScreenSize.x), int(ScreenSize.y));
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(post_programID);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, gBuffTextures[0]);
glUniform1i(UniformPostImage, 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, gBuffDepthTextures);
glUniform1i(UniformDepthImage, 1);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, dirt);
glUniform1i(UniformDirtImage, 2);
glUniform1f(UniformTime, (float)currentTime);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, quad_vertexbuffer);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0 );
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); // 2*3 indices starting at 0 -> 2 triangles
glDisableVertexAttribArray(0);
I'm loading the image from the deferred shader normally, and passing it using:
layout(location = 0) out vec3 image;
All I recieve is the first texture I pass, the position shader. Can anyone tell me how to pass the image from the deferred shader to the post processing shader? Thanks in advance!
Oh, one more question: Do you suggest getting depth via a depth buffer texture in the deferred shader, or just using the world position to calculate it? I know it probably depends on the machine, but there's probably a general go-to answer.
